A possible predisposition to dilated cardiomyopathy in Huntaway dogs

AIM: To compare the prevalence of dilated cardiomyopathy (DCM) in New Zealand Huntaway dogs with the prevalence of DCM in other breeds of dog. METHODS: The necropsy database at Massey University was used to identify cases of DCM diagnosed between January 1999 and March 2006. Dogs were considered to have DCM if echocardiographic, gross necropsy, or histological findings were consistent with this diagnosis. The prevalence in Huntaways was then compared with the prevalence observed in all breeds of dog, as well as the prevalence observed in large breeds of dog. RESULTS: Twelve dogs were identified with DCM. One was diagnosed using echocardiography, while the other 11 were diagnosed by gross necropsy examination. The gross diagnosis of DCM was confirmed histologically in 6/11 dogs. The prevalence of DCM in Huntaways was significantly higher than the prevalence seen in all breeds of dog (p=0.008), and the prevalence in large breeds of dog (p=0.025). All four Huntaways diagnosed with DCM were male, and had an average age of 4 years. Three dogs presented with symptoms attributable to impaired heart function while one presented with symptoms of chronic renal failure. The duration of clinical symptoms prior to presentation ranged between 1 day and 3 weeks. CONCLUSIONS: The results of this study suggest that Huntaways may be predisposed to the development of DCM. Although the increased prevalence in this breed was significant, only small numbers of affected Huntaways were identified, and additional cases are required to confirm these preliminary findings. CLINICAL RELEVANCE: Huntaways are the most common working dog in New Zealand. The premature loss of a working dog is expected to have a significant economic impact on farmers. Further investigation of DCM in Huntaways may allow measures to reduce the prevalence in this breed.     

Hip dysplasia in the New Zealand Huntaway and Heading dog

AIMS: To conduct a practice-based survey to obtain, for the first time, data on hip dysplasia in the New Zealand working dog breeds of Huntaway and Heading Dogs. METHODS: A mailed request and personal approaches to farmer clients of Taihape and Waimarino Veterinary Services were used to recruit dog owners from the Taihape district in the North Island of New Zealand. Recruited dogs were radiographed under anaesthesia in a standard position with both hind limbs extended so that the femurs were parallel and rotated medially. The standard scoring system adopted by the New Zealand Veterinary Association (NZVA) Hip Dysplasia Scheme was used to score the hip radiographs of the dogs. RESULTS: Radiographs of the hips of 141 dogs (93 Huntaways; 48 Heading Dogs), were evaluated. The overall prevalence of hip dysplasia (defined as a combined score from both hips of 10) was 17.7%. Prevalences in Huntaways and Heading Dogs were 23.6% and 6.3%, respectively; in this sample of dogs, the odds ratio (and 95% confidence interval) for Huntaways having a score of 10 was 4.6 (1.316.0) that of Heading Dogs. The average scores were 10.8 for Huntaways and 5.9 for Heading Dogs. Huntaways were at the higher end of the breed average scores for dogs recorded in the NZVA Hip Dysplasia Scheme and Heading Dogs at the lower end. CONCLUSIONS: This preliminary study indicates that hip dysplasia may be a problem in the Huntaway breed. Investigation of the epidemiology of the condition in this breed is warranted and consideration should be given to removing high-risk Huntaways from the breeding pool.     

A prospective study of breed differences in the thermal pain sensitivity of dogs

Objective

To compare the thermal nociceptive thresholds (TNTs) of dogs from three working/sport breeds.

Seasonal variation in the hip score of dogs as assessed by the New Zealand Veterinary Association Hip Dysplasia scheme

Abstract

AIM: To determine whether there is a seasonal variation in the phenotypic hip score of dogs born in New Zealand as assessed by the New Zealand Veterinary Association (NZVA) canine hip dysplasia (CHD) scheme.

