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Evaluation of the risk and age of onset of cancer and behavioral disorders in gonadectomized Vizslas
Abstract
Objective:
To investigate associations between age at gonadectomy and estimated risk or age at diagnosis of neoplastic and behavioral disorders in Vizslas.
Design:
Retrospective cohort study.
Animals:
2,505 Vizslas born between 1992 and 2008.
Procedures:
Data on demographics, gonadectomy status, and age at diagnosis of disease or disorder were obtained with an anonymous online survey and analyzed.
Results:
Dogs gonadectomized at ≤ 6 months, between 7 and 12 months, or at > 12 months of age had significantly increased odds of developing mast cell cancer, lymphoma, all other cancers, all cancers combined, and fear of storms, compared with the odds for sexually intact dogs. Females gonadectomized at ≤ 12 months of age and males and females gonadectomized at > 12 months of age had significantly increased odds of developing hemangiosarcoma, compared with the odds for sexually intact dogs. Dogs gonadectomized at ≤ 6 months of age had significantly increased odds of developing a behavioral disorder. The younger the age at gonadectomy, the earlier the mean age at diagnosis of mast cell cancer, cancers other than mast cell, hemangiosarcoma, lymphoma, all cancers combined, a behavioral disorder, or fear of storms.
Conclusions and clinical relevance:
Additional studies are needed on the biological effects of removing gonadal hormones and on methods to render dogs infertile that do not involve gonadectomy. Veterinarians should discuss the benefits and possible adverse effects of gonadectomy with clients, giving consideration to the breed of dog, the owner's circumstances, and the anticipated use of the dog.
... Another study categorised bitches based on breed size rather than the specific breed itself [21]. Other studies in this review explicitly examined one breed [13,[22][23][24]. The lack of consistency in reporting breeds limits the external validity and prevents appropriate comparison. ...
... Additionally, several studies provided a questionnaire to the owners of the dogs selected [19,23,24]. The use of questionnaires introduces recall bias into these studies, as in one study, owners were reporting the disease conditions of dogs born as many as 16 years previously. ...
... The use of questionnaires introduces recall bias into these studies, as in one study, owners were reporting the disease conditions of dogs born as many as 16 years previously. Recall bias can increase or decrease the observed association between spaying and the development of mammary tumours [24]. ...
Background: Ovariectomy and ovariohysterectomy (spaying) are two surgical procedures commonly performed on dogs. However, the optimum age at which to perform these procedures in dogs remains a contentious issue. Following work published in the 1960s, pre-pubertal spaying became popular largely on the basis that it reduced the risk of mammary cancer development. However, a systematic review published more than 10 years ago questioned this. The objective of this study was to examine the strength and direction of updated literature on the relationship between spaying age of dogs and mammary tumour development and to investigate whether the evidence has changed. Method: A systematic review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. In March 2023, peer-reviewed articles were collected from three databases (CAB direct, Web of Science, and PubMed). Articles were excluded if they were not in English, not peer-reviewed, not relevant to PICO (Population, Intervention, Comparison and Outcome), or if the study investigated the effects of desexing on canines with mammary tumours already or of the prognosis and not development of mammary tumours. Results: Of 232 articles obtained from the initial database search, 13 articles were found to meet the inclusion criteria. Six out of the thirteen papers selected found no evidence of a protective effect of early spaying against mammary tumour development. Conclusion: This review suggests that further breed-specific studies with matched controls on the main risk factors would help address issues such as lack of appropriate statistical analysis, control of biases, and confounding risk factors. The benefits of early spaying should be balanced with other considerations about the optimal age for spaying dogs.
... For those who did undergo spaying, the procedure was performed during adulthood, confirming the protective effects of ovariohysterectomy (OHE) in preventing the development of mammary tumors, as previously described by several authors. These protective effects are likely due to the inhibition of sex steroid effects [23,51,54]. Early neutering, before the first estrous cycle, was routinely recommended for the prevention of mammary cancer in female dogs, as there is substantial evidence linking estrogen with mammary carcinogenesis [23,51,54,55]. ...
... These protective effects are likely due to the inhibition of sex steroid effects [23,51,54]. Early neutering, before the first estrous cycle, was routinely recommended for the prevention of mammary cancer in female dogs, as there is substantial evidence linking estrogen with mammary carcinogenesis [23,51,54,55]. As estrogens are also crucial for the proper functioning of numerous organs, scientists are currently questioning this recommendation [56]. ...
... As estrogens are also crucial for the proper functioning of numerous organs, scientists are currently questioning this recommendation [56]. Some harmful effects, such as urinary incontinence, skeletal muscle disorders, brain aging, and the development of certain tumors, have been associated with early neutering [54,[57][58][59][60][61][62]. ...
Simple Summary
The increasing incidence of cancer in animals is a growing concern, with mammary cancer being the most prevalent form in female dogs. Efforts have been made to prevent and understand the factors contributing to its development. Using data from a veterinary hospital of reference in Brazil, we determined that the size dog, breed type, housing, and body score influence the risk of developing malignant mammary tumors.
Abstract
Mammary cancer is one of the main causes of death in female dogs worldwide, considering that many risk factors are involved in its development. This study aimed to elucidate the relationship between epidemiological and clinical risk factors with the histopathological diagnosis of malignant mammary tumors in dogs treated at the Veterinary Hospital of the Federal University of Uberlândia, which has one of the first veterinary oncology services in Brazil. A retrospective matched case-control study was conducted to identify risk factors for the development of malignant mammary tumors in dogs. The variables analyzed were size dog, breed, housing, type of diet, and body score. Potential risk factors were selected by univariate analysis (p < 0.25) before multivariate forward binary logistic regression. The most frequent benign tumor was the benign mixed tumor (35.2%), and the most frequent malignant tumor was the mixed carcinoma (27.4%). Size dog, breed, housing, and overweight are predictors of malignant mammary tumors in dogs. The highest risk of developing malignant mammary tumors is associated with large female dogs, Yorkshire or Poodle breeds, living outside the home, or being overweight.
... Some dog owners have become interested in exploring alternative sterilization procedures, such as ovary-sparing spay (OSS), in an attempt to minimize potential consequences of traditional gonadectomy (ie, ovariectomy [OVE] and ovariohysterectomy). Proposed gonadectomy consequences include an increased risk for urinary incontinence, 1-3 cranial cruciate ligament (CCL) disease, 4-7 hip dysplasia, 8,9 and certain neoplastic conditions such as osteosarcoma, 10,11 lymphoma, 9,12,13 transitional cell carcinoma, 14 mast cell tumors, 9,12 and hemangiosarcoma. 9,12,13 Ovariohysterectomy has also been associated with the development of obesity [15][16][17] and behavioral issues. ...
... Proposed gonadectomy consequences include an increased risk for urinary incontinence, 1-3 cranial cruciate ligament (CCL) disease, 4-7 hip dysplasia, 8,9 and certain neoplastic conditions such as osteosarcoma, 10,11 lymphoma, 9,12,13 transitional cell carcinoma, 14 mast cell tumors, 9,12 and hemangiosarcoma. 9,12,13 Ovariohysterectomy has also been associated with the development of obesity [15][16][17] and behavioral issues. 15,18,19 Furthermore, some of the proposed effects seem more pronounced if gonadectomy is performed at an early age (prior to 1 year) and in certain breeds (ie, Golden Retriever, Vizsla, and Rottweiler). ...
... 15,18,19 Furthermore, some of the proposed effects seem more pronounced if gonadectomy is performed at an early age (prior to 1 year) and in certain breeds (ie, Golden Retriever, Vizsla, and Rottweiler). 9,[11][12][13] However, there is a paucity of information regarding the outcome of these alternative gonad-sparing sterilization techniques. A relatively novel technique, OSS involves a complete hysterectomy while sparing the ovaries. ...
OBJECTIVE
To evaluate incidences of pyometra and orthopedic, behavioral, urinary/reproductive, neoplastic, or atopic disease processes as outcomes for dogs undergoing either a laparoscopic-assisted ovary-sparing spay/hysterectomy (LapOSS) or a laparoscopic ovariectomy (LapOVE).
ANIMALS
33 client-owned dogs.
PROCEDURES
Medical records of client-owned dogs presenting between August 2013 and May 2020 for elective LapOSS or LapOVE were reviewed. A multiple-choice client questionnaire was emailed to all clients whose dogs’ complete medical records were available.
RESULTS
17 of the 33 dogs were in the LapOSS group, and 16 of 33 dogs were in the LapOVE group. Of the 17 dogs undergoing LapOSS, 5 of 17 (29%) underwent an elective OVE at a later date. The mean follow-up time was 4.2 ± 1.8 years for the LapOSS group and 4.3 ± 2.0 years for the LapOVE group. No dogs developed stump pyometra. One LapOSS dog developed mammary tumor, and 2 others developed nonreproductive malignant neoplasia while 2 of the LapOVE dogs developed malignant neoplasia. One of the LapOSS dogs with malignant neoplasia had an ovariectomy prior to development of disease.
CLINICAL RELEVANCE
Laparoscopic-assisted ovary-sparing spay appears to provide a safe and reliable method of sterilization, with no observable increased risk of pyometra with hysterectomy. Owners must be counseled prior to surgery regarding the consequences of gonadal hormone retention and multiple heat cycles.
... The role of gonadectomy on behavior is complex and evidence for benefits as well as detriments following gonadectomy has been reported. Reproductive-related behaviors (such as urine marking in house, mounting, and roaming) are all reduced or eliminated following gonadectomy [86,87,29].However, fear and aggression tend to be exacerbated [88]. ...
... Many studies have confirmed the presence of LH receptors in vascular endothelial and smooth muscle cells [124,125]. Gonadectomized female dogs have two times the risk for developing splenic hemangiosarcoma and five times the risk for developing cardiac hemangiosarcoma compared to unaltered females [126,88]. Research is needed to determine if canine hemangiosarcomas possess LH receptors and if adjunctive therapy targeting these receptors would extend life expectancy. ...
... Luteinizing hormone receptors are abundant in the skin [37,130]. Several studies have documented an increased risk for developing mastocytoma following gonadectomy in dogs [72,131,88]. ...
Throughout most of the developed world, surgical sterilization via gonadectomy has become a common tool for combating the overpopulation of unwanted dogs as well as to eliminate the risk of reproductive diseases in pet dogs. However, if a surgical sterilization method is chosen that enables a dog to keep its gonads intact while still preventing reproduction, thismay avoid the problems discussed in this article. In the dog as in other normal adult mammals, the hypothalamus secretes gonadotropin-releasing hormone (GnRH), which stimulates the anterior pituitary gland to release of luteinizing hormone. Luteinizing hormone (LH) stimulates the secretion of gonadal steroid hormones (testosterone in males and estrogen/progesterone in females). These gonadal steroid hormones then negatively feedback to the hypothalamus and anterior pituitary to decrease the secretion of GnRH and LH, respectively. However, in the gonadectomized mammal, there is no negative feedback, which results in supraphysiologic circulating concentrations of LH. In gonadectomized dogs, LH concentrations are more than thirty times the concentrations found in normal adult dogs. Although the main role of LH is for reproductive functions (e.g. ovulation, corpus luteum formation), there are LH receptors present throughout the body, not just limited to the reproductive tract. The purpose of LH receptors in non-reproductive tissues is not known but may induce cell division and stimulate nitric oxide release. With constant activation following gonadectomy, these receptors are up regulated, further magnifying the effects of the extremely high LH concentrations in non-reproductive tissues. Canine gonadectomy increases the risk of several non-reproductive long-term disorders caused by extremely high LH including obesity, urinary incontinence, urinary calculi, diabetes mellitus, hypothyroidism, hip dysplasia, cranial cruciate ligament rupture, aggressive and fearful behavior, cognitive dysfunction syndrome, prostate adenocarcinoma, transitional cell adenocarcinoma, osteosarcoma, hemangiosarcoma, lymphosarcoma, and mastocytoma. In this review, the relationship between LH receptor activation in these non-reproductive target tissues will be discussed.
... Research is evolving, and some studies have started to investigate more specific factors. For instance, certain studies have explored the effect of the age at which castration occurs and the dog's lifetime exposure to gonadal hormones [56][57][58][59][60], with more recent research also focusing on the influence of breeds [54,61]. Additionally, the hormonal shifts caused by the suppression of gonadal hormones undoubtedly play a role, although the full extent of these changes is not yet entirely understood. ...
... Increased anxiety, panic, and fear reactions have been reported in numerous studies as potential consequences of neutering [44,[52][53][54][55][56][57][58][59][60][73][74][75]. Of particular note, sound phobias have been highlighted, as several studies report an increase in this phobia following neutering [44,52,59]. ...
The decision to neuter pet dogs remains a significant and ongoing debate from ethical, animal health, and animal welfare perspectives. Millions of dogs worldwide are considered integral family members, and their behavior, as well as the bond they form with their owners, play a key role in the decision to keep them as pets. When behavioral problems arise, neutering is often viewed as a potential solution. However, by removing the source of sexual hormones, neutering creates the potential for both beneficial and harmful effects on a dog’s health and behavior. It is crucial for society to rely on professionals to provide informed advice about whether and when the procedure should be performed on a pet, taking into account the unique risks and benefits of each individual case. Instead, the conclusions drawn from existing research—both in terms of behavior and health aspects—remain inconclusive and sometimes conflicting. Studies have reported higher risks for developing reproductive, urinary, metabolic, and musculoskeletal disorders in neutered dogs. Additionally, some studies suggest increases in stress, fear, anxiety, and even certain types of aggression following neutering. The limitations of current research, the subjectivity of pet owners’ evaluations of their dogs’ behaviors, the influence of various demographic factors, and the complex relationships between sex hormones and other hormones or neurotransmitters all contribute to the challenges in this field of study. Despite these complexities, they also offer promising avenues for future research. This review aims to provide a comprehensive overview of the various effects of neutering on dogs, with a particular focus on behavioral outcomes.
... On the one hand, neutering can lead to an imbalance of testosterone and cortisol, as cortisol competes with the sex steroid hormones for binding sites [8]. This imbalance can lead to increased anxiety, stress, or panic, which is confirmed by some studies [5][6][7][9][10][11][12][13][14][15]. On the other hand, the hormonal shift can lead to a decrease in oxytocin, as the oxytocin receptors are activated by the sex hormones [16]. ...
... Prior research has also examined breed-specific variations in aggressive behaviour, and several studies have found noteworthy breed-specific variations [22,[44][45][46]. Furthermore, some study findings show that the animal's sex, breed, and age of neutering all significantly influence the consequences of the procedure [9][10][11][12]25]. In addition to age at the time of neutering and the dog's previous experiences, individual characteristics and the dog's breed can be decisive factors. ...
Simple Summary
Neutering is one of the most common procedures for dogs worldwide. While motivations for neutering vary, this procedure is often chosen with the hope of addressing undesirable behaviours in male dogs. In our study, 230 mixed-breed dogs (115 neutered and 115 intact) were examined. The dogs were categorised as “small”, “medium”, “large”, and “giant”. An online questionnaire was used, which asked about certain behavioural characteristics on the one hand and personality on the other. The results showed that neutered dogs appeared more stressed and aggressive than intact dogs. In addition, neutered small, medium, and large dogs were more stressed than giant dogs. Neutered dogs were also less social, trainable, emotionally calm and extroverted than intact dogs. This all suggests that neutering should be questioned and decided on an individual basis, as hormonal changes can have a considerable influence on dog behaviour.
Abstract
This study investigates the behavioural differences between neutered and intact dogs. A total of 230 questionnaires of neutered (n = 115) and intact (n = 115) mixed-breed male dogs were collected. Small, medium, large, and giant dogs were analysed to investigate a possible influence of body size. The results showed neuters were significantly more stressed than intacts (multinomial logistic regression, p = 0.001). In terms of stress by influences (such as separation anxiety and anxiety at car rides), neutered small, medium, and large dogs were more stressed than giant dogs (multinomial logistic regression, p = 0.05). Neuters were also found to be more aggressive in general (multinomial logistic regression, p = 0.04) and more aggressive on the walk (multinomial logistic regression, p = 0.02). In addition, personality questionnaires revealed significant differences in all characteristics. Neuters were less emotionally calm (multiple ordinal regression, p = 0.03), less trainable and less sociable (each multiple ordinal regression, p < 0.001). They also scored lower on extraversion (multiple ordinal regression, p = 0.04). These findings highlight the importance of further research into the behavioural effects of neutering dogs, as well as the need for evidence-based guidelines for neutering practices.
... Some studies have suggested that entire animals were more prone to ADHD-like behaviors than castrated dogs [6,9]. Nevertheless, Zink et al. [71] found that neutering could be a risk factor for hyperactivity, whereas Fadel et al. [72] indicated that castrated animals showed higher impulsivity, and Csibra et al. [20] found that neutering dogs had a significatively higher tendency to show inattention and impulsivity. Though, owners Animals 2024, 14, 2067 7 of 18 might try to find a solution to deal with the condition of their dogs by neutering. ...
... Sex: It appears to be more common in males [6,9]. • Neutering in males, due to a lack of regulation caused by decreased testosterone [4,71], although some studies suggest otherwise [73]. ...
