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Abstract

Despite the long history of purebred dogs and the large number of existing breeds, few studies of canine litter size based upon a large number of breeds exist. Previous studies are either old or include only one or a few selected breeds. The aim of this large-scale retrospective study was to estimate the mean litter size in a large population of purebred dogs and to describe some factors that might influence the litter size. A total of 10,810 litters of 224 breeds registered in the Norwegian Kennel Club from 2006 to 2007 were included in the study. The overall mean litter size at birth was 5.4 (± 0.025). A generalized linear mixed model with a random intercept for breed revealed that the litter size was significantly influenced by the size of the breed, the method of mating and the age of the bitch. A significant interaction between breed size and age was detected, in that the expected number of puppies born decreased more for older bitches of large breeds. Mean litter size increased with breed size, from 3.5 (± 0.04) puppies in miniature breeds to 7.1 (± 0.13) puppies in giant breeds. No effect on litter size was found for the season of birth or the parity of the bitch. The large number of breeds and the detail of the registered information on the litters in this study are unique. In conclusion, the size of the breed, the age of the bitch and the method of mating were found to influence litter size in purebred dogs when controlling for breed, with the size of the breed as the strongest determinant.

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... Litter size was 7.2 ± 3.1 pups and differed depending on parity and age of the dam, with younger bitches and primiparous bitches giving birth to larger litters than older and pluriparous dams. The mean litter size of this study was similar to [20][21][22] or higher than [23][24][25][26] what reported for BMD in the literature. Female fertility is higher at a younger age [5,20,23]. ...
... The mean litter size of this study was similar to [20][21][22] or higher than [23][24][25][26] what reported for BMD in the literature. Female fertility is higher at a younger age [5,20,23]. A possible influence of parity on litter size was previously reported [5,23], although results differ between studies and/or breeds. ...
... Female fertility is higher at a younger age [5,20,23]. A possible influence of parity on litter size was previously reported [5,23], although results differ between studies and/or breeds. Borge et al. [23], for example, found that primiparous bitches produced significantly larger litters. ...
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Background Dystocia is an important limiting factor in animal breeding due to its cost, stress for the mother and risk of death for the neonates. Assessment of incidence and characteristics of dystocia and the inherent risk of Cesarean section are of major importance. The aim of the present study was to evaluate the reproductive performance of Bernese Mountain Dogs in Switzerland, with a particular focus on the prevalence of Cesarean sections due to dystocia, and identification of possible risk factors. Results The investigated population included 401 bitches, 207 sires, and 1127 litters. Litter size was significantly influenced by age and parity of the dam. Incidence of Cesarean section was 30.4%, with 2.0% of procedures being elective. History of previous Cesarean section, age of the dam, and a small litter size significantly influenced the risk for Cesarean section. The stillbirth rate was 12.0%, and the number of stillborn pups was significantly higher for litters delivered by Cesarean sections after birth of the first pup. The inbreeding coefficient had a low to non-significant impact on all reproductive parameters (e.g., litter size, number of stillborn pups). Conclusion The sample of Bernese Mountain Dogs of our study had an increased prevalence of Cesarean sections compared to the literature, and advanced age of the dam, litter size and prior Cesarean sections in the dam’s reproductive history was identified as significantly influencing factors. In order to improve pups’ survival rate, elective Cesarean section may be indicated in bitches that have had a previous Cesarean-section/s, are of advanced age, and/or have a small litter.
... In addition, the bitches had to show one of the following signs: The prepartum temperature drop was more than 20 h ago or/and signs of first stage labor were shown for ≥20 h or the temperature had already normalized without progression to second-stage labor; no signs of second-stage labor, but green vulvar discharge for >2 h; unproductive, weak, infrequent abdominal contractions for >4 h without progression; or no abdominal contractions, although fetal fluids passed more than 3 h ago. As the litter size was quite variable, the PUI group was subdivided into small/normal/large litter size (PUI-S, PUI-N, PUI-L) in relation to the average litter size of the respective breed [74]. Litter size within the breed average ± 1 standard deviation (SD) was considered as normal (PUI-N), whereas less or more than ± 1 SD was assigned to PUI-S or PUI-L, respectively [15][16][17]45,46]. ...
... These obviously functional contractions provided the basis for our assumption that OD is suitable for comparison with PUI. The litter size of all OD bitches was normal compared to the described average litter size of the breed [74]. ...
... The aim of the current research was to contribute to a better understanding of uterine inertia, by comparing PUI to OD data. Due to variable litter size in PUI, PUI-N was compared to OD, with litter size in OD being considered as normal according to earlier literature [45,74]. Datasets were separately evaluated for IP and UP. ...
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An altered oxytocin and progesterone receptor (OXTR and PGR, respectively) expression was postulated in canine uterine inertia (UI), which is the lack of functional myometrial contractions. OXTR and PGR expressions were compared in uterine tissue obtained during C-section due to primary UI (PUI; n = 12) and obstructive dystocia (OD, n = 8). In PUI, the influence of litter size was studied (small/normal/large litter: PUI-S/N/L: n = 5/4/3). Staining intensity in immunohistochemistry was scored for the longitudinal and circular myometrial layer and summarized per dog (IP-Myoscore). Mean P4 did not differ significantly between PUI (n = 9) and OD (n = 7). OXTR and PGR expressions (ratios) were significantly higher in PUI (OXTR: p = 0.0019; PGR: p = 0.0339), also for OXTR in PUI-N versus OD (p = 0.0034). A trend for a higher PGR IP-Myoscore was identified (PUI-N vs. OD, p = 0.0626) as well as an influence of litter size (lowest PGR-Myoscore in PUI-L, p = 0.0391). In conclusion, PUI was not related to higher P4, but potentially increased PGR availability compared to OD. It remains to be clarified whether OXTR is upregulated in PUI due to a counterregulatory mechanism to overcome myometrial quiescence or downregulated in OD due to physiological slow OXTR desensitization associated with an advanced duration of labor. Identified OXTR differences between myometrial layers indicate the need for further research.
... Previous publications indicate that the Bernese mountain dog has a relatively high prevalence of reproductive problems. A high prevalence of dystocia and a small litter size compared to similar sized dogs has been reported [1,2]. According to data from the Norwegian Kennel Club mean litter size at birth was 6.4 ± 0.3 (mean ± SE) in 137 litters during a period of two years, 2006-2007. ...
... According to data from the Norwegian Kennel Club mean litter size at birth was 6.4 ± 0.3 (mean ± SE) in 137 litters during a period of two years, 2006-2007. This was lower than the overall mean value (6.9) for large sized dogs [2]. The Bernese mountain dog was ranked as the breed with the highest prevalence of pyometra in ...
... In order to improve reproductive success and to decrease the frequency of dystocia it is important to identify factors affecting these parameters. Previous studies on different breeds have shown that season of the year, age of the bitch, parity and inbreeding level may affect litter sizes in different breeds of dogs [2,[6][7][8]. Factors that may affect puppy survival at and after birth include dystocia, age of the mother and parity [9]. ...
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Background: Good reproductive performance is fundamental for the development of a breed. Previous studies have indicated that the Bernese mountain dog has a relatively high prevalence of reproductive problems such as a high prevalence of dystocia and a low mean litter size. When reproduction is impaired, selection for other traits, including improved health, will become more difficult. The aim of this study was therefore to evaluate reproductive data and factors affecting these in the Bernese mountain dog. Data collected by the Swedish Sennenhund Club during the years 2010-2020 were evaluated by statistical analyses. Results: Information from 1287 reported matings were included with a total of 614 bitches and 399 sires. For five reported matings that did not result in a litter, there was no information about the male identity. The reported matings resulted in 798 litters (62% whelping rate) from 502 bitches and 314 males. Paternal and maternal age had a significant effect on whelping rate with a negative effect of increasing age (P < 0.01). Median litter size at birth (LSB) was 6.00 (range 0-14) and was significantly affected by both paternal (P = 0.021) and maternal age (P < 0.001). Parity affected litter size at birth with a lower litter size in 4 year old bitches giving birth to their first litter compared to bitches giving birth to their second to fourth litters. Stillbirth occurred in 51.6% of the litters with a total of 15.4% puppies being stillborn. Total puppy mortality, including stillbirth, was 19.1%. The only factor affecting stillbirth was LSB while both LSB and season affected the risk of having post-natal puppy loss in the litter. The total prevalence of caesarean sections (CS) was 33.0%. The risk of CS decreased significantly with increasing parity and increased with increasing age. The risk of CS was significantly higher for litters with 1-2 puppies compared with litters with 3-9 puppies. The coefficient of inbreeding (F) calculated on 5 generations had no effect on any of the outcomes. Conclusions: Parity and maternal age had opposite effects on reproductive outcomes with a positive effect of parity on increasing litter size and decreasing CS rate. The proportion of unsuccessful matings was high with a negative effect of increasing age of both males and females.
... This is particularly true for pedigree bitches, which can be prone to obstetric complications due to the anatomy of their birth canal [6][7][8], as is observed with brachycephalic bitches [9,10]. The combination of female age and body size also affects the potential number of puppies per litter [11,12]. This is an important risk factor, especially for females older than 6 years, for miniature and giant breed females with singleton pregnancies, and giant breed bitches carrying more than 11 fetuses [13,14]. ...
... When considering the influence of maternal factors, one cannot forget to mention their effect on the litter size. The litter size directly affects the safety of puppies during birth and depends on the mother's age, breed, and the breeding method [11,12]. The larger the breed, the more pups a litter would potentially contain (up to 11-12 pups), whereas in small and miniature breeds on average, up to 3-5 pups are more common [11,13,14]. ...
... The litter size directly affects the safety of puppies during birth and depends on the mother's age, breed, and the breeding method [11,12]. The larger the breed, the more pups a litter would potentially contain (up to 11-12 pups), whereas in small and miniature breeds on average, up to 3-5 pups are more common [11,13,14]. ...
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The perinatal period has a critical impact on viability of the newborns. The variety of factors that can potentially affect the health of a litter during pregnancy, birth, and the first weeks of life requires proper attention from both the breeder and the veterinarian. The health status of puppies can be influenced by various maternal factors, including breed characteristics, anatomy, quality of nutrition, delivery assistance, neonatal care, and environmental or infectious agents encountered during pregnancy. Regular examinations and pregnancy monitoring are key tools for early detection of signals that can indicate disorders even before clinical signs occur. Early detection significantly increases the chances of puppies’ survival and proper development. The purpose of the review was to summarize and discuss the complex interactions between all elements that, throughout pregnancy and the first days of life, have a tangible impact on the subsequent fate of the offspring. Many of these components continue to pose challenges in veterinary neonatology; thus, publications presenting the current state of knowledge in this field are in demand.
... Body size has been observed to impact both age at first estrus, ovulation frequency, and parity across dog breeds (Borge et al. 2011). To ascertain whether body size was impacting litter size in this cohort, we regressed litter size against median shoulder height. ...
... Finally, age at time of parturition has been shown to impact litter size (Borge et al. 2011;Mandigers et al. 1994). We regressed litter size against the dog's age at the time of litter recording and did not observe an appreciable correlation between these two factors ( Fig. S1c, P = 0.65). ...
... By using a subset of GRLS participants, we find ourselves in the lucky position of assessing this complex relationship in a natural population with, by definition, minimal variation. We do not observe a significant correlation between litter size and maternal body weight, though this has described by others (Borge et al. 2011). However, litter size trends have historically been documented across, but not within breeds, and it could be possible that body size variation within a breed with an already narrow range of acceptable body size could be insufficient to impact litter size. ...
Article
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Inbreeding depression has been demonstrated to impact vital rates, productivity, and performance in human populations, wild and endangered species, and in recent years, the domestic species. In all cases, standardized, high-quality phenotype data on all individuals are invaluable for longitudinal analyses such as those required to evaluate vital rates of a study cohort. Further, many investigators agree upon the preference for and utility of genomic measures of inbreeding in lieu of pedigree-based estimates of inbreeding. We evaluated the association of measures of reproductive fitness in 93 Golden Retrievers enrolled in the Golden Retriever Lifetime Study with a genomic measurement of inbreeding, FROH. We demonstrate a statistically significant negative correlation between fecundity and FROH. This work sets the stage for larger scale analyses to investigate genomic regions associated with fecundity and other measures of fitness.
... Body size has been observed to impact both age at first estrus, ovulation frequency, and parity across dog breeds (Borge et al, 2011). To ascertain whether body size was impacting litter size in this cohort, we regressed litter size against median shoulder height. ...
... Finally, age at time of parturition has been shown to impact litter size (Borge et al, 2011;Mandigers et al, 1994). We regressed litter size against the dog's age at the time of litter recording and did not observe an appreciable correlation between these two factors (Fig S1c, P=.65). ...
... http://dx.doi.org/10.1101/554592 doi: bioRxiv preprint first posted online Feb. 19, 2019; size and maternal body weight, though this has described by others (Borge et al, 2011). However, litter size trends have historically been documented across, but not within breeds, and it could be possible that body size variation within a breed with an already narrow range of acceptable body size could be insufficient to impact litter size. ...
Preprint
Full-text available
Inbreeding depression has been demonstrated to impact vital rates, productivity, and performance in many domestic species. Many in the field have demonstrated the value of genomic measures of inbreeding compared to pedigree-based estimates of inbreeding; further, standardized, high-quality phenotype data on all individuals is invaluable for longitudinal analyses of a study cohort. We compared measures of reproductive fitness in a small cohort of Golden Retrievers enrolled in the Golden Retriever Lifetime Study (GRLS) to a genomic measurement of inbreeding, FROH. We demonstrate a statistically significant negative correlation between fecundity and FROH. This work sets the stage for larger scale analyses to investigate genomic regions associated with fecundity and other measures of fitness.
... In investigations of the reproductive parameters of the Dogo Argentino breed (Caffaratti et al. 2013), the mean litter size was 8.12 (± 3.44), which was in agreement with the study of Feldman and Nelson (2007), who reported an average of eight to ten pups per litter of large breeds. In the investigations conducted by Borge et al. (2011), the number of pups in miniature breed (below 5 kg) litters reached 3.5 (± 0.04). In the same study, the mean litter size observed in 35 deliveries in Yorkshire terriers was 3.5 (± 0.3) with a minimum of one and maximum of six pups. ...