METHODS: Data from dogs born in New Zealand between 1988 and 2009 that have been scored for CHD were retrospectively evaluated for the effect of month of birth on radiographic phenotype. Data included both the total score and the subtotal score, comprising Norberg's angle, the subluxation score and changes to the cranial acetabular edge, for each dog. Datasets were created for all breeds combined and for the four most populous breeds using the scheme (German Shepherd dog, Labrador Retriever, Golden Retriever and Rottweiler) and stratified according to month of birth and season. Due to the skewed nature of the data, a Kruskal–Wallis Rank Sum test was used to test for statistical significance. Additionally, χ² analysis was performed using the median of each dataset (proportion above/below the median). The null hypothesis was that there would be no effect of month of birth, and hence seasonality, on hip phenotype for dogs born and scored in New Zealand by the NZVA.

RESULTS: For all breeds combined, month of birth had an effect on total and subtotal NZVA CHD scores (p<0.001) with a lower total hip score in the autumn months of March and April than other months. When individual large breed data were analysed, there was an effect of month of birth on total and subtotal scores for the Labrador Retriever and the Rottweiler (p≤0.05), but not the German Shepherd dog or Golden Retriever breeds.

CONCLUSIONS: Being born in the autumn was associated with a protective effect on hip phenotype in some breeds. These results suggest that weather and/or another seasonal factor may have a significant environmental effect on the phenotype of the coxofemoral joint.

CLINICAL RELEVANCE: The protective effect of being born in autumn suggests that a decreased level of exercise during subsequent development over winter may positively impact on final coxofemoral joint conformation. Whilst statistically significant, the magnitude of the sparing effect is not likely to be clinically relevant. However, this study, in concert with other studies, may suggest that the effects of exercise can be manipulated to improve hip phenotype.     

Comparison of two canine registry databases on the prevalence of hip dysplasia by breed and the relationship of dysplasia with body weight and height

OBJECTIVE: To compare the results of 2 canine registries for classification of the hip joints for dysplasia by breed, and to relate the percentage of dysplastic dogs with body metric characteristics. SAMPLE POPULATION: Data on the ranking order of hip dysplasia by breed from 2 registries for 156 dog breeds. PROCEDURES: The prevalence of hip dysplasia listed by the Orthopedic Foundation for Animals (OFA) and the breed mean score according to the list of the British Veterinary Association (BVA) Kennel Club Hip Dysplasia scheme were related to weight and height as well as the body mass index (BMI; kg/m(2)) by breed. RESULTS: The OFA ranking order and the percentage of dysplastic dogs were highly correlated with the BVA mean score (rho = 0.74). A significant correlation was found between the prevalence of hip dysplasia and the BMI (r = 0.63). Receiver operating characteristic curve analysis revealed that the highest area under the curve, corresponding to the best discrimination, was at a BMI of 110 kg/m(2) with a criterion value of 15% dysplastic dogs (area under the curve, 0.89). Because the ratio of dogs in the positive and negative groups reflected the prevalence of the condition among breeds in the OFA database, the positive likelihood ratio was 9.32 and the negative likelihood ratio was 0.24. CONCLUSION AND CLINICAL RELEVANCE: The OFA statistics and the BVA mean scores reflected the prevalence of hip dysplasia among dog breeds. Body mass index accurately discriminated between breeds with high or low prevalence of hip dysplasia.     

Distraction index as a risk factor for osteoarthritis associated with hip dysplasia in four large dog breeds*

Objective : To determine if age, breed, gender, weight or distraction index (DI) influenced the risk of radiographic osteoarthritis (OA) of canine hip dysplasia (CHD) in four common dog breeds; the American bulldog, Bernese mountain dog, Newfoundland and standard poodle. Materials and Methods : This was a cross sectional prevalence study with 4349 dogs. Canine hips were evaluated using 3 radiographic projections: the hip-extended view, the compression view and the distraction view. The hip-extended view was examined for the presence of OA. The PennHIP distraction view was utilized to calculate the DI. For all breeds, a multiple logistic regression model incorporating age, weight, gender, and DI was created. For each breed, disease-susceptibility curves grouping dogs on the basis of age were constructed. Receiver-operating characteristic (ROC) curves were developed for each breed regardless of age. Results : For all breeds, DI was the most significant risk factor for the development of OA associated with CHD. Weight and age were also significant risk factors in all four breeds, but gender was not. Clinical Significance : Results from this study support previous findings, that irrespective of breed, the probability of radiographic OA increases with hip joint laxity as measured by the DI. Breed-specific differences in this relationship, however, warrant investigation of all breeds affected by CHD to determine inherent dependency of hip OA on joint laxity. Such findings guide veterinarians in helping dog breeders to make evidence-based breeding decisions and in informing dog owners to implement preventative treatments for CHD for dogs found to be at risk.     