Simple Summary
Similar to humans, dogs could suffer a syndrome similar to Attention-Deficit/Hyperactivity Disorder (ADHD). Several studies suggest that dogs can serve as a model for studying ADHD. This condition leads to behavioral issues like impulsivity, attention problems, hyperactivity, and sometimes aggression, affecting both the dog’s and their caregiver’s quality of life. ADHD-like behavior in dogs is linked to disruptions in neurotransmitters like serotonin and dopamine, similar to humans. It seems to result from a mix of genetics and environment. In addition to the mentioned symptoms, dogs with ADHD-like behavior may also display compulsive behaviors, aggression, inappropriate elimination, fearfulness, epilepsy, foreign body ingestion, and itchiness. While there is no clear veterinary diagnosis for ADHD-like behavior in dogs, validated questionnaires can be helpful, but these cannot be used as a unique diagnostic tool. Treatment may involve medications like fluoxetine, along with environmental enrichment, relaxation techniques, and behavior modification to improve the dog’s and caregiver’s quality of life.
Abstract
Similar to humans, dogs could suffer an Attention-Deficit/Hyperactivity Disorder-like syndrome (ADHD-like). In fact, several studies highlight the use of dogs as a model for studying ADHD. This condition entails behavioral problems expressed through impulsivity, attention issues, hyperactivity, and/or aggression, compromising the quality of life for both the caregiver and the dog. The pathophysiology of ADHD-like is complex and is associated with dysregulation of various neurotransmitters such as serotonin and dopamine. The expression of ADHD-like behavior in dogs would appear to depend on a classical gene–environment interaction as is the case with many neurological disorders in humans. In addition to the described symptomatology, ADHD-like dogs can exhibit strong comorbidities with compulsive behaviors, aggressiveness, inappropriate elimination and fearfulness, in addition to epilepsy, foreign body ingestion, and pruritus. In spite of the fact that there is no veterinary consensus about the diagnosis of ADHD-like, some validated questionnaires could be helpful, but these cannot be used as a unique diagnostic tool. The use of drugs, such as fluoxetine, in addition to an adequate environmental enrichment, relaxation protocols, and behavior modification can achieve an adequate quality of life for both the dog and caregivers.
... While neutering prior to sexual maturity, or 'early' neutering, considered to be between 6 and 14 weeks of age [5], is sometimes recommended [6], the literature is inconsistent, making it challenging to decide on the best time to neuter female dogs. Despite many studies investigating the impact of neutering on health [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24], and to a lesser extent, behaviour [9,12,19,[25][26][27][28][29][30][31][32], no cohort studies have been identified that investigated the impact of the surgical neutering of bitches before or after known puberty on their growth and physical development. ...
... While neutering prior to sexual maturity, or 'early' neutering, considered to be between 6 and 14 weeks of age [5], is sometimes recommended [6], the literature is inconsistent, making it challenging to decide on the best time to neuter female dogs. Despite many studies investigating the impact of neutering on health [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24], and to a lesser extent, behaviour [9,12,19,[25][26][27][28][29][30][31][32], no cohort studies have been identified that investigated the impact of the surgical neutering of bitches before or after known puberty on their growth and physical development. ...
Simple Summary
No previous studies have been identified that have investigated the impact of neutering before or after known puberty on growth and physical development in a large number of bitches. This study was designed to examine data on the physical development, vulval size, and conformation of 306 bitches neutered before (n = 155) or after (n = 151) puberty. Data were gathered for bitches at six- and 17-months of age using bespoke physical assessment forms and digital photographs of the vulva. Bitches neutered before puberty had significantly greater changes in height and smaller changes in measurements of vulval length and width between six- and 17-months of age than those neutered after puberty. Although not significant, bitches neutered before puberty were taller and heavier with smaller vulval size measurements at 17-months of age. At 17-months of age, significantly more bitches neutered before puberty had vulvas that appeared juvenile and recessed at the physical assessment, and significantly more bitches neutered before puberty had vulvas that appeared ‘recessed/inverted’ on the examination of digital images. The results from this study could suggest that neutering before puberty may be a suitable option for large breed bitches. However, any longer-term health consequences of the differences in physical development seen need to be investigated and better understood before recommendations can be made.
Abstract
No previous large prospective cohort studies have been identified that have investigated the impact of the surgical neutering of bitches before or after known puberty on their growth and physical development. This study was designed to examine the data on physical development, vulval size, and conformation for bitches neutered by ovariohysterectomy before puberty (PPN, n = 155) or after puberty (control, n = 151) using a prospective cohort study design. Data were gathered at six- and 17-months of age using bespoke physical assessment forms and digital images of the vulva. PPN bitches had greater changes in height measurements (mean difference = 2.039, SEM = 0.334, 91% CI = 1.471 to 2.608, p < 0.001) and smaller changes in the measurements of vulval length (mean difference = −0.377, SEM = 0.079, 91% CI = −0.511 to −0.243, p < 0.001) and width (mean difference = −0.221, SEM = 0.063, 91% CI = −0.328 to −0.113, p < 0.001) between six- and 17-months of age than for the control bitches. Although not significant, the PPN bitches were taller (mean 58.5 vs. 56.6 cm) and heavier (mean 28.3 vs. 27.3 kg) with smaller vulval size measurements (mean vulval length 2.8 vs. 3.2 cm, mean vulval width 1.7 vs. 2.1 cm) at 17-months of age. At 17-months of age, significantly more PPN bitches had vulvas that appeared juvenile (Yates’ Chi-square = 14.834, D.F. = 1, p < 0.001) and recessed (Yates’ Chi-square = 7.792, D.F. = 1, p = 0.005) at the physical assessment, and significantly more PPN bitches had vulvas that appeared ‘recessed/inverted’ on the examination of digital images (Chi-square = 9.902, D.F. = 1, p = 0.002). The results from this study suggest no contraindications to prepubertal ovariohysterectomy for large breed bitches. However, any longer-term health implications of these differences in physical development need to be investigated and better understood prior to recommendations being made.
... In addition to age and breed predisposing factors, gonad removal in female dogs (ovariohysterectomy) also increases the likelihood for developing hemangiosarcoma. In fact, depending upon which study is referenced, gonadectomized female dogs have two times the risk [4], four times the risk or up to ten times the risk for developing splenic hemangiosarcoma compared to females whose gonads had not been removed [5,6]. It is interesting to note that gonad removal in males does not appear to have the same predisposing affect [4][5][6]. ...
... In fact, depending upon which study is referenced, gonadectomized female dogs have two times the risk [4], four times the risk or up to ten times the risk for developing splenic hemangiosarcoma compared to females whose gonads had not been removed [5,6]. It is interesting to note that gonad removal in males does not appear to have the same predisposing affect [4][5][6]. ...
Gonad removal has been implicated as a risk factor for the development of canine hemangiosarcoma. With gonad removal, there is a loss of negative feedback to the anterior pituitary, resulting in persistently elevated concentrations of luteinizing hormone (LH). LH receptors can be found in gonadal and extragonadal tissues, including the bladder and skin. The aim of this study was to investigate if LH receptors were expressed in canine splenic hemangiosarcoma. Splenic tumor samples submitted to the Oregon State Veterinary Diagnostic Laboratory from referring veterinarians were with routine immunohistochemical methods. In addition, survival time following hemangiosarcoma diagnosis was obtained from the referring veterinarians. Five of the eight splenic hemangiosarcomas (62.5 %) were positive for LH receptor expression. LH receptor cellular localization in splenic hemangiosarcoma was cytoplasmic and granular, similar to the positive control canine skin sections (Figure 1C). There was no positive staining in the negative controls. LH receptor is expressed in a proportion of HSAs but further study need to be done to assess the significance of this finding.
... Neutering has been suggested to impact behaviour in female dogs by many authors (6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21). However, considerable variation between study populations and methodology, alongside contradictory findings, make associations unclear for many behaviours. ...
... However, considerable variation between study populations and methodology, alongside contradictory findings, make associations unclear for many behaviours. The effects of neutering on behaviour are also likely to differ by sex, and between breeds (8,19,(22)(23)(24). The extent of between-study variation for studies, comparing behaviour between neutered and entire female dogs becomes apparent when considering, perhaps, one of the most well-studied behaviours in relation to neutering; aggression. ...
There are few studies that investigate the effect of neutering bitches before or after puberty. The majority of current literature examining the impact of the timing of neutering on health and behaviour has used age rather than the onset of puberty as the key variable. The aim of this prospective cohort study was to investigate the effects of timing of neutering in relation to puberty on behaviour in female dogs reared and trained in an assistance dog programme. The study examined data for bitches neutered before or after puberty to compare scores for six behavioural factors (training and obedience, aggression, fear and anxiety, excitability, attachment and attention-seeking, and social behaviour) measured at 1 and 3 years of age. Labrador and Golden Retriever crossbreed bitches were neutered before (n = 155) or after (n = 151) puberty. Neutering before or after puberty had no impact on mean scores for the six behavioural factors at 1 or 3 years of age. When examining the change in behavioural factor scores between 1 and 3 years of age, only aggression behavioural factor scores were influenced by neutering before or after puberty. Bitches neutered after puberty were less likely to have aggression factor scores that increased between 1 and 3 years of age (OR = 0.959, 90% CI = 0.924 to 0.995, p = 0.06). However, the majority of bitches scored “0” for aggression at both time points (indicating no aggression behaviours were observed), and the number of bitches for which scores increased between 1 and 3 years of age was low (before puberty = 20, after puberty = 9). This is consistent with very mild aggressive behaviours being observed in a small number of animals and is, therefore, of questionable concern. The results suggest that, for Labrador and Golden Retriever crossbreed bitches, neutering before or after puberty has little to no effect on future behaviour. It is recommended that decisions about the timing of neutering are not informed solely by impacts on behaviour, but that they also consider evidence relating to the impacts on bitch health and well-being.
... Old studies are commonly cited to advise spaying before first or second oestrus, in order to prevent mammary tumors (MTs) or pyometra [1][2][3]. But in the last decade, Beauvais pointed out the low statistical reliability of these former studies [4], and many epidemiological studies have since shown that early spaying was significantly associated with increased risks of osteoarthritis, cruciate ligament rupture, immune-mediated diseases, epileptical disorders, or some cancers in female dogs, depending on the breed [5][6][7][8][9][10][11][12]. The idea subsequently emerged that early sterilization was not necessarily conclusive as a preventive measure, at least in some breeds, such as Labrador Retrievers, Golden Retrievers, Rottweilers, and Vizslas. ...
... Beauvais questioned these dogmas in 2012 due to statistical bias found in these former studies [4]. Moreover, some authors have questioned further the preventive interest of early sterilization, because of a higher incidence of various cancers in early-spayed female dogs, at least for some breeds such as Rottweilers, Labrador Retrievers, Golden Retrievers, or Vizslas [5][6][7][8][9]12]. This retrospective study aimed at comparing the prevalence of reproductive pathology including MTs in client-owned female dogs according to their sterilization status, to analyze the causes of death, and to evaluate the impact of MTs on life expectancy. ...
Female dogs, especially intact or neutered lately, are at increased risk for reproductive disorders including mammary tumors (MTs). This retrospective study evaluated the prevalence of reproductive pathology and associated mortality in a cohort of female dogs presented at a single veterinary clinic. The medical records of female dogs born in 2000–2003 were reviewed. The study included 599 cases, of which 293 were followed up until death. Causes of death were analyzed according to the spaying status. Among the 599 female dogs, 306 were intact (51%), 50 (8%) had been spayed before 2 years of age (ES, early spaying), and 243 (41%) after 2 years (LS, late spaying). During their lifetime, 79 dogs (13.2%) developed pyometra, and 160 (26.7%) a mammary tumor. Among the 293 dogs with complete follow-up, 103 (35.1%) had at least one MT during their lifetime, of which 53 (51.5%) died of their mammary cancer. Spayed (ES + LS) female dogs had a 4-fold decreased risk of dying from mammary cancer (OR = 0.23, 95% CI 0.11–0.47, p < 0.0001) compared to intact females. In this low-sterilization rate population, MTs developed in 35.1% of female dogs over their lifetime and was the cause of death in half of them.
... Aan de andere kant toont deze studie aan dat een langere blootstelling aan geslachtshormonen dan weer leidt tot meer urine-markering in huis en scheidingsangst (janken bij weggaan). Ook in een ander onderzoek werd aangetoond dat als reuen gecastreerd worden op een leeftijd jonger dan zes maanden, de kans groter is op het ontwikkelen van angst-geïnduceerde gedragsproblemen zoals angst voor stormen, verlatingsangst, plassen uit onderdanigheid, geluidsfobieën, bijten uit angst en schuwheid (Zink et al., 2014). Vermoedelijk spelen geslachtshormonen tijdens de puberteit dus ook een rol bij het wapenen van honden tegen hun angstgevoel in hun verdere leven. ...
... De laatste jaren zijn daar nog andere bezorgdheden bij gekomen omdat een aantal studies die uitgevoerd werden bij specifieke rassen, verhoogde risico's aantoonden voor bepaalde tumoren, zoals mastceltumoren, lymfoom/lymfosarcoom en hemangiosarcoom en andere neoplasieën bij gegonadectomiseerde honden. Gegonadectomiseerde honden van bepaalde rassen, i.e. golden retrievers (Hart et al., 2014) en vizsla's (Zink et al., 2014), hebben drie tot vijf keer meer kans op deze tumoren terwijl dezelfde tendens niet gevonden wordt bij labrador-retrievers (Hart et al., 2014) en Duitse herders (Hart et al., 2016). Een mogelijke reden van deze stijging in prevalentie van neoplasieën na gonadectomie zou zijn dat geslachtshormonen een rol spelen in het behouden van een constant immunologisch toezicht op kankercellen. ...
1. Castratie bij de reu 2. Sterilisatie bij de teef
... There is growing interest in harnessing the domesticated dog population as an underutilized opportunity to better understand the genetic and non-genetic determinants of healthy aging [16][17][18][19][20][21][22]. Banzato and colleagues [23] developed a clinical FI and tested its association with mortality in 401 dogs of more than 30 breeds. ...
Frailty refers to a state of increased vulnerability to mortality and other adverse outcomes as a consequence of age-related decline in physiologic reserve and function. Comparative biomedical scientists are relied upon to innovate approaches to enhance understanding of the similarities and differences between humans and other animal species that can impact healthy aging. The research aim of this study was to develop a clinical frailty index (FI) in the Exceptional Aging in Rottweilers Study (EARS) and test its ability to predict all-cause mortality in elderly dogs. EARS is an ongoing lifetime cohort study of pet dogs with extreme longevity living in North America. Living 30% longer than the breed average, these dogs represent the canine counterpart to human centenarians. A 34-item FI (EARS-FI) was constructed to assess deficit accumulation using clinical data collected by telephone interviews with owners of 93 dogs with extreme longevity. Health deficits across multiple domains, including cognitive and sensory, cardiovascular and endocrine, and mobility, were included. The association between EARS-FI and subsequent mortality was tested in Kaplan-Meier survival analysis and in age-adjusted Cox proportional hazard models. Median (interquartile range) EARS-FI was 0.43 (0.38–0.50), and the estimated frailty limit was 0.68, consistent with data reported in humans with extreme longevity. Frailty index increased with increasing chronological age (p < 0.001). Deficit accumulation was significantly associated with increased mortality risk. Age-adjusted hazard ratio for mortality per 0.01 unit increase in FI was 1.05 (95%CI, 1.02–1.08; p = 0.001). This work provides the first demonstration of a strong association between frailty and mortality risk in pet dogs with extreme longevity. Notably, EARS-FI showed key features observed in the evaluation of frailty in aging human populations: heterogeneity, increase with chronological age, and estimated limit of <0.7. Validated here as a predictor of mortality in aged pet dogs, EARS-FI offers a useful tool for further comparative analyses of the linkages between deficit accumulation, mortality, and other adverse health outcomes.
... Complementary DNA (cDNA) was synthesized for each sample from tRNA (1 μg) following the manufacturer's instructions for the cDNA synthesis kit. In brief, tRNA (5 μL, 200 ng/μL) was added to a reaction mixture containing 10 mM deoxynucleotide triphosphate mix (1 μL), 0.5 μg/μL oligo(dT) [12][13][14][15][16][17][18] (1 μL), and RNase-free water (5 μL), which was incubated at 65 °C for 5 minutes and then placed on ice for 2 minutes. A second reaction mixture containing 10X reverse transcription buffer (2 μL), 25 mM MgCl 2 (4 μL), 100 mM dithiothreitol (2 μL), and RNase inhibitor (1 μL, 40 U/μL) was added to the reaction mixture and incubated at 42 °C for 2 minutes. ...
OBJECTIVE
The expression of luteinizing hormone (LH) receptors has been reported in canine nonneoplastic and neoplastic lymphocytes. This study aimed to determine the effect of LH receptor activation in neoplastic canine T lymphocytes.
METHODS
Cell lines (CLC, CLK, EMA) derived from 3 dogs with primary T-cell lymphoma were used. Cell lines were previously phenotyped and evaluated for LH receptor expression with flow cytometry. Cell lines were stimulated with increasing concentrations (0, 4, 400, and 4,000 U/mL) of human chorionic gonadotropin (hCG; an LH receptor agonist), RNA was extracted, cDNA was synthesized, and gene expression was determined using quantitative PCR and the 2 -ΔΔCt method. Cell lines were stimulated with the same increasing concentrations of hCG, and cell proliferation, adhesion, and transmigration were determined using commercial assays. The effects of LH receptor activation were compared between hCG concentrations using a one-way ANOVA. Significance was defined as P < .05.
