ArticleLiterature Review

Nutritional Risks to Large-Breed Dogs: From Weaning to the Geriatric Years

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Abstract

Distinctive risk factors for disease are identifiable throughout life stages of large- and giant-breed dogs. From weaning to maturity, improper nutrition is linked to developmental skeletal diseases. As large dogs mature, skeletal diseases and obesity can lead to osteoarthritis. These dogs are difficult to manage when orthopedic or osteoarthritic disease affects mobility and quality of life, thereby increasing the risk of early death. Gastric dilatation and volvulus is another disease that is leading cause of death in large- and giant-breed dogs. Management of health, including proper nutrition, exercise, and weight control, provides the best opportunity for successful aging of large- and giant-breed dogs.

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... En su etapa juvenil (entre 2 y 10 meses en perros de raza pequeña o hasta los 18 meses en razas grandes), el perro tiene un mayor requerimiento de proteínas, energía y calcio que un adulto (Dobenecker et al., 2010). La dieta también debe ser de alta calidad y fácil de digerir, sin sobrealimentar a los animales, principalmente con aportes exagerados de calcio, ya que esto puede predisponer a problemas esqueléticos en perros de razas grandes y a obesidad en los animales alimentados con dietas altas en energía y bajas en proteína (Lauten, 2006). ...
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RESUMEN El objetivo del estudio fue determinar la calidad nutricional de tres alimentos comerciales «Premium» para cachorros fabricados y comercializados en el Ecuador, así como determinar la sensibilidad de la técnica de espectroscopía por infrarrojo cercano (NIRS) para la valoración de los macronutrientes de estos alimentos. Se analizaron las características nutricionales de tres marcas de alimento, tomándose muestras de cuatro lotes por marca. Se determinaron los macronutrientes (proteína, grasa, fibra, almidón, cenizas y humedad) mediante la técnica NIRS, prueba que fue duplicada en dos laboratorios con diferentes equipos. Además, se determinó el perfil de aminoácidos mediante cromatografía líquida (HPLC). En el análisis proximal, los tres alimentos cumplen con los requerimientos de macronutrientes mínimos para garantizar el desarrollo y la salud de los cachorros, aunque uno de ellos presentó una mejor composición nutricional. La técnica de NIRS como prueba rápida es estable para analizar los componentes de los alimentos secos para mascotas; sin embargo, presentó variabilidad al medir principalmente la concentra-ción de grasa (p=0.029) en los tres alimentos, aunque también ocurrió en uno de los
... Although bitches are mostly acquired for breeding, they usually double up for security purpose at older age, especially in security conscious environments (Fielding & Plumridge, 2004).The aftermath of long stay of bitches in breeding Kennels during pregnancy makes them prone to joint conditions, while excessive activities during security process make both sexes prone to varying levels of orthopaedic injuries (Eyarefe & Dei, 2014). The higher case load of orthopaedic conditions in younger dogs (< 1year) compared with adult (> 1year) may be associated with automobile injuries and nutritional osteopathies than other causative factors (Lauten, 2006;Streeter et al., 2009). Young dogs have phobia for kennel confinement and often sleep under owners' vehicles making them prone to orthopaedic injuries (personal observation). ...
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Small animal orthopaedic case records of a 20-year period were surveyed to obtain the prevalence and pattern of orthopaedic conditions presented to the Veterinary Teaching Hospital (VTH), University of Ibadan, Nigeria, with the objective of providing data for planning on small animal healthcare facilities, policy development and veterinary manpower training. Out of 618 small animal surgery cases managed within the period studied, 127 (19.6%) were orthopedic in nature across 22 canine breeds, consisting of dogs (45%), bitches (53%) and 2% unspecified sexes. Orthopedic conditions were prevalent in Alsatian 34.65%, Rottweiler 19.69%, Mongrel 18.11%, Crossbreeds 4.72%, Boerboel 3.94%, Pomeranian 1.54%, Samoyed 1.54%, Caucasian 1.54%, Neapolitan mastiff 1.54%, Lhasa Apso 0.79%, Keeshond 0.79%, Chihuahua 0.79%, French mastiff 0.79%, Tosa 0.79%, Pit-bull 0.79%, Spitz 0.79%, Bull Mastiff 0.79%, Dachshund 0.79% and Doberman pinscher 0.79%. Fracture cases were highest 61.42%, followed by hip dysplasia 14.17%, hip luxation 6.30%, lameness 2.36%, paralysis 1.57%, hock luxation 1.57%, sprain 1.57%, patella luxation 1.57%, abnormal gait 1.57%, arthritis 0.79%, osteosarcoma 0.79%, splayed limb 0.79%, congenital dysgenesis 0.79%, hypertrophic osteodystrophy 0.79%, stiffened stifle joint 0.79%, and unspecified 2.36%. fracture anatomic sites were: femur 57.69%, tibia and fibula 10.26%, humerus 6.41%, radio-ulna 5.13%, mandible 5.13%, metacarpal 3.85%, tibia 3.85%, metatarsal 2.56%, radius 2.56%, rib 1.28% and tarsal 1.28%. The highest occurrence of orthopedic cases was in 2015 (11.02%), while 1998 (1.57%) and 2010 (1.57%) had the least. No case was recorded in 1995 and 1997 (0%). Young dogs (< 1year) were more involved (60.0%) than adult (> 1 year) (32.0%). More cases were recorded in the first quarter (27.56%)-(January-March) than second quarter (April-June (25.20%), than fourth quarter (October –December (24.41%).The third quarter (July-September) had the least (22.83%). The implication of the data to orthopaedic patient management, and planning was discussed. Keywords: Dogs, Orthopaedic conditions, Prevalence, Small animal, Veterinary teaching hospital.
... The animals' respective growth rates and body sizes suggest that the IGF pathway may be involved (Bartke et al. 2003;Tryfonidou et al. 2003). We note that a listing of the terminal diseases found in relationship to small and large dog sizes can be found in Deeb and Wolf (1994), and also with emphasis on cancer (Bronson 1982), and especially for diseases of large dogs (Lauten 2006). ...
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Clinical data from 72 dog breeds of varying size and life expectancy were grouped according to breed body mass and tested for prevalence at ages 4 to 5, ages 7 to 10, and lifetime incidence of non-hereditary, age-related cataract (ARC). The incidence of ARC was found to be directly related to the relative life expectancies in the breed groups: The smallest dog breeds had a lower ARC prevalence between ages 4 and 5 than mid-size breeds and these, in turn, a lower prevalence than the giant breeds. A similar sequence was evident for ages 7 to 10 and for overall lifetime incidence of ARC. These differences became more significant when comparing small and giant breeds only. We could also confirm the inverse relationship between body size and life expectancy in these same sets of dog breeds. Our results show that body size, life expectancy, and ARC incidence are interrelated in dogs. Given that ARC has been shown to be at least partially caused by oxidative damage to lens epithelial cells and the internal lens, we suggest that it can be considered not only as a general biomarker for life expectancy in the canine and possibly other species, but also for the systemic damages produced by reactive oxygen species. This suggests new approaches to examine the gene expression pathways affecting the above-noted linkages.
... There is controversy as to the association of GDV and exercise. Previously, exercise after eating was suggested as a risk factor (Lauten 2006) but this was not supported by findings in a study in Great Danes where no significant association was found between the incidence of GDV and the interval between feeding and daily exercise (Theyse et al. 1998). A study of military dogs in Texas showed an increased incidence of GDV in November, December and January suggesting that factors such as weather in the winter months, or husbandry determined by the weather, could be associated with an increased occurrence (Moore et al. 2008). ...
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To present findings from a case series of gastric dilatation (GD) or gastric dilatation and volvulus (GDV) in working farm dogs in New Zealand that were examined at veterinary clinics, and to identify possible risk factors for GD or GDV in working farm dogs in New Zealand using a case-control study. This retrospective study included a case-series and a case-control study. The case series analysed information from 62 case records of GD or GDV in working farm dogs seen between August 2004 and September 2009 at 13 veterinary clinics throughout New Zealand. Cases were classified as GD or GDV if the diagnosis was confirmed by radiography, surgery or post-mortem examination. Details of history and treatment, as well as outcomes, were obtained for each case. For the case-control study, records of 41 working farm dogs with GD or GDV (cases) seen between April 2008 and April 2009, and 82 working farm dogs examined because of trauma over the same period and in the same 13 clinics (controls), were used to model the risk factors for GD or GDV. From the case-series study, 40/62 (65%) cases of GD or GDV that were examined and treated at the veterinary clinics returned to work. Of the 41 dogs where the gastric contents were recorded, 25 (61%) had predominantly food or bones in the stomach, and 26/27 dogs had a history of having eaten meat, bones or scavenged a carcass. The case-control study showed that the significant risk factors for GD or GDV, compared with control dogs presenting with trauma, were breed, age and season. The odds that a case of GD or GDV was a Huntaway, after adjusting for age and season, was 19 times higher than the odds a control was a Huntaway. Gender and bodyweight were not identified as risk factors. A high proportion of farm working dogs with GD or GDV were successfully treated by veterinarians. The risk of a case of GD or GDV being a Huntaway was significantly higher than for a dog presenting as a trauma case. However the influences of the season of the year, climatic factors and nutritional factors on the pathogenesis need to be identified before adequate preventative measures can be recommended.