Nodular dermatofibrosis and cystic renal disease in three mixed-breed dogs and a Boxer dog

Three mixed-breed dogs and a Boxer dog with nodular dermatofibrosis are described. The three mixed breed dogs had concurrent renal epithelial cysts ( n  = 2) or renal cystadenomas ( n  = 1); these lesions were visualized antemortem on ultrasonographic examination. One of these dogs was a 7-year-old Labrador Retriever-Gordon Setter mixed breed which survived 5 years after diagnosis, and was euthanized for unrelated causes. The Boxer dog had renal cystic adenomatous hyperplasia and renal cystadenocarcinomas which were not visualized on ultrasonographic examination but were diagnosed at necropsy.     

Prevalence of the breed-related glaucomas in pure-bred dogs in North America

Objective To determine the prevalence of the breed‐related glaucomas in pure‐bred dogs presented to the veterinary medical teaching hospitals in North America that participate in the Veterinary Medical Data Base (VMDB). Materials and methods In this retrospective study, age of first diagnosis, breed, and gender data for all breeds of dogs were collected from the VMDB with the clinical diagnosis of primary glaucoma (glaucoma‐NOS) at 5–10 year intervals from 1964 to 2002. The prevalence for each breed (affected dogs compared to all dogs of each breed), any changes over the 38 years, and any gender differences for these glaucomas were determined. Results The prevalence of the primary breed‐related glaucomas has gradually increased from 0.29% (1964–1973); 0.46% (1974–1983); 0.76% (1984–1993); to 0.89% (1994–2002). Breeds that consistently featured among the highest 10 for glaucoma prevalence from four different periods (1964 to 2002) included American Cocker Spaniel, Basset Hound, Wire Fox Terrier, and Boston Terrier. During the last observation period (1994–2002), 22 different breeds had 1% or higher prevalence of the glaucomas. The highest prevalence of glaucomas in 1994–2002 by breed included: American Cocker Spaniel (5.52%); Basset Hound (5.44%); Chow Chow (4.70%); Shar‐Pei (4.40%); Boston Terrier (2.88%); Wire Fox Terrier (2.28%); Norwegian ElkHound (1.98%); Siberian Husky (1.88%); Cairn Terrier (1.82%); and Miniature Poodle (1.68%). A predominance of females with glaucoma occurred in the American Cocker Spaniel, Basset Hound, Cairn Terrier, Chow Chow, English Cocker Spaniel, Samoyed, and perhaps the Siberian Husky, and a predominance of males in the Australian Cattle dog and St Bernard. Age affected the time for first presentation of the glaucomas in the pure‐bred dog. In the majority of breeds the glaucomas were presented for initial diagnosis in dogs between 4 and 10 years of age. Conclusion Breed‐related glaucomas in pure‐bred dogs are frequently presented to the veterinary medical teaching hospitals in North America. The prevalence of the breed‐related glaucomas in the dog appears similar to humans, and in some breeds exceeds that in humans. In many breeds the high prevalence of the glaucomas suggests a genetic basis.     