... In the same study, the mean litter size observed in 35 deliveries in Yorkshire terriers was 3.5 (± 0.3) with a minimum of one and maximum of six pups. The mean number for the breed reported by Borge et al. (2011) was lower than that obtained in the present study, where the mean litter size was 4.1, but the number of observed deliveries was 3.5-fold higher. There was one litter with eight pups (terminated with a caesarean section) and as many as ten litters with seven pups in each. ...
... There was one litter with eight pups (terminated with a caesarean section) and as many as ten litters with seven pups in each. In our previous analysis of 318 Yorkshire terrier litters (1137 pups) (Goleman et al. 2015), the results were similar to those reported by Borge et al. (2011): the mean litter size was 3.58 (± 0.1), but stillborn pups were not included in the analysis. Kelley (2002) reported that the litter size in Yorkshire terrier and Chichuahua breeds ranged from two to five pups, with 80% of the litters having four pups. ...
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The aim of this study was to determine the basic reproductive parameters, i.e., litter size, gestation length, neonatal mortality rate and the type of delivery in Yorkshire terrier dogs, one of the most popular breeds in Poland. We have verified a hypothesis put forward by breeders that larger females have fewer whelping difficulties and produce larger litters and that pregnancies of females having one or two pups last longer. The focus of investigation was reproductive data from 66 Yorkshire terrier females registered in the Lublin Branch of the Polish Kennel Club, an FCI (Federation Cynologique Internationale) member, which whelped 124 litters comprising in total 508 pups from 37 fathers. The data were collected between August 2009 and December 2014. The significance of differences was verified using Mann-Whitney U and Kruskal-Wallis H-tests. The relationships between the recorded dogs’ reproduction traits were estimated by calculation of Spearman’s correlation coefficients with the use of the statistical programmes Statistica and SPSS 20. The investigations have confirmed the hypothesis concerning the larger litter size produced by larger females and the lower incidence of postpartum dystocia; however, the hypothesis of the impact of body weight on the length of pregnancy was rejected. The differences between the body weights of stud females and males reached 125%. The Yorkshire terrier appears to be a good reproductive breed with normal reproductive functions and good reproductive parameters.
... following parturition. It is generally accepted that a significant positive relationship exists between the size of the breed and litter size [67][68][69] . Accordingly, we observed large litters (> 8 puppies) occurring mostly in mediumsized and large breeds. ...
... Therefore, the increased whelping difficulty observed during winter might be more closely related to litter size, rather than seasonality. Nevertheless, several other factors such as age of the bitch, age of the sire, parity, mating method (natural mating or artificial insemination) and breed have also been identified to affect litter size in dogs [68][69][70][71]73,89 . Thus, the interaction between these factors and their influence on ease of whelping requires further research. ...
Article
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For dog breeders, parturition is a critical stage in the reproductive cycle of the dam. Evidence in other mammals suggests that a difficult labour can influence maternal behaviour and offspring viability during the first hours postpartum. However, the effect of whelping difficulty on the onset of maternal behaviour has not yet been investigated in domestic dogs. Here we developed an ease of whelping (EoW) index in dams maintained within a Commercial dog Breeding Establishment (CBE) environment and investigated the relationship between intrinsic and extrinsic factors (breed group according to size/weight, litter size, parity, whelping season and origin of the dam), EoW, early maternal behaviour and puppy perinatal mortality. The behaviour of 30 dams was observed throughout the whelping process, starting 24 h before delivery of the first puppy until birth of the last puppy. Parturition duration, birth interval, and behaviours indicative of distress, restlessness, and general activity were scored and included in a Principal Component Analysis to construct the EoW index. Subsequently, mother–pup interactions and puppy perinatal mortality were recorded during the first 24 and 72 h postpartum respectively. Results showed that EoW was significantly affected by whelping season, litter size and origin of the dam (whether she was born and raised within the CBE or brought in). Furthermore, mothers that experienced more difficult parturitions (higher EoW score) spent more time lying in contact with their puppies during the first 24 h postpartum. Time in contact with puppies was also significantly affected by breed group. Nursing duration was significantly affected by breed group and origin of the dam. Additionally, medium-size breed (10–20 kg) puppies were significantly less likely to experience perinatal mortality than large breeds (> 20 kg). These findings are particularly relevant for the welfare of breeding dams maintained in large-scale CBEs where the staff-to-dog ratio might be insufficient to adequately manage multiple simultaneous parturitions.
... The differences between the age groups were significant (p = 0.03). This finding coincides with previous publications [48,49]. An increase of average litter size with rising body weight in the bitch, as observed in this study (p ≤ 0.001), has also been described by other researchers [49]. ...
... This finding coincides with previous publications [48,49]. An increase of average litter size with rising body weight in the bitch, as observed in this study (p ≤ 0.001), has also been described by other researchers [49]. ...
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Pregnancy and lactation are amongst the most challenging times of a bitch’s life. Most studies focusing on the endocrinological aspect of pregnancy consider only a small number of animals. The aim of this study was to evaluate progesterone (P4) concentrations in a large number of bitches during early, mid and late pregnancy. In total, 126 bitches of various breeds were recruited following a thorough clinical and gynecological examination during estrus. Blood samples were collected three times (T1–T3) during pregnancy or from non-pregnant dogs in diestrus, and P4 was measured via chemiluminescence. At T1 (11–19 days post-ovulation (dpo)), serum P4 concentrations were 30.23 ± 6.65 ng/mL and 28.45 ± 6.26 ng/mL, at T2 (23–32 dpo) they were 22.73 ± 6.27 ng/mL and 22.59 ± 5.77 ng/mL and at T3 (52–60 dpo) they were 6.68 ± 2.18 ng/mL and 3.17 ± 2.26 ng/mL, in pregnant (n = 98) and non-pregnant (n = 23) dogs respectively. The P4 concentrations differed significantly between pregnant and non-pregnant animals at the last examination (p ≤ 0.001). In the context of hypoluteoidism, the gathered data yielded interesting results. Overall, 28 out of 98 pregnant bitches showed a greater decline (>15 ng/mL) in P4 concentrations from early to mid-pregnancy, and 56 bitches showed P4 concentrations lower than deemed adequate (>20 ng/mL at T1 and T2, >5 ng/mL at T3) according to existing recommendations. Despite not being supplemented with P4, none of those animals suffered from abortion or preterm delivery. Considering that supplementation of P4 can entail considerable risks for the bitch and the puppies, more research on P4 concentration patterns, diagnosis of hypoluteoidism and treatment indications and options is indicated.
... As litter size varied in PUI bitches ranging from 2 to 11, the PUI group was divided into three subgroups based on the litter size in relation to the average litter size of the respective breed [36]. Litter size was considered normal (PUIeN), when the number of puppies born was within ±1 standard deviation (SD) of the breed average. ...
... Litter sizes in OD were normal in relation to the average litter size of the respective breed [36]. Bitches in the OD group were in the second stage of labour and still presented strong spontaneous abdominal contractions and strong abdominal straining in response to feathering on digital vaginal stimulation. ...
Article
Prostaglandin (PG) E2 plays a crucial role in the endocrine network of canine parturition and we hypothesized that PGE2, 15-hydroxyprostaglandin dehydrogenase (HPGD) and PG-transporter (PGT) might be involved in the development of primary uterine inertia (PUI). We investigated PTGE synthase (PTGES), PTGE receptors 2/4 (PTGER2/4), HPGD and PGT expression on the mRNA- and protein-level in interplacental (IP) and uteroplacental (UP) tissues of bitches presented with dystocia undergoing emergency caesarean section. Groups were formed retrospectively based on strict criteria: PUI (n = 12; small/normal/large litter - PUI-S/N/L: n = 5/4/3), and obstructive dystocia (OD, n = 8). Respective mRNA expressions (ratio) between PUI and OD in IP and UP, between PUI dogs with different litter sizes, between PUI-N and OD in IP, and overall between IP and UP were compared. PTGES, PTGER2, PTGER4, HPGD and PGT mRNA expressions did not differ significantly between PUI and OD in IP or UP. PUI-N PTGES mRNA expression was higher than PUI-S/L (P = 0.0203/P = 0.0186) and OD (P = 0.0314). Higher PTGES (P = 0.0112) and a tendency for higher PTGER2 (P = 0.059) mRNA-expressions were detected in UP versus IP. Other than hypothesized, we did not find a difference in PGE2 production and signaling between PUI and OD, indicating that altered uterine PTGES, PTGER2, PTGER4, HPGD and PGT expression was likely not causative for PUI. However, higher PTGES expression in PUI-N compared to OD might point to a possible role of PGE2 during the course of parturition. Higher PTGES expression in PUI-N compared to PUI-S/L indicates an influence of litter size, the underlying cause and biological relevance of which remain to be clarified.
... Puppies were classified on the basis of the outcome: healthy (live born and healthy for 7 days after birth, Group 1), dead (live born but death occurring within 7 days after birth, Group 2). The litter size for each breed, in terms of the number of puppies, was compared with reference values [22]. If the litter size in the present study was greater than the reported mean value for the breed (litter size), it was defined as large (L); litters instead characterized by a lower number of puppies, compared with reference values, were defined small (S). ...
... If the litter size in the present study was greater than the reported mean value for the breed (litter size), it was defined as large (L); litters instead characterized by a lower number of puppies, compared with reference values, were defined small (S). As for the breeds not mentioned by Borges et al. [22], the litter size was defined large or small consistently with the live bodyweight of the breed and the criterion of affinity with other breeds belonging to the same morphological group according to the Fédération Cynologique Internationale (http://www.fci.be/en/nomenclature, accessed on 27 March 2021). ...
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Placenta is essential for the development of the fetus, and its impaired function can lead to a negative outcome (i.e., neonatal mortality). In dogs, investigations on placenta histology and neonatal outcome in healthy bitches are lacking, and a contribution is provided in this study to emphasize the use of placenta histology in practice. Fifty-one placentas from 11 litters were collected during cesarean section, classified according to the litter size (large (L) or small (S)) and the outcome, this latter as healthy (Group 1) or dead within 7 days (Group 2). The placenta/puppy weight ratio (PPR) was calculated, and specimens were formalin-fixed and paraffin-wax embedded, and on the resulting histological slides, capillary density (CD) was quantified. Among necrosis, calcification, and intravascular leucocytes, only the presence of multifocal-confluent necrosis (significantly more frequent in Group 2) was associated with a higher risk of death within 7 days (odds ratio = 30.7). Mixed logistic regression ruled out the effect on death both of a bitch and cesarean type (programmed vs. emergency). PPR and CD values were associated with litter size; large litters had lower PPR (p < 0.01) and higher CD (p < 0.05) than small litters. The relationship between PPR and CD was negative and significant (p < 0.01). Necrosis was a frequent finding in canine placentas, but only when multifocal-confluent was it associated with a poor outcome. The litter size influenced PPR (lower in L) and CD (higher in L), and this is likely due to the plasticity of placenta adaptation.
... This is consistent with the strong association of cattle stature with height genetics and uterus gene expression in humans 67 , and with the bidirectional association of endometriosis and diverse psychiatric traits in women 68 . Body and litter sizes are strongly correlated in wolves and dogs, hinting the same genetic network could be involved in determining body, uterus and brain sizes and functions 69,70 . Mendelian Randomization studies in humans show causal relationships between neurobiological and puberty traits, and BMI 71,72 . ...
... Consistent with that, the higher-powered geneset of canine behavioral GWA corrected for body mass showed enrichment for puberty traits and BMI. In humans and wolves/dogs, reproductive traits are also correlated with both external pigmentation and longevity 69,70,73 . Body-wide analysis of gene expression for age of menarche GWA in humans was only significant for five brain tissues, three of which were prioritized in this work: anterior cingulate, hypothalamus and pituitary 72 . ...
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Genetic studies show a general factor associated with all human psychopathology and strongly correlated with personality and intelligence, but its basis is unknown. We performed genome scans of 17 normal and problem behaviors in three multi-breed dog cohorts. 21 of 90 mapped loci were supported for the same, or a related, trait in a second cohort. Several of those loci were also associated with brain structure differences across breeds; and six of the respective top-candidate genes are also associated with human brain structure and function. More broadly, the geneset of canine behavioral scans is supported by enrichment for genes mapped for human behavior, personality, cognition, psychopathology and brain structure. The biology implicated includes, neurogenesis, axon guidance, angiogenesis, brain structure, alternative splicing, disease association, Hox-family transcription factors, and subiculum expression. Because body size and behavior are correlated in dogs, we isolated the effect of body size in the dog mapping and in the comparative human UK Biobank analyses. Our dog findings are consistent with pleiotropy of diverse brain traits with energy metabolism and growth, and suggest behavioral variations often affect neurogenesis. There is support for such pleiotropy in humans and well-powered genetic studies of human psychiatric traits consistently implicate neurogenesis. We propose a genetic network which underlies neuron birth and development throughout life is associated with evolutionary adaptation of behavior and the general psychopathology factor. This understanding has implications for genetic and environmental contributions to psychiatric disease. We discuss how canine translational models can further accelerate the study of psychopathology. Author summary We genetically mapped diverse normal and problem behaviors in dogs. The well-established approach we used is ideally suited for finding variation that is common across dog breeds and for pin-pointing the most likely gene candidates. Our analysis of the genes implicated at 90 genome regions shows they are enriched for i) genes mapped for diverse brain functions and pathologies in humans; ii) genes involved in brain development throughout life; and iii) footprints of evolution in dogs, humans and other animals. We propose that is consistent with evolutionary conservation of the general genetic factor of mental health in humans, which is correlated with personality and intelligence. The implications are that this super-network of genes is preferentially targeted by evolutionary adaptation for behavior and that its dysregulation increases risk of mental health disorders.
... Afterwards, the PUI group was divided into three subgroups based on their litter size relative to the breed average litter size [47]. Normal litter size (PUIeN) was defined, when the number of puppies born was within ±1 standard deviation (SD) of the breed average. ...
