Genetic improvement of canine hip dysplasia through sire selection across countries.

Breeding against canine hip dysplasia (HD) may benefit from the importation of foreign sires. When foreign sires are evaluated on a different HD scale, this may diminish the efficacy. Using stochastic simulations, we evaluated genetic change and inbreeding levels for different scenarios of importing sires with high genetic merit for HD. Population size and genetic parameters (e.g. heritability, accuracy of selection, genetic correlation) were based on actual data for HD in Golden retrievers and Labrador retrievers in the UK and Sweden. For countries with different HD scales and an estimated breeding value (EBV) evaluation in place, the importation was useful if imported sires had EBV rankings in the top 50% and if genetic correlations between EBV systems were above 0.85. When importing sires with EBV rankings in the top 10%, moderate accuracies of EBVs (>0.40) and moderately strong genetic correlations (>0.70) were needed. Selection against HD without the importation of sires may increase inbreeding levels, while the importation of sires can decrease inbreeding levels. For national genetic evaluation and selection programmes, importing sires with high genetic merit can be an effective breeding strategy, but care is needed to estimate reliable EBVs.

Effect of a commercially available fish-based dog food enriched with nutraceuticals on hip and elbow dysplasia in growing Labrador retrievers.

The aim of this study was to evaluate the prevalence of hip and elbow dysplasia in a group of growing Labrador retrievers fed a fish-based diet enriched with nutraceuticals with chondroprotective properties. The puppies ranged from 3 to 12 mo of age and were divided into 2 groups, each fed a different diet. The control diet consisted of a high quality, chicken-based dog food, while the test diet was a fish-based dog food, enriched with nutraceuticals. Hip and elbow joints were radiographed and scored at 6 and 12 mo of age. Overall, 42 dogs completed the study. At 12 mo of age, no differences were found between the groups in the prevalence of hip and elbow dysplasia, although dogs fed the fish-based food enriched with nutraceuticals had a less severe grade of osteoarthritis at 12 mo. It was concluded that the fish-based diet with nutraceuticals did have beneficial effects on the development of severe osteoarthritis.

L'objectif de la présente étude était d'évaluer la prévalence de dysplasie de la hanche et du coude dans un groupe de chiens Labrador en croissance nourris avec une diète à base de poisson enrichie de neutraceutiques ayant des propriétés chondroprotectrices. L'âge des chiots variait de 3 à 12 mois et ils ont été divisés en deux groupes, chacun étant nourri avec une diète différente. La diète témoin consistait d'un aliment de haute qualité pour chien à base de poulet, alors que la diète test était un aliment pour chien à base de poisson et enrichi avec des neutraceutiques. Les articulations des hanches et des coudes ont été radiographiées à 6 et 12 mois d'âge. Un total de 42 chiens a complété l'étude. À 12 mois d'âge, aucune différence n'a été trouvée entre les groupes dans la prévalence de dysplasie de la hanche et du coude, bien que les chiens nourris avec la diète à base poisson enrichie de neutraceutiques avaient un score d'ostéoarthrite moins sévère à 12 mois. Il a été conclu que la diète à base de poisson enrichie de neutraceutiques avait des effets bénéfiques sur le développement d'ostéoarthrite sévère.(Traduit par Docteur Serge Messier).

El Pennhip modificado y la sinfisiodesis juvenil pubiana como prevención de displasia de cadera canina en las Fuerzas Armadas / Modified Pennhip and juvenile pubic symphysiodesis as canine hip dysplasia prevention in the Armed Forces

INTRODUCCIÓN: La displasia de cadera canina es la principal causa física de exclusión de los perros de los programas de adiestramiento en las Fuerzas Armadas y los Cuerpos y Fuerzas de Seguridad del Estado, es por ello importante realizar una criba temprana de esta patología. OBJETIVO: Determinar la eficacia del procedimiento del Penn-Hip modificado y la sinfisiodesis juvenil pubiana como método para prevenir el desarrollo de la displasia de cadera canina. MATERIAL Y MÉTODO: Estudio descriptivo y ambispectivo que compara el porcentaje de displasia de cadera canina en una cohorte prospectiva, tras la realización de un programa de screening y cirugía profiláctica, con los resultados de una cohorte histórica. RESULTADOS: El porcentaje de displasia de cadera canina fue el doble en la cohorte histórica comparándola con la cohorte prospectiva tras la implantación del programa, siendo las diferencias estadísticamente significativas (OR: 2,20; IC 95%: 1,03-4,67). CONCLUSIONES: Es necesaria la instauración de programas de screening y profilaxis de displasia de cadera canina, en el ámbito militar al mejorar la producción de perros aptos para el trabajo en las Fuerzas Armadas y en los Cuerpos y Fuerzas de Seguridad del Estado