Dangerous dogs in Berlin in comparison to the dog population--ways to reduce the dangerousness of dogs

The law for handling and control of dogs in Berlin of September 29, 2004 was enacted to prevent the risks for humans and animals when ever they have contact with dogs. "Dangerous dogs" are defined by this law. There are 10 breeds of dogs supposed to be dangerous due to specific characteristics of their breed ("listed breeds"). The dangerousness of a dog's breed is not identical with the dangerousness of an individual dog. The subject of this study is to examine the potential dangerousness of dog breeds and not the individual dangerousness of a dog. This study refers to statistics of incidents between dogs and humans in Berlin for the years 1998 to 2004. The population density of a breed is based on the dogs assessed for tax purposes in Berlin of January 1, 2005 and on the dog registrations maintained at veterinary hospitals. The fourfold-table-test was used to compare the quantity of the recorded incidents of two statistically independent dog breeds. Of the total population of 107,804 tax assessed dogs in Berlin in 2004, 0.9% was documented as dogs involved in incidents with humans. The incidents per year decreased in the "listed breeds"about 68% and in the "unlisted breeds" about 41% during the last 7 years in Berlin. Therefore, the probability (the odds ratio) of a breed to be conspicuous was analysed.The values for the calculation of this probability were the number of dogs of a breed having been involved in incidents compared to the population of this breed based on tax records.The comparison of the probability of a breed with another to be conspicuous was used to compile a cluster of breeds which had the same probability to be conspicuous in 2004. A cluster was assessed for dogs of the following breeds: Sheep dogs, Rottweiler, Doberman, Pitbull Terrier and American Staffordshire Terrier. A listing of breeds is not the right way to reduce the potential dangerousness of a dog, especially in the private domain of their owners. Most incidents with dogs occur in the private domain which normally is not recorded in the statistics of incidents. Therefore, it is more effective to support activities which include the training of abilities of the dog owners.Training by experts can enable dog owners to avoid conflict situations with their dog, or in case of conflict, to take appropriate actions.     

Long-term assessment of pancarpal arthrodesis performed on working dogs in New Zealand

AIM: To determine the outcomes following unilateral pancarpal arthrodesis (PCA) in working dogs in New Zealand, in terms of return to work and ability, as assessed by the owner. METHODS: Working dogs treated using unilateral PCA were identified by searching the medical records of the Massey University Veterinary Teaching Hospital (MUVTH) by diagnosis and breed code. Eight Heading dogs (working Collies) and four New Zealand Huntaways were identified with carpal pathology that had been treated by dorsal-plate application, bone-grafting, and casting. All dogs were actively in work on sheep or cattle farms at the time of injury. Case files and radiographs were retrospectively analysed, and the ability of the dog to work after surgery and owner satisfaction with the outcome were assessed using a questionnaire conducted at a mean follow-up interval of 5 years. RESULTS: Following arthrodesis, 6/12 (50%) dogs could perform duties as before surgery. A further four (33%) dogs could perform most former duties. Ten of the twelve owners were satisfied or very satisfied with resultant mobility and work performance of their dogs. Post-operative complications occurred in 50% of dogs, but in only one case affected the eventual outcome. Eleven owners felt surgical repair was worthwhile in a trained working dog. CONCLUSIONS: Unilateral PCA carries a good prognosis for working dogs in New Zealand to return to work, even on hill-country properties. CLINICAL RELEVANCE: This study may allow veterinarians to provide a more accurate prognosis for working dogs requiring PCA. Working dogs that have sustained severe carpal injury including hyper-extension injury, luxation and fracture, or dogs with crippling carpal osteoarthrosis (OA) can return to work after PCA.     

Analysis of uroliths from cats and dogs in New Zealand, 1993-96

AIMS: Canine and feline uroliths were analysed to determine the prevalence of particular types of urolith and the dog breeds at risk. METHODS: Three hundred and sixty-nine uroliths recovered from 316 dogs and 53 cats between November 1993 and December 1996 were analysed by X-ray diffraction, and by infrared spectrometry where X-ray diffraction alone was non-diagnostic. RESULTS: Bitches of small breeds especially Welsh corgi and Bichon frise, were most frequently affected. Struvite was the most common urolith (204 dogs). Oxalate (60 dogs) was the second most prevalent urolith identified, followed by cystine (24 dogs). The breeds producing cystine calculi were: Dalmatian, Bassett hound, Borzoi, Newfoundland, Shetland sheepdog, Labrador, Chihuahua, Fox terrier, English bulldog, Bichon frise, Doberman pinscher, Border collie. Silica uroliths were identified for the first time in New Zealand. All feline uroliths were struvite. CONCLUSION: The results are useful in determining the prevalence of specific types of urolith in New Zealand and the breeds at risk of forming them.     