RESULTS
LH receptor stimulation increased LH receptor gene expression in the CLC cell line, and there was a trend for increased expression in the EMA cell line but no effect in the CLK cell line. Activation of LH receptors increased proliferation in all 3 cell lines, endothelium adhesion in 2 cell lines (CLC, CLK), and transmigration in 2 cell lines (CLK, EMA).
CONCLUSIONS
LH receptor stimulation using hCG increased LH receptor gene expression in neoplastic canine T lymphocytes and increased cell proliferation, adhesion, and transmigration.
CLINICAL RELEVANCE
These findings may provide a physiologic mechanism for the increased incidence of lymphoma reported in dogs with sustained supraphysiologic LH concentrations.
... Most of the female dogs involved in this study were not sterilized, aligning with findings suggesting that OVH offers a protective effect against mammary tumor development, likely through sex steroid inhibition [12,[29][30][31]. Notably, 74% of malignant tumors were identified in intact dogs, diagnosed at a significantly younger age compared to spayed dogs (9.20 vs. 10.09 ...
Simple Summary
Canine mammary tumors are the most common tumor in intact female dogs. This study aimed to investigate the clinicopathological, immunohistochemical, and cytogenetic features of canine mammary tumors. This study is relevant due to the fact that canine and human breast cancer share similar epidemiological and histopathological characteristics, reinforcing the potential for dogs to serve as an effective animal model for human breast cancer research.
Abstract
Cancer is a complex pathological condition associated with substantial rates of mortality and morbidity in both humans and animals. Mammary gland tumors in intact female dogs are the most prevalent neoplasms. Surgical intervention remains the primary treatment choice. Alternative therapeutic options have emerged, with histopathological examination being fundamental to confirm the diagnosis and to decide the best therapy. This research focused on the clinicopathological, immunohistochemical, and cytogenetic aspects of canine mammary tumors (CMTs). Most of the animals were mixed-breed, with the majority being older than seven years, and only 16.7% had been spayed before surgery. Caudal abdominal and inguinal mammary glands were the most affected, with regional mastectomy being the predominant treatment (75.0%). Of all the tumors, 29.1% were benign, while 70.9% were malignant. Complex adenoma was the most common benign tumor, whereas tubulopapillary carcinoma was the most common malignant type. Grade III tumors (17.6%) were the least encountered, while grades I and II exhibited a similar prevalence (41.2%). All the carcinomas were classified as luminal, and cytogenetics analysis demonstrated a high chromosomal instability with significant aneuploidy observed in all cases and polyploidy detected in 62.5%. This study holds significance as canine and human breast cancers share similar characteristics, suggesting that dogs could be a valuable model for human breast cancer research. Further studies with larger sample sizes are needed to enhance our understanding of CMTs.
... This increased stress and insecurity of neutered dogs again give an indication of the behavioural-biological consequences of gonadectomy, which was also identified by Zink et al. [74] in neutered Vizslas. ...
Neutering dogs is a widespread method and is carried out for various behavioural and husbandry reasons. This study’s main objective is to investigate the behavioural correlations between neutering and the breed of male dogs. In order to possibly find breed-dependent differences in the behaviour of intact and castrated dogs, a differentiation between two clades - the “Huskies“(chow chow, shar pei, akita/shiba inu, alaskan malamute, siberian/alaskan husky) and the “Bulldogs” (german boxer, english/french bulldog, old english mastiff, boston terrier, english bull terrier, staffordshire bull terrier, american staffordshire terrier), based on Parker et al. [1], was made.
Using an online questionnaire,, 31 neutered and 37 intact male dogs from the clade “Huskies“ and 30 neutered and 38 intact male dogs from the clade “Bulldogs”, participated in the study (N = 136).The survey included detailed questions on the dogs’ personality and any associated issues as well as a behavioural anamnesis. Further questions relating to four of the “big five” personality dimensions based on the “Budapest questionnaire” by Turcsán et al. from 2011 [2] were also added.
The results show, that neutered males from both breed clades more frequently displayed aggression toward humans than intact males (multinomial logistic regression, p = 0.002). When it came to aggression towards other dogs, it was the “Huskies” that differed significantly from the “Bulldogs“(multinomial logistic regression, p = 0.04) with being more aggressive. There were also significant differences in stress-related behaviour depending on castration status and breed (multinomial logistic regression, p < 0.001; Cramer’s V = 0.33) and only the castration status had an impact on the significance (multinomial logistic regression, p < 0.001). The analysis also revealed significance for stress-indicating behaviour with dependence on neutering status (multinomial logistic regression, p < 0.001) and showed that stress as well as uncertainty are significantly more common in neutered dogs depending on breed and neutering status (multinomial logistic regression, p < 0.001; Cramer’s V = 0.42), in that only neutered “Bulldogs“ were stressed, but more “Huskies“ overall.
According to the Budapest questionnaire data, the “Bulldog” clade had considerably greater extraversion scores overall (ordinal regression, p < 0.001) than the “Huskies“.
Our findings highlight the risks and potential negative effects of neutering. Gonadectomy in no way substitutes for the dog receiving the necessary socialization, training, or bonding. Although in some circumstances it might have a favourable impact on the dog’s behaviour, it should not be seen as a panacea for unwanted behaviour. Given that not all behaviours are influenced by sex hormones, every castration decision must be weighed up individually.
... castrated male dogs are reportedly obese [9][10][11]. ...
Vertebrate animals often exhibit sexual dimorphism in body shape. In mammals, decreases in sex hormones caused by testicular castration can affect body shape and occasionally lead to pathologies such as obesity. Post-castration obesity can also be problematic for the health of companion animals, including non-mammals. In order to understand the mechanism of post-castration obesity in vertebrates other than mammals, experimental models are required. We examined whether the Iberian ribbed newt, which has recently become a popular experimental model for amphibian research, could serve as a model for analyzing changes in body shape after castration. In newts, new testes can be regenerated after removal of differentiated testes. We analyzed changes in body shape by removing the testes under conditions in which they could regenerate or conditions in which they could not regenerate. Removal of the testes reduced blood testosterone levels. The body weight and abdominal girth of the newts were increased compared with normal male newts. Transcriptome analysis of the liver showed that a set of genes related to lipid metabolism was continuously up-regulated in castrated newts. Our study suggests that changes in body shape after castration are common in vertebrates. Iberian ribbed newts are thus a suitable model for comparative studies of the long-term physiologic- and endocrine-level effects of castration.
... Studies showed that neutering increase HSA development especially in the spleen and heart. Hormonal association with canine HSA has been reported with regard to spaying, and female dogs spayed at a later age have a higher percentage of HSA development compared to female dogs spayed at an early age (8,9). Spayed female dogs have 5 times more risk of HSA than intact female dogs (10). ...
An 11-year old, Rottweiler bitch was presented to the clinic with the complaint of a huge mass protruding from the left side of the vulvar labium. The bitch had been ovariohysterectomized due to the pyometra 2 years ago. The perivulvar mass was surgically removed by using an electrocautery device under general anesthesia. Macroscopically, the pedunculated mass was 20 cm x 25 cm in diameter, capsulated and slightly firm. Histopathological examination revealed that the mass was a hemangiosarcoma originating from the mucosa. Marked anisocytosis and anisokaryosis were noted in microscopic examination. Immunohistochemically, neoplastic cells showed positive staining for von-Willebrand factor-related antigen. On postoperative 3rd and 12th month follow-up protocols, the female dog was in good health condition and no metastases were detected in any organ. In this report, clinical follow-up, histological and immunohistological examination of a rare perivulvar hemangiosarcoma case in a female dog was presented.
... The incidence increases with age and seems to be more prevalent in middle-sized to large breeds (40). Also, early neutralization (<1 years old) is suggested to increase the risk of cL in golden retriever (36) and vizsla (41), whereas no link was existed in Labrador Retriever (12). Generally, intact female dogs are less represented with cL (40). ...
... As for any surgical procedure, collateral surgical damage can occur, such as urinary incontinence [148], development of lymphomas [149], and chronic pain. These effects of surgery can severely compromise the welfare of those animals. ...
Simple Summary
In several countries, there are practices, ideologies, rooted traditions, or legal gaps that represent challenges to animal welfare. These particularly relate to the consideration of the welfare domains of nutrition, environment, health, behavior, and corresponding mental state. In this article, we discuss some of the challenges with respect to animal welfare that arise in Latin America. Controversial topics concerning aesthetic and management practices in small animals and with the keeping of wildlife in Latin American regions are discussed. The focus is on the legal and ethical aspects, as well as the current efforts, that these countries are making to address and incorporate global welfare standards into domestic and wild animal practice and regulation.
Abstract
Animal welfare is a societally relevant issue that is globally attracting increased attention. This is in addition to the importance placed on welfare for the animals themselves. However, the content and application of laws protecting animals’ welfare vary across countries. In Latin America, there are a range of common practices or activities involving certain animal species, many of which are legal, that can impair an animal’s quality of life. These include the performance of aesthetic surgical procedures; bull-, cock-, and dog fighting; and the existence of circuses that exhibit animals. The extent and impact of these practices being dependent on the socioeconomic, cultural, territorial, and regulatory landscape of each country. Particularly, Ibero-American regions face welfare challenges that might be influenced by traditions and relevant legal gaps. The objective of this article is to review controversial practices carried out in companion and entertainment animals in Latin America, with a focus on legal aspects, as well as the current efforts being made to address and incorporate global welfare standards into domestic and wild animal practice and regulation.
... Some studies report differences in behaviour between neutered and entire bitches, 2-6 while others found no difference. [7][8][9][10][11] Additionally, neutering bitches at different ages, [12][13][14][15] or before or after puberty [16][17][18][19][20] have been reported to have an effect on behaviour in some studies but not in others. [21][22][23] However, when the aforementioned studies are critically reviewed, it becomes apparent that the age of the dogs is used to imply whether the dogs are preor postpubertal, which is a potentially flawed assumption that may account for the conflicting findings. ...
Background
There are contradictory findings in the literature relating to the effects of timing of neutering on bitch behaviour that make decision making regarding neutering timing difficult.
Methods
A scoping review was designed to identify and chart the evidence on the effect of neutering timing in relation to puberty on the behaviour of female domesticated dogs. A protocol was registered, and literature searches were conducted in CAB Abstracts, Medline and Web of Science. Studies were reviewed against the inclusion criteria. Data on study and population characteristics and behavioural outcomes were extracted for the final included studies.
Results
A total of 1048 publications were reviewed; 13 were retained for inclusion and charting. Only one of the two studies that classified bitches as pre‐ or postpubertal presented results for the analysis of behaviours. The remaining 11 studies classified bitches by age at neutering.
Limitations
Since the scoping review searches were conducted, further relevant studies may have become available. The search strategy may not have identified all available literature; however, databases were used that provide high levels of coverage of veterinary literature.
Conclusion
This scoping review identified a lack of evidence to document the impact of neutering bitches before or after puberty on behaviour.
... In addition, neutering appeared to be an important risk factor for being ADHD-like, and entire animals were more prone to suffering ADHD-like behaviors than castrated dogs and had higher DIAS scores, as previously described [37,65]. Nevertheless, Zink et al. [66] found that neutering could be a risk factor for hyperactivity, whereas Fadel et al. [67] indicated that castrated animals showed higher DIAS scores. Nevertheless, some owners could try to find a solution for dealing with the condition of their dog by neutering. ...
Simple Summary
Attention deficit hyperactivity disorder (ADHD) is a relatively common neurodevelopmental disorder mainly affecting children and adolescents. ADHD is associated with significant social stigma, psychosocial adversities, and reduced working abilities. As with humans, dogs can suffer from ADHD-like behaviors, but to date, there are few studies on this condition in the canine species. Therefore, the present study analyzed the levels of serum serotonin and dopamine in dogs with signs that are similar to the ones presented in human patients with ADHD (compared to control dogs) that were assessed clinically and through different behavior scales. The results obtained indicate that both neurotransmitters have a tendency to be observed in lower concentrations in dogs presenting behavioral signs consistent with ADHD-like disorders. This finding may be useful for contributing to the study of the diagnosis and treatment of this disorder in dogs. ADHD-like associated behaviors can disrupt the normal coexistence of the dogs in their homes and contribute to abandonment, which continues to be a major social and animal welfare problem today.
Abstract
As with humans, dogs can suffer from attention deficit hyperactivity disorder-like (ADHD-like) behaviors naturally and exhibit high levels of hyperactivity/impulsivity and attention deficit problems, making the domestic dog a potential animal model for ADHD. ADHD has a very complex pathophysiology in which many neurotransmitters are involved, such as serotonin and dopamine. The aim of the study was to evaluate serum serotonin and dopamine levels in dogs with ADHD-like symptomatology. Fifty-eight dogs were studied, of which, thirty-six were classified as ADHD-like after physical and behavioral assessments. Additionally, the dogs’ owners performed a series of scientifically validated questionnaires which included C-BARQ, the Dog Impulsivity Assessment Scale, and the Dog-ADHD rating scale. Serum from every animal was collected after the behavioral assessments and analyzed with commercial ELISA tests for serotonin and dopamine determination. Kruskal–Wallis tests and Lasso regressions were applied to assess the relationships between both neurotransmitters and the ADHD-like behaviors (as assessed by clinical evaluation and through the different questionnaires). The dogs clinically classified as ADHD-like showed lower serotonin and dopamine concentrations. Further, serotonin and dopamine levels were also linked to aggression, hyperactivity, and impulsivity. Decreased serotonin concentrations were also related to fear, attachment, and touch sensitivity. Finally, it must be noted that our data suggested a strong relationship between serotonin and dopamine and ADHD-like behaviors.
... Previous studies have focused on age at cancer diagnosis, or age at death from cancer, for individual breeds [16][17][18] or for specific cancer types [19][20][21], making the findings difficult to generalize to other breeds or to mixed-breed dogs. Some of the larger, population-based studies that incorporated a more diverse selection of breeds were conducted in Europe [2,3,22,23] where common breeds may not be representative of breeds that are common in the United States; additionally, cancer incidence and cancer types observed in these studies may be different from those seen in a US population, given environmental differences and spay/neuter rates in Europe versus the United States. ...
The goal of cancer screening is to detect disease at an early stage when treatment may be more effective. Cancer screening in dogs has relied upon annual physical examinations and routine laboratory tests, which are largely inadequate for detecting preclinical disease. With the introduction of non-invasive liquid biopsy cancer detection methods, the discussion is shifting from how to screen dogs for cancer to when to screen dogs for cancer. To address this question, we analyzed data from 3,452 cancer-diagnosed dogs to determine the age at which dogs of certain breeds and weights are typically diagnosed with cancer. In our study population, the median age at cancer diagnosis was 8.8 years, with males diagnosed at younger ages than females, and neutered dogs diagnosed at significantly later ages than intact dogs. Overall, weight was inversely correlated with age at cancer diagnosis, and purebred dogs were diagnosed at significantly younger ages than mixed-breed dogs. For breeds represented by ≥10 dogs, a breed-based median age at diagnosis was calculated. A weight-based linear regression model was developed to predict the median age at diagnosis for breeds represented by ≤10 dogs and for mixed-breed dogs. Our findings, combined with findings from previous studies which established a long duration of the preclinical phase of cancer development in dogs, suggest that it might be reasonable to consider annual cancer screening starting 2 years prior to the median age at cancer diagnosis for dogs of similar breed or weight. This logic would support a general recommendation to start cancer screening for all dogs at the age of 7, and as early as age 4 for breeds with a lower median age at cancer diagnosis, in order to increase the likelihood of early detection and treatment.
... female dogs, spayed female dogs have 2 to 10 times the risk of developing hemangiosarcoma. [10][11][12] Luteinizing hormone (LH) is secreted by the anterior pituitary gland in brief low-amplitude pulses in sexually intact female and male dogs to stimulate the synthesis of estrogen and testosterone, respectively. 13 These gonadal steroid hormones then negatively feedback to decrease the secretion of LH. ...
Objective:
To determine luteinizing hormone receptor (LHR) expression and response to LHR activation in isolated canine splenic hemangiosarcoma cell lines in vitro.
Samples:
In vitro cultures of commercially available canine splenic hemangiosarcoma cell lines (EFS, GRACE-HSA, and DAL-4).
Procedures:
The percentage of each cell line expressing LHR was determined by immunocytochemistry. Cells were then treated with increasing doses (7.5 ng/mL, 75 ng/mL) of recombinant canine luteinizing hormone (cLH) for 48 hours and evaluated using a cell proliferation assay.
Results:
The percentage of cells expressing LHR was 17.2 ± 4.5%, 11.8 ± 3.1%, and 6.9 ± 2.5% in EFS, GRACE-HSA, and DAL-4, respectively. There was significant increase in cell count in the DAL-4 and EFS cell lines following a 48-hour incubation at the highest cLH concentration (P = .028 and P = .019, respectively). There was not a significant increase in cell count in the GRACE-HSA cell line at either cLH concentration.
Clinical relevance:
Activation of LHR results in cell proliferation in some canine splenic hemangiosarcoma cell lines. These results may explain why spayed and castrated dogs with high circulating LH concentrations may develop hemangiosarcoma more frequently than intact dogs.