... PUI-S stands for small, PUI-N for normal (average) and PUI-L for large litter size. Litter size classification was done according to the average of the breed [47]. Bars denotes the mean and whiskers the standard deviation. ...
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Primary uterine inertia (PUI) is the most common type of dystocia in dogs. We hypothesized that PUI develops because of lower than normal expression of the basic contractile elements in the uterus, i.e., smooth muscle (SM) α- and γ-actin and SM-myosin, and that the expression of these proteins is influenced by the number of fetuses present in utero. Full-thickness inter-placental uterine biopsies were collected during Cesarean sections from dogs with PUI (n = 11) and from bitches with obstructive dystocia (OD) but still presenting strong labor contractions (designated as the control group, n = 7). Relative gene expression was determined by real-time (TaqMan) qPCR, and protein localization by immunohistochemistry. Gene expression between PUI and OD bitches, and between PUI bitches carrying small, large, or average number of fetuses according to their breed, were compared. Uterine SM-γ-actin and SM-myosin mRNA levels were significantly higher in PUI than in OD dogs, while SM-α-actin did not differ. PUI bitches carrying large litters had lower uterine SM-γ-actin gene expression than those with small litters (P = 0.008). Immunostaining for SM-actin isoforms and SM-myosin was present in the myometrium, and localization pattern and staining intensity appeared similar in the PUI and OD groups. All proteins stained in blood vessels, and SM-γ-actin was also present in endometrial luminal and glandular epithelium. In conclusion, higher uterine SM-γ-actin and SM-myosin gene expression in PUI bitches, compared with OD dogs, might be an indication of abnormal progression with labor. Whether this is the cause of PUI due to an intrinsic error of the myometrium not becoming committed to labor, or the consequence of inadequate endocrine or mechanical stimuli, is not clear. Litter size was previously shown to be one of the risk factors for the development of uterine inertia in dogs, and our findings suggest possible differing uterine pathophysiology of PUI with respect to litter size.
... La plupart des chiffres actuellement disponibles ont été obtenus à partir d'un nombre restreint d'élevages (souvent dans un seul et pour une race donnée), à l'étranger et sont pour certains, maintenant anciens. Seules les tailles de portée par race et les taux de mortalité des chiots ont été calculés sur des populations de grande taille, en Australie (500 portées) et en Norvège (10 810 portées) (Borge et al., 2011 ;Gill, 2001). ...
... La prolificité moyenne (nombre moyen de chiots nés totaux par portée) était de 4,8 ± 3,1 chiots. Deux équipes avaient obtenu des prolificités similaires sur 35 et 37 portées de Bulldog : 4,7 et 4,9 chiots nés totaux respectivement (Borge et al. 2011 ;Tønnessen et al. 2012). ...
... The mean litter size found in this study was 3.04 (±1.76 SD), which is not in agreement with Burgess et al. [21], who found an average of 5.8 puppies per litter for English Bulldog bitches. Likewise, Wydooghe et al. [35] recorded a mean of 6.0 puppies for this breed, whereas Borge et al. [36] found an average litter size for the English Bulldog of 5.4 pups (37 litters). In this later study, 8.2% of neonatal pups had a fetal pathology, mainly palatoschisis and anasarcous feti, a figure very similar to the one observed in the present study. ...
... In the present study, bitches with higher body weight had larger litter sizes, which is in line with observations of other researchers [36,41] where it has been documented that litter size is affected by the bitch's weight or size. It has been observed that bitches of medium and large size had more ovulations than those of small size [28], although litter size not necessarily corresponds to the number of corpora lutea due to embryonic mortality [42]. ...
Article
The aim of this study was to evaluate the effect of body weight, oxytocin deposition in the uterus at artificial insemination (AI), vaginal cytology, serum progesterone (P4) concentration at AI, semen volume and total sperm cells per AI on whelping rate and litter size of English Bulldogs bitches following intrauterine surgical semen deposition. Seventy-eight English Bulldog bitches were artificially inseminated via semen infusion (number of sperm cells inseminated 300-2500 × 106) at the uterine body with fresh semen without extender and under general anesthesia. Whelping rate was greater (P < 0.05) in bitches with >23 kg than bitches with <23 kg (83.9 vs 63.8%). Whelping rate was greater (P < 0.01) in bitches with >75% vaginal cornified epithelium at AI (85.1%) than animals with <75% cornified epithelium (51.6%). Whelping rates were influenced (P < 0.01) by the semen volume at AI (54.3% vs 86.1% for bitches receiving <4 mL or >4 mL of semen). Litter size was larger (P < 0.05) in bitches >23 kg than lighter animals (3.72 ± 1.79 and 2.30 ± 1.46 pups per litter, respectively). Litter size was not influenced by sperm concentration, semen volume, vaginal cytology, serum P4 concentration and infusion of oxytocin in the uterus at AI (P > 0.1). The results of this study indicate that increasing body weight of English Bulldog bitches is related to higher whelping rates and larger litter size. Also, >75% of superficial cornified vaginal cells (squamous) at AI and >4 mL semen volume maximize whelping rates in this breed of dogs.
... The following data were drawn from the medical records of each bitch: age at diagnosis; number of aglepristone treatments; intervals between diagnosis and relapse, as well as to first and last litters; number of litters after treatment, and LS. The difference from the expected LS, ΔLS, in each patient was calculated as the difference between the actual and the expected LS for the specific breed [29]. Rates of success, relapse, and pregnancy were calculated for each group as follows: successfully treated/treated bitches, relapsed/treated bitches, and pregnant/mated bitches, respectively, expressed as ratios. ...
... Most bitches were pregnant at the first estrus after treatment and their fertility was successfully preserved for almost two years, allowing breeders to obtain up to three more litters from a female that would otherwise be excluded from reproduction. Moreover, apart from the high pregnancy rate, fertility was preserved as indicated by the maintenance of the expected LS of each breed [29], without a significant change in ΔLS among the four groups. The overall fertility rate after treating pyometra in this study was notably higher than that previously reported by Ros et al. [23] (69%), suggesting that a longer treatment period may allow a more permanent uterine healing. ...
Article
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Cystic endometrial hyperplasia-pyometra complex (CEH/P) is a challenge in canine reproduction. Present study aimed to assess fertility after medical treatment. One-hundred-seventy-four bitches affected by CEH/P received aglepristone on days 1, 2, 8, then every 7 days until blood progesterone < 1.2 ng/mL; cloprostenol was administered on days 3 to 5. Records were grouped according to bodyweight (BW): small (< 10 kg, n = 33), medium (10 ≥ BW < 25 kg, n = 44), large (25 ≥ BW < 40 kg, n = 52), and giant bitches (BW ≥ 40 kg, n = 45). Age; success rate; aglepristone treatments number; relapse, pregnancy rates; diagnosis-relapse, -first, -last litter intervals; litters number after treatment, and LS were analyzed by ANOVA. Overall age was 5.14 ± 1.75 years, without difference among groups. Treatment was 100% successful, without difference in treatments number (4.75 ± 1.18), relapse (15/174, 8.62%) and pregnancy (129/140 litters, 92.14%) rates, intervals diagnosis-relapse (409.63 ± 254.9 days) or -last litter (418.62 ± 129.03 days). The interval diagnosis-first litter was significantly shorter (163.52 ± 51.47 days) and longer (225.17 ± 90.97 days) in small and giant bitches, respectively. Overall, 1.47 ± 0.65 litters were born after treatment. Expected LS was achieved in each group, as shown by ΔLS (actual-expected LS by breed, overall -0.40 ± 1.62) without differences among groups. Concluding, CEH/P affects younger dogs than previously described. Relapses were rarer than previously reported. Medical treatment with aglepristone+cloprostenol is effective and safe, preserving subsequent fertility, as demonstrated by negligible changes in LS.
... Phenotypic reproductive trait data for litter size (number of pups), cesarean rate, stillbirth rate and gestation length across 128 breeds were collected from a variety of breeder's handbook and primary journal articles [31,[37][38][39][40][41][42][43][44][45][46][47] (see also Supplementary File S1). We also included body mass as a control trait. ...
... To identify SNPs that are significantly associated with variation in litter size among breeds, we retrieved litter size data from 10 810 litters of 224 breeds registered in the Norwegian Kennel Club [37]. ...
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Background and objectives: The diversity of eutherian reproductive strategies has led to variation in many traits, such as number of offspring, age of reproductive maturity and gestation length. While reproductive trait variation has been extensively investigated and is well established in mammals, the genetic loci contributing to this variation remain largely unknown. The domestic dog, Canis lupus familiaris is a powerful model for studies of the genetics of inherited disease due to its unique history of domestication. To gain insight into the genetic basis of reproductive traits across domestic dog breeds, we collected phenotypic data for four traits, cesarean section rate, litter size, stillbirth rate and gestation length, from primary literature and breeders' handbooks. Methodology: By matching our phenotypic data to genomic data from the Cornell Veterinary Biobank, we performed genome-wide association analyses for these four reproductive traits, using body mass and kinship among breeds as covariates. Results: We identified 12 genome-wide significant associations between these traits and genetic loci, including variants near CACNA2D3 with gestation length, MSRB3 and MSANTD1 with litter size, SMOC2 with cesarean section rate and UFM1 with stillbirth rate. A few of these loci, such as CACNA2D3 and MSRB3, have been previously implicated in human reproductive pathologies, whereas others have been associated with domestication-related traits, including brachycephaly (SMOC2) and coat curl (KRT71). Conclusions and implications: We hypothesize that the artificial selection that gave rise to dog breeds also influenced the observed variation in their reproductive traits. Overall, our work establishes the domestic dog as a system for studying the genetics of reproductive biology and disease. Lay summary: The genetic contributors to variation in mammalian reproductive traits remain largely unknown. We took advantage of the domestic dog, a powerful model system, to test for associations between genome-wide variants and four reproductive traits (cesarean section rate, litter size, stillbirth rate and gestation length) that vary extensively across breeds. We identified associations at a dozen loci, including ones previously associated with domestication-related traits, suggesting that selection on dog breeds also influenced their reproductive traits.
... The next, now intensively investigated question is that of fertility problems in bitches (lowering of litter size, poor litter viability, stillbirths or cryptorchidism in male pupps) or shortage of male individuals in a litter, and subsequently improper sex ratio and sex difference in a population that could be caused by different environmental and genetic factors, for example inbreeding (Mandigers et al. 1994;Bobic Gavrilovic et al. 2008;Dolf et al. 2008;Gubbels et al. 2009;Borge et al. 2011;Tonnessen et al. 2012;Leroy et al. 2015;Mostert et al. 2015;Sichtar et al. 2016). ...
... Many environmental and genetic factors affect more or less LS and other fertility traits in dogs, but the most important genetic factors are the size of dog breed, its genetic structure and inbreeding level. Borge et al. (2011) found the same mean LS values as in our study for Beagle and GR breeds registered in the Norwegian Kennel Club. However, average LS for LR and GSD breeds was lower than that reported by the cited authors. ...
Article
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The aim of the study was to analyze retrospectively the influence of inbreeding on fertility traits in five dog breeds: German Shepherd dog (GSD), Golden (GR) and Labrador (LR) Retrievers, Beagle and the Tatra Shepherd dog (TSD). The data were 436 litters, with the total of 2560 puppies: 1307 males and 1206 females. The parents of the litters were 163 dogs and 228 bitches. For each litter the litter size, number of male and female puppies, sex ratio, and sex difference were calculated. The fixed effects of breed, of litter birth year and linear regression coefficients on litter and parents’ inbreeding were included in the linear model for litter traits. The correlations between litter traits and litter parents’ inbreeding were also estimated. The average litter size was 5.87 (± 2.53) for all breeds. GSD had the smallest average litter size differences in years and the lowest fluctuations of sex ratio with litter size. In other dog breeds those differences were much bigger. The difference between the number of male and female offspring in a litter depended on the breed. The lowest percentage of inbred parents was found for LR, and the highest for TSD. Mating non-inbred animals, in most cases also unrelated, was frequent in all breeds. The inbreeding level of parents had significant influence on the litter traits only for TSD. For the Beagles low, positive and significant correlation between the number of female offspring in a litter and the dam’s inbreeding level and the sex ratio below 0.5 suggests sex ratio disturbance. The correlation coefficients between litter inbreeding and litter size for majority of examined dog breeds were positive but not significant. The conclusion is that in Poland at first obligatory monitoring of the inbreeding level for all breeds should be applied.
... ii) Average litter size is 7.5 puppies. In a study on Norwegian Kennel Club registrations, mean litter size was 6.9 ± 0.2 for LR (15). In The Seeing Eye breeding program, mean litter size at birth for LR was 6.8 ± 2.3 (16). ...
... Mean litter size varies between breeds, so results will vary by breed. In the Norwegian study, German Shepherd Dogs and Belgian Shepherds (also known as Groenendael) had smaller litter sizes (6.1 ± 0.1 and 6.4 ± 0.4, respectively, and Golden Retrievers had larger litter sizes (7.5 ± 0.2) (15). In The Seeing Eye study, German Shepherd Dogs had a mean litter size of 6.4 ± 2.5 (16). ...
Article
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Currently, demand for US-bred and born detector dogs exceeds available supply, while reliance on foreign-bred sources introduces many unnecessary and unwanted risks. With proper management of a domestic supply line, U.S. breeders can improve both health and behavior by applying scientific principles to breeding and raising of detector dogs. A cooperative national detector dog breeding and development program will mitigate the current shortage of domestic-bred dogs that meet the health and behavior standards required by government, military, and law enforcement agencies. To coordinate such a cooperative, we propose a Detector Dog Center of Excellence (DDCoE) led by representatives of academic canine science programs guided by an advisory board of stakeholders. As a non-governmental organization, the DDCoE will oversee selective breeding of dogs owned by breeders, purchase the resulting puppies, and its members will supervise puppy raising until dogs are of a suitable age to be purchased by government agencies or other working dog organizations. The DDCoE will serve as an approved vendor to facilitate the procurement process. Breeding decisions will be based on proven quantitative genetic methods implemented by a specialized database. A national working dog semen bank will ensure conservation of diverse genetic material and enhance selection response by providing numerous potential sires. As a data collection and genetic evaluation center, the DDCoE will lead research to define quantitative traits involved in odor detection, to understand how these traits develop, and methods to optimize training of dogs endowed with enhanced odor detection ability.