VERTEBRAL HEART SIZE IN RETIRED RACING GREYHOUNDS

The vertebral heart size (VHS) is used to objectively assess cardiac dimensions on thoracic radiographs. A high VHS suggest the presence of cardiac pathology, such as dilated cardiomyopathy, degenerative atrioventricular valvular disease, pericardial effusion, pericardioperitoneal diaphragmatic hernia, tricuspid dysplasia, ventricular septal defect, or patent ductus arteriosus, among others. However, breed or body conformation can influence the VHS. Because Greyhounds have a high prevalence of physiologic systolic murmurs associated with high aortic velocity, and large cardiac dimensions when compared with dogs of similar size, they are frequently suspected of having heart disease. The purpose of this study was to compare the VHS in normal Greyhounds with those in Rottweilers, and a group of dogs from various other breeds using both analog and digital radiology. The VHS was significantly higher in Greyhounds (P< 0.0001), when compared with Rottweilers and to other dog breeds. The mean VHS on lateral radiographs for Greyhounds was 10.5 +/- 0.1, for Rottweilers it was 9.8 +/- 0.1, and for mixed breed dogs it was 10.1 +/- 0.2. This study confirms that the relative cardiomegaly reported in necropsy and echocardiographic studies in Greyhounds is easily detected using plain radiography and the VHS.     

Breed-specific pro-inflammatory cytokine production as a predisposing factor for susceptibility to sepsis in the dog

Objective: To determine whether 2 dog breeds with a high risk for parvoviral enteritis, a disease associated with sepsis, produce stronger pro‐inflammatory cytokine responses to a stimulus than dogs with a lower risk. Design: Blinded comparison. Setting: University outpatient clinic. Animals: Healthy, unrelated, purebred Doberman Pinschers (n=10) and Rottweilers (n=9) with age‐matched mixed‐breed dogs (n=7). Interventions: Heparinized, whole‐blood samples were collected from each dog and incubated for 6 hours with lipopolysaccharide. Plasma was collected, and bioassays were used to determine the concentrations of TNF‐α and IL‐6. The mean values obtained from the high‐risk breeds were compared with the mean obtained from the mixed‐breeds. Measurements and main results: The mean TNF‐α production from dogs with a high risk for parvoviral enteritis (1321±161 pg/mL; Doberman Pinscher and Rottweiler) was greater (P<0.05) than that from lower risk, mixed‐breed dogs (674±186 pg/mL). There were no differences in TNF‐α levels between Doberman (1128±247 pg/mL) and Rottweiler (1563±pg/mL) breeds or between any breeds with regard to IL‐6 production. Conclusions: The magnitude of TNF‐α production by peripheral blood monocytes was the greatest in the dogs with breed‐related risk for parvoviral enteritis. However, additional studies are needed to prove a causal relationship between high TNF and predilection for parvoviral enteritis. Regardless, breed appears to be a predisposing factor for variations in cytokine production that could impact the host response to infection and other inflammatory insults.     

Congenital sensorineural deafness in dogs: a molecular genetic approach toward unravelling the responsible genes

Deafness is often diagnosed in different dog breeds and has been identified as a significant problem for breeders, owners and clinicians. The aetiology can be inherited or acquired, and a distinction must be made between sensorineural and conductive forms of deafness. This paper provides a brief overview of the varieties of findings in different dog breeds and in one breed in particular including prevalence, phenotypic and gender associations, histology, modes of inheritance and the number of contributing genes in congenital sensorineural deafness. We have also described molecular genetic approaches to canine hearing loss and discuss how comparative genomics could help reduce the prevalence of deafness in affected breeds leading to new insights into the molecular mechanisms of auditory function in both dogs and humans.     