... Several resources cite increased odds for development of nonreproductive tumors in dogs castrated younger than 1 year of age. 2,16,17 However, many of these studies are retrospective, and sources of bias such as longer lifespan of castrated dogs, among others, lead to lack of proof of direct causation. Both AAHA and the AVMA support early-age castration to reduce the numbers of unwanted and homeless animals, citing animal welfare and overpopulation concerns. ...
The most commonly performed surgical
procedures in small animal practices in
North America are for reproductive sterilization
(spay/neuter). Surgical sterilization of the male
dog and cat is commonly accomplished via
orchiectomy. In addition to sterilization,
orchiectomy substantially reduces the incidence
of the most common canine prostatic diseases
(benign prostatic hyperplasia and prostatitis),
can be used to prevent or manage tumors of the
testes, and is often used to modify unwanted
behaviors (e.g., roaming, territorial marking,
intermale aggression, unwanted sexual
behaviors). The veterinary medical literature reveals numerous
variations in sterilization techniques; this update
highlights those that are the most contemporary and
clinically relevant. This article features several efficient
techniques and other helpful methods that can increase
positive outcomes and decrease complications.
... 25 Compared to intact females and males, lymphoma is 4 times more common in spayed and neutered Viszlas. 28 Occurrence of lymphoma was higher in spayed than intact females. 10 Absence of gonadal hormones in the dogs sampled for the current study may have masked effects of sex on LHR expression. ...
Purpose of this investigation was to determine if luteinizing hormone receptor (LHR) expression in canine lymphoma was affected by body weight, sex, immunophenotype (B cell, T cell) or tumor stage. Formalin-fixed, paraffin-embedded lymphoma tissue samples from spayed and neutered dogs (n = 40), representing multiple breeds and mixed breeds, were subjected to routine immunohistochemical techniques using a polyclonal LHR antibody. Percentage of cells positive for LHR and the staining intensity (scored 0 - 3) were determined at 400 x magnification. Data were expressed as mean ± standard deviation and significance was defined as p < 0.05. Differences between sex and tumor phenotype, body weight and tumor stage were compared. All tumor samples had cells positive for LHR. However, percentage of cells expressing LHR and its immunostaining intensity varied among individuals. There were no significant differences in percentage of LHR positive cells or staining intensity within sex or immunophenotype. Additionally, there was no significant association between percentage of LHR positive cells or staining intensity within body weight or tumor stage. We concluded that increased risk of lymphoma in spayed and neutered dogs was not related to body weight, sex, immunophenotype or tumor stage. However, it is possible that risk of lymphoma may be related to increased LHR activation following gonadectomy.
... in the United States to decrease problems with overpopulation and is required by law before adoption in some states.46 Gonadectomy also eliminates the potential for reproductive tract diseases and decreases the incidence of hormone-associated diseases, such as mammary tumors in female dogs and sexually dimorphic (mounting, marking, roaming) behaviors in males.[47][48][49][50] Recently, however, multiple studies have suggested that loss of gonadal hormones is associated with increased incidence of several diseases. ...
Objective
To determine the effect of sex and neuter status on trauma survival in dogs.
Design
Multi‐institutional prospective case series, September 2013 to March 2019, retrospectively analyzed.
Setting
Level I and II Veterinary Trauma Centers.
Animals
Consecutive sample of 2649 dogs in the American College of Veterinary Emergency and Critical Care Veterinary Committee on Trauma patient registry meeting inclusion criteria. For inclusion, dogs had to have complete data entries, be postpubertal (≥7 months age in females and ≥10 months age in males), and have sustained moderate to severe trauma (animal trauma triage [ATT] score ≥5/18). Dogs that were dead upon arrival, euthanized for financial or unknown reasons alone, or that were presented by a Good Samaritan but subsequently humanely euthanized were excluded.
Measurements and Main Results
Data collected included age, sex, neuter status (intact, neutered), trauma type (blunt, penetrating, both), outcome (survived to hospital discharge, died, euthanized), and reason for euthanasia (grave prognosis, financial reasons, or both). Of 2649 eligible dogs, 56% survived to hospital discharge (n = 1469). Neutered females had a significantly higher survival rate (58.3% vs 51.3%; P = 0.03) compared to intact females, and neutered males had a significantly higher survival rate (56.6% vs 50.7%; P = 0.04) compared to intact males. There was no significant difference in survival between intact females and intact males (P = 0.87) or between neutered females and neutered males (P = 0.46). Mean cumulative ATT score was higher in intact groups and was found to be a significant predictor of survival (P < 0.01). Based on logistic models, overall odds of survival were 20.7% greater in neutered dogs.
Conclusions
Gonadectomy is associated with lower ATT scores and improved survival after moderate to severe trauma in both female and male dogs.
... Longer walk times also present greater opportunity for dog fights. The role of neutering alone in reducing dog aggression is controversial, with more recent behavioural research suggesting the development of aggression is influenced by many other factors including age of neutering and environmental factors (Zink et al., 2014;Farhoody et al., 2018;McGreevy et al., 2018;Feltes et al., 2020); neither of which were assessed in this study. However, neutered dogs more commonly survived to discharge (75.6% vs. 39.1%, ...
Dog-dog and dog-cat attacks can result in severe medical, financial, and emotional injury to pets and owners. The characteristics of dog-dog and dog-cat attack victims, the circumstances surrounding these attacks and the financial burden from veterinary visits is not reported in Australia. Medical records from 459 animals that were presented to the emergency service of four specialty hospitals in Melbourne, Australia in 2018 following a dog attack were assessed via univariate and multivariate methodologies with a retrospective case-control study design. Animals who had been attacked by a dog comprised 2.4% of the overall caseload at these four hospitals. Risk factors identified in dog-dog attack victims for presenting to a veterinary emergency hospital after being attacked were being cross-bred (OR = 1.4, p = 0.014, 95% CI = 1.07 - 1.84) and neutered (OR = 1.4, p = 0.035, 95% CI = 1.03-2.00). Being aged >2-7years was protective (OR = 0.70, p = 0.010, CI = 0.48-0.88). Dogs from houses with a lower Socio-economic Indices for Areas score (SIEFA) were more likely to be attacked at home by a known attacker, compared to those from houses with a higher SIEFA score who were more likely to be attacked in public by a dog unknown to them (p = <0.001). Cats who presented following a dog attack had a 46.3% survival to discharge, compared to 91.8% in dogs (p < 0.001). Final cost of treatment for dogs and cats was similar (median AU 360, respectively). Further research is needed to evaluate the population of dogs and cats attacked by dogs, to inform and direct public education campaigns aimed at reducing their incidence and overall burdens.
... These current results confirmed the absence of this association. However, some published statistics suggest that castration and sterilization increase risk of having MCT, (Kiupel et al., 2005;White et al., 2011;Zink et al., 2014;Mochizuki et al., 2017) underlining a possible role of sex hormones in their oncogenesis. As the reproductive status of the target canine population under study was not identified, the conclusions herein obtained cannot be properly interpreted. ...
Background:
Skin tumors are the most frequently diagnosed lesions, of which 7%-21% are mast cell tumors (MCTs). There is a great effort to identify factors that can influence the prospective course of MCTs. Although, the histological grade is considering an important predictor helping to determine the malignancy and metastatic potential of MCTs.
Aim:
In this study, an epidemiological analysis of risk factors (breed, age, sex, and anatomical site) for dogs having MCTs was evaluated considering the respective MCTs histological grade in comparison to other skin tumors.
Methods:
The study included 244 dogs affected by cutaneous MCTs from a universe of 1,185 dogs diagnosed with skin tumors. A univariable analysis with Fisher exact test was performed to determine the odds ratios (ORs) with 95% confidence intervals (CIs).
Results:
Boxers had a higher predisposition to Patnaik's grade I (OR = 5.9, 95% CI 2.648-13.152) and to Kiupel's low-grade MCTs (OR = 2.6, 95% CI 1.539-4.447). Labrador retrievers (OR = 2.1, 95% CI 1.423-3.184), and pugs (OR = 12.9, 95% CI 2.336-70.931) had a predisposition for Patnaik's grade II MCTs and Kiupel's low-grade lesions (OR = 2.3, 95% CI 1.478-3.597; OR = 17.1, 95% CI 3.093-94.377, respectively). French bulldogs had a higher risk to grade III MCTs (OR = 7.9, 95% CI 2.381-26.072). Pit bulls had a predisposition to grade III MCTs and Kiupel's high-grade tumors (OR = 4.4, 95% CI 1.221-16.1 and OR = 4.962, 95% CI 1.362-18.077, respectively). Bull terriers (OR = 12.7, 95% CI 2.098-76.818) presented higher risk for having low-grade MCTs. The perigenital area and trunk exhibit a greater risk for high grading lesion (OR = 6.6, 95% CI 2.679-16.334; OR = 1.9, 95% CI 1.028-3.395, respectively) and the limbs had a predisposition to grade II tumor (OR = 1.6, 95% CI 1.134-2.395). A decreased risk of having MCT was seen in older dogs (from 7-10 years to 11-18 years) compared to that in the reference group (4-6 years).
Conclusion:
When comparing to canine skin tumors, this study showed a relationship between MCT histological grading and the risk factors, age, breed, and topography of canine MCTs. The variations noted in the clinical presentation of MCTs amongst predisposed dog breeds reinforces the relevance of the genetic background in MCTs carcinogenesis.
... Within the Mastiff group, Stivason (2015) also found similar results in unpublished data with 33 of the 43 Mastiffs recorded that died of cancer neutered. For further investigation and beyond the focus of this study, White et al., (2011) found that mast cell tumours were prevalent in large and giant breed neutered females as noted by Zink et al., (2014) where the younger the age of neutering, the earlier the diagnosis of Hemangiosarcoma and Lymphoma. Furthermore, Hoffman et al., (2017) found that entire males had a slightly higher life span which was much greater for neutered females with earlier work by Hoffman et al., (2013) suggesting that sterilised dogs were more likely to die of neoplasia than infectious, degenerative or vascular disease. ...
Despite being ranked 33 in Americas most popular breeds (American Kennel Club, 2020), there is a lack of research addressing longevity and death related health problems of Mastiff dog breeds and specifically commonly kept Bull Mastiffs and English Mastiffs. Likely a result of small founder populations and minimal breeding geographical locations, limited genetic variation is found making it important to determine key health concerns which may reduce longevity. The purpose of this study was to report findings from an online global survey of owners of deceased Mastiffs detailing breed, age at death, and if known, cause of death. Owner information was also collected including location by continent and country and the owners breeding or hobbyist experience. A closed-question survey was used via an online network of global Mastiff clubs and associations totalling a useable sample of 1,036 dogs across a range of breeds. Notably, it is reported that age and cause of death varied dependant on breed. Results indicate that the median age of death for all dogs was 8 years with mean age of death in Europe was 7.72 years and 8.17 years in North America with the most common cause of death identified for all dogs as cancer (47%), old age (16%), cardiac problems (8%) and gastric problems including GDV and bloat (7%). The mean age of death for cancer dogs was 7.85 years with 23 types of cancer stated with Osteosarcoma being the most commonly recorded and specifically for neutered animals. As the survey was aimed at hobbyist and registered breeders, study findings contribute to knowledge of Mastiff mortality with the aim of promoting welfare of the breed.
... Sexually intact dogs were less likely to have separation anxiety as compared with neutered dogs, but all data are correlational, not causal (Flannigan and Dodman, 2001;Takeuchi et al., 2001). Dogs gonadectomized at 6 months of age had significantly increased odds of developing fear of storms, separation anxiety, fear of noises, fear of gunfire, timidity, excitability, submissive urination, aggression, hyperactivity, and fear biting (Zink et al., 2014) in a retrospective, correlational study. In our study, castration only showed a preventive effect for aggression toward dogs of the same household, although the sample size is small and the dogs were not yet socially mature at the final owner evaluation. ...
These proceedings contain oral and poster presentations from various experts on animal behaviour and animal welfare in veterinary medicine presented at the conference.
... In een studie van Belanger et al. (2017) waarin 90.000 honden van verschillende rassen werden geobserveerd, werd aangetoond dat gonadectomie een significant hoger risico op de ontwikkeling van osteosarcoom, lymfoom, mastceltumoren en hemangiosarcoom inhield voor beide geslachten. In meerdere rasspecifieke studies bij vizsla's (Zink et al., 2014), golden retrievers en labrador-retrievers (de la Riva et al., 2013;Hart et al., 2014) en Duitse herders (Hart et al., 2016) werd echter aangetoond dat het risico op bepaalde tumoren na castratie afhangt van ras en geslacht. Bij vizsla's werd in een studie van Zink et al. (2014) bijvoorbeeld vastgesteld dat het risico op lymfoom zowel bij de reu als de teef 4,3 keer groter was na gonadectomie dan bij intacte honden. ...
In recent years, gonadectomy in dogs has become the subject of growing criticism. Novel studies have demonstrated that this type of surgery can have negative effects on the dog's health, effects that at first sight cannot be linked to the removal of the gonads or the absence of sex steroids. In this review, the literature on the long term-health effects of gonadectomy in dogs is described. The most important medical indication for ovariectomy in a bitch is lowering the risk of pyometra and mammary tumors, diseases which arc prevalent in intact bitches. Spaying is often done in young bitches because of the protective effect it has on the development of mammary tumors. However, recent research has shown that orthopedical problems and some non-genital tumors are more prevalent in dogs after gonadectomy, especially if spayed before puberty. Results of these studies also show a major impact of the breed of the dog, hence a general advice for the dog population is not feasible. Veterinarians have to evolve towards a patient-specific advice in this matter.
... In een studie van Belanger et al. (2017) waarin 90.000 honden van verschillende rassen werden geobserveerd, werd aangetoond dat gonadectomie een significant hoger risico op de ontwikkeling van osteosarcoom, lymfoom, mastceltumoren en hemangiosarcoom inhield voor beide geslachten. In meerdere rasspecifieke studies bij vizsla's (Zink et al., 2014), golden retrievers en labrador retrievers (de la Riva et al., 2013;Hart et al., 2014) en Duitse herders (Hart et al., 2016) werd echter aangetoond dat het risico op bepaalde tumoren na castratie afhangt van ras en geslacht.Bij vizsla's werd in een studie van Zink et al. (2014) bijvoorbeeld vastgesteld dat het risico op lymfoom zowel bij de reu als de teef 4,3 keer groter was na gonadectomie dan bij intacte honden. Bij labrador retrievers en Duitse herders had gonadectomie in onderzoek van Hart et al. (2014van Hart et al. ( , 2016 echter geen impact op het risico op lymfoom. ...
Argumenten tegen gonadectomie worden steeds vaker gehoord. Nieuwe studies tonen immers aan dat de ingreep voor de hond negatieve gevolgen kan hebben die op het eerste zicht niet rechtstreeks met het weghalen van de gonaden of de geslachtshormonen verband houden. In het voorliggende overzichtsartikel wordt de huidige literatuur over de langetermijngevolgen van gonadectomie op de gezondheid van de hond beschreven. De belangrijkste reden voor het ovariëctomiseren van een teef is de afname van het risico op pyometra en mammatumoren in vergelijking met intacte teven. De beschermende werking tegen mammatumoren is de reden waarom de operatie vaak op jonge leeftijd uitgevoerd wordt. Echter, in recent onderzoek werd aangetoond dat gewrichtsproblemen en bepaalde niet-genitale neoplasieën vaker voorkomen bij honden na gonadectomie, vooral bij prepuberaal geopereerde dieren. De resultaten van deze studies tonen grote rasverschillen aan, waardoor een algemeen advies over gonadectomie voor de hele hondenpopulatie niet realistisch is. De evolutie naar een ‘advies op maat’ dringt zich op.
... Intact dogs seemed to be calmer and less aggressive than neutered ones in certain aspects of behaviors. Flannigan and Dodman [19] and Zink et al. [20] reported that castrated dogs are highly excited and anxious than uncastrated ones. Most surveys and medical records illustrate that neutered dogs show separation anxiety and storms of fear than uncastrated dogs. ...
Objective:
This study was carried out to study the influence of gender, neuter status, and training method on police dog narcotics olfaction performance, behavior, and welfare.
Materials and methods:
A total of 120 German Shepherds aged 1-3 years were used for this study. The dogs were separated into two experiments. The first experiment (32 dogs and 28 bitches) was used to study the influence of gender on olfaction and smell to narcotics in police dog performance and training methods with behavioral problems and welfare. The second experiment (30 dogs and 30 bitches) was used to study the influence of sexual status (entire or neutered) on the smelling of narcotics in police dog performance by comparing with intact dogs and bitches.
Results:
We found that there were significant differences in sex in training to detect narcotics. Male German Shepherds were found to be significantly more trainable than females. Neutering causes a difference in trainability in male and female dogs. Gonadectomy had adverse effects on training. The intact male and female German Shepherds were found to be significantly more trainable than the neutered ones, and the reward-based method was found to be significantly more trainable than punishment. Dog training methods incorporated by punishment result in pain, suffering, emotional instability, symptoms of depression, aggression, unwanted barking, growling at other people, not under control all time, less trainability, increased problematic behavior, and decreased dog welfare.
Conclusion:
Reward-based method is associated with lower lousy behavior and dogs with good behavior, such as, attachment attention behavior, dogs under the control of handler all times, higher trainability, less problematic behavior, and increased dog welfare.