... Complications arising from feeding nutritionally imbalanced diets include osteodystrophy, osteopenia and nutritional secondary hyperparathyroidism (Kawaguchi et al. 1993;De Fornel-Thibaud et al. 2007;Hutchinson et al. 2012). These dietary imbalances are of most concern in growing puppies, especially those of large or giant breeds where dietary calcium : phosphorus ratios and energy levels during the growing period have greater implications on health status (Schoenmakers et al. 2000;Lauten 2006). Labrador retrievers, the most popular breed in this study, are large breed dogs and would be at risk of diseases caused by nutritional imbalance during growth. ...
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In Sri Lanka, home-cooked diets are often fed due to the cost and poor availability of commercial diets. Milk has traditionally been a popular food to give to dogs in this country. There is a recent perceived increase in the number of owners choosing commercial diets for their pets. This study aimed to determine how dog owners visiting a single veterinary practice in Colombo fed their pets. We hoped that this would help achieve a general understanding of pet feeding practices in Sri Lanka and gain some basic demographic information on the owned dog population. The study was conducted via questionnaires distributed to pet owners visiting a first opinion and referral practice in Colombo. Hundred questionnaires were collected and analysed, 69% of study dogs were neutered, 42% of dogs were fed only home-cooked food, while 18% were fed only commercial food. About 40% of dogs were fed a mixture of commercial and home-cooked food, 49% of dogs were fed milk as a separate meal in addition to their normal diet and 57% of dogs received dietary supplements. Dogs consuming commercial food for more than half their intake were no less likely (P = 0.75) to receive dietary supplements than dogs fed homemade food for more than half their diet. This study provides some basic information regarding the feeding practices and demographics of the owned dog population in one Sri Lankan city, Colombo, highlighting some areas of concern.
... This diversity is not surprising when we consider the variation in adult size between the different breeds, which, with mature body weights range from 1 kg (Chihuahua) to ≥ 90 kg (St. Bernard), is the greatest diversity across mammalian species (Lauten 2006). The amount of energy a particular dog will finally need is significantly influenced by factors such as the age, breed, size, activity, en-vironment, temperament, insulation characteristics of the skin and hair coat, body condition or disease. ...
Article
Full-text available
The purpose of this study was to compare the in vitro digestibility levels and chemical compositions of commercial extruded dry-type adult dog foods with different types of protein contents [fish meat (F-dog foods) (n = 7), lamb meat (L-dog foods) (n = 9), or poultry meat (P-dog foods) (n = 8)]. The in vitro digestion values of premium commercial dog foods were examined at three stages: gastric digestion, small intestine digestion and large intestine digestion/fermentation. The metabolisable energy (ME), crude protein (CP), starch, diethyl ether extract (EE) and ash contents and the in vitro cumulative gas production values of all the premium dog foods dif-fered significantly among the commercial brands in the same category (F-, L- or P-dog foods) (P < 0.05). The crude fibre (CF) and the CP/1 000 kcal ME values of the F- and P-dog foods demonstrated a significant difference among the commercial brands (P < 0.05). The organic matter disappearance (OMd) values of the L-dog foods showed a significant difference among the commercial brands (P < 0.05); but the OMd values of the F- and P-dog foods did not differ among the commercial brands (P > 0.05). The average values of the OMd for the F-dog foods were more rapid than the average for the L- and P-dog foods, in the evaluation of all the foods (P = 0.001). Besides, the price of the L-dog foods was positively correlated with the OMd and CP of the L-dog foods; however, it was negatively correlated with the NFE (nitrogen free extract) and CHO (total carbohydrates) of the L-dog foods (P < 0.05). The CP values of the L-dog foods were positively correlated with the OMd values (P < 0.05). Although price is an important determinant of food quality in the L-dog foods, it is not in the F- and P-dog foods. In the general evaluation of all the dog foods, there was no correlation among the food price and the digestibility and the nutrient content for all of the premium dog foods. The present study indicated that the energy, nutrient matter and di- gestibility of premium dog foods changed with the change in the variety and the amount of the feedstuffs. The digest-ibility of the dog foods with the fish meat were higher than those of the other dog foods. The amount of protein that an adult dog will receive with 1 000 kcal of DM (dry matter) consumption of premium dog foods with fish meat and chicken meat, varied among the brands. This point showed the need to pay attention to the food con-sumption amount of the dogs and the energy-protein balance in their diets, especially dog foods with fish meat and chicken meat.
... In these cases, even though the genetic background might be crucial for the development of joint mechanical instability, years of genetic selection by dog breeders has not reduced the incidence of the disease [3]. Factors such as nutritional imbalance [4,5], chronic inflammation [6,7], ageing [8,9] and obesity [10,11] are linked to the development of OA in dogs and in humans. These factors are also associated with oxidative stress [12]. ...
Article
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Background Oxidative stress plays an important role in the pathogenesis of disease, and the antioxidant physiological effect of omega-3 from fish oil may lead to improvement of canine spontaneous osteoarthritis (OA). Methods In this prospective randomized, controlled, double-blinded study, we assessed haematological and biochemical parameters in dogs with OA following supplementation with either a concentrated omega-3 deep sea fish oil product or corn oil. Blood samples from 77 client-owned dogs diagnosed as having OA were taken before (baseline) and 16 weeks after having orally ingested 0.2 ml/Kg bodyweight/day of deep sea fish oil or corn oil. Circulating malondialdehyde (MDA), glutathione (GSH), non-transferrin bound iron (NTBI), free carnitine (Free-Car), 8-hydroxy-2-deoxyguanosine (8-OH-dG), and serum fatty acids, haemograms and serum biochemistry were evaluated. Differences within and between groups from baseline to end, were analysed using repeated samples T-test or Wilcoxon rank test and independent samples T-test or a Mann-Whitney test. ResultsSupplementation with fish oil resulted in a significant reduction from day 0 to day 112 in MDA (from 3.41 ± 1.34 to 2.43 ± 0.92 μmol/L; P < 0.001) and an elevation in Free-Car (from 18.18 ± 9.78 to 21.19 ± 9.58 μmol/L; P = 0.004) concentrations, whereas dogs receiving corn oil presented a reduction in MDA (from 3.41 ± 1.34 to 2.41 ± 1.01 μmol/L; P = 0.001) and NTBI (from −1.25 ± 2.17 to −2.31 ± 1.64 μmol/L; P = 0.002). Both groups showed increased (albeit not significantly) GSH and 8-OH-dG blood values. Dogs supplemented with fish oil had a significant reduction in the proportions of monocytes (from 3.84 ± 2.50 to 1.77 ± 1.92 %; P = 0.030) and basophils (from 1.47 ± 1.22 to 0.62 ± 0.62 %; P = 0.012), whereas a significant reduction in platelets counts (from 316.13 ± 93.83 to 288.41 ± 101.68 × 109/L; P = 0.029), and an elevation in glucose (from 5.18 ± 0.37 to 5.32 ± 0.47 mmol/L; P = 0.041) and cholesterol (from 7.13 ± 1.62 to 7.73 ± 2.03 mmol/L; P = 0.011) measurements were observed in dogs receiving corn oil. Conclusions In canine OA, supplementation with deep sea fish oil improved diverse markers of oxidative status in the dogs studied. As corn oil also contributed to the reduction in certain oxidative markers, albeit to a lesser degree, there was no clear difference between the two oil groups. No clinical, haematological or biochemical evidence of side effects emerged related to supplementation of either oil. Although a shift in blood fatty acid values was apparent due to the type of nutraceutical product given to the dogs, corn oil seems not to be a good placebo.
... Regardless, if left untreated, GDV can progress to tissue damage, shock, and death. Several risk factors have been identified including diet [18,19] and feeding regimes [2], age [1,4], behavior [2,20], and genetics [1,[3][4][5] suggesting that both environmental and genetic factors influence the risk of GDV. Previously, we identified variants of genes in both the adaptive and innate immune systems, toll-like receptor 5 (TLR5) and the dog version of human leukocyte antigen of the Major Histocompatibility Complex genes (DLA88; Class 1 and DRB1, Class 2), that were associated with increased risk of GDV [8]. ...
Article
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Background Large and giant dog breeds have a high risk for gastric dilatation-volvulus (GDV) which is an acute, life-threatening condition. Previous work by our group identified a strong risk of GDV linked to specific alleles in innate and adaptive immune genes. We hypothesize that variation in the genes of the immune system act through modulation of the gut microbiome, or through autoimmune mechanisms, or both, to predispose dogs to this condition. Here, we investigate whether differences in the canine fecal microbiome are associated with GDV and are linked to previously identified risk alleles. Methodology/Principle findings Fecal samples from healthy Great Danes (n = 38), and dogs with at least one occurrence of GDV (n = 37) were collected and analyzed by paired-end sequencing of the 16S rRNA gene. Dietary intake and temperament were estimated from a study-specific dietary and temperament questionnaire. Dogs with GDV had significantly more diverse fecal microbiomes than healthy control dogs. Alpha diversity was significantly increased in dogs with GDV, as well as dogs with at least one risk allele for DRB1 and TRL5. We found no significant association of dietary intake and GDV. Dogs with GDV showed a significant expansion of the rare lineage Actinobacteria (p = 0.004), as well as a significantly greater abundance of Firmicutes (p = 0.004) and a significantly lower abundance of Bacteroidetes (p<0.004). There was a significant difference in the abundance of 10 genera but after correction for multiple comparisons, none were significant. Bacterial phyla were significantly different between controls and dogs with GDV and at least one risk allele for DRB1 and TRL5. Actinobacteria were significantly higher in dogs with GDV and with one risk allele for DRB1 and TLR5 but not DLA88 genes. Furthermore, Collinsella was significantly increased in dogs with at least one risk allele for DRB1 and TLR5. Logistic regression showed that a model which included Actinobacteria, at least one risk allele,and temperament, explained 29% of the variation in risk of GDV in Great Danes. Conclusions The microbiome in GDV was altered by an expansion of a minor lineage and was associated with specific alleles of both innate and adaptive immunity genes. These associations are consistent with our hypothesis that immune genes may play a role in predisposition to GDV by altering the gut microbiome. Further research will be required to directly test the causal relationships of immune genes, the gut microbiome and GDV.