... Although without significance, probably due to small number of transports during the summer (8/43), this study showed that a lower whelping rate may be expected during the hot summer months compared to other seasons. The effect of season on litter size and pregnancy rate has been well established (BORGE et al., 2011). The tendency for seasonal variations in whelping rate was reported for fresh, chilled and frozen thawed semen, with the lowest fertility in July (LINDE-FORSBERG, 2002). ...
Article
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The objectives of this study were to investigate the effect of the dog's age, semen quality, and the duration and season of semen transit on whelping rate and litter size after insemination with transported chilled extended semen. The sperm rich fraction was collected from 43 dogs of 18 breeds, which were presented at the Clinic for chilled semen transport, in the period from 2017 to 2021. Immediately after collection, the total sperm concentration and count, motility, membrane integrity (HOS test), the percentage of live spermatozoa and sperm morphology (eosin nigrosin staining) were evaluated. The sperm rich fraction was centrifuged and diluted with Tris-fructose-citrate extender with the addition of 20% (v/v) egg yolk, then chilled and prepared for shipping. A dose consisted of at least 200x10 6 live, motile, morphologically normal spermatozoa. The data on the dog's age, chilled sperm transit time, the season of transit, and the whelping rate and litter size after insemination were recorded. The whelping rate was 55.8% with a mean (±SEM) litter size of 4.71±0.58 pups. The total number of spermatozoa was higher in artificial insemination (AI) that resulted in whelping compared to unsuccessful AI (P<0.05). No difference was observed for any of other sperm quality parameters tested, such as the dog's age or season of transit regarding whelping rate or litter size. Transit time significantly affected the whelping rate (P<0.01), at (mean±SEM) 21.50±1.28 and 37.00±5.59 h in successful and unsuccessful AI, respectively. In conclusion, analysis of the factors related to the dogs identified total sperm count and transit time as factors that significantly affected whelping rates in bitches inseminated with transported chilled extended semen.
... Data about age and parity were very similar to those previously reported [23]. As expected, in agreement with other authors [31] a significant difference in litter size was observed among the BBSs, with the highest number of puppies in large-sized litters and the smallest in the small-sized, in agreement with Borge et al. [32]. ...
Article
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The Apgar score (AS) represents a key tool for neonate assessment, but the possible breed effect on AS in newborn puppies has never been investigated. Therefore, data from 234 dog litters born by caesarean section, grouped according to breed body size (BBS) (small, medium, large), were evaluated. Live-birth puppies were assessed through AS within 5 min of delivery, and classified in viability classes: 0–3 severely distressed, 4–6 moderately distressed, 7–10 not distressed. Statistical analysis evaluated possible differences of AS and viability class according to BBS, and between BBS and puppies’ mortality. Results showed no differences in the distribution of mortalities among BBSs. However, an effect of BBS on the AS was found, with small-sized puppies being the most represented in the severely distressed class, but having the best survival chance compared to large-sized newborns. Through receiver-operating-characteristics analysis, the AS new cutoff values for survival and for death <24 h and 24 h–7 days of age were identified, and the viability classes were redefined, with a narrower class of moderately distressed puppy specific for each BBS. In conclusion, the refining of the AS in dog species is imperative, with cutoff values and viability classifications that must be adapted to the BBS.
... Sarkar and Biswas (2005) demonstrated in humans that a full moon favored the conception of male offspring; however, Staboulidou et al. (2008) did not find any relation with birth rate or gender. An influence of season at conception failed to be found on litter size in dogs (Borge et al. 2011;Wigham et al. 2017). To the authors' knowledge, the influence of season on offspring sex ratio has not been previously examined. ...
Article
The effect of seasonal variation and lunar cycles on reproductive parameters in dogs is unknown. Lunar cycles have important effects on several biological events. Controversy exists about the influence of lunar cycles on offspring sex ratio. This study examined the sex offspring distribution of 973 puppies (48% females and 52% males) from 150 bitches in Italy between 2015 and 2020. A two-way ANOVA followed by post-hoc t-test (Bonferroni correction) was used to analyze the influence of season and lunar phase on offspring sex ratio at conception. Sex offspring distribution was not affected by season, whereas lunar phase had a significant effect (p< .05). During the new moon, the proportion of male puppies born was significantly lower than during the full moon phase (p < .05). We conclude that season had no effect on sex offspring distribution. The new moon phase at conception appeared to be related to a lower male sex ratio at birth. Further studies assessing additional factors will help provide a better understanding of the lunar cycle differences observed in the sex ratio distribution of dogs.
... Inclusion of body weight in the analysis was performed to account for the significant body weight difference found between the PUI and OD groups (P = 0.017). To investigate if litter size has an effect on uterine physiology and the expression of our target genes, PUI bitches were further sub-grouped according to litter size using breed-specific data from Borge et al. [52], and as described in our previous study [8]. Small litter size (PUI-S) or large litter size (PUI-L) were defined as below the mean -1 standard deviation (SD) or above the mean + 1 SD of the litter size for the breed, respectively. ...
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The underlying functional and molecular changes in canine primary uterine inertia (PUI) are still not clarified. Leptin (Lep) and obesity negatively affect uterine contractility in women, partly mediated by the RhoA/Rho kinase pathway, affecting myometrial calcium sensitization. We hypothesized that increased uterine Lep/Lep receptor (LepR) or decreased RhoA/Rho kinase expression contributes to PUI in dogs, independent of obesity. Dogs presented for dystocia were grouped into PUI (n = 11) or obstructive dystocia (OD, still showing strong labor contractions; n = 7). Interplacental full-thickness uterine biopsies were collected during Cesarean section for relative gene expression (RGE) of RhoA, its effector kinases (ROCK1, ROCK2), Lep and LepR by qPCR. Protein and/or mRNA expression was evaluated by immunohistochemistry and in situ hybridization. RGE was compared between groups by one-way ANOVA using body weight as covariate with statistical significance P < 0.05. Uterine ROCK1 and ROCK2 gene expression was significantly higher in PUI than OD, while RhoA and Lep did not differ. LepR RGE was below the detection limit in 5 PUI and all OD dogs. Litter size had no influence. Lep, LepR, RhoA, ROCK1, ROCK2 protein and/or mRNA were localized in the myometrium and endometrium. Uterine protein expression appeared similar between groups. LepR mRNA signals appeared stronger in PUI than OD. In conclusion, lasting, strong labor contractions in OD resulted in downregulation of uterine ROCK1 and ROCK2, contrasting the higher expression in PUI dogs with insufficient contractions. The Lep-LepR system may affect uterine contractility in non-obese PUI dogs in a paracrine-autocrine manner.
... Inclusion of body weight in the analysis was performed to account for the significant body weight difference found between the PUI and OD groups (P = 0.017). To investigate if litter size has an effect on uterine physiology and the expression of our target genes, PUI bitches were further sub-grouped according to litter size using breed-specific data from Borge et al. [52], and as described in our previous study [8]. Small litter size (PUI-S) or large litter size (PUI-L) were defined as below the mean -1 standard deviation (SD) or above the mean + 1 SD of the litter size for the breed, respectively. ...
... Although domestic dogs are considered non-seasonal breeders, seasonal effects on the reproductive performance of bitches remain contradictory (Wei et al. 2018). Studies failed to demonstrate a season influence on litter size (Borge et al. 2011;Wigham et al. 2017), but, to the authors' knowledge, no influence on growth rate has been previously examined. The aim of the present study was, therefore, to investigate ranges of physiological body weight for LR and the effect of sex, litter size, and photoperiod of birth (long photoperiod vs short photoperiod) on body weight gain during early critical stages of puppy development. ...
Article
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Several studies have recently investigated the birth weight of puppies from different pure-bred dogs. In general, birth weight decreased with litter size but there has been limited investigation into factors influencing growth during early development. The first month of life includes three stages of puppy development: neonatal (0–13 days), transitional (14–20 days), and first week of socialisation period (21–28 days). The aim of this study was to evaluate bodyweight and growth rate of 120 Labrador Retriever (LR) puppies during early development. Puppies from 19 show-line bitches under standardised composition of diet during pregnancy and lactation were involved in this study. Puppies were weighed weekly from birth to 28 days using an electronic digital balance. Relative weight gain (ΔW) was calculated for the neonatal period [ΔW1 = (Wday14-Wday0)/Wday0], transition period [ΔW2 = (Wday21-Wday14)/Wday14] and first week of socialisation period [ΔW2 = (Wday28-Wday21)/Wday21]. The effects of covariates on ΔW were assessed using generalised linear mixed models. Sex and photoperiod had no impact on relative weight gain, whereas litter size had a significant effect at ΔW1 (p
... Different breeds were selected in each group, with larger-size breeds represented in the placebo group. As previously described [36], this difference might have affected the litter size discrepancy between groups, which was significantly greater (p = 0.004) in the placebo than the ADAPTIL ® group. To increase the accuracy of the results, the effect of litter size was integrated as a covariate in the statistical models, since it was an unwanted difference between the groups. ...
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ADAPTIL®, a dog-appeasing pheromone, was shown to modify the dam–puppies’ interactions during the neonatal period but could also influence the weaning period. Fourteen bitch/litter dyads continuously exposed to ADAPTIL® from the third/fourth weeks until the seventh/eighth weeks postpartum were compared to 11 dyads exposed to a placebo. Maternal and puppy behaviours were video-recorded, and at three time points (weeks three/four, weeks five/six and weeks seven/eight) after parturition. The well-being of the puppies and the overall relationship with the bitch were assessed using visual analogue scales (VAS) completed by the caregivers. All mothering behaviours, such as time of contact, licking and the amount of time dedicated to nursing puppies, decreased gradually from weeks three/four to weeks seven/eight. A switch in nursing position was observed over time: the use of the standing position increased compared to the lying position. The treatment had an effect on the nursing position: bitches in the ADAPTIL® group nursed more often in a lying (p = 0.007) or sitting position (p = 0.037), whereas for the placebo group, they favoured the standing position (p = 0.011). Once the puppies became more demanding for suckling, the bitches started showing rejection signs or aggressive growling, with a peak at weeks seven/eight. The pheromone seemed to reduce the intensity of avoidance in bitches exposed to ADAPTIL® at all time points. The score of all events combined as a sign of frustration showed a difference over the full period (p = 0.003), with the placebo group having a significantly higher score. From the caregiver perspective (through the VAS), under ADAPTIL®, the bitches were calmer when puppies tried to suckle (p = 0.001), more tolerant towards pups (p = 0.025), showed a greater motherly attitude (p = 0.016), the puppies cried less when left alone (p < 0.001) and interactions amongst pups were more harmonious (p = 0.055). Under ADAPTIL®, the bitches were less annoyed by the puppies, who seemed to cope better with frustration. The breeders perceived a benefit of the pheromone during the weaning period.
... In terrestrial mammals, there is an inverse relationship between vocalization fundamental frequency (f0) and body size, the larger an animal (and therefore the size of the vocal folds within larynx), the lower the fundamental frequency (f0) it can produce (Fletcher 2004;Taylor et al. 2008;Baotic et al. 2015;Charlton and Reby 2016;Martin et al. 2017). The domestic dog provides a convenient model for studying vocal cues to body size across breeds (Riede and Fitch 1999;Taylor et al. 2008), because over 400 breeds of domestic dogs are currently recognized (Borge et al. 2011;Shearman and Wilton 2011), which differ considerably in body size (Yordy et al. 2020). ...
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In domestic dogs Canis familiaris, vocal traits have been investigated for barks and growls, and the relationship between individual body size and vocal traits investigated for growls, with less corresponding information for whines. In this study, we examined frequency and temporal traits of whines of 20 adult companion dogs (9 males, 11 females), ranging in body weight from 3.5 to 70.0 kg and belonging to 16 breeds. Dog whines (26–71 per individual, 824 in total) were recorded in conditioned begging contexts modeled by dog owners. Whines had three independent fundamental frequencies: the low, the high and the ultra-high that occurred singly as monophonic calls or simultaneously as two-voice biphonic or three-voice polyphonic calls. From the smallest to largest dog, the upper frequency limit varied from 0.24 to 2.13 kHz for the low fundamental frequency, from 2.95 to 10.46 kHz for the high fundamental frequency and from 9.99 to 23.26 kHz for the ultra-high fundamental frequency. Within individuals, the low fundamental frequency was lower in monophonic than in biphonic whines, whereas the high fundamental frequency did not differ between those whine types. All frequency variables of the low, high and ultra-high fundamental frequencies correlated negatively with dog body mass. For duration, no correlation with body mass was found. We discuss potential production mechanisms and sound sources for each fundamental frequency; point to the acoustic similarity between high-frequency dog whines and rodent ultrasonic calls and hypothesize that ultra-high fundamental frequencies function to allow private, “tete-a-tete” communication between members of social groups.
... The average number of puppies/ litter is a bit higher than 3.1-3.6 puppies/litter reported for miniature/small/toy canine breeds [3,4,34]. In the present study, a significant reduction of Apgar score was found for litters of 7 puppies in comparison to all the smaller litters, with an exception for litters composed by only one puppy. ...