Prevalence of canine cataract: preliminary results of a cross-sectional study

Objective In this study 2000 dogs were examined ophthalmoscopically to determine presence of cataract. Materials and methods The dogs examined were predominantly from veterinary hospital populations but also from the Waltham Center For Pet Nutrition, rehoming charities and breeding kennels. Prevalence of cataract was thus determined for different age groups (year cohorts). The age at which prevalence of cataract was 50% (C₅₀) was determined indirectly from a fitted prevalence curve. Results The mean ± standard deviation of C₅₀ for all dogs in the study was 9.4 ± 3.3 years. All dogs over 13.5 years were affected by some degree of lens opacity. C₅₀ was determined for animals of different genders and different breeds. For dogs of six breeds sufficient data were available for calculation of breed‐specific C₅₀. In these dogs C₅₀ was positively correlated with longevity with a least squares correlation coefficient of 0.74. Conclusion The study yields novel findings regarding the prevalence and incidence of cataract in the dog and forms the basis for considerable further work on the epidemiology and pathophysiology of age‐related cataract in the dog.     

Mucopolysaccharidosis type VI in a Miniature Poodle-type dog caused by a deletion in the arylsulphatase B gene

Abstract

AIM: To investigate and characterise an inborn error of metabolism in a dog with skeletal and ocular abnormalities.

METHODS: A 2.5-year-old small male Miniature Poodle-like dog was presented with gross joint laxity and bilateral corneal opacities. Clinical examination was augmented by routine haematology, serum chemistry, radiographs, pathology, enzymology and molecular genetic studies. Euthanasia was requested when the dog was 3 years of age because of progressively decreasing quality of life.

RESULTS: Radiology revealed generalised epiphyseal dysplasia, malformed vertebral bodies, luxation/subluxation of appendicular and lumbosacral joints with hypoplasia of the odontoid process and hyoid apparatus. These clinical and radiographic findings, together with a positive urinary Berry spot test for mucopolysaccharides, and metachromatic granules in leucocytes, were indicative of a mucopolysaccharidosis (MPS), a lysosomal storage disease. Histological lesions included vacuolation of stromal cells of the cornea, fibroblasts, chondrocytes, macrophages and renal cells. The brain was essentially normal except for moderate secondary Wallerian-type degeneration in motor and sensory tracts of the hind brain. Dermatan sulphate-uria was present and enzymology revealed negligible activity of N-acetylgalactosamine-4-sulphatase, also known as arylsulphatase B, in cultured fibroblasts and liver tissue. A novel homozygous 22 base pair (bp) deletion in exon 1 of this enzyme's gene was identified (c.103_124del), which caused aframe-shift and subsequent premature stop codon. The “Wisdom pure breed-mixed breed” test reported the dog as a cross between a Miniature and Toy Poodle.

CONCLUSIONS: The clinicopathological features are similar to those of MPS type VI as previously described in dogs, cats and other species, and this clinical diagnosis was confirmed by enzymology and molecular genetic studies. This is an autosomal recessively inherited lysosomal storage disease.

CLINICAL RELEVANCE: The prevalence of MPS VI in Miniature or Toy Poodles in New Zealand and elsewhere is currently unknown. Due to the congenital nature of the disorder, malformed pups may be subject to euthanasia without investigation and the potential genetic problem in the breed may not be fully recognised. The establishment of a molecular genetic test now permits screening for this mutation as a basis to an informed breeding policy.     