Background
Effects of neutering on bitch health have been reported, and are suggested to relate to bitch age at the time of neutering for some diseases. However, variation between published studies in terms of study populations and methodologies makes comparison and consolidation of the evidence difficult.
Objective
A scoping review was designed to systematically search the available literature to identify and chart the evidence on the effect of neutering timing in relation to puberty on five health outcomes: atopy, developmental orthopaedic disease (DOD), neoplasia, obesity and urogenital disease.
Design
A protocol was registered, and literature searches were conducted in CAB Abstracts, Medline and Web of Science. Studies were reviewed against inclusion criteria. Data on study and population characteristics and health outcomes were charted for the final included studies.
Results
A total of 1,145 publications were reviewed across all five searches; 33 were retained for inclusion and charting. Only six of the 33 studies categorised the timing of surgical neutering as prepubertal or post-pubertal; one investigating mammary neoplasia and the other five, urogenital disease, commonly urinary incontinence. No studies were identified that examined the impacts of neutering bitches before or after puberty on atopy, DOD or obesity. One study considered bitches that were pre or post-pubertal at the time of the first treatment with deslorelin acetate for oestrus suppression and 26 examined the effects on health related to age, rather than pubertal status, at neutering.
Conclusion
This scoping review suggests that robust evidence to support veterinarians, those working with dogs and dog owners when discussing the timing of neutering relative to puberty does not yet exist. The impact of neutering before or after puberty on atopy, DOD, neoplasia, obesity and urogenital disease in female domesticated dogs remains unclear.
OBJECTIVE
To compare health and behavior outcomes for dogs that underwent vasectomy or ovary-sparing spay (hysterectomy) with sexually intact dogs or dogs that had undergone traditional castration or spay.
SAMPLE
6,018 dog owners responded to a web-based survey between November 3, 2021, and January 7, 2022.
PROCEDURES
Participants were asked demographic questions and to provide information about 1 or more dogs (living or deceased). Options for reproductive status were as follows: sexually intact, castrated, spayed (ovariohysterectomy or ovariectomy), vasectomy, or ovary-sparing spay (hysterectomy). Participants were asked questions about orthopedic and other health problems, cancer, and problematic behavior. Logistic regression models, survival analyses, and descriptive statistics were used to assess relationships between reproductive status and outcomes.
RESULTS
Owners provided valid surveys for 6,018 dogs, including 1,056 sexually intact, 1,672 castrated, and 58 vasectomized male dogs and 792 sexually intact, 2,281 spayed, and 159 female dogs that had undergone ovary-sparing spay. Longer exposure to gonadal hormones, regardless of reproductive status, was associated with reduced odds of general health problems and both problematic and nuisance behaviors.
CLINICAL RELEVANCE
TTo our knowledge, this study provides the first data on health and behavior outcomes of vasectomy and ovary-sparing spay in dogs and is the first to compare these outcomes to sexually intact and gonadectomized dogs. It adds to accumulating data on the mixed benefits and risks of removing the gonads to prevent reproduction and emphasizes the importance of developing an informed, case-by-case assessment of each patient, taking into consideration the potential risks and benefits of spaying or neutering and alternative reproductive surgeries.
Removal of the gonads with surgical sterilization results in a loss of negative feedback to the hypothalamus and anterior pituitary. The sustained supraphysiologic luteinizing hormone (LH) concentrations in gonadectomized dogs can significantly alter organ function and even induce neoplastic changes. For example, gonad removal has a profound effect on thyroid function and is reported to be the most significant cause for the development of hypothyroidism in dogs. Thirty percent more gonadectomized dogs develop hypothyroidism compared with intact dogs. Within the canine thyroid, LH receptors are co-localized with thyroid stimulating hormone (TSH) receptors. Continuous LH receptor activation in gonadectomized dogs may interfere TSH receptor function by consuming second messengers involved in G-protein receptor cell signaling, preventing the action of TSH when it binds to its receptor in the thyroid, resulting in hypothyroidism. The incidence of anterior cruciate ligament ruptures is significantly increased following gonad removal independent of breed, sex, weight or body condition. Luteinizing hormone receptors are expressed in the cruciate ligament and continuous LH receptor activation may increase laxity in these ligaments, resulting in joint instability. Both male and female gonadectomized dogs are at a significantly increased risk for lymphoma and hemangiosarcoma. Luteinizing hormone receptors are also abundant in these tissues. Research in four canine hemangiosarcoma cell lines found that LH receptor activation induces cell proliferation. In addition, research in three canine T-cell lymphoma cell lines found that LH receptor activation induces cell proliferation, adhesion, and invasion as well as increases LH receptor expression. Research is needed to determine if LH reducing strategies using gonadotropin releasing hormone agonists will increase remission times in gonadectomized dogs with LH receptor-positive tumors. In conclusion, among the non-reproductive functions of gonads, suppression of LH secretion and resulting LH receptor overexpression appear necessary in maintaining endocrine, musculoskeletal, and anti-neoplastic health.
Domestic dogs differ enormously in both their morphology and behavior. Numerous factors can influence the development and expression of canine behavior and, more generally, determine the success of the pet–owner relationship. This chapter considers the role of nature and nurture in shaping canine behavior. The influence of factors intrinsic to the animal is outlined, focusing on research that has explored the role of breed, sex, and cerebral lateralization in guiding canine behavior and cognitive functioning. The chapter goes on to consider the role of more extrinsic factors that can influence the development of dog behavior, discussing the contribution of early experience, source of acquisition, training techniques, and owner-related traits including personality and attachment style. The article points to the enormous amount of individual variation that exists between dogs and the myriad of factors that can work together to shape the behavior and functioning of the animal we see before us.
Behavior can change as a result of medical problems or physiological changes, and behavior changes are likely to be the first signs of stress, disease, and poor welfare in any animal. If shelter operations, behavior, and/or medical staff identify behaviors that may have an underlying medical cause, they can be addressed immediately, relieving suffering and increasing the adoptability of the animal. Conversely, if medical conditions that cause or exacerbate problematic behaviors are missed, time may be wasted on training or attempted behavior modification, thus prolonging suffering and time spent in the shelter. Only by safeguarding both physical and emotional health can we improve overall quality of life for animals in our care, facilitate their placement in homes, and help prevent their return to the shelter.
The goal of cancer screening is to detect disease at an early stage when treatment may be more effective. Until recently, cancer screening in dogs has relied upon annual physical examinations and routine laboratory tests, which are largely inadequate for detecting preclinical disease. With the introduction of non-invasive liquid biopsy cancer detection methods, the discussion is shifting from How to screen dogs for cancer to When to screen dogs for cancer . To address this question, data from 3,452 cancer-diagnosed subjects were analyzed to determine the age at which dogs of certain breeds and weights are typically diagnosed with cancer. In the study population, the median age at cancer diagnosis was 8.8 years, with males diagnosed at younger ages than females, and spayed/neutered dogs diagnosed at significantly later ages than intact dogs. Overall, weight was inversely correlated with age at cancer diagnosis, and purebred dogs were diagnosed at significantly younger ages than mixed-breed dogs. For breeds with 10 or more subjects, a breed-based median age at diagnosis was calculated. A weight-based linear regression model was developed to predict the median age at diagnosis for breeds represented by fewer than 10 subjects and for mixed-breed dogs. The study findings support a general recommendation to start cancer screening for all dogs at the age of 7, and as early as 4 years of age for breeds with a lower median age at cancer diagnosis, in order to increase the chances of early detection and treatment.
The topic of surgical sterilization in companion animals is evolving. Although early spay and neuter has been advocated to prevent overpopulation of unwanted pets, recent research has focused on the timing of gonadectomy in relation to risk of various neoplasms, orthopedic conditions, and miscellaneous conditions. Many of these studies are breed-specific or draw from large veterinary medical databases, making it difficult to guide recommendations on the timing of sterilization across various breeds and mixed-breeds. This article attempts to synthesize the data and help guide decision making on the type and timing of sterilization procedures performed, including gonad sparing sterilization surgeries.
Canine castration prevents reproduction or unwanted sexual behavior. It can be performed therapeutically for testicular tumors, for population control, or as prevention or adjunct treatment for several androgen-dependent diseases including prostatic disorders, perianal adenomas, and perineal hernia. Laparoscopic castration for dogs has been proved to be efficient in eliminating testicular endocrine function and spermatogenesis in different independent studies. The abdomen is widely clipped and conventionally prepared for laparoscopic surgery. Dog position, cannula placement, pneumoperitoneum pressures, and operating room set up are similar to that of devascularizing castration. Cryptorchid, or undescended, testes are those that have not completed their migration from the retroperitoneal space near the caudal pole of the kidney into the scrotum. A variety of surgical techniques currently exist for treatment of cryptorchid testicles. Surgical complications include infection, hemorrhage, and ecchymosis around the incision sites, swelling, and subcutaneous emphysema. Postoperative recovery should be similar to that of other abdominal surgeries.
Laparoscopic ovariectomy (LapOVE) and ovariohysterectomy (LapOVH) have become two of the most popular, if not the most commonly performed, minimally invasive soft tissue procedures in veterinary medicine in the United States. In women, laparoscopic hysterectomy is the treatment of choice in most cases and has even been shown to have the same efficacy as open surgery in treatment of cervical cancer with fewer postoperative complications. The data on decreased pain perception in patients undergoing LapOVH or LapOVE are clear. There are very few relative contraindications to a LapOVH or LapOVE other than severe cardiopulmonary compromise or known diaphragmatic hernia, which would make carbon dioxide insufflation dangerous. Surgical preparation for any surgical patient begins the night before the procedure with appropriate fasting. Postoperative care for LapOVE and LapOVH include basic pain medication, incision care, and exercise restriction. The instrumentation of hysterectomy is like that of laparoscopic ovariectomy/OHE.
The Can de Palleiro (CP) is an autochthonous canine breed from Galicia (NW Spain). Interestingly, no previous research has been published about the behaviour of this breed. Thus, the aim of the present study was to obtain a deeper understanding of CP behavioural and temperamental traits and detect any potentially problematic behaviour by using the Canine Behavioural Assessment and Research Questionnaire (C-BARQ) and the Socially Acceptable Behaviour (SAB) test. Behavioural information was obtained from 377 dogs—177 CPs and 200 general population (GP) dogs—using the C-BARQ. Additionally, 32 dogs were enrolled to perform the SAB test (19 CPs and 13 GP dogs) in order to directly evaluate their temperament. Our results indicated that CP dogs had a lower tendency to show aggressiveness towards their owners (0.18 times lower, p = 0.033) and less fear of other dogs (by 0.43 times, p = 0.001), as well as higher trainability levels (2.56 times higher, p < 0.001) when compared to GP dogs. CP dogs also had increased odds of showing chasing behaviour (3.81 times higher, p < 0.001). Conversely, CPs had reduced odds of non-social fear, separation-related problems and excitability (by 0.42, 0.35 and 0.48 times, respectively; p < 0.001, p < 0.001 and p = 0.002). The current research represents a starting point for the study of the behaviour of CPs, which appear to be a working breed, with guarding and, especially, herding characteristics.
Long-acting gonadotropin-releasing hormone (GnRH) analogs, which are approved for male dogs and ferrets, have been used off-label to suppress estrus in bitches predisposed to the side effects of spaying. Health data from the past 12 years were evaluated from bitches without progestogen pretreatment that received deslorelin acetate (DA) to suppress estrus for the first time before the age of 4.5 years. The study population included 32 client-owned bitches repeatedly treated with either 4.7 mg or 9.4 mg DA implants for a period of 5.3 ± 3.4 years (range 0.5–11.3 years). Follow-up information concerning immediate side effects of DA occurring within five months after the first DA treatment (n = 23) as well as long-term side effects of sustained gonadal suppression occurring after five months up to three years (n = 2), three years up to five years (n = 2) or more than five years (n = 8) were assessed through a questionnaire. Treatment was considered successful if no major side effects requiring medical treatment occurred, which applied to 26 out of 32 (81 %) bitches. In the six remaining bitches, the following major side effects led to treatment discontinuation: persistent urinary incontinence (n = 1), reoccurring induced heat (n = 1), uterine disease (n = 3) and/or ovarian tumor (n = 3). The bitches recovered completely after surgical spaying and/or DA implant removal. Minor side effects that did not require therapy or affect animal welfare included body weight changes (n = 18), subtle behavioral changes (n = 13), induced heat (n = 12), coat changes (n = 11), pseudocyesis (n = 6), transient urinary incontinence (n = 4), and/or temporary thickening of the uterine wall with little anechogenic content (n = 2). To examine a possible causal relationship between adverse side effects and DA treatment, further studies should compare the frequency of pathologies between groups of GnRH-treated, intact and spayed bitches of similar breeds and ages. Nevertheless, DA application before the age of 4.5 years may be a means of postponing surgical spaying for several years in breeds at high risk for developing urinary incontinence. Before DA is used in bitches, owners should be fully informed regarding possible side effects.
Advice of the French Food Safety Agency on the risk of dog bites and the relevance of breed specific laws made by a subgroup of the Animal Health and Welfare Committee. An evaluation of risk process : identification of the hazard, evaluation of risk i.e emission X expostion and consequences. Advice given on demand of Department of Agriculture related to Laws of 1999, 2007 and 2008 concerning dangerous dogs. Relevance of categorization of dog breeds is discussed as well as the methods of behavioural evaluation.
Reproduction is a risky affair; a lifespan cost of maintaining reproductive capability, and of reproduction itself, has been demonstrated in a wide range of animal species. However, little is understood about the mechanisms underlying this relationship. Most cost-of-reproduction studies simply ask how reproduction influences age at death, but are blind to the subjects' actual causes of death. Lifespan is a composite variable of myriad causes of death and it has not been clear whether the consequences of reproduction or of reproductive capability influence all causes of death equally. To address this gap in understanding, we compared causes of death among over 40,000 sterilized and reproductively intact domestic dogs, Canis lupus familiaris. We found that sterilization was strongly associated with an increase in lifespan, and while it decreased risk of death from some causes, such as infectious disease, it actually increased risk of death from others, such as cancer. These findings suggest that to understand how reproduction affects lifespan, a shift in research focus is needed. Beyond the impact of reproduction on when individuals die, we must investigate its impact on why individuals die, and subsequently must identify the mechanisms by which these causes of death are influenced by the physiology associated with reproductive capability. Such an approach may also clarify the effects of reproduction on lifespan in people.
In contrast to European countries, the overwhelming majority of dogs in the U.S. are neutered (including spaying), usually done before one year of age. Given the importance of gonadal hormones in growth and development, this cultural contrast invites an analysis of the multiple organ systems that may be adversely affected by neutering. Using a single breed-specific dataset, the objective was to examine the variables of gender and age at the time of neutering versus leaving dogs gonadally intact, on all diseases occurring with sufficient frequency for statistical analyses. Given its popularity and vulnerability to various cancers and joint disorders, the Golden Retriever was chosen for this study. Veterinary hospital records of 759 client-owned, intact and neutered female and male dogs, 1-8 years old, were examined for diagnoses of hip dysplasia (HD), cranial cruciate ligament tear (CCL), lymphosarcoma (LSA), hemangiosarcoma (HSA), and mast cell tumor (MCT). Patients were classified as intact, or neutered early (<12 mo) or late (≥12 mo). Statistical analyses involved survival analyses and incidence rate comparisons. Outcomes at the 5 percent level of significance are reported. Of early-neutered males, 10 percent were diagnosed with HD, double the occurrence in intact males. There were no cases of CCL diagnosed in intact males or females, but in early-neutered males and females the occurrences were 5 percent and 8 percent, respectively. Almost 10 percent of early-neutered males were diagnosed with LSA, 3 times more than intact males. The percentage of HSA cases in late-neutered females (about 8 percent) was 4 times more than intact and early-neutered females. There were no cases of MCT in intact females, but the occurrence was nearly 6 percent in late-neutered females. The results have health implications for Golden Retriever companion and service dogs, and for oncologists using dogs as models of cancers that occur in humans.
The most common way of controlling or altering the behaviour of companion animals is through gonadectomy. Information about the behavioural effects of gonadectomy comes from extrapolation of findings from laboratory studies and from surveys of pet owners whose pets were castrated or spayed. The role of the placebo effect in the latter source of information is unknown. With these limitations in mind, both laboratory studies and pet owner surveys have provided information indicating that: (1) it is the sexually dimorphic behavioural patterns that are reduced or eliminated in males by castration; (2) not all males undergo a change in behaviour following castration; (3) experience and age at time of castration does not predict which males will be altered by castration; and (4) there are apparent species-specific differences between dogs and cats with regard to percentage of males showing a behavioural change related to castration.