... Intriguingly, distinct OA type-specific epidemiological patterns exist in dogs, notably between breeds, and OA is clearly influenced by body size, obesity, sex, neuter status and age 12 . Obesity, for instance, is a known risk factor for human 19 and dog OA 20 , but evaluating its role as an independent risk factor in humans is difficult. However, work with inbred experimental dog colonies has revealed that dietary restriction reduces OA. ...
Article
Osteoarthritis (OA) is a global disease that, despite extensive research, has limited treatment options. Pet dogs share both an environment and lifestyle attributes with their owners, and a growing awareness is developing in the public and among researchers that One Medicine, the mutual co-study of animals and humans, could be beneficial for both humans and dogs. To that end, this Review highlights research opportunities afforded by studying dogs with spontaneous OA, with a view to sharing this active area of veterinary research with new audiences. Similarities and differences between dog and human OA are examined, and the proposition is made that suitably aligned studies of spontaneous OA in dogs and humans, in particular hip and knee OA, could highlight new avenues of discovery. Developing cross-species collaborations will provide a wealth of research material and knowledge that is relevant to human OA and that cannot currently be obtained from rodent models or experimentally induced dog models of OA. Ultimately, this Review aims to raise awareness of spontaneous dog OA and to stimulate discussion regarding its exploration under the One Medicine initiative to improve the health and well-being of both species.
... On the contrary, Ca and P were at recommended values; however, the Ca/P ratio in some cases exceed the maximum recommended of 2.5 (Table 10). Calcium and phosphorus intake should be strictly monitored in dogs as malnutrition is a risk factor for developmental orthopedic diseases and secondary nutritional hyperparathyroidism in large breed puppies and dogs [79,80]. Finally, n = 2/158 samples (1.26%) were found to be contaminated with Salmonella spp. ...
Article
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... This diversity is not surprising when we consider the variation in adult size between the different breeds, which, with mature body weights range from 1 kg (Chihuahua) to ≥ 90 kg (St. Bernard), is the greatest diversity across mammalian species (Lauten 2006). The amount of energy a particular dog will finally need is significantly influenced by factors such as the age, breed, size, activity, en-vironment, temperament, insulation characteristics of the skin and hair coat, body condition or disease. ...
Article
Full-text available
The purpose of this study was to compare the in vitro digestibility levels and chemical compositions of commercial extruded dry-type adult dog foods with different types of protein contents [fish meat (F-dog foods) (n = 7), lamb meat (L-dog foods) (n = 9), or poultry meat (P-dog foods) (n = 8)]. The in vitro digestion values of premium commercial dog foods were examined at three stages: gastric digestion, small intestine digestion and large intestine digestion/fermentation. The metabolisable energy (ME), crude protein (CP), starch, diethyl ether extract (EE) and ash contents and the in vitro cumulative gas production values of all the premium dog foods differed significantly among the commercial brands in the same category (F-, L-or P-dog foods) (P < 0.05). The crude fibre (CF) and the CP/1 000 kcal ME values of the F-and P-dog foods demonstrated a significant difference among the commercial brands (P < 0.05). The organic matter disappearance (OMd) values of the L-dog foods showed a significant difference among the commercial brands (P < 0.05); but the OMd values of the F-and P-dog foods did not differ among the commercial brands (P > 0.05). The average values of the OMd for the F-dog foods were more rapid than the average for the Land P-dog foods, in the evaluation of all the foods (P = 0.001). Besides, the price of the L-dog foods was positively correlated with the OMd and CP of the L-dog foods; however, it was negatively correlated with the NFE (nitrogen free extract) and CHO (total carbohydrates) of the L-dog foods (P < 0.05). The CP values of the L-dog foods were positively correlated with the OMd values (P < 0.05). Although price is an important determinant of food quality in the L-dog foods, it is not in the F-and P-dog foods. In the general evaluation of all the dog foods, there was no correlation among the food price and the digestibility and the nutrient content for all of the premium dog foods. The present study indicated that the energy, nutrient matter and di-gestibility of premium dog foods changed with the change in the variety and the amount of the feedstuffs. The digest-ibility of the dog foods with the fish meat were higher than those of the other dog foods. The amount of protein that an adult dog will receive with 1 000 kcal of DM (dry matter) consumption of premium dog foods with fish meat and chicken meat, varied among the brands. This point showed the need to pay attention to the food consumption amount of the dogs and the energy-protein balance in their diets, especially dog foods with fish meat and chicken meat.
... Dogs show wide variations with respect to their body weight, from around 1 kg to 90 kg (Lauten 2006). As a result, the energy requirement of dogs does not have a linear relationship with bodyweight. ...
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Red meat from tuna canning factory was used to develop a pet food for dogs. Feed was developed by mixing cooked, dried, and powdered red meat with cereal flours in varying proportion. The combination that gave maximum hardness for the feed was selected as optimum. The developed feed had a crude protein content of 20.2 ± 0.95% and crude fat content of 4.70 ± 0.37%. Analysis of mineral content showed that it is rich in macro minerals, including phosphorus (2843.67 ± 206 ppm), sodium (1333.54 ± 56 ppm), and calcium (400.04 ± 21 ppm). Amino acid content of the feed showed that it meets the dietary requirements of dogs in terms of threonine, methionine, histidine, lysine, arginine, and tryptophan. Polyunsaturated fatty acid content of the feed was dominated by linoleic acid, followed by DHA and EPA.
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A 6-month-old intact female giant schnauzer dog fed a nutritionally unbalanced homemade diet was evaluated because of a 1-month history of lameness and difficulty walking. Abnormalities identified on ancillary tests, in conjunction with the dog's clinical improvement following diet change, suggested a diagnosis of vitamin D deficiency and nutritional secondary hyperparathyroidism. This report underlines the importance of appropriate feeding management, especially during the vulnerable growth phase.
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How well can you answer pet owners' questions about proper diet and feeding? Canine and Feline Nutrition, 3rd Edition describes the role of nutrition and its effects upon health and wellness and the dietary management of various disorders of dogs and cats. By using the book's cutting-edge research and clinical nutrition information, you'll be able to make recommendations of appropriate pet food and proper feeding guidelines. Pet nutrition experts Linda P. Case, MS, Leighann Daristotle, DVM, PhD, Michael G. Hayek, PhD, and Melody Foess Raasch, DVM, provide complete, head-to-tail coverage and a broad scope of knowledge, so you can help dog and cat owners make sound nutrition and feeding choices to promote their pets' health to prolong their lives. Tables and boxes provide quick reference to the most important clinical information. Key points summarize essential information at a glance. A useful Nutritional Myths and Feeding Practices chapter dispels and corrects common food myths.New clinical information covers a wide range of emerging nutrition topics including the role of the omega-3 and omega-6 fatty acid families in pet health and disease management. Coverage of pet food safety and pet food ingredients includes both commercially and home-prepared foods and provides answers to pet owners' questions on these topics. Completely updated content reflects the latest findings in clinical nutrition research. Information regarding functional ingredients and dietary supplementation provides a scientifically based rationale for recommending or advising against dietary supplements. Guidelines for understanding pet food formulations and health claims differentiate between "market-speak" and actual clinical benefits for patients, with practice advice for evaluating and selecting appropriate foods.
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It is well established that small dogs on average have a longer life span than do large dogs; however, the exact mechanisms responsible for this difference are a subject of considerable debate. Based on clinical data of over 100.000 individual eye exams from 72 dog breeds of varying size and life span provided by the CERF database, it can be demonstrated that breed size, life span and the age at which dogs develop non-hereditary, age-related cataracts (ARC) interact: The smallest dog breeds have a lower ARC prevalence between both ages 4 to 5 and for overall life span than medium-sized breeds, which in turn have a lower prevalence than giant breeds. These differences become statistically more significant when comparing small and giant breeds only. Given that ARC has been shown to be at least partially caused by the accumulation of oxidative damage to the lens, it is likely that it can not only be considered as a general biomarker for life expectancy in the domestic dog, but also for the systemic damages caused by reactive oxygen species (ROS) during the aging process. This suggests that large breeds accumulate more such damage earlier in life than small breeds do, which could be explained by their longer growth period and faster rate of growth, during which the body's normal protective mechanisms may be insufficient. The correlation between ARC incidence, lifespan, and body size suggests new ways of studying the gene expression pathways affecting these attributes, notably those involving insulin-like growth factor 1 (IGF-1). Accumulating more pathological, hormonal and molecular data for dog breeds of different body sizes and rates of growth should also provide new approaches regarding the influence of ROS and the IGF-1 pathway on life span, age-related pathologies and the rate and extent of cell replication that accompanies them.