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Background: In the dog, the correct management of parturition and the prompt neonatal evaluation and assistance can reduce the perinatal mortality rates that are particularly high in toy breeds. Newborn evaluation and factors addressing prognosis are pivotal to guarantee the correct neonatal assistance. Assessment of the Apgar score with viability classification and birthweight are recognized as predictors for neonatal survival in dogs, but breed-specific data are needed for a more feasible application in the dog species, in which wide differences among breeds are known. The present study aimed therefore to: (a) assess the role of Apgar score and birthweight as predictors for the survival of Chihuahua newborn puppies in the first 24 h of life; (b) to assess a cut-off of the Apgar score and birthweight values that can predict the survival of Chihuahua newborn puppies in the first 24 h after birth; (c) to assess the possible effect played by maternal parity, newborn gender and litter-size on Apgar score in Chihuahua newborn puppies, in order to provide breed-specific data for a better neonatal assistance. Results: Data obtained from 176 normal developed Chihuahua puppies born by elective Caesarean section, showed that 62%, 28% and 10% of puppies were classified in the Apgar score classes 7-10, 4-6 and 0-3, respectively, with survival at 24 h after birth of 97%, 96%, 39%, in the three Apgar classes of viability, respectively. Apgar score was a better predictor for survival at 24 h after birth than birthweight (AUC 0.93, P < 0.0001; AUC 0.69, P < 0.01, respectively). Litter-size of 7 puppies/litter plays a negative effect on Apgar score. Apgar score is a better predictor of survival at 24 h than birthweight, and the best cut-off of Apgar score for survival at 24 h after birth is 4, with 96% sensitivity and 77% specificity. Conclusions: The different proportion of "normal viable" and "less viable" neonates in comparison to other studies highlights that Chihuahua puppies born by elective Caesarean section should be carefully evaluated at birth to provide correct assistance.
... Breed-specific growth patterns might be expected due to huge variations in size and conformation. Even within the same breed large variations in birth weight exist due to the existence of different (1) lines/types but mostly because of the considerable variation in litter size as affected by age and parity of the bitch, time of mating, number of matings, semen quality, or inbreeding levels (Borge, Tonnessen, Nodtvedt, & Indrebo, 2011;Leroy, Phocas, Hedan, Verrier, & Rognon, 2015) which is negatively correlated with birth weight. Total weight of the litter is in average about 13.5% of the bitch weight after parturition irrespective of litter size, so the smaller the litter, the larger the individual pups can be (Mila et al., 2015). ...
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Neonatal mortality in puppies is highly variable, with large scale surveys still reporting average values around 10% –15%. Weight measurement is the simplest way to monitor the development of the puppies, and a weight loss during the first 48 hr has been recognized as one of the factors that puts puppies at a higher risk of neonatal mortality. However, little is known about what constitutes optimum growth up to 3 weeks. In this study, a mathematical formula with the form P = P0 exp (0.13084 x ‐ 0.001616 x2), where P is weight on Day x and P0 is weight on Day 0, obtained by multiple linear regression, is presented and validated with data from 345 puppies belonging to 60 litters of 19 different breeds, from toy to giant size, showing that it appropriately describes maximum puppy growth rate during the neonatal period for all breeds. This formula is in agreement with previous studies and generic recommendations that can be found in the literature on puppy growth from birth to 21 days regarding relative daily weight gain. It can be easily introduced in a spreadsheet or used to build growth charts that can help the breeder or the veterinarian in monitoring and evaluating puppy growth during the neonatal period. Although deviations from the maximum growth rate can now be quantified, there is still a need to determine the limits beyond which supplementary feeding is advised/required. Maximum puppy weight growth rate during the first 3 weeks can be described by an equation of the exponential type.Puppy weight can be predicted with this equation given weight on Day zero (birth day) and age of the puppy This equation is shown to properly describe puppy weight increase, irrespective of birth weight and breed
... Dogs are polytocous animals with overall mean litter size of 5.4 (range 1 -18) (Borge et al., 2011). But in some instances, single fetus pregnancy is observed in bitches termed as "single pup syndrome" (Jackson, Page258 2004) and is considered as high-risk pregnancy. ...
... Mean litter sizes are reported to vary widely for the breeds investigated in our study [10,23,24]. The results of the present analysis, as well as the findings of previous reports, are compared in Table 7. ...
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Weight at birth (bBW) and early weight gain have been linked to the risk of neonatal mortality. Pups are described to be of low bBW if weighing less than one standard deviation (SD) below the mean. Most studies classified breeds according to their expected adult bodyweight. Our aim was to evaluate the breed specificity of these parameters. We assessed the bBW of 213 puppies of Bernese Mountain Dog (BMD), Tibetan Terrier (TT), and Lhasa Apso (LA) breeds, as well as the neonatal growth rate of 133 puppies of BMD and TT. BMD puppies were born relatively smaller than puppies of TT and LA (p ≤ 0.0001) and gained less weight than TT puppies during the first 14 days (p ≤ 0.05). Litter size had a significant impact on bBW and daily gain until the onset of the third week for BMD (p < 0.0001 and p = 0.0005, respectively) and TT (p = 0.0003 and p = 0.0064, respectively). When using bBW means and SD specifically assessed according to breed, 29 out of the 213 neonates of our study were judged as being of low bBW, whereas, when using the classical criteria (based on breed groups), the number of low bBW pups was 160 of 213. These results suggest that evaluations of bBW and neonatal growth should be performed in a breed-specific manner.
... c Multiple regression on 100 breeds with complete data showed that number of registrations is not related to average coefficient of inbreeding, but body size is significantly positively related to inbreeding 1 3 breeds. Specifically, since large breeds have larger litters (Borge et al. 2011), it is likely that fewer females reproduce in large breeds compared to small breeds, leading to reduced female effective population size and increased inbreeding. Sex-specific differences in reproductive behavior, such as polygyny in natural populations or the use of popular sires in domestic animal breeding, lead to differences in sex-specific effective population sizes. ...
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Inbreeding poses a real or potential threat to nearly every species of conservation concern. Inbreeding leads to loss of diversity at the individual level, which can cause inbreeding depression, and at the population level, which can hinder ability to respond to a changing environment. In closed populations such as endangered species and ex situ breeding programs, some degree of inbreeding is inevitable. It is therefore vital to understand how different patterns of breeding and inbreeding can affect fitness in real animals. Domestic dogs provide an excellent model, showing dramatic variation in degree of inbreeding and in lifespan, an important aspect of fitness that is known to be impacted by inbreeding in other species. There is a strong negative correlation between body size and lifespan in dogs, but it is unknown whether the higher rate of aging in large dogs is due to body size per se or some other factor associated with large size. We used dense genome-wide SNP array data to calculate average inbreeding for over 100 dog breeds based on autozygous segment length and found that large breeds tend to have higher coefficients of inbreeding than small breeds. We then used data from the Veterinary medical Database and other published sources to estimate life expectancies for pure and mixed breed dogs. When controlling for size, variation in inbreeding was not associated with life expectancy across breeds. When comparing mixed versus purebred dogs, however, mixed breed dogs lived about 1.2 years longer on average than size-matched purebred dogs. Furthermore, individual pedigree coefficients of inbreeding and lifespans for over 9000 golden retrievers showed that inbreeding does negatively impact lifespan at the individual level. Registration data from the American Kennel Club suggest that the molecular inbreeding patterns observed in purebred dogs result from specific breeding practices and/or founder effects and not the current population size. Our results suggest that recent inbreeding, as reflected in variation within a breed, is more likely to affect fitness than historic inbreeding, as reflected in variation among breeds. Our results also indicate that occasional outcrosses, as in mixed breed dogs, can have a substantial positive effect on fitness.
... In dogs, a relationship between BW and various physiological characteristics, such as lifespan, litter size and heart rate, has been reported (Borge et al., 2011;O'Neill et al., 2013;Hezzell et al., 2013). There is an effect of BW on uterine blood flow in non-pregnant bitches (Freitas et al., 2017). ...
Article
The aim of this study was to compare uterine and umbilical artery blood flow and fetal heart rate (FHR) in small, medium and large body weight (BW) dogs during the second half of pregnancy. Purebred pregnant bitches were assigned to one of the following groups according to their BW: small (S; ≤10 kg), medium (M; 11-25 kg) and large (L; >25-45 kg). Uterine and umbilical Doppler and M-mode ultrasonography was conducted every 10 days from Day 30-60 (Day 0 = first day of gestation). From Day 40, uterine and umbilical artery resistance index (RI) progressively and differentially decreased in the three groups (P < 0.01) being less in L than S bitches (P < 0.01). Litter size but not maternal BW (P > 0.1) affected uterine RI on Days 40 (r = 0.39; P < 0.01) and 50 (r = 0.41; P < 0.01). Conversely, on Day 60, maternal BW (r = 0.61; P < 0.01) had an effect on uterine RI while litter size did not (P > 0.1). Fetal heart rate increased from Day 30-50 and decreased to the time of parturition (P < 0.01) without differences among groups at any time point (P > 0.1). Uterine and umbilical blood flow differentially increased throughout mid- and late-pregnancy in breeds with large and small BW. These differences were affected by litter size on Days 40 and 50, and by maternal BW on Day 60. Conversely, during this same period, FHR did not vary among BW groups. Physiological variations should be considered when gestational ultrasonic examination is interpreted in different BW bitches.
... Litter size in the dog varies with breed, and in some breeds it also varies with age. 47 Consequently, the association between litter size and various analytes ideally should have been investigated for each breed separately, which was not feasible owing to the small number of dogs in each breed group herein. Although all dogs had been regularly dewormed, fecal tests had not been performed, and therefore, the presence of occult intestinal parasitism, potentially contributing to ID, could not have been ruled out. ...
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Background: Hypocobalaminemia, hypofolatemia and iron deficiency are associated with pregnancy-related anemia (PRA) and neonatal survival (NS) in women. Similar associations have not been investigated in pregnant bitches. Objectives: To investigate time course and associations of serum cobalamin, folate and iron status indicators with hematological variables and NS in pregnant bitches. Animals: Forty-eight pregnant bitches. Methods: A prospective cohort study. Pregnancy was confirmed by abdominal ultrasonography twice during mid- and late pregnancy, concurrently with blood sampling. Associations among pregnancy stage, NS and laboratory variables were assessed by generalized estimating equations. Results: Compared with midpregnancy, serum cobalamin (adjusted mean [95% confidence interval, CI]) decreased at late pregnancy (430 pg/mL [394-466] versus 330 pg/mL [303-357], respectively; P < .001), whereas serum folate did not. Every increment of 1 in parity number or litter size corresponded to 28.6 pg/mL (95% CI, 5.6-51.6; P = .02) and 20.3 pg/mL (95% CI, 10.9-29.7; P < .001) decrease in serum cobalamin concentration. Compared with midpregnancy, serum iron (P < .001) and transferrin saturation (P = .01) increased at late pregnancy. The decrease in red blood cell count (P < .001) at late pregnancy was significantly, albeit weakly, correlated with decreasing serum folate concentration (r = 0.33; P = .02). None of the measures was associated with NS. Conclusions and clinical significance: Pregnancy-related anemia was common at late pregnancy. Unlike in women, in pregnant bitches, serum iron and transferrin saturation were increased at late pregnancy. Future studies are warranted to investigate the clinical ramifications of hypocobalaminemia in pregnant bitches and the utility of prophylactic folate administration in mitigating PRA.
... The whole offspring percentage of males in our German Shepherd population was very similar to that observed for several breeds [38], including German Shepherds [38,39]. The average litter size of our dog group was lower than those observed for large breeds [43]; but considering German Shepherds, it was either similar [44] or lower [38,45] than those previously reported. ...
... This was an indication that operating kennels was a sustainable business and possibly a reliable source of income. A higher number of the kennels sourced their parent stock locally with a lesser number their stock from Europe and South Africa though this factor was not significantly associated with adult dog morbidity and mortality as reported earlier in studies by Gill, (2001), Indrebø et al., (2007) and Borge et al., (2011). ...
Article
Kennels provide dogs for security and for companionship; however, management errors can lead to increased susceptibility to infections hence an increase in morbidity and mortality within the populations. A cross-sectional study of 35 kennels was conducted in Nairobi, Kenya to determine the effect management practices have on the occurrence of diseases in kenneled adult dog populations. The management practices examined were hygiene, type of housing, type of beddings, provision of heat, food types, provision of veterinary services, deworming practices, ectoparasite control methods, quarantine and euthanasia protocols and methods for diagnosis of diseases. Food types (P=0.006) and ectoparasite control methods (P=0.008) were found to be the strongest independent management factors for morbidity and mortality of the kenneled adult dog population respectively. These management risk factors should be considered by kennel owners when developing disease management programs for their dogs to easily alleviate avoidable morbidities and mortalities.
... Finally, there was no evidence of regular seasonal variations in litter size in this assistance dog breeding colony, consistent with a larger (of 10,810 litters from 224 breeds), although shorter, study undertaken in Norway. 12 An association between litter size and several other factors, such as age, general health and parity, has also been reported. 27 However, an association between litter size and these other factors was not investigated here for the reasons mentioned above, and because all of the bitches in the present study were healthy at the time of mating. ...
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Evidence of seasonality in oestrus in bitches within specialist breeding programmes, such as those for assistance dogs, may support colony management through tailoring the distribution of resources required for breeding throughout the year. However, at present there are conflicting data regarding seasonality in oestrus (and litter size) in domestic dogs. The primary objective of this study was to investigate seasonal variations in oestrus and litter size in a large assistance dog breeding colony in the UK in order to optimise colony management. The authors analysed the annual distribution of 3624 observations of oestrus collected from 568 brood bitches from January 2005 to June 2014. The authors also evaluated the relationship between month and litter size for 1609 litters observed during the same period. There was no evidence of regular seasonal variations in oestrus or litter size by meteorological season or month. The lack of seasonality in oestrus may be a function of dogs in the UK, particularly valuable breeding bitches, being exposed to fairly constant environmental conditions throughout the year as a consequence of artificial light and heating during the winter months. The authors’ findings suggest that special consideration of the annual distribution of oestrus and litter size is unnecessary for the management of assistance dog breeding colonies similar to those in the UK.
Article
The economic efficiency of fur animal farms is considerably influenced by reproductive performance. The objectives of this study are to determine the effects of individual and maternal inbreeding, birth year, and dam and sire age on litter size at birth (LSB) and at weaning (LSW) and on preweaning mortality (PWM) in a red fox herd under long‐term selection, and to determine the heritability of these traits. In total, 37,973 pedigreed individuals were used to calculate the inbreeding coefficients, based on records of 14,527 litters of 3856 dams born from the year 1958 to 2015. Two data sets (all data and data for the Polish variety) were analyzed. The highest heritability was estimated for PWM (0.292, 0.306) and the lowest for LSW (0.114, 0.115). In contrast to paternal and maternal inbreeding, litter inbreeding was found to exert a significant influence. The absence of significant effects of most varieties may suggest relatively large genetic similarity in the world red fox population. This corresponds with the similarity of the results obtained for the total herd and for the Polish variety. Favorable genetic trends were observed for the studied traits, indicating that the selection applied had been a relatively effective approach to improving these traits.