Estrogen treatment exerts a protective effect on experimental autoimmune encephalomyelitis (EAE) and is under clinical trial for multiple sclerosis therapy. Estrogens have been suspected to protect from CNS autoimmunity through their capacity to exert anti-inflammatory as well as neuroprotective effects. Despite the obvious impacts of estrogens on the pathophysiology of multiple sclerosis and EAE, the dominant cellular target that orchestrates the anti-inflammatory effect of 17β-estradiol (E2) in EAE is still ill defined. Using conditional estrogen receptor (ER) α-deficient mice and bone marrow chimera experiments, we show that expression of ERα is critical in hematopoietic cells but not in endothelial ones to mediate the E2 inhibitory effect on Th1 and Th17 cell priming, resulting in EAE protection. Furthermore, using newly created cell type-specific ERα-deficient mice, we demonstrate that ERα is required in T lymphocytes, but neither in macrophages nor dendritic cells, for E2-mediated inhibition of Th1/Th17 cell differentiation and protection from EAE. Lastly, in absence of ERα in host nonhematopoietic tissues, we further show that ERα signaling in T cells is necessary and sufficient to mediate the inhibitory effect of E2 on EAE development. These data uncover T lymphocytes as a major and nonredundant cellular target responsible for the anti-inflammatory effects of E2 in Th17 cell-driven CNS autoimmunity.
Mammary neoplasms are the most common neoplasm in female dogs. This article describes the embryologic development, normal anatomy, and histology of the canine mammary gland from the onset of first estrous and the changes that occur in the mammary gland during the estrus cycle. The clinical features of canine mammary gland tumors and their relation to prognosis are discussed, including age, hormones, breed, diet, and obesity. Additional clinical prognostic factors including clinical presentation, tumor size, and lymph node status at the time of presentation are discussed in relation to diagnosis and tumor staging. Immunohistochemical evaluation of the cell differentiation markers of the normal and neoplastic canine mammary gland is described and compared with similar studies in humans; the ways these markers may be used to assist with the prognosis of canine mammary neoplasms are discussed.
Aging is associated with a general dysregulation in immune function, commonly referred to as "immune senescence". Several studies have shown that female sex steroids can modulate the immune response. However, the impact of menopause-associated loss of estrogen and progestins on immune senescence remains poorly understood. To help answer this question, we examined the effect of ovariectomy on T-cell homeostasis and function in adult and aged female rhesus macaques. Our data show that in adult female rhesus macaques, ovariectomy increased the frequency of naïve CD4 T cells. In contrast, ovariectomized (ovx) aged female rhesus macaques had increased frequency of terminally differentiated CD4 effector memory T cells and inflammatory cytokine-secreting memory T cells. Moreover, ovariectomy reduced the immune response (T-cell cytokine and IgG production) following vaccination with modified vaccinia ankara in both adult and aged female rhesus macaques compared to ovary-intact age-matched controls. Interestingly, hormone therapy (estradiol alone or in conjunction with progesterone) partially improved the T-cell response to vaccination in aged ovariectomized female rhesus macaques. These data suggest that the loss of ovarian steroids, notably estradiol and progesterone, may contribute to reduced immune function in post-menopausal women and that hormone therapy may improve immune response to vaccination in this growing segment of the population.
The Regional Shelter Relinquishment Study sponsored by the National Council on Pet Population Study and Policy (NCPPSP) is a US research project designed to explore the characteristics of relinquished dogs and cats, their owners, and the reasons for relinquishment. The NCPPSP Regional Shelter Study, which was conducted between February 1995 and April 1996, found that behavioural problems, including aggression toward people or non-human animals, were the most frequently given reasons for canine relinquishment and the second most frequently given reasons for feline relinquishment. No association was found between category of relinquishment (behavioural, mixed, non-behavioural) and gender, number of times mated (males), number of litters (females), purebred status, declaw status, and number of visits to the veterinarian within the past year, for either dogs or cats. Associations were found between category of relinquishment and number of pets in the household, number of pets added to the household, neuter status of female dogs and cats , neuter status of male dogs, training level, age of pet relinquished, length of ownership, and pets acquired from shelters. Associations also were found between the state in which the pet was relinquished and income level of owner.
Pyometra is a common and lethal disease in bitches characterised by uterine bacterial infection leading to subsequent systemic illness. The objectives of the present thesis were to investigate the incidence of the disease in relation to breed and age, to assess bacteriological aspects of pyometra and to evaluate the involvement of endotoxin and prostaglandin F2α in the pathogenesis.
Animal insurance data revealed age- and breed-dependent differences in the incidence of pyometra. On average 23-24% of all bitches studied experienced pyometra before 10 years of age. Data presented in this study indicate that certain breeds have a genetic pre-disposition for pyometra.
Bacteriological genotype examinations showed that pyometra is most likely caused by Escherichia coli clones originating from the normal flora of each dog, i.e. not by clones spreading between animals. The resistance among E. coli isolates from pyometra bitches against antimicrobials commonly used in canine practice was low and not likely to cause therapy failure. Data on antimicrobial resistance of E. coli from urinary tract infections were generally not suitable for selecting antimicrobial treatment of pyometra.
Systemic endotoxemia was confirmed in bitches with pyometra. The plasma levels of endotoxin were correlated with concentrations of the prostaglandin F2α metabolite (PG-metabolite). This indicates the usefulness of PG-metabolite in the diagnosis of endotoxemia in bitches. Bitches with pyometra also had increased blood concentrations of PG-metabolite compared with bitches with cystic endometrial hyperplasia (CEH). The present study revealed that in bitches with fluid in the uterus, the analysis of PG-metabolite in combination with percentage band neutrophils can distinguish between pyometra and CEH. The levels of PG-metabolite are predictive of the severity of pyometra since they were correlated to criteria of a systemic inflammatory response and also to the length of hospitalisation.
In summary, this thesis provides data on breed- and age-related differences in the incidence of pyometra, which will be helpful in future studies of the disease and breeding programmes. In addition, clarification of key bacteriological and pathophysiological characteristics of the development of pyometra can improve diagnostic and therapeutic strategies and increase survival rates.
To identify canine and household characteristics associated with relinquishment of a pet dog to an animal shelter.
Case-control study.
Households that relinquished dogs for adoption (case households) and a random sample of current dog-owning households in the same community (control households).
Potentially modifiable factors that explained the highest proportion of relinquishment were owners not participating in dog obedience classes after acquisition, lack of veterinary care, owning a sexually intact dog, inappropriate care expectations, and dogs having daily or weekly inappropriate elimination. Dogs obtained from shelters, kept in crates, or acquired at > or = 6 months of age were at increased risk of relinquishment. Greater purchase price was associated with decreased risk of relinquishment, but relinquishment was not associated with the degree of planning to acquire the dog. Dogs with behavioral problems and little veterinary care were at greater risk of relinquishment than were dogs with regular veterinary care, and behavioral problems were associated with inappropriate care expectations.
Risk factors identified in this study can be modified by dog owners and veterinarians to decrease the estimated 2 million dogs euthanatized annually in animal shelters. Veterinarians should educate owners about typical dog behavior, routine care requirements and training, and the importance of regular veterinary visits; should incorporate wellness concepts in their practice; and should focus on preventive medicine and behavioral consultation.
To determine whether 9 problem behaviors in adult male dogs were affected by castration and to examine the influence of age and duration of problem behavior on behavioral effects of castration.
Cohort study.
57 male dogs > 2 years old at the time of castration that had > or = 1 of the targeted problem behaviors.
Data were collected by telephone contact with owners to identify dogs that had > or = 1 problem behavior before castration and to estimate the improvement (ie, decrease) in the objectionable behaviors after castration. Problem behaviors of interest included urine marking in the house, mounting, roaming, fear of inanimate stimuli, aggression toward human family members, aggression toward unfamiliar people, aggression toward other dogs in the household, aggression toward unfamiliar dogs, and aggression toward human territorial intruders.
Effects of castration on fear of inanimate stimuli or aggression toward unfamiliar people were not significant. For urine marking, mounting, and roaming, castration resulted in an improvement of > or = 50% in > or = 60% of dogs and an improvement of > or = 90% in 25 to 40% of dogs. For remaining behaviors, castration resulted in an improvement of > or = 50% in < 35% of dogs. Significant correlations were not found between the percentage of improvement and age of the dog or duration of the problem behavior at the time of castration.
Castration was most effective in altering objectionable urine making, mounting, and roaming. With various types of aggressive behavior, including aggression toward human family members, castration may be effective in decreasing aggression in some dogs, but fewer than a third can be expected to have marked improvement. Age of the dog or duration of the problem behavior does not have value in predicting whether castration will have a beneficial effect.
An animal insurance database containing data on over 200,000 dogs was used to study the occurrence of pyometra with respect to breed and age during 1995 and 1996 in Swedish bitches <10 years of age. A total of 1,803 females in 1995 and 1,754 females in 1996 had claims submitted because of pyometra. Thirty breeds with at least 800 bitches insured each year were studied using univariate and multivariate methods. The crude 12-month risk of pyometra for females <10 years of age was 2.0% (95% confidence interval = 1.9-2.1%) in 1995 and 1.9% (1.8-2.0%) in 1996. The occurrence of pyometra differed with age, breed, and geographic location. The risk of developing pyometra was increased (identified using multivariate models) in rough Collies, Rottweilers, Cavalier King Charles Spaniels, Golden Retrievers, Bernese Mountain Dogs, and English Cocker Spaniels compared with baseline (all other breeds, including mixed breed dogs). Breeds with a low risk of developing the disease were Drevers, German Shepherd Dogs, Miniature Dachshunds, Dachshunds (normal size), and Swedish Hounds. Survival rates indicate that on average 23-24% of the bitches in the databases will have experienced pyometra by 10 years of age. In the studied breeds, this proportion ranged between 10 and 54%. Pyometra is a clinically relevant problem in intact bitches, and differences related to breed and age should be taken into account in studies of this disease.
To evaluate the long-term risks and benefits of early-age gonadectomy, compared with traditional-age gonadectomy, among cats adopted from a large animal shelter.
Retrospective cohort study.
1,660 cats.
Cats underwent gonadectomy and were adopted from an animal shelter before 1 year of age; follow-up was available for as long as 11 years after surgery (median follow-up time, 3.9 years). Adopters completed a questionnaire about their cats' behavior and medical history. When possible, the cats' veterinary records were reviewed. Statistical analyses were conducted to identify any associations between the occurrence of 47 medical and behavioral conditions and the cats' age at gonadectomy.
Among male cats that underwent early-age gonadectomy (< 5.5 months of age), the occurrence of abscesses, aggression toward veterinarians, sexual behaviors, and urine spraying was decreased, whereas hiding was increased, compared with cats that underwent gonadectomy at an older age. Among male and female cats that underwent early-age gonadectomy, asthma, gingivitis, and hyperactivity were decreased, whereas shyness was increased.
Gonadectomy before 5.5 months of age was not associated with increased rates of death or relinquishment or occurrence of any serious medical or behavioral condition and may provide certain important long-term benefits, especially for male cats. Animal shelters can safely gonadectomize cats at a young age, and veterinarians should consider recommending routine gonadectomy for client-owned cats before the traditional age of 6 to 8 months.
To determine whether exposure to lawn or garden chemicals was associated with an increased risk of transitional cell carcinoma (TCC) of the urinary bladder in Scottish Terriers.
Case-control study.
83 Scottish Terriers with TCC (cases) and 83 Scottish Terriers with other health-related conditions (controls).
Owners of study dogs completed a written questionnaire pertaining to exposure to lawn or garden chemicals during the year prior to diagnosis of TCC for case dogs and during a comparable period for control dogs.
The risk of TCC was significantly increased among dogs exposed to lawns or gardens treated with both herbicides and insecticides (odds ratio [OR], 7.19) or with herbicides alone (OR, 3.62), but not among dogs exposed to lawns or gardens treated with insecticides alone (OR, 1.62), compared with dogs exposed to untreated lawns. Exposure to lawns or gardens treated with phenoxy herbicides (OR, 4.42) was associated with an increased risk of TCC, compared with exposure to untreated lawns or gardens, but exposure to lawns or gardens treated with nonphenoxy herbicides (OR, 3.49) was not significantly associated with risk of TCC.
Results suggest that exposure to lawns or gardens treated with herbicides was associated with an increased risk of TCC in Scottish Terriers. Until additional studies are performed to prove or disprove a cause-and-effect relationship, owners of Scottish Terriers should minimize their dogs' access to lawns or gardens treated with phenoxy herbicides.
To determine whether canine ovariohysterectomy or orchiectomy affects the prevalence of anterior cruciate ligament injury, we compared injury rates of anterior cruciate ligaments of animals that had gonadectomy and animals that were sexually intact as a function of gender, breed, or size. Records of 3218 dogs treated in one orthopaedic veterinary practice during a 2-year period were retrospectively reviewed. Anterior cruciate ligament injury, diagnosed by a history of acute hind limb lameness and by positive anterior drawer test, was confirmed at the time of surgery. The prevalence of anterior cruciate ligament rupture in all dogs was 3.48%. Females that had ovariohysterectomy and males that had orchiectomy had a significantly higher prevalence of anterior cruciate ligament rupture than the sexually intact dogs. Larger dogs had an increased prevalence of anterior cruciate ligament injury compared with smaller or medium-sized dogs, with the increased rupture rates for sterilized animals holding across breeds and sizes. Sterilization of either gender increased the prevalence of anterior cruciate ligament injury, suggesting a potential effect of gonadal gender on prevalence of injury of this ligament.
BACKGROUND
High grade prostatic intraepithelial neoplasia (PIN) is the most likely precursor of human prostate cancer and is commonly found in men undergoing prostatic needle biopsy for suspected cancer. Recent work has demonstrated that pet dogs, like humans, develop PIN spontaneously and in association with prostate cancer. Pet dogs are the most domesticated animal, sharing the habitat and oftentimes the diet of their owners. If PIN and prostate cancer are strongly related to environmental factors, then the prevalence of these findings might differ in a population of dogs such as military working dogs which is not exposed to the habitat and diet of humans. In this study, we determined the prevalence of PIN in prostates of aged military working dogs with and without prostatic adenocarcinoma.
METHODS
Cases were selected from the military working dog slide and tissue archive at the Armed Forces Institute of Pathology, Washington, DC. The most recent 329 necropsies (1991 to 1996) were examined histologically by multiple reviewers; of these, 199 dogs (60%) were found to have evaluable prostatic tissue. In addition, the most recent 50 necropsies (1958 to 1996) with the diagnosis of prostatic cancer were examined, of which 25 cases (50%) were found to have evaluable prostatic adenocarcinoma. In most cases, a single large transverse section of prostatic tissue was available for review. Medical records for each dog were reviewed independently, and age, clinical history, indications for euthanasia, and other health problems were recorded.
RESULTS
High grade PIN was identified in 3% of dogs (6 of 199 dogs) without prostate cancer. A total of 50.8% of dogs in this study group (101 of 199 dogs) were known to be sexually intact, 26.7% of dogs (53 of 199 dogs) were castrated, and the status of the remaining 22.6% of dogs (45 of 199 dogs) was unknown. High grade PIN was present in 18 of 25 dogs (72%) with prostatic adenocarcinoma. Of these cases, 11 dogs (44%) were castrated, 4 dogs (16%) were intact, and the status of 10 dogs (40%) dogs was unknown. Gleason scores ranged from 6 to 10, with a mean of 8.4 and a median of 8.
CONCLUSIONS
High grade PIN is present in a small but substantial number (3%) of military working dogs. Of military working dogs with prostatic adenocarcinoma, 72% had high grade PIN. The true prevalence in each of these cohorts is likely to be higher given the sampling variation inherent in evaluating a single random histologic section. Aged male dogs seem to have substantial clinical utility as an animal model for prostatic carcinogenesis. We recommend that serial sectioning and total embedding of the prostate should be used to more thoroughly characterize premalignant and malignant diseases in aged military working dogs. This method will provide important data to determine whether a model of spontaneous PIN in elderly dogs may have clinical utility in developing strategies directed toward preventing and treating prostate. Prostate 36:189–193, 1998. © 1998 Wiley‐Liss, Inc.