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Objective: To establish the types of initial questions used by veterinarians in companion animal practice to solicit nutritional history information from owners of dogs and cats, the dietary information elicited, and the relationship between initial question-answer sequences and later nutrition-related questions. Design: Cross-sectional qualitative conversation analytic study. Sample: 98 appointments featuring 15 veterinarians drawn from an observational study of 284 videotaped veterinarian-client-patient visits involving 17 veterinarians in companion animal practices in eastern Ontario, Canada. Procedures: Veterinarian and client talk related to patient nutrition was identified and transcribed; conversation analysis was then used to examine the orderly design and details of talk within and across turns. Nutrition-related discussions occurred in 172 visits, 98 of which contained veterinarian-initiated question-answer sequences about patient nutritional history (99 sequences in total, with 2 sequences in 1 visit). Results: The predominant question format used by veterinarians was a what-prefaced question asking about the current content of the patient's diet (75/99). Overall, 63 appointments involved a single what-prefaced question in the first turn of nutrition talk by the veterinarian (64 sequences in total). Dietary information in client responses was typically restricted to the brand name, the subtype (eg, kitten), or the brand name and subtype of a single food item. When additional diet questions were subsequently posed, they typically sought only clarification about the food item previously mentioned by the client. Conclusions and clinical relevance: Results suggested that question design can influence the accuracy and completeness of a nutritional history. These findings can potentially provide important evidence-based guidance for communication training in nutritional assessment techniques.
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Although veterinary practitioners know that nutrition can make a difference in the health and recovery from disease or illness in dogs and cats, they may feel poorly equipped to provide unbiased information on nutrition. This article provides information about evaluating and recommending diets and interpreting a pet food label to allow for comparisons among pet foods and discussion about how to do a nutritional assessment. It provides an example of how nutritional assessment and recommendation were successfully introduced into a busy private practice. Finally, some of the myths and misperceptions about nutrition are discussed with information provided from evidence-based research.
Article
Examples of naturally occurring musculoskeletal disorders are extremely common in veterinary species and provide a valuable comparative research resource, which can provide compelling comparative data on the aetiopathogenesis and treatment of many common human musculoskeletal diseases. In particular, orthopaedic diseases are a common morbidity in both dogs and horses. In this review, we give an overview of the common musculoskeletal diseases encountered in these species: for instance, tendon and ligament injuries, arthropathies and stress fractures, as well as an insight into the basic biology of these conditions. In doing so, we aim to demonstrate the similarities and differences between these disorders and similar conditions in man.
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This study examined the effects of dietary fat on the fatty acid composition of liver and bone, and on the concentration of insulin-like growth factor-I (IGF-I) in liver and bone, as well as the relationship of these factors to bone metabolism. Day-old male broiler chicks were given a semipurified diet containing one of four lipid sources: soybean oil (SBO), butter+corn oil (BC), margarine+corn oil (MAC), or menhaden oil+corn oil (MEC) at 70 g/kg of the diet. At 21 and 42 d of age, chicks fed MEC had the highest concentration of (n-3) fatty acids [20:5(n-3), 22:5(n-3) and 22:6(n-3)] in polar and neutral lipids of cortical bone but the lowest amount of 20:4(n-6) in polar lipids. Diets containing t-18:1 fatty acids (MAC and BC) resulted in t18:1 accumulation in bone and liver. Bone IGF-I concentration increased from 21 to 42 d in chicks given the SBO and BC diets. Tibial periosteal bone formation rate (BFR) was higher in chicks given BC compared with those consuming SBO and MEC at 21 d. The higher BFR and concentrations of hexosamine in serum and IGF-I in cartilage, but lower 20:4(n-6) content in bone polar lipids in chicks given BC compared with those given SBO suggest that BC optimized bone formation by altering the production of bone growth factors. A second study confirmed that dietary butter fat lowered ex vivo prostaglandin E2 production and increased trabecular BFR in chick tibia. These studies showed that dietary fat altered BFR perhaps by controlling the production of local regulatory factors in bone.
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A case-control study was conducted to investigate whether age, gender, neuter status, type of food, feeding frequency, food intake time, interval between feeding and exercise, duration of exercise and overall physical activity were risk factors for gastric dilatation volvulus (GDV) in the great dane. The sample population consisted of 38 great danes with acute GDV (cases) and 71 great danes owned by members of the Dutch Great Dane Association (controls). Information on the risk factors was collected by using clinical data in combination with a questionnaire, and the data were analysed by backward stepwise conditional logistic regression analysis. Dogs fed a diet containing particles of food > 30 mm in size (kibble and/or dinner and/or home-prepared food with large pieces of meat) had a lower risk of GDV than dogs fed a diet containing only particles < 30 mm in size (kibble or dinner and/or canned meat and/or home-prepared food cut into small pieces or ground in a food processor). Increasing age was also a risk factor for GDV. Gender, neuter status, feeding frequency, food intake time, the interval between feeding and exercise, the duration of exercise, and overall physical activity were not identified as risk factors. Feeding a diet including large pieces of meat may help to reduce the incidence of GDV in great danes.
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Elbow dysplasia is a non-specific term denoting abnormal development of the elbow. Elbow dysplasia encompasses the clinical and radiographic manifestation of ununited anconeal process, fragmented medical coronoid process, osteochondritis dissecans, erosive cartilage lesions and elbow incongruity. The net result is elbow arthrosis, which may be clinically inapparent or result in marked lameness. These conditions may be diagnosed by means of routine or special radiographic views and other imaging modalities, or the precise cause of the arthrosis or lameness may remain undetermined. Breeds most commonly affected are the rottweiler, Bernese mountain dog, Labrador and golden retriever and the German shepherd dog. Certain breeds are more susceptible to a particular form of elbow dysplasia and more than 1 component may occur simultaneously. The various conditions are thought to result from osteochondrosis of the articular or physeal cartilage that results in disparate growth of the radius and ulna. Heritability has been proven for this polygenic condition and screening programmes to select suitable breeding stock have been initiated in several countries and have decreased the incidence of elbow dysplasia.
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Objective: To compare incidence of and breed-related risk factors for gastric dilatation-volvulus (GDV) among 11 dog breeds (Akita, Bloodhound, Collie, Great Dane, Irish Setter, Irish Wolfhound, Newfoundland, Rottweiler, Saint Bernard, Standard Poodle, and Weimaraner). Design: Prospective cohort study. Animals: 1,914 dogs. Procedure: Owners of dogs that did not have a history of GDV were recruited at dog shows, and the dog's length and height and depth and width of the thorax and abdomen were measured. Information concerning the dogs' medical history, genetic background, personality, and diet was obtained from owners, and owners were contacted by mail and telephone at approximately 1-year intervals to determine whether dogs had developed GDV or died. Incidence of GDV based on the number of dog-years at risk was calculated for each breed, and breed-related risk factors were identified. Results and clinical relevance: Incidence of GDV for the 7 large (23 to 45 kg [50 to 99 lb]) and 4 giant (> 45 kg [> 99 lb]) breeds was 23 and 26 cases/1,000 dog-years at risk, respectively. Of the 105 dogs that developed GDV, 30 (28.6%) died. Incidence of GDV increased with increasing age. Cumulative incidence of GDV was 5.7% for all breeds. The only breed-specific characteristic significantly associated with a decreased incidence of GDV was an owner-perceived personality trait of happiness.
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OBJECTIVE: To identify non-dietary risk factors for gastric dilatation-volvulus (GDV) in large breed and giant breed dogs. DESIGN: Prospective cohort study. ANIMALS: 1,637 dogs > or = 6 months old of the following breeds: Akita, Bloodhound, Collie, Great Dane, Irish Setter, Irish Wolfhound, Newfoundland, Rottweiler, Saint Bernard, Standard Poodle, and Weimaraner. PROCEDURE: Owners of dogs that did not have a history of GDV were recruited at dog shows, and the dog's length and height and the depth and width of its thorax and abdomen were measured. Information concerning the dog's medical history, genetic background, personality, and diet was obtained from the owners, and owners were contacted by mail and telephone at approximately 1-year intervals to determine whether dogs had developed GDV or died. Incidence of GDV, calculated on the basis of dog-years at risk for dogs that were or were not exposed to potential risk factors, was used to calculate the relative risk of GDV. RESULTS AND CLINICAL RELEVANCE: Cumulative incidence of GDV during the study was 6% for large breed and giant breed dogs. Factors significantly associated with an increased risk of GDV were increasing age, having a first-degree relative with a history of GDV, having a faster speed of eating, and having a raised feeding bowl. Approximately 20 and 52% of cases of GDV among the large breed and giant breed dogs, respectively, were attributed to having a raised feed bowl.
Article
A study has been made of certain mineral requirements of the growing dog and factors which affect them. Data obtained from these studies indicate that an interdependence exists among certain mineral elements which influence the requirements profoundly. It has been demonstrated that the growing dog required 0.37 of calcium as a minimal level to provide a satisfactory growth rate, normal development and well-mineralized skeletal structures. Doubling or tripling the dietary phosphorus in a ration just adequate in calcium increased the calcium requirement as measured by growth. The requirement was unaffected by a high fat diet. Diets which contained calcium in excess of 0.60% reduced the availability, function and the retention of phosphorus in growing dogs fed a ration just adequate in phosphorus. In contrast to the negligible effect of high dietary fat (20%) upon the need for calcium, the high-fat diet increased the phosphorus needs of the ration from 0.22 to 0.30%, an increase necessitated by a reduced feed ingestion. Evidence was obtained which showed that phytin phosphorus was utilized better at low dietary levels of calcium. It was observed that the availability of phytin phosphorus in some instances was more closely related to the dietary calcium/phytin phosphorus ratio than to the ratio of calcium/total phosphorus.