Article
Prominent differences in aging among and within species present an evolutionary puzzle. The theories proposed to explain evolutionary differences in aging are based on the axiom that selection maximizes fitness, not necessarily life span. This implies trade-offs between investment in self-maintenance and investment in reproduction, where high investments in growth and current reproduction are associated with short life spans. Fast growth and large adult size are related to shorter life spans in the domestic dog, a bourgeoning model in aging research; however, whether reproduction influences life span in this system remains unknown. Here we test the relationship between reproduction and differences in life span among dog breeds, simultaneously controlling for shared ancestry and recent gene flow. We found that shared ancestry explains a higher proportion of the among-breed variation in life history traits, in comparison with recent gene flow. Our results also show that reproductive investment negatively impacts life span, and more strongly so in large breeds, an effect that is not merely a correlated response of adult size. These results suggest that basic life history trade-offs are apparent in a domestic animal whose diversity is the result of artificial selection and that among-breed differences in life span are due to a combination of size and reproduction.
Article
The article presents the results of a study of reproductive indicators in female German Shepherd dogs in terms of age changes: litter size (multiple pregnancies), duration of pregnancy, live weight of puppies. For a sample of 158 breeding dogs, the mean multiple pregnancy for the entire sample was 5.8 ± 0.018 puppies per 123 fruitful matings. The authors found out that the litter size varied depending on the age of the females. During the study period, the least number of litters consisted of one and ten puppies, respectively, three and one; also 6 litters consisted of two puppies, 9 consisted of 3 puppies, 15 litters each numbering 4, 7 and 8 puppies, 23 litters of 5 puppies, 25 litters of 6 puppies, 7 litters of 9 puppies, 4 litters of 11 puppies. The maximum litter size of 11 puppies was recorded in dogs aged 3, 4 and 6 years, the minimum litter size consisting of one puppy was recorded in dogs aged 5 and 6 years. There was a trend towards a decrease in the period of pregnancy with an increase in the age of the dog, which was significant in comparison between the age groups of 2 and 7 years. Also, a high safety of offspring was noted in all the studied age periods, which was in the range from 92.75 to 100%, separately for litters with the number of puppies 2-6, the safety was 100%, for multiple litters with the number of puppies 7-11 heads, this indicator was 98.05% . Statistically significant differences were registered in terms of multiple pregnancy at the age of 2 and 3 years and at the age of 7 and 8 years, at (P < 0.05).
Article
Birth weight (bW) is considered an indicator of neonatal maturity and a predictor of neonatal mortality. According to its importance, many efforts have been made so far to identify physiological body weight ranges at birth. Due to the high heterogeneity among breeds, optimal bW is difficult to define in dogs. The aim of this study was to carefully analyze the shape and pattern of the bW distribution in dogs. Furthermore, the role of breed on bW determination was specifically investigated in relation to maternal (age, weight, height, diet, season, litter size) and neonatal (sex, malformations, assistance at birth) aspects. For these purposes two canine breeds with very similar phenotypic characteristics, Golden and Labrador retrievers, were selected. An accurate statistical model to explore bW distribution and compare it between Goldens and Labradors was developed. At birth most of the Golden and Labrador pups (estimated 95th percentile) weighed up to 630 g and 500 g, respectively. The estimated 5th percentile of bW distributions was 295 g in Golden and 290 g in Labrador pups. These lowest values could be indicative cut-offs of underweight pups. The probability of neonatal mortality within 1 week of life decreased with increasing bW (P = 0.031) and was higher in Golden than Labrador pups even though this difference was not significant. In conclusion, our results suggest that genetics have a relevant influence on the determination of birth weight which is confirmed to be closely associated with neonatal mortality.
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Membrane proteins are prone to misfolding and degradation. This is particularly true for mammalian forms of the gonadotropin-releasing hormone receptor (GnRHR). Although they function at the plasma membrane, mammalian GnRHRs accumulate within the secretory pathway. Their apparent instability is believed to have evolved through selection for attenuated GnRHR activity. Nevertheless, the molecular basis of this adaptation remains unclear. We show that adaptation coincides with a C-terminal truncation that compromises the translocon-mediated membrane integration of its seventh transmembrane domain (TM7). We also identify a series of polar residues in mammalian GnRHRs that compromise the membrane integration of TM2 and TM6. Reverting a lipid-exposed polar residue in TM6 to an ancestral hydrophobic residue restores expression with no impact on function. Evolutionary trends suggest variations in the polarity of this residue track with reproductive phenotypes. Our findings suggest that the marginal energetics of cotranslational folding can be exploited to tune membrane protein fitness.
Chapter
This chapter contextualizes the dog-human relationship in the dog's origin as a scavenger on the fringes of human settlements over 15,000 years ago. It then reviews the evidence for unique evolved cognitive structures in dogs that could explain their success in a human-dominated world. Failing to find evidence of unique human-like social-cognitive capacities I then review uncontroversial facts of dogs' basic behavioral biology, including reproductive and foraging behavior and, particularly, affiliative and attachment-related behaviors. This leads to consideration of dogs' social behavior, both conspecific and toward other species, especially humans. I draw attention to a seldom-noted apparent contradiction between dogs' stronger affectional bonds toward humans than toward members of their own species. Dogs' social groups also show steeper social hierarchies accompanied by more behaviors indicating formal dominance than do other canid species including wolves. I resolve this contradiction by proposing that dogs' intense sensitivity to social hierarchy contributes to their willingness to accept human leadership. People commonly control resources that dogs need and also unknowingly express behaviors which dogs perceive as formal signs of dominance. This may be what Darwin was referring to when he endorsed the idea that a dog looks on his master as on a god. Whatever the merits of this idea, if it serves to redirect behavioral research on dogs in human society more toward the social interactions of these species in their diverse forms of symbiosis it will have served a useful function.
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Extreme phenotypic diversity, a history of artificial selection, and socioeconomic value make domestic dog breeds a compelling subject for genomic research. Copy number variation (CNV) is known to account for a significant part of inter-individual genomic diversity in other systems. However, a comprehensive genome-wide study of structural variation as it relates to breed-specific phenotypes is lacking. We have generated whole genome CNV maps for more than 300 canids. Our data set extends the canine structural variation landscape to more than 100 dog breeds, including novel variants that cannot be assessed using microarray technologies. We have taken advantage of this data set to perform the first CNV-based genome-wide association study (GWAS) in canids. We identify 96 loci that display copy number differences across breeds, which are statistically associated with a previously compiled set of breed-specific morphometrics and disease susceptibilities. Among these, we highlight the discovery of a long-range interaction involving a CNV near MED13L and TBX3, which could influence breed standard height. Integration of the CNVs with chromatin interactions, long noncoding RNA expression, and single nucleotide variation highlights a subset of specific loci and genes with potential functional relevance and the prospect to explain trait variation between dog breeds.
Thesis
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The primary objective of this project is determination of best practice guidelines for the British Columbia Society for Prevention of Cruelty to Animals (BC SPCA) in partnering with BC First Nations communities in addressing self-identified domestic dog welfare and overpopulation issues. The practices recommended will be used by the organisation to develop a resource toolkit to be used by BC SPCA staff and volunteers in developing these partnerships.
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In der vorliegenden Arbeit wurde eine Ressourcen-Liste der Schweizer Entlebucher Sennenhunde erstellt. Sie umfasst Eintragungen von mehr als 12‘000 Hunden mit Merkmalen und verwandtschaftlichen Beziehungen und erleichtert genetische Analysen stark. Getestet wurde diese Ressourcen-Liste für unterschiedliche Ausprägungen der Rutenform. Eine bekannte Mutation, die in einigen anderen Hunderassen eine Stummelrute bewirkt, wurde erstmals auch bei kurzschwänzigen Entlebucher Sennenhunden nachgewiesen. Diese Mutation soll autosomal dominant vererbt werden. Die Segregationsanalyse unterstützt diese Hypothese, weil das Hauptgen Modell die untersuchten Daten am besten erklärt. Allerdings wird durch die Segregationsanalyse ein unvollständig dominanter Erbgang favorisiert. Für die Vererbung von Knickruten wurde ein klarer genetischer Einfluss nachgewiesen, aber es war nicht möglich, diese genetische Komponente näher zu charakterisieren. Zusätzlich wurden die Zuchtdaten für die Jahre 2000-2009 erhoben und ausgewertet. Entgegen der weit verbreiteten Meinung konnte gezeigt werden, dass das Vorkommen von Stummelruten, Knickruten und Stummel-Knickruten keinen negativen Einfluss auf die Wurfgrösse hat. Weitere Untersuchungen sind nötig, um die Vererbung der unterschiedlichen Rutenformen besser zu charakterisieren, wobei eine qualitativ bessere Erfassung und Klassifizierung der Phänotypen mit bildgebender Diagnostik prioritär ist. Summary A resource list for Entlebucher Mountain dogs was created. It contains entries for more than 12‘000 dogs with their relationships and certain traits, thereby markedly facilitating genetic analyses. This resource list was tested for different phenotypic variations of the tail. A known mutation causing short tails in some dog breeds was shown for the first time to segregate also in Entlebucher Mountain dogs. This mutation is believed to be inherited in an autosomal dominant fashion. The segregation analysis supports this hypothesis, because the major gene model explained the inheritance of short tails in Entlebucher Mountain dogs the best. However, this analysis favours an incomplete dominant inheritance. For kinked tails a genetic component could be clearly demonstrated but it was not possible to further characterize it. Furthermore, breeding data for the years 2000-2009 were collected and analysed. In contrast to common belief, the presence of short, kinked and short-kinked tails in litters is not leading to smaller litter sizes. Additional investigations will be necessary to clarify the inheritance of the different tail phenotypes. Better recording and classification of the phenotypes using imaging procedures will be of outmost importance.
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Background The Australian dingo continues to cause debate amongst Aboriginal people, pastoralists, scientists and the government in Australia. A lingering controversy is whether the dingo has been tamed and has now reverted to its ancestral wild state or whether its ancestors were domesticated and it now resides on the continent as a feral dog. The goal of this article is to place the discussion onto a theoretical framework, highlight what is currently known about dingo origins and taxonomy and then make a series of experimentally testable organismal, cellular and biochemical predictions that we propose can focus future research. Discussion We consider a canid that has been unconsciously selected as a tamed animal and the endpoint of methodical or what we now call artificial selection as a domesticated animal. We consider wild animals that were formerly tamed as untamed and those wild animals that were formerly domesticated as feralized. Untamed canids are predicted to be marked by a signature of unconscious selection whereas feral animals are hypothesized to be marked by signatures of both unconscious and artificial selection. First, we review the movement of dingo ancestors into Australia. We then discuss how differences between taming and domestication may influence the organismal traits of skull morphometrics, brain and size, seasonal breeding, and sociability. Finally, we consider cellular and molecular level traits including hypotheses concerning the phylogenetic position of dingoes, metabolic genes that appear to be under positive selection and the potential for micronutrient compensation by the gut microbiome. Conclusions Western Australian Government policy is currently being revised to allow the widespread killing of the Australian dingo. These policies are based on an incomplete understanding of the evolutionary history of the canid and assume the dingo is feralized. However, accumulated evidence does not definitively show that the dingo was ever domesticated and additional focused research is required. We suggest that incorporating ancient DNA data into the debate concerning dingo origins will be pivotal to understanding the evolutionary history of the canid. Further, we advocate that future morphological, behavioural and genetic studies should focus on including genetically pure Alpine and Desert dingoes and not dingo-dog hybrids. Finally, we propose that future studies critically examine genes under selection in the dingo and employ the genome from a wild canid for comparison. Electronic supplementary material The online version of this article (10.1186/s12983-019-0300-6) contains supplementary material, which is available to authorized users.
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Ductus venosus (DV) closure plays a key role in hepatic circulation adaptation to postnatal metabolic function, and DV patency might develop a congenital portosystemic shunt (CPSS). The noninvasive Color Flow Mapping (CFM) examination, a validated method to diagnose CPSS in adult dogs, is routinely performed to assess DV closure after birth in humans. This study aimed to describe the feasibility of the ultrasonographic evaluation of the DV after birth and to determine its closure time in healthy Great Dane neonates. Patency of DV in serial Color Flow Mapping (CFM) examinations and bodyweight (BW) were recorded on Days 0‐3‐6‐9 in 24 neonates that were classified as having patent (PDV) or closed ductusvenosus (CDV) basing on CFM signal presence/absence. Since the 3rd day, DV diameter was recorded. Data were analysed by ANOVA (p < 0.05). All dogs resulted healthy 1 year later. The number of PDV and CDV puppies at birth was not different on Day 3 (24 and 0 vs. 22 and 2, PDV and CDV, respectively), whereas it resulted different on Days 6 (24 and 0 vs. 14 and 10) and 9 (24 and 0 vs. 0 and 24); on Day 3, it was different compared to Days 6 and 9; on Day 6, it was different from Day 9. Reduction of DV diameter resulted positively related to neonatal BW growth. The CFM evaluation of DV closure after birth in Great Dane puppies represents a feasible technique. Present results suggest the time of functional closure in normal neonates within 9 days after birth. Thus, CFM examination, as an early screening test for DV patency evaluation, performed 10 days after birth, may identify suspicious dogs at risk that would require further investigations. Further studies are needed to deepen the role of a delayed closure in low bodyweight and preterm puppies.