Introduction: The aim of the study was to investigate a diagnostic protocol for patellar luxation (PL) in respect to its usability as a screening method in the framework of breeding programs. Further, the influence of breed, age, body mass, gender and neutering on the prevalence of PL has been investigated. Methods: In a period of 8 years (1996-2004) 432 small and miniature-breed dogs have been examined for patellar luxation. In order to achieve the diagnostic efficiency required for genetic screenings performed in the framework of breeding programs, this examination was based on the concept of a standardized examination protocol that included clinically examination with inspection as well as palpation. The diagnostic criteria were lameness, palpation and evaluation of patellar tracking in standing and recumbent position of the dog with special focus on the presence of any patellofemoral instability. A further diagnostic criterion was the deviation of the tibial tuberosity and any perceivable crepitation of the knee joint during all manipulations performed. The findings of patellar luxation were valuated according to PUTNAM's (1968) graduation. X-rays have not been performed. To find out whether the investigated diagnostic criteria fulfil the demands on consistency and validity needed for screening, diagnostic rank correlation coefficients between the single diagnostic criteria and the final PL-finding have been calculated. The influence of breed, age, body mass, gender and neutering on the occurrence of PL was investigated by calculating odds ratios using a multifactorial logistic regression model. The significance testing of the resulting odds ratios was performed by calculating the corresponding 95 % confidence intervall. Results: In 61.6 % of the examined dogs we found patellar luxation, but only in 15.5 % (right knee) and 12.8 % (left knee) a permanent lameness could be observed; in 3.5 % (right kee) and 4.6 % (left knee) there was an intermittent lameness. Therefore nearly 40 % of the animals with patellar luxation were clinically normal and would not have been detected as carriers of patellar luxation without screening diagnostic. The investigated diagnostic criteria showed significant correlation among each other and with the final PL-finding and therefore proved to be consistent and meaningful with regard to PL- investigation. The parameters "luxation in standing" and "luxation in recumbent position" showed the highest rank-correlation to the final findings. Thus it appears that, in general, this examination protocol is suitable for PL-screenings. The investigation of the influence of the parameters "body mass", "age", "gender" and "neutering" on the occurrence of PL showed that except "gender" all attributes are associated with occurrence of PL. An increase in body mass of 1 kg decreases the odds of suffering from PL to the 0.8fold (p < 0.05), an increase of age of one year increases the odds of suffering from PL to the 1.1fold (p = 0.051). Neutered dogs showed a 3.10fold odds for suffering from PL (p < 0.05). To detect breed predispositions for patellar luxation odds ratios were calculated for each breed that was represented in the study by more than 10 animals, including Jack Russell Terrier, Mops, Papillon, Pekingese, Shih Tzu, Tibet Terrier, West Highland White Terrier, Poodle, Yorkshire Terrier, Malteser and Chihuahua. 2 breeds showed a significantly different outcome with regard to increase of suffering from PL. The Jack Russell Terrier had an odds ratio of 0.31 with corresponding 95 % confidence intervals 0.14 -0.67 and therefore showed a reduced chance of PL compared with all other breeds. On the other hand the Poodles (including the miniature- and toy-variants) with an odds ratio of 5.62 with corresponding 95 % confidence intervals 1.93-16.41 showed a higher chance of PL compared with all other breeds. This result gives some evidence on a genetic background of PL. Nevertheless the genetic basis of PL should be investigated more accurately by family analyses and heritability studies. Conclusions: Referring to the consistency and validity of the diagnostic criteria the diagnostic protocol used in this study seems to be suitable as screening method for PL. As 2 of the investigated breeds showed a significantly higher or lower chance for suffering from PL a genetic background of PL can be postulated. Based on the results of this study it would be highly recommended for breeding associations to introduce screening programs for patellar luxation in small and miniature breed dogs as described in this study in combination with a redefinition of breeding goals aimed at the extreme miniaturization of the affected dog breeds.
A retrospective cross-sectional survey of dog-owning veterinary clients was undertaken in 1996 in the three Canadian provinces of New Brunswick, Nova Scotia, and Prince Edward Island, to generate a population of dogs for future use in a more detailed survey on canine behaviour. The questionnaire was designed to detect which dogs had or had not bitten a person living in the same household, and included both demographic and behaviour questions. Twenty veterinary clinics were enlisted to administer the questionnaire to their clientele. Data was collected on 3226 dogs, a response rate of 81.4%. Dogs were predominantly purebred (60.1%) and neutered (71.6%). The Labrador Retriever was the most commonly reported of 110 breeds. There were slightly more female than male dogs, and significantly more female dogs were neutered (P
A Veterinary Medical Database search from 1982 to 1995 identified 1,383 dogs with tumors of the heart from a total population of 729,265 dogs (0.19% incidence). Hemangiosarcoma (HSA) was the most common cardiac tumor identified. In the subset of dogs with specific histologic diagnoses, the number with HSA was almost 10-fold that of the 2nd most common tumor, aortic body tumor. Primary heart tumors were more common than cardiac metastases. When biologic behavior was noted, most heart tumors were classified as malignant. Cardiac tumors (excluding lymphoma) occurred most often in dogs between the ages of 7 and 15 years. In very old dogs (>15 years), the frequency of cardiac tumors was the same or lower than that of the youngest age group. Tumors occurred with similar frequency in males and females, but the relative risk for spayed females was >4 times that for intact females. For HSA, spayed females had >5 times greater relative risk than did intact females. The risk for castrated males was slightly greater than that for intact males, which had 2.4 times the relative risk of intact females. Thus, neutering appeared to increase the risk of cardiac tumor in both sexes. Intact females were least likely to develop a cardiac tumor, whereas spayed females were most likely to develop a tumor. Twelve breeds had greater than average risk of developing a cardiac tumor, whereas 17 had lower risk.
Objective
Estrogens influence many physiologic processes and are also implicated in the development or progression of numerous diseases, including autoimmune disorders. Aberrations of lymphocyte homeostasis that lead to the production of multiple pathogenic autoantibodies, including autoantibodies specific to estrogen receptor (ER), have been detected in the peripheral blood of patients with systemic lupus erythematosus (SLE). This study was undertaken to assess the presence of both anti-ERα and anti-ERβ antibodies in sera from patients with SLE, to analyze the effect of these antibodies on peripheral blood T lymphocyte homeostasis, and to evaluate their role as determinants of disease pathogenesis and progression.Methods
Anti-ER antibody serum immunoreactivity was analyzed by enzyme-linked immunosorbent assay in samples from 86 patients with SLE and 95 healthy donors. Phenotypic and functional analyses were performed by flow cytometry and Western blotting.ResultsAnti-ERα antibodies were present in 45% of the patients with SLE, whereas anti-ERβ antibodies were undetectable. In healthy donors, anti-ERα antibodies induced cell activation and consequent apoptotic cell death in resting lymphocytes as well as proliferation of anti-CD3–stimulated T lymphocytes. A significant association between anti-ERα antibody values and clinical parameters, i.e., the SLE Disease Activity Index and arthritis, was found.Conclusion
Our data suggest that anti-ERα autoantibodies interfere with T lymphocyte homeostasis and are significantly associated with lupus disease activity.
ABSTRACTA questionnaire about their dogs' behaviour was administered to the owners of 150 spayed bitches at the time of spaying and again six months later. It was also administered twice with the same time interval to a control group of 150 unspayed bitches, group matched for breed and age. Principal component analysis of the questionnaire responses yielded 13 factors. On two of these factors, ‘indiscriminate appetite’ and ‘dominance aggression towards family members’, the scores of the spayed bitches showed a significant increase compared with their controls. The spayed bitches most likely to show an increase in dominance aggression were puppies under one year, already showing some aggression.
One hundred and fifteen dogs with neoplasms of the lower urinary tract (bladder and/or urethra) were retrospectively evaluated at five referral institutions participating in ongoing studies by the Veterinary Cooperative Oncology Group. Most tumors were malignant (97%) and of epithelial origin (97%). Lower urinary tract tumors were more common in older dogs weighing greater than 10 kg. The following significant (P less than 0.05) statistical associations were found using the University of Guelph hospital population as control; there was no sex predisposition although the female:male ratio was 1.95:1. Neutered dogs were predisposed as were Airedale Terriers, Beagles, and Scottish Terriers, whereas German Shepherds were significantly under-represented among dogs with lower urinary tract tumors. These statistical associations should be interpreted cautiously because of possible demographic differences in hospital populations among the University of Guelph and other cooperating institutions. There were no significant correlations between age, gender, weight, breed, response to therapy, and survival time. Clinical signs were indicative of lower urinary tract disease and included hematuria, stranguria, and pollakiuria. The laboratory data were nonspecific except for urinalysis test results. Hematuria and inflammatory urinary sediments were most commonly reported; neoplastic cells were identified in the urine sediment of 30% of dogs with lower urinary tract tumors. Contrast cystography was a useful noninvasive diagnostic method since 96% of the dogs had a mass or filling defect in the lower urinary tract demonstrated by this technique.(ABSTRACT TRUNCATED AT 250 WORDS)
High grade prostatic intraepithelial neoplasia (PIN) is the most likely precursor of human prostate cancer and is commonly found in men undergoing prostatic needle biopsy for suspected cancer. Recent work has demonstrated that pet dogs, like humans, develop PIN spontaneously and in association with prostate cancer. Pet dogs are the most domesticated animal, sharing the habitat and oftentimes the diet of their owners. If PIN and prostate cancer are strongly related to environmental factors, then the prevalence of these findings might differ in a population of dogs such as military working dogs which is not exposed to the habitat and diet of humans. In this study, we determined the prevalence of PIN in prostates of aged military working dogs with and without prostatic adenocarcinoma.
General Considerations Descriptions of Mammary Tumors
A commonly-stated advantage of neutering bitches is a significant reduction in the risk of mammary tumours, however the evidence for this has not previously been assessed by systematic review. The objectives of this study were to estimate the magnitude and strength of evidence for any effect of neutering, or age of neutering, on the risk of mammary tumours in bitches. A systematic review was conducted based on Cochrane guidelines. Peer-reviewed analytic journal articles in English were eligible and were assessed for risk of bias by two reviewers independently. Of 11,149 search results, 13 reports in English-language peer-reviewed journals addressed the association between neutering/age at neutering and mammary tumours. Nine were judged to have a high risk of bias. The remaining four were classified as having a moderate risk of bias. One study found an association between neutering and a reduced risk of mammary tumours. Two studies found no evidence of an association. One reported "some protective effect" of neutering on the risk of mammary tumours, but no numbers were presented. Due to the limited evidence available and the risk of bias in the published results, the evidence that neutering reduces the risk of mammary neoplasia, and the evidence that age at neutering has an effect, are judged to be weak and are not a sound basis for firm recommendations.
Sex hormones play an important role as modulators of the immune system. A growing body of evidence shows reciprocal relationship between sex steroids and the immune system. Since the innate immune response determines the type of adaptive immune response, hormonal effects on the innate immune response may affect subsequent adaptive immunity. The sex steroids estrogens, progesterone and testosterone regulate growth, differentiation, survival and function of many cell types involved in homeostasis and immunity. The presence of sex steroid receptors on immune cells indicates that sex steroids may exert their biological effects by binding to these receptors. Sex steroids and immunity are closely connected, and their mutual regulation is involved in the maintenance of immune balance. Understanding the mechanisms of action of sex steroids on immune cells is important for further progress in the development of novel therapies for chronic diseases associated to immune dysregulation. This review describes the effects of sex steroids on the different immune system cells, and the possible implications of these effects on the incidence of many diseases.
Anecdotal beliefs and limited research suggest variable patterns of mortality in age, size, and breed cohorts of dogs. Detailed knowledge of mortality patterns would facilitate development of tailored health-maintenance practices and contribute to the understanding of the genetic basis of disease.
To describe breed-specific causes of death in all instances of canine mortality recorded in the Veterinary Medical Database (VMDB)(a) between 1984 and 2004. We hypothesized that causes of death, categorized by organ system (OS) or pathophysiologic process (PP), would segregate by age, body mass, and breed.
74,556 dogs from the VMDB for which death was the outcome of the recorded hospital visit.
Retrospective study. Causes of death from abstracted VMDB medical records were categorized by OS and PP and analyzed by age, breed, and breed-standard mass of dog.
Causes of death, categorized by OS or PP, segregated by age, breed, and breed-standard mass. Young dogs died more commonly of gastrointestinal and infectious causes whereas older dogs died of neurologic and neoplastic causes. Increasing age was associated with an increasing risk of death because of cardiovascular, endocrine, and urogenital causes, but not because of hematopoietic or musculoskeletal causes. Dogs of larger breeds died more commonly of musculoskeletal and gastrointestinal causes whereas dogs of smaller breeds died more commonly of endocrine causes.
Not all causes of death contribute equally to mortality within age, size, or breed cohorts. Documented patterns now provide multiple targets for clinical research and intervention.
Invasive bladder cancer results in over 10,000 deaths yearly in the United States alone. More effective therapy for invasive bladder cancer is clearly needed. As new cellular and molecular targets for therapy are identified, relevant animal models are needed to test new therapeutic strategies aimed at these targets prior to human clinical trials. The purpose of this review is to characterize spontaneous invasive transitional cell carcinoma of the urinary bladder (TCC) in dogs, to summarize the similarities and differences between canine and human invasive TCC, and to describe how canine TCC could serve as a relevant model of human invasive bladder cancer. Information was summarized from 102 dogs with TCC evaluated and treated at the Purdue University Veterinary Teaching Hospital, from a review of the Veterinary Medical Data Base, and from reports in the literature. Canine TCC was found to be very similar to human invasive bladder cancer in histopathologic characteristics, molecular features, biological behavior including metastasis, response to medical therapy, and prognosis. Differences between canine and human TCC were few, but included gender predilection with a male:female ratio of 2.8:1 in humans versus a male:female ratio of 0.5:1 in dogs. The location of the TCC within the bladder also differed: Most canine TCC was trigonal in location, whereas more than 50% of human TCC was in the lateral and posterior walls of the bladder. Considering the great similarity between invasive bladder cancer in humans and dogs, spontaneous canine TCC can be considered a relevant animal model of human invasive bladder cancer.
This study describes the clinical and histopathological findings in dogs with mammary gland tumours, and compares the histopathological and clinical evidence consistent with progression from benign to malignant to human breast cancer epidemiology. Clinical and histopathological data on 90 female dogs with 236 tumours was included. Dogs with malignant tumours were significantly older than dogs with benign tumours (9.5 versus 8.5 years), P = 0.009. Malignant tumours were significantly larger than benign tumours (4.7 versus 2.1 cm), P = 0.0002. Sixty-six percent had more than one tumour, and evidence of histological progression was noted with increasing tumour size. Dogs with malignant tumours were significantly more likely to develop new primary tumours than dogs with benign tumours, P = 0.015. These findings suggest that canine mammary tumours progress from benign to malignant; malignant tumours may be the end stage of a histological continuum with clinical and histopathological similarities to human breast carcinogenesis.
Androgens have been used in the treatment of bone marrow failure syndromes without a clear understanding of their mechanism of action. Blood counts of patients with dyskeratosis congenita or aplastic anemia with mutations in telomerase genes can improve with androgen therapy. Here we observed that exposure in vitro of normal peripheral blood lymphocytes and human bone marrow-derived CD34(+) cells to androgens increased telomerase activity, coincident with higher TERT mRNA levels. Cells from patients who were heterozygous for telomerase mutations had low baseline telomerase activity, which was restored to normal levels by exposure to androgens. Estradiol had an effect similar to androgens on TERT gene expression and telomerase enzymatic activity. Tamoxifen abolished the effects of both estradiol and androgens on telomerase function, and letrozole, an aromatase inhibitor, blocked androgen effects on telomerase activity. Conversely, flutamide, an androgen receptor antagonist, did not affect androgen stimulation of telomerase. Down-regulation by siRNA of estrogen receptor-alpha (ER alpha), but not ER beta, inhibited estrogen-stimulated telomerase function. Our results provide a mechanism for androgen therapy in bone marrow failure: androgens appear to regulate telomerase expression and activity mainly by aromatization and through ER alpha. These findings have potential implications for the choice of current androgenic compounds and the development of future agents for clinical use.
The purpose of this study was to characterize canine prostate cancer using immunohistochemical staining specific for acinar and urothelial/ductal tissue and correlate these results with the dogs' castration status/castration time. Seventy dogs with prostate cancer were included, 71% were castrated and 29% were intact. Compared with an age-matched control population, castrated dogs were at increased risk of prostate cancer, odds ratio 3.9. Immunohistochemical staining was performed on 58 cases. Forty-six of the 58 stained positive for cytokeratin 7 (CK 7) (ductal/urothelial origin) and one of the 58 stained positive for prostate-specific antigen. Dogs with CK 7-positive tumours were younger when castrated than dogs with CK 7-negative tumours, 2 versus 7 years (P = 0.03); dogs castrated at <or=2 years of age were more likely to be CK 7-positive (P = 0.009). These results show that most canine prostatic carcinomas are of ductal/urothelial, androgen-independent origin. This is consistent with the epidemiological findings, showing increased risk in castrated dogs. Canine prostate cancer may, therefore, not be a realistic model for the human disease.
In a retrospective study involving 42 dogs, it was concluded that the objectionable male behavioral patterns of roaming, fighting with other males, urine marking in the house, and mounting of other dogs or people are amenable to alteration by other castration in adulthood. Roaming was reduced in 90% of the dogs.
The medical records of 31 dogs diagnosed with prostatic carcinoma at the teaching hospital between January 1970 and October 1987 were reviewed to determine whether gender status had an effect on the clinical features or biologic behavior of the disease. The only significant difference between sexually intact and castrated dogs was increased prevalence of pulmonary metastasis in castrated dogs.
Data on age, sex, and breed were obtained from surgical pathologic records of 92 dogs with splenic hemangiosarcoma (SHS) and for 125 dogs with splenic hematoma (SHA) diagnosed in 1985 at the University of Pennsylvania School of Veterinary Medicine. Further information on body weight, clinical and surgical findings, and survival time was obtained for 59 dogs (64.1%) with SHS and 91 dogs (72.8%) with SHA. Splenic hemangiosarcoma was markedly more common in dogs 8 to 13 years old, and SHA was appreciably more common in dogs greater than or equal to 8 years old, compared with dogs 1 to 7 years old. Compared with sexually intact females, only spayed females were at significantly (odds ratio [or], 2.2; 95% confidence interval [CI], 1.2 to 4.1) increased risk for developing SHS; sex predisposition was not found for dogs with SHA. The German Shepherd Dog was the only breed with increased risk for development of either SHS (OR, 4.7; 95% CI, 2.7 to 7.8) or SHA (OR, 2.8; 95% CI, 1.7 to 4.9), compared with all other purebred dogs. Association of tumor type for 7 commonly reported clinical signs with observance of hemoperitoneum at surgery was determined; anorexia (P = 0.01), collapse (P = 0.01), and hemoperitoneum (P less than 0.001) were significantly more common in dogs with SHS. The median survival time for dogs with SHS was 19 days, compared with 338 days for dogs with SHA (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
Ovariectomy, even when performed at an advanced age, was found to be to some extent protective against mammary tumour development in dogs. Bitches treated with progestins had a slightly higher risk for mammary tumours (all types, benign and malignant) than controls. Progestin treatment did not increase the risk of mammary cancer. Benign tumours in (treated and untreated) dogs appeared earlier than malignant ones. Progestin treatment resulted in earlier appearance of both benign and malignant tumours than in controls. The ratio solitary/multiple mammary tumours was not significantly different between treated and untreated dogs.