Article
The phosphorus requirement of the dog has been established with a natural diet which contained 0.33% of phosphorus, of which 76% was shown to be available. Hence, it is believed that the marginal phosphorus requirement corrected for unavailable phosphorus was 0.25%. This confirms previous work. Data have been obtained which demonstrate the appearance of inorganic, phospholipid, ester-type and nucleic acid phosphorus in the gastrointestinal tract from non-dietary sources. The subsequent decrease in concentration of these compounds in one or more sections of the tract demonstrated that these forms of phosphorus were largely available to the dog. Twenty to 40% of the ingested phytin was degraded with better utilization of phytin phosphorus at higher levels of inorganic phosphate (Ca/phosphorus ratios nearer to 1.2). The availability of phosphorus other than that from phytin or inorganic phosphate did not appear to be affected by the dietary Ca/phosphorus ratio.
Article
An analysis of hypertrophic osteodystrophy (HOD), craniomandibular osteopathy (CMO) and canine distemper virus (CDV) infection was undertaken. Risk factors (age, breed, sex, neuter status, weight, geographical and seasonal distribution) of the three diseases were determined and compared. Patient records were searched using the Veterinary Medical Database (VMDB) during the period of 1980 through 1989. This search identified 131 cases of HOD, 68 cases of CMO and 1,757 of CDV infection. Dogs less than six months of age were identified to be at greatest risk for HOD, CMO and CDV. The Great Dane, Cairn Terrier and the Greyhound were identified to be at highest risk for HOD, CMO and CDV infection, respectively. Males puppies were twice as likely to develop HOD. We concluded, from the risk factors analyzed, that risk factors for HOD, CMO or CDV infection were not similar. Patient information was obtained from clinical cases of 16 veterinary teaching hospitals to examine a possible relationship between Hypertrophic Osteodystrophy (HOD), Craniomandibular Osteopathy (CMO), and Canine Distemper Virus (CDV) infections. Risk factors for each disease were determined. Subjective comparison of risk factors for HOD and CMO did not support the notion of a relationship between HOD and CMO. In addition, no evidence for a possible relationship between CDV and HOD or CMO was found.
Article
Acute gastric dilatation (AGD) is a disease which is identical in many species of animal, including man. This 6.5 yr study reports findings in 33 dogs and 14 monkeys with AGD. Necropsy revealed 4 morphologic variations: AGD; AGD with volvulus; AGD with rupture; and AGD with volvulus and rupture. A common underlying or predisposing disease was not uncovered by necropsy or histopathology. Field studies disclosed management factors related to AGD as well as successful methods of emergency treatment. Experimental engorgement of dogs failed to reproduce AGD; engorgement plus pharmacologic interference with cardial function, and gastric inoculation with fresh stomach contents were equally unsuccessful. Analyses of gastric gas from affected dogs and monkeys revealed 15.6% to 89.0% carbon dioxide; culture of gastric contents revealed increased numbers of Clostridium and Bacillus spp. Clostridia were the only gas producing bacteria recoverable in gastric contents of 14 of 15 cases. Following gastric ligation and inoculation with cultivated gastric contents from naturally occurring cases, 3 of 16 experimental dogs developed AGD. Acute gastric dilatation was concluded to be multifactorial in origin, occurring when the greedy eater, fermentative flora, readily fermentable substrate, and management errors or antecedent gastric disease interact. Volvulus was postulated to occur secondarily, as a result of reverse peristalsis against a closed cardia. Vertical shaking is described as a treatment of AGD with volvulus, and oral treatment with antibiotics and simethicone containing antacid preparations are advocated. Surgical correction of volvulus comprises counterclockwise rotation of the stomach. Preventive measures recommended include: feeding twice or 3 times daily; avoidance of exclusive diets of commercially prepared grain and soybean feeds; cognizance of prodromal signs and emergency treatment; and prophylactic use of antibiotics or bloat preventives. 217 references are cited.
Article
Hypertrophic osteodystrophy is an idiopathic bone disease of young, large-breed dogs. Patients with the disease typically present with acute lameness and limb swelling over the metaphyseal regions of long bones. Because hypertrophic osteodystrophy is an orthopedic disorder that affects young dogs, diagnostic differentials include other juvenile orthopedic diseases (e.g., osteochondrosis, retained cartilaginous cores, and nutritional bone disease). The condition is characterized by osseous proliferation and increased bone remodeling. Although the cause of hypertrophic osteodystrophy is currently unknown, recent studies have implicated virus infection in the pathogenesis. Hyperostosis of the calvarium is an apparently rare disease that occurs in bull mastiffs. The clinical and pathologic features of calvarial hyperostosis are similar to those of craniomandibular osteopathy.
Article
Reflecting the prime role of 1α,25(OH)2D3 in calcium homeostasis, the activity of 25-hydroxyvitamin D3 1α-hydroxylase, a key enzyme for 1α,25(OH)2D3 biosynthesis, is tightly regulated by 1α,25(OH)2D3, PTH and calcitonin. Its significant activity is found in kidney, though the enzymatic activity is also reported in extra-renal tissues. In the present study, we found that the 1α-hydroxylase gene abundantly expresses in kidney, and at low levels in other tissues and in some cell lines. Positive and negative regulations of 1α-hydroxylase gene by PTH, calcitonin, or 1α,25(OH)2D3 were observed at transcriptional levels in kidneys of animals and in a mouse proximal tubule cell line. Moreover, the protein kinase A inhibitor abrogated the PTH-mediated positive regulation. In mice lacking the vitamin D receptor, the 1α-hydroxylase gene expression was overinduced, and the inducible effect of either PTH or calcitonin, but not the repression by 1α,25(OH)2D3, was evident. Thus, vitamin D receptor is essential for the negative regulation by 1α,25(OH)2D3. Moreover, we demonstrate that renal 1α-hydroxylase gene expression in chronic renal failure model rats was decreased and the positive effect by PTH and calcitonin was diminished. The present study demonstrates that PTH and calcitonin positively regulate renal 1α-hydroxylase gene expression via PKA-dependent and independent pathway, respectively, and that 1α,25(OH)2D3 negatively regulates it mediated by vitamin D receptor. Furthermore, in a moderate state of chronic renal failure, renal cells expressing the 1α-hydroxylase gene appear to have diminished potential in response to PTH and calcitonin.
Article
Radiographs from four dogs with non-specific signs of digestive disturbances showed displacement of the fundus and pylorus corresponding to a 180o rotation of the stomach. All the dogs belonged to breeds with a high incidence of typical gastric torsion with dilatation. The possible importance of this gastric instability in the development of an acute attack of gastric torsion is discussed.
Article
Of 285 dogs with gastric volvulus treated surgically, 30 (10.5%) required partial gastrectomy because of necrosis along the greater curvature of the body or fundic region of the stomach. Initially, the 30 dogs were treated with intravenous administration of lactated Ringer's solution, antibiotics, and corticosteroids. The stomach was decompressed with an oral gastric tube or by percutaneous gastrocentesis. Diagnosis of gastric volvulus was made by abdominal radiography and confirmed at surgery. At surgery, the stomach was decompressed and repositioned. Gastric viability was determined by evaluation of serosal color and perfusion, vascular patency, the degree of active bleeding from the incised gastric wall, and by palpation of the gastric wall; intravenous fluorescein dye evaluation was performed in some dogs. Twenty-seven dogs developed postoperative complications, 19 (63%) of which died. Eleven dogs recovered.
Article
To test the hypothesis that breeds of dogs with a deeper and narrower thorax have an increased risk of gastric dilatation-volvulus (GDV), thoracie depth, width, and length were measured for 437 dogs of 17 different breeds using radiographs on file at the Veterinary Teaching Hospital of the Purdue University School of Veterinary Medicine for the period of 1977 to 1993. These data were applied to risk estimates of GDV that were generated from a separate case control study using the Veterinary Medical Data Base. Multiple linear regression analysis was used to relate the mean thoracie measurements and the ideal, adult body size of the breeds to the risk of each breed developing GDV. When the risk of GDV was evaluated as a function of the mean thoracie depth/width ratio alone, or as a function of the thoracie depth/width ratio plus ideal adult breed weight, 37% (p = 0.022), respectively, of the variability in GDV risk was explained. These findings support the hypothesis tested and suggest that selective breeding can be used to decrease a breed's risk of GDV over time.
Article
Body measurements, history of gastric dilatation-volvulus (GDV), and other data were obtained for 155 Irish setters at the 1994 National Specialty Show. The dogs ranged in age from 6.5 months to 12.4 years (mean+/-standard deviation [SD], 3.6+/-2.6 years); 11 (7%) of the dogs had histories of GDV. Gastric dilatation-volvulus risk increased 33% for each year of age (p of 0.01). Dogs with the deepest thorax relative to width (ratio range, 1.61 to 1.85) had a significantly greater GDV risk than those with the shallowest thorax (ratio range, 1.20 to 1.50); the odds ratio was 8.45; the 95% confidence limits were 1.44 to 49.57; and the p value equaled 0.02. Having a relative (particularly a parent) with GDV also increased GDV risk. Five-generation pedigrees yielded a significantly higher mean coefficient of relationship for the 11 dogs with GDV than for the 11 dogs without GDV.