INTRODUCTION: Canine hip dysplasia is the main clinic cause of exclusion of dogs from training programs in the Armed Forces and Police Corps so it is important to make an early selection of this pathology. OBJECTIVE: To determine the efficiency of the modified Penn-Hip method and the juvenile pubic symphysiodesis as a way of preventing canine hip dysplasia development. MATERIAL AND METHOD: Ambispective descriptive study which compares the percentage of canine hip dysplasia between a historical cohort and a prospective cohort after the instauration of a screening and surgical prophylactic program. RESULTS: The percentage of canine hip dysplasia from the historical cohort doubled the one from the prospective cohort after carrying out the program, obtaining statistically significance differences (OR: 2,20; IC 95%: 1,03-4,67). CONCLUSIONS: Implementation of a screening and prophylactic program of canine hip dysplasia is needed to improve work-suited canine production in the Armed Forces and Police Corps

Selection against canine hip dysplasia: success or failure?

Canine hip dysplasia (CHD) is a multifactorial skeletal disorder which is very common in pedigree dogs and represents a huge concern for canine welfare. Control schemes based on selective breeding have been in operation for decades. The aim of these schemes is to reduce the impact of CHD on canine welfare by selecting for reduced radiographic evidence of CHD pathology as assessed by a variety of phenotypes. There is less information regarding the genotypic correlation between these phenotypes and the impact of CHD on canine welfare. Although the phenotypes chosen as the basis for these control schemes have displayed heritable phenotypic variation in many studies, success in achieving improvement in the phenotypes has been mixed. There is significant room for improvement in the current schemes through the use of estimated breeding values (EBVs), which can combine a dog's CHD phenotype with CHD phenotypes of relatives, other phenotypes as they are proven to be genetically correlated with CHD (especially elbow dysplasia phenotypes), and information from genetic tests for population-relevant DNA markers, as such tests become available. Additionally, breed clubs should be encouraged and assisted to formulate rational, evidenced-based breeding recommendations for CHD which suit their individual circumstances and dynamically to adjust the breeding recommendations based on continuous tracking of CHD genetic trends. These improvements can assist in safely and effectively reducing the impact of CHD on pedigree dog welfare.

Diagnosis, genetic control and preventive management of canine hip dysplasia: a review.

Despite expensive screening and breeding programmes, hip dysplasia (HD) continues to be one of the most common orthopaedic diseases in dogs. The vast majority of dogs afflicted with HD show minimal to no clinical signs, but it can also be a highly debilitating condition for both working and pet dogs. Hip joint laxity is considered a major risk factor for the development of degenerative joint disease and a definitive diagnosis is made if characteristic signs are evident on a ventrodorsal view of the pelvis. Early prediction of the condition can be made using stress radiographic techniques to evaluate the passive hip laxity. The diagnosis of HD may be used for the purpose of selecting breeding stock or to decide on the best treatment approach. Breeding programmes based on individual dog phenotypes have been ineffective and a selection procedure based on breeding value (BV) estimation is recommended. Traditional conservative and surgical treatment approaches are reserved for dogs with overt clinical signs of the disease but such treatments can be expensive and aggressive, and are often ineffective in eliminating clinical signs or subluxation and in preventing the development of degenerative joint disease. The implementation of breeding programmes based on BVs and further research into early prediction/diagnosis of HD and effective preventive treatment approaches are essential.

Update of a retrospective cohort study of changes in hip joint phenotype of dogs evaluated by the OFA in the United States, 1989-2003.

OBJECTIVE: To determine whether there has been improvement in canine hip joint phenotype classifications of dogs whelped from 1989 to 2003 by the Orthopedic Foundation for Animals (OFA), by examining results of radiographic evaluations and identifying any trends in percentages of dogs classified as having desirable hip joint phenotypes. STUDY DESIGN: Retrospective cohort study. SAMPLE POPULATION: OFA radiographic classifications (n=431,483) on dogs whelped between 1989 and 2003. METHODS: Numbers and percentages of dogs classified by hip joint phenotypes were determined for 2-year cohorts. Differences between breeds and sexes were assessed using the Fisher's exact test, and odds ratios with 95% confidence intervals were calculated to express associations. The Cochran-Armitage test for trend was calculated to identify significant trends over time. RESULTS: There were statistically significant (P<.05) increases in the proportion of all breeds of dogs evaluated as excellent and good from 1993 to 2003, controlling for gender and age at evaluation. Labrador Retrievers, Bernese Mountain Dogs, and Rottweilers had the highest proportions of excellent and good scores, and the highest rates of improvement in excellent and good scores were seen in Bernese Mountain Dogs and Rottweilers. CONCLUSIONS: Results support the contention that there have been improvements in hip joint phenotype classifications in dogs in the United States since the previous study (1989-1992), through increases in the proportion of dogs receiving excellent and good classifications. CLINICAL RELEVANCE: Hip joint phenotype classifications can be used by dog breeders to develop breeding programs to improve the hip joints of future generations of dogs.