Article
The aim of this prospective cohort study was to utilize multivariable statistical methods to identify factors that significantly affected whelping rate, litter size and gestation length in a large population of bitches of many different breeds, presented for routine breeding management. In addition, we aimed to determine the incidence of dystocia and the proportion of bitches undergoing a caesarean section procedure. A total of 1146 individual bitches representing 84 different breeds contributed 1203 inseminations over the 9 year (2007–2015) study period. Bitches were inseminated with either frozen-thawed (n = 645), fresh (n = 543) or chilled (n = 15) semen from 1371 different males. The mean (SD) whelping rate was 74± 4% and the mean litter size was 5.8 ± 3.1 pups per litter for all bitches in the study. The whelping rate was significantly lower in bitches inseminated with frozen-thawed semen compared with bitches inseminated with fresh semen (71% vs 80% respectively; P < 0.001). Semen that was classified as having poor motility (<30% progressive) resulted in a significantly lower whelping rate (37%) than semen classified as good (30–65% progressive; whelping rate = 67%) or excellent (>65% progressive; whelping rate = 79%). There was a linear decline in whelping rate with advancing age. Greyhounds and Labradors demonstrated a significantly higher whelping rate (88% and 94% respectively) compared with all other breeds (71.3%, P < 0.001). Bitches inseminated with frozen-thawed semen had significantly smaller litter sizes than bitches inseminated with fresh semen (5.4 ± 3.1 vs 6.2 ± 3.0 pups per litter respectively; P = 0.02). Smaller breeds had significantly smaller litters (4.4 ± 2.1 pups) than medium (5.2 ± 2.9 pups), large (5.9 ± 2.9 pups) or giant (6.7 ± 3.8 pups) breeds. For each advancing year of age, litter size decreased by 0.13 pups per litter. The mean (SD) gestation length from LH0 was 65 ± 1.9 d. Greyhounds had a significantly longer pregnancy duration (68.0 ± 1.5 d) than other breeds. For each additional year of bitch age, gestation length increased by 0.11 days (P < 0.01), and for each additional pup per litter, gestation length was reduced by 0.08 days (P < 0.05). Of the 890 bitches for which whelping outcomes were recorded; 409 (46%) whelped normally without assistance, 249 (28%) had an elective C-section, 205 (23%) underwent an emergency C-section and 27 (3%) were medically managed or required veterinary assistance for dystocia. Brachycephalic breeds were 11.3 (95CI = 9.3–17.9; P < 0.001) times more likely to have a C-section compared to all other breeds. Bitches with litter sizes of one or two pups had a C-section rate of 83%, whereas bitches with litter sizes of three or more pups had a C-section rate of 43% (P < 0.001). This study provides important clinical information to optimise whelping rates, litter size and the prediction of whelping in certain breeds for clinicians working in canine reproduction.
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To describe the frequency of caesarean sections in a large sample of pedigree dogs in the UK. Data on the numbers of litters born in the previous 10 years were available from a cross-sectional study of dogs belonging to breed club members (2004 Kennel Club/BSAVA Scientific Committee Purebred Dog Health Survey). In this survey 151 breeds were represented with data for households that had reported on at least 10 litters (range 10-14,15): this represented 13,141 bitches which had whelped 22,005 litters. The frequency of caesarean sections was estimated as the percentage of litters that were reported to be born by caesarean section (caesarean rates) and are reported by breed. The dogs were categorised into brachycephalic, mesocephalic and dolicocephalic breeds. The 10 breeds with the highest caesarean rates were the Boston terrier, bulldog, French bulldog, mastiff, Scottish terrier, miniature bull terrier, German wirehaired pointer, Clumber spaniel, Pekingese and Dandie Dinmont terrier. In the Boston terrier, bulldog and French bulldog, the rate was > 80%. These data provide evidence for the need to monitor caesarean rates in certain breeds of dog.
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In this study 470 bitches were inseminated; 405 with fresh semen into the cranial vagina and 65 with frozen semen transcervically into the uterus. The pregnancy rate was 65.7% with fresh semen and 41.5% with frozen. When corrected for stage of oestrus at the time of insemination and for semen quality the pregnancy rate was 83.8% with fresh semen and 69.3% with frozen semen. The pregnancy rate improved with an increase in the number of inseminations. Inseminations with fresh semen before the time of ovulation (less than 17.3 nmol progesterone/l) were often successful. With frozen semen the peripheral plasma level of progesterone at the time of insemination was greater than 30 nmol/l in all but 1 of the bitches that became pregnant. This difference is assumed to be attributable to a longer survival time of several days for fresh semen than for frozen-thawed semen. Cytological scoring was a satisfactory method for determining the stage of oestrus when using fresh semen, but more precise methods are needed when using frozen semen. Semen quality was difficult to correlate with fertility. Pregnancies were obtained with fresh semen of inferior quality, although the litter size was smaller. With frozen semen no pregnancies resulted when the semen quality was poor. Litter size was estimated to be 21.5% smaller in bitches inseminated with fresh semen compared with naturally mated bitches. Litter size in bitches inseminated with frozen semen was 23.3% smaller than in bitches inseminated with fresh semen. Puppy deaths occurred in 35.5% of the litters in this study. The overall puppy death rate during the first 3 weeks of life was 11.9%. Although not statistically significant, there was a tendency for bitches treated with antibiotics at the time of mating or during early pregnancy to have a higher pregnancy rate and a larger litter size. There was also a tendency for breed differences in pregnancy rate, although not significant.
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During 1990 and 1991, 527 artificial insemination (AI) procedures were performed by 40 veterinarians, under the Swedish Kennel Club control scheme, and reported to the Kennel Club within 14 days. The most common reason for AI (37.2%) was import of fresh and frozen semen or quarantine, i.e. introduction of new genetic material. Fresh semen (468 AIs) was deposited into the cranial vagina, and frozen semen (59 AIs) was inseminated transcervically into the uterus. Pregnancy rates were 54.7% with fresh and 39.0% with frozen semen. When corrected for stage of oestrus at the time of AI and semen quality, the pregnancy rates were 62.3 and 51.1%, respectively. Bitches inseminated with frozen semen had a 29.7% lower pregnancy rate and 30.5% smaller litter size than bitches receiving fresh semen; these differences were statistically significant. Forty-four bitches (8.4%) were also mated. Their pregnancy rate was significantly higher (88.6%; 90.7% corrected) than that of bitches inseminated with fresh semen only. Pregnancy rate was significantly higher in bitches inseminated twice with fresh semen than in those inseminated once only. Litter size and gestation length increased with the number of AIs. Most bitches whelped 62 days after a single AI with fresh or frozen semen, but the gestation period varied between 55 and 69 days. There were significant differences in fertility between breeds. Pup deaths occurred in 33.8% of the litters and the pup death rate during the first 3 weeks of life was 11.6%. The number of pups resulting from AI amounted to 1.1% of the total number of pups registered with the Swedish Kennel Club.
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To define the mode of inheritance of the dorsal ridge and investigate if the ridge predisposes to the congenital abnormality dermoid sinus in the Rhodesian ridgeback. Segregation analysis was performed, including 87 litters (n=803) produced in Sweden between 1981 and 2002. Data were corrected to avoid bias in the segregation ratio. Chi-squared analysis was performed including 402 litters (n=3598) for the evaluation of a possible genetic correlation between the ridge and dermoid sinus. The ridge is inherited in an autosomal dominant mode and predisposes for dermoid sinus. The frequency of ridgeless offspring in the Swedish Rhodesian ridgeback population is estimated to be 5.6 per cent. Rhodesian ridgeback dogs that carry the ridge trait are predisposed to dermoid sinus.
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In most animal taxa, longevity increases with body size across species, as predicted by the oxidative stress theory of aging. In contrast, in within-species comparisons of mammals and especially domestic dogs (e.g. Patronek et al., '97; Michell, '99; Egenvall et al., 2000; Speakman et al., 2003), longevity decreases with body size. We explore two datasets for dogs and find support for a negative relationship between size and longevity if we consider variation across breeds. Within breeds, however, the relationship is not negative and is slightly, but significantly, positive in the larger of the two datasets. The negative across-breed relationship is probably the consequence of short life spans in large breeds. Artificial selection for extremely high growth rates in large breeds appears to have led to developmental diseases that seriously diminish longevity. J. Exp. Zool. (Mol. Dev. Evol.) 306B, 2006.
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Dystocia occurs more commonly in some breeds of dogs than others. The Boxer breed is one of the highrisk breeds for whelping problems. The aim of this study was to document some reproductive parameters and the frequency of dystocia in Boxers. Two questionnaires were sent to the breeders of Boxers in Sweden during 1994 to 1997. Data from 253 whelpings and 1671 pups was received, which constitutes 56.5% of all Boxer litters registered with the Swedish Kennel Club during these years. Data was analysed using Chi-square test, and Fischer's exact test. Dystocia occurred in 32% of the individual bitches, and in 27.7% of all the whelpings. Caesarian section was performed in 22.8% of all the whelpings and in 80.1% of the cases of dystocia. Medical treatment was tried in 20 cases but was successful only in 5 (25%). The dystocia was of maternal origin in 68.6% and of fetal origin in 28.6% of cases. The most common reasons for dystocia were primary uterine inertia (60%) and malpresentation of the fetus (26%). Dystocia increased with increasing age of the bitch from four years of age. Average litter size was 6.6 (+/- 2.2) pups born, and 5.0 (+/- 2.1) pups registered. Pup mortality was 24%. Stillbirths accounted for 6.1% of the pup deaths and 1% died in the neonatal period, while 15.6% of the pups were euthanised, the majority because they had disqualifying white coat colour. Cryptorchidism was observed in 9.8% of the male pups born and in 13.4% of the male pups that were registered. The Boxer suffers a high frequency of dystocia, mainly due to uterine inertia, but also fetal malpresentation. Breeders should be advised to include easy whelpings in their breeding program.
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The rate of perinatal death is variable but highest during parturition, immediately after birth and in the first days of life. Infectious diseases, above all bacterial, are the second most important cause of mortality after losses during parturition. A lot of factors are involved predisposing puppies and kittens to bacterial infections: respiratory distress, hypothermia, hypoglycaemia, dehydration, congenital abnormalities. E. coli, streptococci and staphylococci, Klebsiella sp., Pseudomonas sp., Enterobacter sp., Proteus sp. and anaerobes are regularly involved in bacterial infections in neonates. Postmortem findings especially document E. coli, Staphylococcus or Streptococcus species as causes of disease and death shortly after birth. The environment and mothers are suspected as sources of infection (vaginal discharge, milk, faeces, oropharynx, skin) for puppies and kittens. Genetic relatedness of bacterial strains in puppies and their mothers was found in staphylococci and E.coli. These results indicate that for repeated cases of bacterial infections in neonates diagnostic procedures of milk, vaginal and faecal swabs from bitches result in isolation of the responsible bacteria with a high probability and suggest that preterm treatment could help to control bacterial diseases and losses in pups.
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The United Kingdom pedigree-dog industry has faced criticism because certain aspects of dog conformation stipulated in the UK Kennel Club breed standards have a detrimental impact on dog welfare. A review of conformation-related disorders was carried out in the top 50 UK Kennel Club registered breeds using systematic searches of existing information. A novel index to score severity of disorders along a single scale was also developed and used to conduct statistical analyses to determine the factors affecting reported breed predisposition to defects. According to the literature searched, each of the top 50 breeds was found to have at least one aspect of its conformation predisposing it to a disorder; and 84 disorders were either directly or indirectly associated with conformation. The Miniature poodle, Bulldog, Pug and Basset hound had most associations with conformation-related disorders. Further research on prevalence and severity is required to assess the impact of different disorders on the welfare of affected breeds.
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Dystocia is a frequent problem in the dog, with regard to breed-specific factors, litter size, duration of expulsion, various intervals between puppies and various causes of maternal, foetal or combined origin. In the present study, results were obtained from management of 530 dogs of 54 breeds, between 1 and 13 years of age, presented with dystocia over a period of 8 years in an obstetrical clinic with mostly identical diagnostic and therapeutic schedules. Data on age of the dam, parturition number, breed size, causes of dystocia, duration of expulsion time, kind of obstetrical aid, and last but not least, the influence of all therapeutic aspects on survival of the puppies were analysed. Dams of miniature and small breeds (59.4%) had a high incidence for dystocia in this population. Uterine forces (inertia and spasm), malpresentation of the foetus and litter size (single pup pregnancies, hyperfoetation) were the most common causes for dystocia. Duration of expulsion stage had the highest influence on puppy survival (p < 0.001). In the case of medical treatment, medication with oxytocin led to higher puppy losses compared with other medicaments. Older primiparous bitches (>6 years of age) had a significantly higher risk to have special obstetric conditions and stillbirths compared with young primiparous bitches. The scope of this study was to analyse the parameters that were most useful for a rapid diagnosis to maximize puppy survival, to avoid false diagnosis and to choose the best therapeutic strategy. The present data show that in addition to the established criteria for management of dystocia in the dog, new diagnostic approaches are necessary to improve obstetrical care.
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A 3-year mortality and morbidity survey was conducted in a research foxhound breeding colony. Its purpose was to identify specific problem areas for further study and rectification. Three-hundred and thirty-nine litters (2,872 puppies) were whelped. Seventeen percent (17.4%) of the puppies died before weaning and 4.0% died between weaning and 30 weeks of age. Major puppy losses (55.6% of the total mortality) occurred during the 1st week after birth. The majority of deaths during this period was attributable to stillbirth, immaturity or runting, trauma and congenital abnormalities. The predominant causes of death thereafter were pneumonia, malnutrition, and gastrointestinal disease. The most frequent causes of morbidity among puppies were respiratory disease, anorexia and dehydration, skin disorders, and gastrointestinal disease. These entities were most commonly observed during the 2 weeks before and after weaning at 6 weeks of age. Clinical disease problems among breeding stock were few and were easily resolved. Fighting and infections of the skin and ear canals constituted 75.5% of the cases observed.
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Breed, geographic, and seasonal distributions of canine births registered with the American Kennel Club for the years 1971 to 1973, accompanied by litter size and sex ratio data, were studied. A few breeds accounted for a large portion of the births. The breed distribution of births changed as popularity of various canine types waxed and waned. The geographic distribution of births generally paralleled the pattern of human population and was relatively stable. A distinct, repetitive seasonal distribution of births was evident. Human intervention probably molded much of this pattern, but genetic factors and environmental conditions also were involved. Litter size and sex ratio varied primarily with breed rather than with region or season and hence appeared genetically based.