Article
Concomitant intravenous administration of 25-hydroxycholecalciferol and [3H] vitamin D3 to vitamin D-depleted rats did not affect the conversion of [3H] vitamin D3 to 25-OH-[3H] vitamin D3 as indicated by a serum 25-OH-[3H] vitamin D3 to content at 3 and 24 h identical to those observed in animals receiving [3H] vitamin D3 alone. Similarly, pre-dosing with 25-OH vitamin D3 24 h earlier did not affect the conversion. Co-administration to vitamin D depleted rats of vitamin D2 or D3, at 200-fold higher doses than a control group receiving tracer [3H] vitamin D3 alone, resulted in serum 25-OH vitamin D levels that were 15-20 fold higher than the control, indicating a similar metabolic fate for synthetic and natural vitamin D in rats and the ability of increased substrate to overwhelm hepatic constraints on 25-OH vitamin D production. Following intravenous administration of 25-OH-[3H] vitamin D3 to vitamin D depleted rats, hepatic 3H content decreased in parallel with serum radioactivity. Hepatic accumulation of intravenously administered vitamin D3 ([14C] vitamin D3) alone or with 25-OH-[3H] vitamin D3, by vitamin D-depleted rats revealed a marked preference for vitamin D3; the hepatic accumulation of [14C] vitamin D3 increased to 35% of the dose by 45 min, at which time 25-OH-[3H] vitamin D3 hepatic content was 7-fold less, and decreasing. Chromatography of extracts of hepatic subcellular fractions revealed more [14C] vitamin D3 than 25-OH-[3H] vitamin D3 in the microsomes, the reported site of calciferol 25-hydroxylase. Circulating 25-OH vitamin D, therefore, has comparatively minimal potential for hepatic accumulation. Product inhibition of the calciferol 25-hydroxylase must, therefore, result from recently synthesized hepatic 25-OH vitamin D, and is not affected by exogenous 25-OH vitamin D3.
Article
This review demonstrates that manufactured pet foods contain more than adequate levels of all the essential nutrients needed by normal dogs and cats. Under normal circumstances, therefore, it is completely unnecessary to supplement the rations of these animals with protein, energy, fatty acids, vitamins, or minerals. We have tried to show that, in addition to being unnecessary, supplementation of the rations of normal animals may be quite dangerous, leading to serious--indeed, sometimes fatal--clinical consequences. Pet food manufacturers have responded to newer information regarding increased requirements for specific nutrients such as taurine and potassium. Thus, supplements of these nutrients, as well, are unnecessary in the absence of specific clinical indications. As practitioners, we should be wary of beneficial effects claimed for nutritional supplements. Anecdotal comments, in particular, should be discounted completely. Objective data, including statistical evaluation demonstrating efficacy, should be demanded before accepting claims for such products. Finally, the use of nutritional supplements should be restricted to those cases in which specific clinical problems dictate their use.
Article
Gastric dilatation-volvulus is a dramatic and life-threatening disease of large-breed dogs. The cause is unknown, but ingestion of dry cereal-based food is frequently incriminated as a predisposing factor. The purpose of this study was to examine the effect of commercial diets on gastric motility and emptying in the dog. Four large-breed dogs were fed 3 different diets (diet A = canned meat-based; B = cereal-based with 77% added water; and C = dry cereal-based) in a randomized block design. Each experiment was done in triplicate. Motility was assessed, using 5 AgAgCl electrodes and 2 strain gauges sutured along the serosa of the stomach and proximal duodenum. Dogs were fed at the same time each day and the time to change from the fed to the fasted pattern of gastrointestinal motility (changeover) was measured. Gastric emptying was assessed by recording gastric radioactivity. After feeding a meal mixed with 99mTc-labeled resin, the log of activity was plotted against time, and the half-time of gastric emptying (t1/2 GE) was calculated. Mean (+/- SEM) times from feeding to changeover for the 3 diets were: diet A, 9.7 +/- 0.9; B, 10.5 +/- 0.4; and C, 11.0 +/- 0.8 hours. Diet had minimal influence on the half time of gastric emptying (diet A, 2.2 +/- 0.3; B, 2.6 +/- 0.4; and C, 2.9 +/- 0.3 hours; P greater than 0.05). The data indicate that gastric motility and emptying in healthy large-breed dogs were not affected by dietary composition. Because most large dogs are fed cereal-based food for reasons of cost and ease of use, these diets may have been wrongly incriminated as a predisposing factor in gastric dilatation-volvulus.
Article
The osteochondroses are defined in this symposium as idiopathic conditions, characterized by disorderliness of endochondral ossification, including both chondrogenesis and osteogenesis, superimposed upon a formerly normal growth mechanism. The classification being employed is based on anatomical site of involvement and, consequently, the potential for deformity as a guide for establishing management objectives and selection of treatment alternatives. Articular osteochondroses may cause alterations in the shape and form of the joint surface as a potential source of later degenerative arthritis. Irregularities may occur as a result of either primary or initial involvement of articular and epiphyseal growth cartilage and subjacent endochondral ossification (humeral condylosis, Freiberg's disease, etc.), including degrees of subjacent bony nucleus fragmention and necrosis; or secondary or initial necrosis of all or part of the bony nucleus of an epiphysis (Legg-Calve-Perthes syndrome) or epiphysoid bone (Kohler's disease) and epiphyseal endochondral ossification, which may alter gross epiphyseal architecture. Osteochondrosis dissecans is characterized by segmental epiphyseal necrosis. Interference with vascularity to the longitudinal growth plate may lead to secondary or partial necrosis of the physis and longitudinal growth arrest. Nonarticular osteochondroses (apophyses) may produce local self-limited syndromes during growth and result in surface bony prominences or irregularity at tendon attachments (Osgood-Schlatter, Panner's, trochanteric, etc.), ligament attachments (vertebral ring, elbow epicondyles, malleoli, etc.), and miscellaneous sites of impact or multiple stress (Sever's disease of os calcis, etc.), with no effect on the articulations or longitudinal growth. Osteochondroses of the longitudinal growth plate may lead to tibia vara (Blount's disease), physeal osteochondrosis of the proximal medial tibia, or vertebral osteochondrosis (Scheuermann's disease), osteochondrosis of the longitudinal growth plate of vertebrae.
Article
Two hundred ninety-five case records were included in an analysis of dogs treated by a standardized protocol for gastric dilatation/volvulus syndrome between 1986 and 1992. A breed predisposition was demonstrated for Great Danes, German Shepherd Dogs, large mixed-breed dogs, and Standard Poodles. One hundred and ninety-three dogs had gastric dilatation and volvulus (GDV) confirmed at surgery, 66 had simple gastric dilatation (GD), and 36 others had gastric dilatation but volvulus could not be proved or disproved (GD +/- V). Among dogs with GDV, the fatality rate was 15% (29/193). Twenty-six (13.5%) dogs with GDV underwent partial gastrectomy, and 8 (31%) died or were subsequently euthanatized. In comparing the group of dogs with GDV that survived to those that died, there were no statistical differences in the age of dog, time between onset of clinical signs and admission, time from admission to surgery, or duration of anesthesia. Cardiac arrhythmias were detected in 40% (78/193) of the dogs with GDV. There also was no statistical correlation between development of a cardiac arrhythmia and outcome in dogs with GDV. The causes of death in dogs with GDV were multiple and varied; presumed gastric necrosis was a common reason for intraoperative euthanasia (11 dogs). Among dogs with GD or GD +/- V, the fatality rate was 0.9% (1/102).