As mammary tumours occur frequently in the dog and cat but rarely in other domestic animals, only the tumours of these two species are classified. The epithelial tumours are termed "complex" when they consist of cells resembling both secretory and myoepithelial cells: these tumours are biologically less malignant than tumours of the "simple" type in which only one of these kinds of cell is present. The carcinomas are subdivided into adenocarcinoma, solid carcinoma, spindle cell carcinoma, anaplastic carcinoma, squamous cell carcinoma, and mucinous carcinoma. The term "carcinosarcoma or malignant mixed tumour" was used only when there were cells morphologically resembling not only one or both of the epithelial components but also connective tissue cells with their products of differentiation. The benign tumours are classed as adenoma, papilloma, fibroadenoma, or benign soft tissue tumour. The dysplasias are described under the following headings: cyst, adenosis, regular typical epithelial proliferation in ducts and lobules (epitheliosis), duct ectasia, fibrosclerosis, and lobular hyperplasia.
Data from 10,769 dogs with rupture of the cranial cruciate ligament (CCL) were compared with data from a control population of 591,548 dogs to determine whether age, breed, gender, or body weight was associated with prevalence of CCL rupture. Prevalence of CCL rupture increased as dogs became older, with peak prevalence in dogs 7 to 10 years old. Among breeds represented by > 1,000 individuals, Rottweilers, Newfoundlands, and Staffordshire Terriers had the highest prevalence of CCL rupture, whereas Dachshunds, Basset Hounds, and Old English Sheepdogs had the lowest. Neutered dogs, whether male or female, had a higher prevalence of CCL rupture than did sexually intact dogs. The dog's age at the time of ovariohysterectomy was not associated with prevalence of CCL rupture. Dogs weighing > 22 kg had a higher prevalence of CCL rupture, compared with dogs weighing < 22 kg, and tended to rupture their CCL at a younger age.
High grade prostatic intraepithelial neoplasia (PIN) is the most likely precursor of human prostate cancer and is commonly found in men undergoing prostatic needle biopsy for suspected cancer. Recent work has demonstrated that pet dogs, like humans, develop PIN spontaneously and in association with prostate cancer. Pet dogs are the most domesticated animal, sharing the habitat and oftentimes the diet of their owners. If PIN and prostate cancer are strongly related to environmental factors, then the prevalence of these findings might differ in a population of dogs such as military working dogs which is not exposed to the habitat and diet of humans. In this study, we determined the prevalence of PIN in prostates of aged military working dogs with and without prostatic adenocarcinoma.
Cases were selected from the military working dog slide and tissue archive at the Armed Forces Institute of Pathology, Washington, DC. The most recent 329 necropsies (1991 to 1996) were examined histologically by multiple reviewers; of these, 199 dogs (60%) were found to have evaluable prostatic tissue. In addition, the most recent 50 necropsies (1958 to 1996) with the diagnosis of prostatic cancer were examined, of which 25 cases (50%) were found to have evaluable prostatic adenocarcinoma. In most cases, a single large transverse section of prostatic tissue was available for review. Medical records for each dog were reviewed independently, and age, clinical history, indications for euthanasia, and other health problems were recorded.
High grade PIN was identified in 3% of dogs (6 of 199 dogs) without prostate cancer. A total of 50.8% of dogs in this study group (101 of 199 dogs) were known to be sexually intact, 26.7% of dogs (53 of 199 dogs) were castrated, and the status of the remaining 22.6% of dogs (45 of 199 dogs) was unknown. High grade PIN was present in 18 of 25 dogs (72%) with prostatic adenocarcinoma. Of these cases, 11 dogs (44%) were castrated, 4 dogs (16%) were intact, and the status of 10 dogs (40%) dogs was unknown. Gleason scores ranged from 6 to 10, with a mean of 8.4 and a median of 8.
High grade PIN is present in a small but substantial number (3%) of military working dogs. Of military working dogs with prostatic adenocarcinoma, 72% had high grade PIN. The true prevalence in each of these cohorts is likely to be higher given the sampling variation inherent in evaluating a single random histologic section. Aged male dogs seem to have substantial clinical utility as an animal model for prostatic carcinogenesis. We recommend that serial sectioning and total embedding of the prostate should be used to more thoroughly characterize premalignant and malignant diseases in aged military working dogs. This method will provide important data to determine whether a model of spontaneous PIN in elderly dogs may have clinical utility in developing strategies directed toward preventing and treating prostate.
A case-control study using the Veterinary Medical Data Base (VMDB) was conducted to test the hypothesis that increasing height and increasing weight are important risk factors for osteosarcoma in dogs. The role of other host factors was also explored. The cases comprised 3062 purebred dogs with histologically or radiographically confirmed osteosarcoma admitted to 24 veterinary teaching hospitals in the United States and Canada between 1980 and 1994. The controls were 3959 purebred dogs with other diagnoses obtained randomly by frequency matching to cases for institution and year of diagnosis. The risk of osteosarcoma rose with increasing age, increasing body weight, increasing standard weight and increasing standard height. Compared with the German Shepherd breed, the highest risk of osteosarcomas was found for large and giant breeds, while small breeds had reduced risks. A twofold excess risk was observed among neutered dogs. Adjustment of risk estimates for standard height adjusted for standard weight, and vice versa, showed a stronger and more consistent association of osteosarcoma with increasing height than increasing weight.
A Veterinary Medical Database search from 1982 to 1995 identified 1,383 dogs with tumors of the heart from a total population of 729,265 dogs (0.19% incidence). Hemangiosarcoma (HSA) was the most common cardiac tumor identified. In the subset of dogs with specific histologic diagnoses, the number with HSA was almost 10-fold that of the 2nd most common tumor, aortic body tumor. Primary heart tumors were more common than cardiac metastases. When biologic behavior was noted, most heart tumors were classified as malignant. Cardiac tumors (excluding lymphoma) occurred most often in dogs between the ages of 7 and 15 years. In very old dogs (>15 years), the frequency of cardiac tumors was the same or lower than that of the youngest age group. Tumors occurred with similar frequency in males and females, but the relative risk for spayed females was >4 times that for intact females. For HSA, spayed females had >5 times greater relative risk than did intact females. The risk for castrated males was slightly greater than that for intact males, which had 2.4 times the relative risk of intact females. Thus, neutering appeared to increase the risk of cardiac tumor in both sexes. Intact females were least likely to develop a cardiac tumor, whereas spayed females were most likely to develop a tumor. Twelve breeds had greater than average risk of developing a cardiac tumor, whereas 17 had lower risk.
To describe clinical features of dogs < 2 years old with rupture of the cranial cruciate ligament (CCL) and to evaluate breed, sex, and body weight as risk factors.
Case-control study.
201 dogs < 2 years old with rupture of the CCL and 804 age-matched control dogs.
Medical records were reviewed for breed, sex, and body weight, and results were compared with results of age-matched control dogs.
Breed predisposition was detected for Neapolitan Mastiff, Akita, Saint Bernard, Rottweiler, Mastiff, Newfoundland, Chesapeake Bay Retriever, Labrador Retriever, and American Staffordshire Terrier. Increased risk was detected for neutered males and neutered females, compared with sexually intact males and sexually intact females, respectively. Differences in prevalence of rupture of the CCL were not detected between all males and females, sexually intact males and sexually intact females, or neutered males and neutered females. Body weights of dogs with ruptured CCL were significantly greater than those of control dogs.
Several large breeds of dogs are predisposed to rupture of the CCL at a young age.
Incidence of pyometra observed in our colony-raised beagle dogs over a 12-year period is described. Pyometra was observed in 25 female dogs of more than 4 years old, frequently at 8-11 years, with the average age of onset 9.36 +/- 0.38 years. The incidence of the disease was 15.2% of the female dogs (n = 165) more than 4 years old. Clinical findings useful in the diagnosis of this disease included an excretion of pus from the cervix, rapid increase in leukocyte count, and enlarged uterus as revealed by radiography. The relationships of delivery, estrus cycles to this disease are discussed. Ovariohysterectomy or uterectomy was the only effective method of treatment. In conclusion, the results indicated that pyometra might be an age-related disease because it occurred particularly in aged dogs.
The present retrospective study investigated the frequency of prostate carcinoma (PCA) among prostate abnormalities in dogs and determined whether castration influences the incidence of PCA in dogs. During the years 1993-1998, 15,363 male dogs were admitted to the Utrecht University Clinic of Companion Animals, and of these dogs 225 were diagnosed with prostatic disease. In addition, another 206 male dogs were diagnosed as having prostatic disease based on cytologic examination of aspiration biopsies submitted by referring veterinarians. Benign prostatic hyperplasia was diagnosed in 246 dogs (57.1%), prostatitis in 83 dogs (19.3%), and PCA in 56 dogs (13%). Dogs with PCA were significantly older (mean age=9.9 years) than dogs with other prostatic diseases (mean age=8.4 years). The Bouvier des Flandres breed had an increased risk (odds ratio (OR)=8.44; 95% CI 4.38-16.1) of having PCA. Castration (26/56) increased the risk (OR=4.34; 95% CI 2.48-7.62) of PCA. The mean age at diagnosis of PCA in castrated dogs and in intact male dogs was not significantly different. The interval between castration and onset of prostatic problems was highly variable, suggesting that castration does not initiate the development of PCA in the dog, but it does favour tumor progression.
Although experimental and clinical evidence suggest that endogenous sex hormones influence bone sarcoma genesis, the hypothesis has not been adequately tested in an appropriate animal model. We conducted a historical cohort study of Rottweiler dogs because they frequently undergo elective gonadectomy and spontaneously develop appendicular bone sarcomas, which mimic the biological behavior of the osteosarcomas that affect children and adolescents. Data were collected by questionnaire from owners of 683 Rottweiler dogs living in North America. To determine whether there was an association between endogenous sex hormones and risk of bone sarcoma, relative risk (RR) of incidence rates and hazard ratios for bone sarcoma were calculated for dogs subdivided on the basis of lifetime gonadal hormone exposure. Bone sarcoma was diagnosed in 12.6% of dogs in this cohort during 71,004 dog-months follow-up. Risk for bone sarcoma was significantly influenced by age at gonadectomy. Male and female dogs that underwent gonadectomy before 1 year of age had an approximate one in four lifetime risk for bone sarcoma and were significantly more likely to develop bone sarcoma than dogs that were sexually intact [RR +/-95% CI = 3.8 (1.5-9.2) for males; RR +/-95% CI = 3.1 (1.1-8.3) for females]. Chi(2) test for trend showed a highly significant inverse dose-response relationship between duration of lifetime gonadal exposure and incidence rate of bone sarcoma (P = 0.008 for males, P = 0.006 for females). This association was independent of adult height or body weight. We conclude that the subset of Rottweiler dogs that undergo early gonadectomy represent a unique, highly accessible target population to further study the gene:environment interactions that determine bone sarcoma risk and to test whether interventions can inhibit the spontaneous development of bone sarcoma.
The National Consensus Group recommends that all women with tumors larger than 1 cm be offered chemotherapy regardless of tumor histology of lymph node status. This recommendation is to ensure that everyone at risk for failing, even though the risk may be low in women with relatively small tumors and favorable histology, has a choice and receives the benefit of adjuvant chemotherapy. This type of treatment recommendation may also be made in dogs based on recognized, well-accepted prognostic factors such as tumor size, stage, type, and histologic differentiation. Based on the limited clinical information available in veterinary medicine, the drugs that are effective in human breast cancer, such as cyclophosphamide, 5-fluorouracil, and doxorubicin, may also have a role in the treatment of malignant mammary gland tumors in dogs. Randomized prospective studies are needed, however, to evaluate the efficacy of chemotherapy in dogs with high-risk mammary gland tumors and to determine which drugs and protocols are the most efficacious. Until such studies are performed, the treatment of canine mammary gland tumors will be based on the individual oncologist's understanding of tumor biology, experience, interpretation of the available studies, and a little bit of gut-feeling. Table 2 is a proposal for treatment guidelines for malignant canine mammary gland tumors according to established prognostic factors, results from published veterinary studies, and current recommendations for breast cancer treatment in women.
Drug transporters significantly influence drug pharmacokinetics and pharmacodynamics. P-glycoprotein (P-gp), the product of the MDR1 (ABCB1) gene, is among the most well-characterized drug transporters, particularly in veterinary medicine. A number of clinically relevant, structurally and functionally unrelated drugs are substrates for P-gp. P-gp is expressed by a variety of normal tissues including the intestines, renal tubular cells, brain capillary endothelial cells, biliary canalicular cells, and others, where it functions to actively extrude substrate drugs. In this capacity, P-gp limits oral absorption and central nervous system entry of many substrate drugs. A number of MDR1 polymorphisms have been described in human patients, some of which result in altered drug pharmacokinetics and susceptibility to diseases such as Parkinson's disease, inflammatory bowel disease, refractory seizures, and others. An MDR1 polymorphism in herding breed dogs, including collies and Australian shepherds, has been demonstrated to be the cause of ivermectin sensitivity in these breeds. Recent evidence suggests that this polymorphism, a 4-bp deletion mutation, results in increased susceptibility to the toxicity of several drugs in addition to ivermectin. Furthermore, data in rodent models suggest that P-gp may play an important role in regulating the hypothalamic-pituitary-adrenal axis.
Cases of hemangiosarcoma submitted to the Colorado State University Veterinary Diagnostic Laboratory during a 6-year period were reviewed. Visceral hemangiosarcomas represent less than 2% of canine specimens submitted for histologic examination and nonvisceral hemangiosarcoma less than 1%. Most nonvisceral hemangiosarcomas of dogs occur in skin. Hemangiosarcomas are less common in cats and usually occur in skin. They are also rare in other animal species. Animals with nonvisceral hemangiosarcomas are usually mature; dogs and cats average 10 years of age. The tumors develop in many different locations, and there is no sex predilection. A wide variety of dog breeds are affected, but Italian greyhounds, greyhounds, and whippets are overrepresented. Clinical outcomes of 76 cases of nonvisceral hemangiosarcomas in dogs and cats were obtained from submitting veterinarians. Completeness of excision of a tumor is the most important factor that can be used in predicting clinical outcome for an affected dog or cat. In all cases in which the animals were clinically normal for at least 1 year after surgical removal of a nonvisceral hemangiosarcoma, the margins were reported to be free of neoplastic cells. Degree of differentiation, mitotic rate, size of tumor, and presence or absence of epidermal ulceration, mast cells, or solar elastosis did not correlate with clinical outcome.
Estrogens have been shown to modulate immune responses. Several studies have demonstrated the capacity of T cells, B cells, and monocytes to respond to estrogens and estrogen receptor (ER) expression in these cell types has been reported. However, little is known regarding the relative expression in these cells of ERalpha and the more recently identified ERbeta. In the present study, results of quantitative TaqMan RT-PCR analyses indicate that ERs are differentially expressed in PBMC subsets. CD4+ T cells express relatively high levels of ERalpha mRNA compared with ERbeta, whereas B cells express high levels of ERbeta mRNA but low levels of ERalpha. Peripheral blood CD8+ T cells and monocytes express low but comparable levels of both ERs. This quantitative analysis of ER expression in distinct PBMC subsets may provide a basis for dissecting the mechanisms of immune modulation by estrogens and identifying therapeutic targets for the treatment of inflammatory and immunologic disorders.
To determine incidence, risk factors, and heritability estimates of hind limb lameness caused by hip dysplasia in a birth cohort of Boxers.
1733 Boxers from 325 litters.
Status of Boxers with respect to clinical signs of canine hip dysplasia (cCHD) was registered during an 8-year period. Survival analysis accounted for dogs lost to follow-up. Effective heritability for developing cCHD was estimated by use of a proportional hazard model on the basis of the Weibull distribution. Parametric survival models were developed to identify the influence of potential risk factors.
Cumulative hazard rate for cCHD from 7 weeks to 8 years of age was 8.5%. Dogs that were kept on a floor covered with a slippery material were 1.6 times as likely to develop cCHD, compared with dogs kept on a nonslippery floor. Risk of cCHD doubled in dogs from litters with a high preweaning mortality rate. Dogs that were neutered at 6 months prior to a diagnosis of CHD were 1.5 times as likely to develop cCHD, compared with sexually intact dogs. Dogs >5 years of age were 1.8 times as likely to develop cCHD, compared with younger dogs. Estimated effective heritability of cCHD was 0.11. In terms of the risk of cCHD in progeny, mean estimated breeding value (EBV) of the 10 best and 10 worst sires was -0.32 and 0.42, respectively.
Registration of Boxers that develop cCHD may provide a strategy for disease prevention. In addition to diagnostic evaluation of radiographs, sire EBVs provide useful information for breeding selection decisions.