Transmission of relaxin and estrogens to suckling canine pups via milk and possible association with hip joint laxity.

OBJECTIVE: To determine whether abnormal laxity of hip joints of canine pups with genetic predisposition to hip dysplasia (HD+) is related to ingestion of milk-borne hormones. ANIMALS: 7 female Labrador Retrievers with HD+ and 8 with low predisposition to hip dysplasia (HD-) and their offspring. PROCEDURES: Immunoactive relaxin, estrogen, and estrogen precursor concentrations in milk of HD+ lactating bitches and in serum of their pups were compared with those of HD- bitches and pups. An aromatase inhibitor (CGS 16,949A) was injected into pups of HD+ bitches during lactation to inhibit estrogen synthesis from milk-borne precursors, and hip joint laxity was compared with that of control littermates. Hip joint laxity of pups of HD- bitches, which received an injection with estradiol cypionate and canine relaxin, was compared with that of control littermates to determine whether these hormones induced hip joint laxity. RESULTS: High concentrations of estrogens and relaxin were found in milk of HD+ and HD- bitches throughout lactation. Serum concentrations of milk-derived relaxin and total estrogens were similar in all pups, but estradiol-17B was detected only in pups of HD+ bitches. Hip joint laxity was reduced in pups that received CGS 16,949A. Hip joint laxity was INCREASED IN PUPS OF HD- BITCHES THAT RECEIVED ESTRADIOL CYPIONATE AND RELAXIN. CONCLUSIONS AND CLINICAL RELEVANCE: Milk-borne maternal hormones and precursors were absorbed into the circulation of canine neonates and may play a role in hip joint laxity in HD+ pups. Phenotypic expression of hip dysplasia may therefore be preventable by antihormone treatment.

Evaluation of a circumferential femoral head osteophyte as an early indicator of osteoarthritis characteristic of canine hip dysplasia in dogs.

OBJECTIVE: To determine the relationship between a circumferential femoral head osteophyte (CFHO) and osteoarthritis characteristic of canine hip dysplasia, and to ascertain whether CFHO, like osteoarthritis, varies between diet-restricted and control-fed dogs. DESIGN: Longitudinal cohort study. ANIMALS: 48 Labrador Retrievers. PROCEDURES: Dogs were paired by size, sex, and litter and assigned to 1 of 2 equal groups at 2 months of age. The control-fed group was fed ad libitum, and the diet-restricted group was fed 25% less on a pairwise basis of the same diet for life. The dogs' hip joints were radiographed yearly for life. Each radiograph was evaluated for radiographic signs of osteoarthritis characteristic of hip dysplasia and for the presence and severity of a CFHO. RESULTS: 41 of the 48 (85.4%) dogs had a CFHO, which was detected at a median age of 5.4 years, and 33 of those 41 (80.5%) developed radiographic evidence of osteoarthritis. Nineteen (79.2%) dogs in the diet-restricted group and 22 (91.7%) in the control-fed group had a CFHO at a median age of 9 and 3 years, respectively. Of the dogs with a CFHO, 12 (63.2%) in the diet-restricted group and 20 (90.0%) in the control-fed group developed radiographic evidence of osteoarthritis characteristic of hip dysplasia at a median age of 11 and 6.5 years, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated a relationship between the CFHO and subsequent development of radiographic signs of osteoarthritis. If a CFHO is present in Labrador Retrievers, it might be considered an early indicator of osteoarthritis.

Lifelong diet restriction and radiographic evidence of osteoarthritis of the hip joint in dogs.