Article
As in herbivores and omnivores, the biosynthesis of vitamin D3 in the skin exposed to ultraviolet (uv) light is generally expected to also occur in the dog and the cat. The purpose of this in vitro study was to measure the concentrations of vitamin D3 and its precursor 7-dehydrocholesterol (7DHC) in dog and cat skin before and after a quantitatively and qualitatively standardized exposure to uv light. The results are compared to those obtained by the same method in the skin of the rat. The efficiency of extracting 7DHC and vitamin D3 from skin was 72 +/- 8% and 67 +/- 3%, respectively. In dog and cat skin the concentrations of nonesterified 7DHC were below the detection limit of the HPLC system. Therefore, skin extracts were saponified and total 7DHC and vitamin D3 concentrations were measured by normal-phase HPLC. Before irradiation with uv-B light the total concentrations of 7DHC were 1858 +/- 183, 1958 +/- 204, and 17,620 +/- 2345 ng/cm2 skin (mean +/- SEM; n = 5) for the dog, the cat, and the rat, respectively. The corresponding concentrations of vitamin D3 were 211 +/- 44, 193 +/- 18, and 161 +/- 32 ng/cm2 skin for the dog, the cat, and the rat, respectively. Irradiation of standard solutions of 7DHC with 0.15 J uv-B light/min resulted in a time-dependent decrease in 7DHC and a concomitant increase in previtamin D3.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
The Veterinary Medical Data Base was usd to conduct an epidemiologic study of gastric dilatation and dilatation-volvulus (GDV) to describe changes over time in frequency of canine hospital admissions, to identify risk factors, and to estimate their relative importance. Cases in this case-control study included 1,934 dogs with GDV that were admitted to 12 participating veterinary hospitals from 1980 to 1989. The controls were 3,868 dogs with other diagnoses that were randomly selected from the same hospitals. Frequency of GDV per 1,000 canine hospital admissions ranged from 2.9 to 6.8. The case fatality rate was 28.6 and 33.3% for gastric dilatation alone and for gastric dilatation with volvulus, respectively. Using logistic regression analysis, the odds ratio (OR) and its 95% confidence limits (95% CL) for GDV associated with purebred vs mixed-breed dogs were 2.5 and 2.1, 3.0, respectively. The risk of GDV was associated with increasing age (chi 2 = 305.6, P < 0.0001) and increasing weight (chi 2 = 627.8, P < 0.0001). Significant association of GDV risk with sex or neuter status was not found. The 5 breeds having at least 10 cases and 8 controls and with the highest risk of GDV were Great Dane (OR, 10.0; 95% CL, 6.4, 15.6), Weimaraner (OR, 4.6; 95% CL, 2.3, 9.2), Saint Bernard (OR, 4.2; 95% CL, 2.3, 7.4), Gordon Setter (OR, 4.1; 95% CL, 1.8, 9.3), and Irish Setter (OR, 3.5; 95% CL, 2.4, 5.0). The effect of increasing body weight on GDV risk was less than that of increasing ideal adult breed weight, determined by published breed standards.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
A study was done to determine whether radiographic-distraction measurement of coxofemoral joint (hip) laxity at 4 and 8 months of age can serve as a predictor of hip dysplasia in older Labrador Retrievers. The method of Smith, Biery, and Gregor was used for radiologic examination of hips and for evaluation of radiographs. Mean (+/- SEM) distraction laxity (ie, distraction index) for 10 adult disease-free dogs was 0.29 +/- 0.05, whereas a group of 8 dogs with dysplastic hips had mean distraction index of 0.60 +/- 0.10 (P < 0.05). Mean distraction index at 4 months of age for 11 pups of 4 litters from matings between dogs with normal hips was 0.39 +/- 0.07, and was 0.54 +/- 0.04 for 31 pups of 7 litters from matings between dogs with hip dysplasia. The distraction index and, thus, joint laxity at that age was significantly (P = 0.0351) different for the 2 groups. The distraction index at 4 months correlated positively with the distraction index at a later age at necropsy (r = 0.43; P = 0.0289). Distraction index < 0.4 at 4 months of age predicted normal hips in 88% of cases and distraction index > or = 0.4 predicted hip dysplasia in 57% of the dogs. Logistic regression modeling indicated that the odds of a hip being normal decreased with increasing distraction index, and thus, with increasing joint laxity. The logistic regression models provided a reasonable mathematical description of the data. Based on the logistic model of the data, distraction indexes between 0.4 and 0.7 at either 4 or 8 months of age were not associated strongly enough with evidence of disease to be clinically reliable in predicting, on an individual basis, the outcome for dysplastic hip conformation when dogs were older. Index > 0.7 was associated with high probability for developing dysplastic joints and distraction index < 0.4 predicted normal hips with high probability.
Article
Controversy exists regarding the role of GH and insulin-like growth factor-I (IGF-I) in the modulation of calcitriol production. While their administration increases serum levels of 1,25-dihydroxyvitamin D, the mechanism remains unknown. Investigations have also implicated GH as a causal factor underlying renal 25-hydroxyvitamin D-1 alpha-hydroxylase activity [1(OH)ase] secondary to phosphate depletion. Thus, we investigated the effects of IGF-I on 1(OH)ase and the relationships between these actions and those of phosphate depletion. Our studies indicate that IGF-I administration to normal mice results in a dose-dependent (0-10 micrograms/h) increase in 1(OH)ase with maximum effects evident after 24 h, independent of changes in serum calcium, phosphorus, and glucose levels. Similarly, hormone administration to phosphate-depleted mice increases enzyme activity (6.06 +/- 0.96 vs. 13.97 +/- 1.67 fmol/mg.min) but to a level significantly greater than that achieved in normals (2.72 +/- 0.4 vs. 5.01 +/- 0.56 fmol/mg.min). Furthermore, the response represents an additive increment of the effects elicited by maximum doses of IGF-I and phosphate depletion, suggesting that the hormone- and phosphate-dependent enzyme stimulation occur by different mechanisms. Thus, our data establish that IGF-I stimulates renal 1(OH)ase activity in a time- and dose-dependent fashion. However, they do not support the hypothesis that IGF-I modulates the effects of phosphate-depletion on 1(OH)ase activity. Regardless, the documentation that IGF-I stimulates enzyme function provides an explanation for many observed physiological states associated with concomitant alterations of hormone levels and calcitriol production.
Article
In growth studies with young Great Danes (0-6 months old), the effects of ad libitum (nine animals) or restricted feed supply (70-80% of ad libitum supply; 17 dogs, 9 of them bearing additional weight loads, 15% of body weight attached to the shoulder) were investigated with regard to development of the skeleton and bone composition. Growth disturbances of the skeleton were seen in every group, but the incidence increased with ad libitum feeding. Fast growth led to the valgus syndrome in fore- and hindlimbs, while hyperextensions of the carpal joint were seen, independently of the growth intensity. Weight loading in connection with energy restriction could not reproduce the same effects as ad libitum feeding. The mineral and protein concentrations in the bones (related to fat-free dry matter) were not affected either by the different feeding levels or by the weight loading.
Article
1,25-Dihydroxyvitamin D3 [1,25(OH)2D3] plays a key role in phosphate (Pi) homeostasis through its phosphatemic actions on intestine and bone. In turn, dietary Pi restriction increases serum 1,25(OH)2D3 by stimulating its production, but its effect on vitamin D catabolism is less clear. Here we have examined the effects of dietary Pi on the expression of the renal vitamin D-24-hydroxylase (24-OHase), the first enzyme in the catabolic pathway for vitamin D compounds. Rats fed a low Pi (0.02% P) diet showed a fivefold decrease in renal 24-OHase mRNA compared with rats fed a normal Pi (0.67% P) diet. 24-OHase mRNA and 24-OHase activity decreased within 24 h of Pi restriction, reached a minimum by 48 h, and remained low through 14 days. Decreased 24-OHase mRNA was observed with more moderate Pi restriction (0.2% P), but higher Pi (1.2% P) did not increase 24-OHase mRNA over the 0.8% P diet. 24-OHase mRNA correlated well with plasma Pi (r = 0.862, P < 0.001). In conclusion, renal 24-OHase expression is regulated by dietary phosphate at the mRNA level.
Article
The gastric dilatation-volvulus (GDV) syndrome in the dog is considered to be multifactorial. The medical records of 42 dogs treated for GDV between 1990 and 1994 were reviewed in an effort to evaluate the correlation between GDV and preexisting gastrointestinal disease. Twenty-three cases fit the inclusion criteria of an intestinal biopsy taken at the time of corrective surgery and a complete medical history. The microscopic jejunal changes expected from the acute vascular compromise in these animals were diffuse edema, dilatation of lymphatics with possible lymphangiectasia, mucosal degeneration, diapedesis of neutrophils, and rare hemorrhage. These changes were discounted. Of the 23 biopsies, 14 (61%) were consistent with the presence of an underlying inflammatory disease, and of these 14, 12 (86%) were accompanied by case histories of prior gastrointestinal disturbances. This study raises the possibility of an association between GDV and inflammatory bowel disease.
Article
The influence of growth hormone (GH) on calcium–phosphorus metabolism and modulation of vitamin D metabolism has been demonstrated, but the mechanism remains unclear. We investigated the effect of a 6-month course of GH therapy on vitamin D and mineral metabolism in twelve GH-deficient children. Before GH therapy, levels of vitamin D metabolites and other biochemistry data were within normal ranges. All patients responded to GH therapy with increased growth velocity. 1,25-Dihydroxyvitamin D levels increased after 1 month of treatment and remained at these higher levels, with a significant increase found at 3 months ( P < 0·05), whereas 24,25-dihydroxyvitamin D levels were decreased at 1 and 3 months, the latter being a significant decrease ( P < 0·05), and then returned to the baseline levels at 6 months. 25-Hydroxyvitamin D levels did not change significantly. A significant increase in serum insulin-like growth factor-I (IGF-I) levels occurred during the 6 months of treatment (1 month, P < 0·01; 3 and 6 months, P < 0·001). Serum parathyroid hormone (PTH) levels decreased significantly at 3 and 6 months (3 months, P < 0·01; 6 months, P < 0·05). Serum calcium and phosphorus levels did not change significantly. Significant increases were found in the urinary calcium/urinary creatinine ratio (3 and 6 months, P < 0·05) and the percent tubular reabsorption of phosphorus levels (1 and 3 months, P 0·05). The results of this study confirmed the actions of GH on renal tubules with increases in calcium excretion and phosphorus reabsorption, and indicate that the action of GH on modulating vitamin D metabolism may be IGF-I mediated, not PTH mediated. European Journal of Endocrinology 136 45–51
Article
A direct relationship between vitamin D receptor (VDR) level and target cell responsiveness to 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) has been shown in osteoblast-like cell lines. However, we previously found an inverse relationship between the TGF beta-induced VDR up-regulation and subsequent 1,25-(OH)2D3-induced biological responses. A clear inhibition of the 1,25-(OH)2D3-induced stimulation of osteocalcin and osteopontin expression was observed. A biological response that has formerly been shown to be coupled to VDR level is 24-hydroxylase activity. This enzyme initiates the C24 oxidation of the side-chain, followed by cleavage and ultimate metabolic clearance of both 25-(OH)D3 and its metabolite 1,25-(OH)2D3. With UMR 106 (rat) and MG 63 (human) osteoblast-like cells, we show that after preincubation with TGF beta, which causes an increase in VDR level, 1,25-(OH)2D3 induction of 24-hydroxylase activity is also stimulated. In addition, we provide evidence that variations in VDR level induced by other means (PTH, EGF, medium change) are also closely associated with 1,25-(OH)2D3-induced 24-hydroxylase activity. Furthermore, we show that in MG 63 cells, but not in UMR 106 cells, TGF beta itself was able to increase the activity of the enzyme 24-hydroxylase. As 24-hydroxylation is the initial step in the further C24 oxidation of 1,25-(OH)2D3, our results indicate a close coupling of VDR level and the degradation of its ligand, 1,25-(OH)2D3. This mechanism may provide an important regulatory feedback in the action of 1,25-(OH)2D3 at target tissue/cell level.