Article
During late pregnancy (greater than 50 days) the pattern of uterine electrical activity is characterized by episodes of activity lasting 3-10 min and recurring at a low frequency (maximum 2.5/h). During the last 7 days before delivery there is a progressive qualitative change in activity which is correlated with the decrease in plasma progesterone concentration. Together with significant quantitative changes in uterine activity which occur during the last 24 h before parturition and after the sharp fall in progesterone concentration this suggests that progesterone plays a crucial role in the process of parturition in the bitch. Experiments with a calcium-channel antagonist have demonstrated the important role of Ca2+ ions in uterine contractility in dogs, but further investigations will be necessary to illustrate the clinical significance of hypocalcaemia in relation to primary uterine inertia. By marking all fetuses in utero before term by means of a radio-opaque substance, it was demonstrated that, when one or more pups were left in each uterine horn after birth of a pup, 78.2% of the pups were expelled from the contralateral horn. Assessment of the blood gas and acid-base status in spontaneously born puppies indicated that the initial state of acidosis is more severe than in several other domestic species. A mild to severe combined respiratory-metabolic acidosis occurs in almost every newborn puppy.
Article
— On the basis of the evaluation of Beagle breeding records extending over a 8-year period dealing with one strain of English dogs and one of American dogs, criteria are pointed out which are of value when assessing the productivity of the total breeding station and of the individual bitch. These criteria form the basis of breeding and commercial planning. The question as to how long the individual bitch can remain productive for breeding and when she should be excluded from breeding for economic considerations is discussed.Résumé— Sur la base de données relatives à 8 années d'activité d'un chenil d'élevage de chiens Beagle de race anglaise et de race américaine, I'auteur définit divers critères permettant d'évaluer la productivité totale du chenil et celle de chaque chienne. Ces critères servent de base aux prévisions en matière de reproduction et de vente. L'auteur examine en outre la dude de vie utile de la chienne reproductrice et la durée de reproduction rentable.Zusammenfassung— Eine Auswertung von Protokollen der Spuerhundzuechtung (Beagle), die sich ueber einen Zeitraum von 8 Jahren erstrecken und je eine Zucht englischer und amerikanischer Hunde umfassen, ist die Basis von Kriterien, die alswervtoll fuer eine Abschaetzung der Produktivitaet sowohl einer gesamten Zuechterei als auch einer einzelnen Huendin aufgefuehrt werden. Diese Kriterien bilden die Grundlage fuer die Zucht und fuer die kommerzielle Planung. Die Frage, wielange eine einzelne Huendin fuer die Zuechtung produktiv bleiben kann und wann sie am wirtschaftlichen Gruenden vom Zuechten ausgeschlouen werden soll, wird behandelt.
Article
In a study comparing animal life spans and in vitro clonal proliferative capacity of skin fibroblasts in groupings of small, middle, large, and very large breeds of dogs of specific ages, the following results were obtained: (1) their life spans were inversely correlated to the frame sizes of the breeds; (2) the percent of large clones present in clone size distributions from the small dogs was inversely proportional to the age of the subjects (this was not true for the large breeds; however, animals older than 8 years were not available in those breeds); and (3) the group composed of the two largest breeds (Great Dane and Irish Wolfhound) had the shortest life spans and also had significantly smaller percentages of large skin fibroblast clones formed in vitro than either of the two groupings of smaller dogs at any age studied. It appears that within the domestic dogs the large body size is accompanied by shorter life span and, in the two largest breeds, decreased cellular growth potential.
Article
This paper presents puppy mortality and postmortem findings for a birth cohort of boxer puppies born in the Netherlands between January 1994 and March 1995. In all, 457 litters were registered, of which 414 (90.6 per cent) were involved in the study. The 414 litters contained 2629 puppies, a mean litter size of 6.4 puppies. Of the 2629 puppies 571 (21.7 per cent) died or were euthanased before they were weaned at 50 days of age; there were 147 (25.7 per cent) stillbirths; 102 (17.9 per cent) were euthanased because they were white; 269 (47.1 per cent) of the puppies died during the first 21 days of life and 53 (9.3 per cent) puppies died between days 22 and 50. The cause of death or the reason for euthanasia was assessed by either the breeder or the veterinarian in 176 of these 269 puppies but was not determined in the other 93 puppies. Three hundred and two puppies were examined postmortem; the most important cause of death or reasons for euthanasia were inflammatory disorders (102; 33.8 per cent), non-inflammatory disorders such as asphyxia and malnutrition (66; 21.9 per cent), euthanasia because they were white (51; 16.9 per cent), and congenital abnormalities (45; 14.9 per cent). No cause of death or reason for euthanasia could be found for 38 puppies (12.6 percent)
Article
To determine relative impact of genetic, common-litter, and within-litter factors on puppy mortality. 2,622 Boxer puppies of 413 litters born during a 14-month period. For each puppy, pedigree was determined, and litter in which it was born was registered. Overall mortality and mortality per specific cause of death were analyzed by use of a model that included an additive genetic effect, common-litter effect, within-litter effect, and regression of mortality on inbreeding coefficient. Relative importance of the effects was determined from estimates of the variance in mortality explained by each factor. 22% of the puppies died before reaching 7 weeks old. Stillbirth was the most frequent cause of death, followed by infection. Most observed differences were attributable to within-litter factors, which explained 67% of the variance in death attributable to infection and < or = 96% of the variance in death attributable to asphyxia. Common-litter factors were more important than additive genetic factors. Variance attributed to common-litter factors ranged from 2% for cheiloschisis, palatoschisis, or cheilopalatoschisis to 30% for death attributable to infection, and variance attributed to additive genetic factors ranged from 0% for asphyxia to 14% for euthanatized because of white color. Inbreeding coefficient had a significant effect on death attributable to infection, which increased 0.26% for each percentage increase of inbreeding. Additive genetic factors have less impact on preweaning mortality than common-litter factors, which in turn have less impact than within-litter factors. Mortality attributable to infection increases significantly with increases in inbreeding.
Article
A retrospective analysis was performed to determine the effects of age, breed, parity, and litter size on the duration of gestation in the bitch. Bitches at two locations were monitored from breeding to whelping. A total of 764 litters whelped from 308 bitches (36 large hounds, 34 Golden Retrievers, 23 German Shepherd Dogs (GSD), and 215 Labrador Retrievers). By breed, the number of whelpings was 152, 72, 58, and 482 for the hounds, Golden Retrievers, German Shepherd Dogs, and Labrador Retrievers, respectively. Whelping was predicted to be 57 d from the first day of cytologic diestrus in the hounds or 65 d from the initial progesterone rise in the other breeds. The average gestation duration (calculated as 8 d prior to Day 1 of cytologic diestrus in hounds or measured from the initial progesterone rise in other breeds) by breed (days +/- S.D.) was 66.0 +/- 2.8, 64.7 +/- 1.5, 63.6 +/- 2.1, and 62.9 +/- 1.3 for the hounds, Golden Retrievers, German Shepherd Dogs, and Labrador Retrievers, respectively. The relationship of age, breed, parity, and litter size with the difference in gestation duration was evaluated using log linear modeling. Age or parity had no effect on gestation duration. Compared to Labrador Retrievers, the German Shepherd Dogs, Golden Retrievers and hounds were more likely to have a longer gestation duration; three, four and nearly eight times as likely, respectively. Bitches whelping four or fewer pups were significantly more likely to have a longer gestation duration than those whelping five or more pups; the prolongation averaging 1 d.
Article
From 1994 to 2003, a total of 526 bitches of 99 different breeds were artificially inseminated in 685 estrus cycles with domestic (n = 353) or imported (n = 332) frozen-thawed semen from 368 males. The overall whelping rate was 73.1% and mean (+/- S.E.M.) litter size 5.7 +/- 0.1 pups. The whelping rate was higher after intrauterine insemination (75.0%; n = 665) than after intravaginal insemination (10.0%, n = 20; P < 0.05). Insemination at the optimal time resulted in a higher whelping rate (78%, n = 559; P < 0.01) and larger litter size (5.8 +/- 0.2; P < 0.05) than inseminations performed late or too late (55.7% and 4.5 +/- 0.5, n = 61). Two inseminations (n = 384) yielded a higher whelping rate (P < 0.05) and mean litter size (P < 0.01) than one insemination (n = 241), 78.1% and 6.0 +/- 0.2 and 70.5% and 5.1 +/- 0.2, respectively. For inseminations performed at the optimal time, however, the whelping rate was not significantly different for bitches inseminated twice (79.3%, n = 358) versus once (76.8%, n = 168), but the litter size was larger (6.0 +/- 0.2 and 5.3 +/- 0.3). Semen classified as of poor quality (progressive motility < 50% or percentage abnormal sperm > 20%) resulted in a lower whelping rate (P < 0.01) than semen classified as of good quality (progressive motility > or = 50% and percentage abnormal sperm < or = 20%), 61 and 77%, respectively. Small breeds (n = 50) had a smaller litter size (3.9 +/- 0.3; P < 0.01) than larger breeds (medium [5.7 +/- 0.3, n = 94], large [5.9 +/- 0.2, n = 295] or giant breeds [6.1 +/- 0.5, n = 62] [P < 0.01]). Bitches older than 6 years had a lower whelping rate (68.2%) than younger ones (77.0%; P < 0.05). The duration of pregnancy was longer (P < 0.01) for bitches with a litter size of < 3 pups (61.7 +/- 0. 4 days, n = 30) than for bitches with larger litters (60.5 +/- 0.1 days, n = 177). These results show the potential of transcervical intrauterine insemination for routine artificial insemination in dogs. The results with frozen semen inseminations were optimised by inseminating bitches < or = 6 years old 2 and 3 days after ovulation with semen of good quality from males < or = 8 years old.
Article
Artificial insemination of 31 bitches with fresh, undiluted, semen resulted in 22 31 conceptions (71%) and the birth of 124 puppies. Inseminations using at least 220 x 10(6) spermatozoa of normal morphology resulted in a mean pregnancy rate of 81.5% (22 27 ). The pregnancy rates were significantly influenced by the total number of progressively motile or morphologically normal sperm cells per ejaculate (P < 0.05). The pregnancy rate was not influenced by the percentage of progressively motile or morphologically normal sperm cells per ejaculate (P > 0.1). Litter size was not influenced by sperm motility or morphology (P > 0.1).
Article
This study was undertaken to determine the association between life spans and breed size in the dog, based upon data derived from the pet population. Seventy-seven American Kennel Club breeds were analyzed with data collected for more than 700 dogs. Multiple linear regression analysis was carried out with longevity as the dependent variable and height or weight as the independent variable. A negative correlation was observed between height and longevity (r=-0.603, p<0.05), and between weight and longevity (r=-0.679, p<0.05). Weight was the significant predictor of life span (p<0.001), revealing that breeds smaller by weight generally live longer than heavier breeds. These data form the ground work for investigations of aging utilizing the dog as a model and provide owners with a quantitative method for predicting lifespan of dog breeds, thereby aiding in pet selection.
Article
To estimate the incidence and breed predilection for canine dystocia using data from insurance claims. The risk factors for cesarean section (CS) were assessed for bitches with dystocia. Retrospective, longitudinal study. Insurance claims records (1995-2002) from a Swedish animal insurance database (Agria), including approximately 200,000 bitches. The overall incidence rate of dystocia in insured bitches was calculated by dividing the number of reimbursed dystocia claims with the number of dog years at risk. Subsequently, incidence rates were stratified by breed, region, and habitat. The proportion of bitches with a dystocia claim that had CS were calculated, and risk factors for CS were assessed using a logistic regression model. Between 1995 and 2002, 3894 (2%) of 195,931 Swedish bitches included in the study had a reimbursed insurance claim for dystocia. The overall incidence rate of dystocia was 5.7 cases/ 1000 dog years at risk. Some breeds like the Scottish terrier were at increased risk of dystocia. Among bitches with dystocia, 63.8% were treated by CS. Dystocia in the bitch is more common than reported earlier. The risk of developing dystocia varies by breed, and a high percentage (63.8%) of affected bitches undergo CS. Clinical Relevance- Breeders and veterinarians could use this information to better predict which bitches are likely to experience dystocia and/or CS.
Article
The aim of this study was to examine the differences, between seasons of the year, in the distribution of matings and whelpings, litter size, pup deaths, and sex ratio in domestic dogs. Furthermore, we wanted to examine the effects of age and parity of the bitch at the time of whelping on litter size, as well as the effect of litter size on gestational length. A final aim was to investigate the fertility and frequency of whelping problems in a private kennel of Drever dogs. Data from the Swedish Kennel Club (SKK) registry for the Drever breed during 1995-2006, comprising a total of 2717 litters, were analyzed together with more detailed data from a private, professional kennel of Drevers, with a total of 285 matings and 224 whelpings, during the same time period. The most matings took place during winter, and the fewest during summer; consequently, most whelpings occurred during the winter and spring seasons. Of the 285 mated bitches, 78.6% whelped, 6.25% experienced dystocia, and 5.36% underwent Cesarean section. The pup death rate was 7.6%. The largest litters were born during spring. Litter size was negatively correlated with duration of pregnancy (r=-0.18). Each pup more than average caused a shortening of the gestation by 0.25 days, and each pup less a corresponding lengthening. Bitches giving birth to their first litter after 4 years of age produced a smaller litter than younger bitches. Litter size decreased after 5 years in all bitches. The number of born pups at the private kennel increased from the first to the third parity, then decreased. The number of registered pups increased from the first to the second parity in the SKK data and from the second to the third parity in the data from the private kennel, then decreased. Mating a bitch only once resulted in a smaller litter size. None of the studied factors had any effect on the sex ratio of the pups. There were significant differences between males in whelping rate among the mated bitches, but no difference in mean litter size, which indicates a female problem rather than a male one. Available data suggest that the domestic dog is still under considerable seasonal influence, although modified by ambient and management factors.
Available at: http://www. fci.be
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Fédération C. Internationale (FCI). Available at: http://www. fci.be/. Accessed: December 13, 2011.
Available at: http://www.thekennelclub. org.uk
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the Kennel Club, UK. Available at: http://www.thekennelclub. org.uk/. Accessed: December 13, 2011.
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