OBJECTIVE: To evaluate the effects of diet restriction on development of radiographic evidence of hip joint osteoarthritis in dogs. DESIGN: Longitudinal cohort study. ANIMALS: 48 Labrador Retrievers from 7 litters. PROCEDURES: Forty-eight 6-week-old puppies from 7 litters were paired with littermates by sex and weight, and each pairmate was randomly assigned to 1 of 2 groups of 24 dogs each. Starting at 8 weeks of age, 1 group was fed ad libitum (control fed) and the other was fed 25% less (restricted fed) of the same diet for life on a pairwise basis. The dogs' hip joints were radiographed in the standard ventrodorsal hip-extended view at multiple intervals prior to 1 year of age and at annual intervals thereafter on the basis of birth anniversary. A board-certified radiologist unaware of group assignment scored the radiographs for evidence of osteoarthritis. RESULTS: Prevalence of radiographic evidence of hip joint osteoarthritis in all dogs increased linearly throughout the study, from an overall prevalence of 15% at 2 years to 67% by 14 years. Restricted-fed dogs had lower prevalence and later onset of hip joint osteoarthritis. Median age at first identification of radiographic evidence of hip joint osteoarthritis was significantly lower in the control-fed group (6 years), compared with the restricted-fed group (12 years). CONCLUSIONS AND CLINICAL RELEVANCE: Restricted feeding delayed or prevented development of radiographic signs of hip joint osteoarthritis in this cohort of Labrador Retrievers. Lifetime maintenance of 25% diet restriction delayed onset and reduced severity of hip joint osteoarthritis, thus favorably affecting both duration and quality of life. In addition, the data indicated that development of hip joint osteoarthritis was not bimodal in these dogs but occurred as a continuum throughout life.

An epidemiological approach to prevention and control of three common heritable diseases in canine pedigree breeds in the United Kingdom.

This paper reviews recent epidemiological research in the United Kingdom for controlling deafness in Dalmatians, glaucoma in flat coated retrievers and great Danes and hip dysplasia in flat coated retrievers, Newfoundlands, Gordon setters and Labrador retrievers. These studies assessed the prevalence of the disease, identified the factors affecting prevalence, and developed predictive statistical models of offspring/parent relationships. For each disease/breed combination, the research identified those sires and dams that might justifiably be regarded as suitable/unsuitable as potential parents in a selective breeding strategy to control or prevent the disease. Future progress in the control of these diseases is likely to come from greater understanding of their mode of inheritance. Insight, even for these complex diseases, can be derived from further detailed statistical evaluation of datasets such as those described in this paper.

Effect of public symphysiodesis on pelvic development in the skeletally immature greyhound.

OBJECTIVE: To evaluate the effect of pubic symphysiodesis (PS) on pelvic development in skeletally immature dogs. STUDY DESIGN: Prospective randomized clinical trial. ANIMALS: Eight 4 month-old, sexually intact female Greyhounds. METHODS: Initial PS was performed at 4 months of age using a powered stapling device. Because of failure of the initial surgery, a second PS was performed 1 month later by resecting the pubic symphysis with a rongeur followed by placement of handmade bone staples in four dogs. Sham PS was performed in four control dogs at 4 months of age. Pubic growth rate and pelvic development were evaluated using standard plane radiography and computed tomography. Specific measurements included acetabular ventroversion, Norberg angle, lateral center-edge angle, and pelvic inlet dimensions. Hip distraction indices were determined as well. RESULTS: PS at 4 months of age using a stapling device failed. Pubic symphysiodesis using hand made staples was successful at 5 months of age and did not result in any clinically significant intraoperative or postoperative complications. Pubic symphysiodesis markedly decreased pubic symphysis growth in the treatment group. Hip distraction indices and pelvic inlet circumference, area, and width significantly decreased in treated dogs compared to those in the control group. Acetabular ventroversion was significantly increased in treated dogs compared to those in the control group. CONCLUSIONS: PS decreases pelvic canal size, increases acetabular ventroversion, and does not appear to have any clinically significant complications. CLINICAL RELEVANCE: PS performed in skeletally immature dogs with hip dysplasia may provide an effect similar to a triple pelvic osteotomy and warrants further investigation.

Controlling canine hip dysplasia in Finland.

The aim of the study was to evaluate the Finnish Kennel Club's hip-dysplasia screening and control programs. As a retrospective study, records of hip-dysplasia screening of 69,349 dogs in 22 breeds that were born in 1988-1995 were analyzed and compared to data from prior to 1988. In most breeds, no significant changes in dysplasia prevalence could be found. In English cocker spaniels, golden and Labrador retrievers and Rottweilers a significant decrease - but in boxers, Dobermans, German Shepherd dogs and rough collies a significant increase - in prevalence was detected. In flat-coated retrievers overall prevalence increased - but the prevalence of severe hip-dysplasia decreased significantly during the study period. The present control program has not resulted in fast progress. Selecting against hip-dysplasia cannot be expected to be very effective, when based only on mass selection on phenotypic observations. Predicted breeding values based on progeny testing would probably give better results. Also, breeders' compliance and commitment to programs is not always high and other selection criteria in breeding are thought to be more important. Modern society has high demands for animal welfare and consumer issues, and breeders and kennel societies should pay more attention to health issues in breeding pedigreed dogs.