Article
A study was conducted of 101 dogs (i.e., case dogs) that had acute episodes of gastric dilatation-volvulus (GDV) and 101 dogs (i.e., control dogs) with nonGDV-related problems. The control dogs were matched individually to case dogs by breed or size, and age. Predisposing factors that significantly (p less than 0.10) increased a dog's risk of GDV were male gender, being underweight, eating one meal daily, eating rapidly, and a fearful temperament. Predisposing factors that decreased the risk of GDV significantly were a "happy" temperament and inclusion of table foods in a usual diet consisting primarily of dry dog food. The only factor that appeared to precipitate an acute episode of GDV was stress.
Article
Dietary phosphate (Pi) regulates the production of 1,25-dihydroxyvitamin D3. This control is blunted in hypophysectomized (HPX) rats but can be restored by growth hormone (GH) or IGF-I. The regulation of the vitamin D catabolism by Pi, GH and IGF-I is less clear. In the present study, we found that the activity and transcript levels of the catabolic enzyme, vitamin D-24-hydroxylase (24-OHase) were decreased 3- and 5-fold, respectively, during Pi restriction in normal rats, but this effect is greatly reduced in HPX rats. Examination of the serum chemistries revealed that HPX rats on the high Pi diet had lower serum Pi levels than normal rats on this diet, presumably due to the known defective reabsorption of Pi by HPX rats. Treatment of HPX rats, adapted to a 0.6% P diet, with GH (150 micrograms) or IGF-I (80 micrograms) suppressed 24-OHase mRNA levels by 88% and 64%, respectively, by 20 hours and these effects were preceded by decreases in serum Pi. Our findings show that the 24-OHase is regulated by dietary Pi and this control is modulated by hypophysectomy, GH and IGF-I.
Article
Questionnaires were used to obtain data about Irish setters with gastric dilatation (GD) and control Irish setters. The risk of GD increased with age (P < 0.01) but was not associated with gender. Age and gender-matched controls were compared with cases (n = 74). Predisposing risks were aerophagia (unadjusted odds ratio 12.44, P < 0.001), a single food type (adjusted odds ratio 3.15, P < 0.01) and feeding once daily (adjusted odds ratio 2.90, P < 0.02). Apparent risk from a dry food diet and a condition score of less than 2 was not confirmed by logistic regression. Precipitating risks were recent kennelling (unadjusted odds ratio 100, P < 0.005) or a car journey (unadjusted odds ratio 3.29, P < 0.025). No risk was attributed to intensity or duration of exercise, temperament, appetite, speed of eating, vomiting or diarrhoea.
Article
Reflecting the prime role of 1alpha,25(OH)2D3 in calcium homeostasis, the activity of 25-hydroxyvitamin D3 1alpha-hydroxylase, a key enzyme for 1alpha,25(OH)2D3 biosynthesis, is tightly regulated by 1alpha,25(OH)2D3, PTH and calcitonin. Its significant activity is found in kidney, though the enzymatic activity is also reported in extra-renal tissues. In the present study, we found that the 1alpha-hydroxylase gene abundantly expresses in kidney, and at low levels in other tissues and in some cell lines. Positive and negative regulations of 1alpha-hydroxylase gene by PTH, calcitonin, or 1alpha,25(OH)2D3 were observed at transcriptional levels in kidneys of animals and in a mouse proximal tubule cell line. Moreover, the protein kinase A inhibitor abrogated the PTH-mediated positive regulation. In mice lacking the vitamin D receptor, the 1alpha-hydroxylase gene expression was overinduced, and the inducible effect of either PTH or calcitonin, but not the repression by 1alpha,25(OH)2D3, was evident. Thus, vitamin D receptor is essential for the negative regulation by 1alpha,25(OH)2D3. Moreover, we demonstrate that renal 1alpha-hydroxylase gene expression in chronic renal failure model rats was decreased and the positive effect by PTH and calcitonin was diminished. The present study demonstrates that PTH and calcitonin positively regulate renal 1alpha-hydroxylase gene expression via PKA-dependent and independent pathway, respectively, and that 1alpha,25(OH)2D3 negatively regulates it mediated by vitamin D receptor. Furthermore, in a moderate state of chronic renal failure, renal cells expressing the 1alpha-hydroxylase gene appear to have diminished potential in response to PTH and calcitonin.
Article
The vitamin D endocrine systems plays a critical role in calcium and phosphate homeostasis. The active form of vitamin D, 1, 25-dihydroxyvitamin D(3) [1,25(OH)(2)D(3)], binds with high affinity to a specific cellular receptor that acts as a ligand-activated transcription factor. The activated vitamin D receptor (VDR) dimerizes with another nuclear receptor, the retinoid X receptor (RXR), and the heterodimer binds to specific DNA motifs (vitamin D response elements, VDREs) in the promoter region of target genes. This heterodimer recruits nuclear coactivators and components of the transcriptional preinitiation complex to alter the rate of gene transcription. 1,25(OH)(2)D(3) also binds to a cell-surface receptor that mediates the activation of second messenger pathways, some of which may modulate the activity of the VDR. Recent studies with VDR-ablated mice confirm that the most critical role of 1, 25(OH)(2)D(3) is the activation of genes that control intestinal calcium transport. However, 1,25(OH)(2)D(3) can control the expression of many genes involved in a plethora of biological actions. Many of these nonclassic responses have suggested a number of therapeutic applications for 1,25(OH)(2)D(3) and its analogs.
Article
The skeletal development of three groups of great dane dogs, fed a diet composed according to the published nutritional requirements for dogs (controls) or with increased calcium or calcium and phosphorus content, was examined radiographically, histologically and biochemically. The diets were fed from the time the dogs first began eating food in addition to their dam's milk, until they were 17 weeks old. Thereafter, the calcium and phosphorus intakes of the dogs in the high calcium groups were normalised for a further 10 weeks. The dogs fed the high calcium diet without a proportionally high phosphorus intake became hypercalcaemic and hypophosphataemic, and had severe disturbances in skeletal development, growth, and mineralisation which were typical for rickets. After their calcium intake was normalised the lesions of rickets resolved but osteochondrotic lesions became apparent. The dogs fed the high calcium and phosphorus diet became slightly hypophosphataemic, their growth was retarded, and they had disturbances in skeletal development resembling osteochondrosis, which had only partly resolved after 10 weeks on the normal calcium and phosphorus diet.
Article
The purpose of this paper is to summarize recent advances in our understanding of the physiological role of 24(R),25(OH)(2)D(3) in bone and cartilage and its mechanism of action. With the identification of a target cell, the growth plate resting zone (RC) chondrocyte, we have been able to use cell biology methodology to investigate specific functions of 24(R),25(OH)(2)D(3) and to determine how 24(R),25(OH)(2)D(3) elicits its effects. These studies indicate that there are specific membrane-associated signal transduction pathways that mediate both rapid, nongenomic and genomic responses of RC cells to 24(R),25(OH)(2)D(3). 24(R),25(OH)(2)D(3) binds RC chondrocyte membranes with high specificity, resulting in an increase in protein kinase C (PKC) activity. The effect is stereospecific; 24R,25(OH)(2)D(3), but not 24S,25-(OH)(2)D(3), causes the increase, indicating a receptor-mediated response. Phospholipase D-2 (PLD2) activity is increased, resulting in increased production of diacylglycerol (DAG), which in turn activates PKC. 24(R),25(OH)(2)D(3) does not cause translocation of PKC to the plasma membrane, but activates existing PKCalpha. There is a rapid decrease in Ca(2+) efflux, and influx is stimulated. 24(R),25(OH)(2)D(3) also reduces arachidonic acid release by decreasing phospholipase A(2) (PLA(2)) activity, thereby decreasing available substrate for prostaglandin production via the action of cyclooxygenase-1. PGE(2) that is produced acts on the EP1 and EP2 receptors expressed by RC cells to downregulate PKC via protein kinase A, but the reduction in PGE(2) decreases this negative feedback mechanism. Both pathways converge on MAP kinase, leading to new gene expression. One consequence of this is production of new matrix vesicles containing PKCalpha and PKCzeta and an increase in PKC activity. The chondrocytes also produce 24(R),25(OH)(2)D(3), and the secreted metabolite acts directly on the matrix vesicle membrane. Only PKCzeta is directly affected by 24(R),25(OH)(2)D(3) in the matrix vesicles, and activity of this isoform is inhibited. This effect may be involved in the control of matrix maturation and turnover. 24(R),25(OH)(2)D(3) causes RC cells to mature along the endochondral developmental pathway, where they become responsive to 1alpha,25(OH)(2)D(3) and lose responsiveness to 24(R),25(OH)(2)D(3), a characteristic of more mature growth zone (GC) chondrocytes. 1alpha,25(OH)(2)D(3) elicits its effects on GC through different signal transduction pathways than those used by 24(R),25(OH)(2)D(3). These studies indicate that 24(R),25(OH)(2)D(3) plays an important role in endochondral ossification by regulating less mature chondrocytes and promoting their maturation in the endochondral lineage.