Epidemiologic factors associated with the anatomic location of intrahepatic portosystemic shunts in dogs

OBJECTIVE: To determine whether breed, sex, country of origin, and age are associated with anatomic location of intrahepatic portosystemic shunts (IHPSS) in dogs. STUDY DESIGN: Multi-institutional retrospective case series. SAMPLE POPULATION: Dogs (n=125) with IHPSS from the veterinary teaching hospitals of the University of Florida (21), Sydney University (44), and the University of California-Davis (60). METHODS: Dogs with surgical/necropsy confirmation of single IHPSS were identified. Data were analyzed using logistic regression for associations between age, breed, sex, and country with the anatomic location of IHPSS. RESULTS: Right (34%), left (34%), and central divisional IHPSS (32%) were prevalent with approximately equal frequency in Australia; in the United States, the prevalence of right (24%) and central divisional (26%) combined was similar to left divisional IHPSS (51%). Country (P=048), sex (P=.016), and Australian cattle dog ([ACD], P=.025) were significantly associated with IHPSS location. Dogs in Australia had 2.5-fold higher odds of having right versus left divisional IHPSS. Males and ACD had 2.8- and 5.6-fold higher odds of having right versus left divisional IHPSS. Australian dogs were significantly older than those in the United States (P<.0001) and ACD were significantly older than other breeds (P=.0067). CONCLUSIONS: Although country of origin, breed, and sex had significant associations with anatomic location of IHPSS, signalment does not appear to be a strong predictor of shunt location when used alone. CLINICAL RELEVANCE: For the common breeds in this report, signalment is only occasionally helpful in predicting likelihood of anatomic division in IHPSS. Australian cattle dogs and male dogs have a statistical association with right (versus left) divisional IHPSS. If advanced imaging techniques are not available, veterinary surgeons should be prepared to locate and address any anatomic configuration of IHPSS in a dog.     

Comparison of two radiographic techniques for evaluation of hip joint laxity in 10 breeds of dogs

OBJECTIVE: To evaluate hip joint laxity in 10 breeds of dogs via 2 radiographic techniques. ANIMALS: 500 clinically normal dogs. DESIGN: Prospective study. PROCEDURE: Radiographs obtained via routine hip joint evaluations performed in sedated dogs of 10 popular breeds were randomly selected from a database. Measurements of distraction index (DI) and hip-extended index (HEI) on 1 hip joint radiograph randomly chosen from each dog were made. RESULTS: Mean age of dogs was 20.7 months. Mean HEI was 0.17 (range, 0.0 to 0.72) and mean DI was 0.44 (range, 0.07 to 0.96). Borzois had uniformly tight hip joints as judged by use of both methods and were considered the gold standard by which hip joint laxity was judged (all Borzois had DI < or = 0.32). Overall, DI was significantly greater than HEI. Within each breed, mean DI was always greater than mean HEI. Significant differences were detected among breeds for HEI; however, compared with DI, the magnitude of differences among breeds was less. CONCLUSIONS AND CLINICAL RELEVANCE: Distraction radiography detected the greatest range and magnitude of passive hip laxity in the 10 breeds of dogs. The difference in values between breeds known to have high prevalence of canine hip dysplasia and those in Borzois was greater for DI than for HEI. Breeds must be evaluated individually because of inherent differences in hip joint laxity.     

The effects of dog breed development on genetic diversity and the relative influences of performance and conformation breeding

Genetic diversity was compared among eight dog breeds selected primarily for conformation (Standard Poodle, Italian Greyhound and show English Setter), conformation and performance (Brittany), predominantly performance (German Shorthaired and Wirehaired Pointers) or solely performance (field English Setter and Red Setter). Modern village dogs, which better reflect ancestral genetic diversity, were used as the standard. Four to seven maternal and one to two Y haplotypes were found per breed, with one usually dominant. Diversity of maternal haplotypes was greatest in village dogs, intermediate in performance breeds and lowest in conformation breeds. Maternal haplotype sharing occurred across all breeds, while Y haplotypes were more breed specific. Almost all paternal haplotypes were identified among village dogs, with the exception of the dominant Y haplotype in Brittanys, which has not been identified heretofore. The highest heterozygosity based on 24 autosomal microsatellites was found in village dogs and the lowest in conformation (show) breeds. Principal coordinate analysis indicated that conformation‐type breeds were distinct from breeds heavily used for performance, the latter clustering more closely with village dogs. The Brittany, a well‐established dual show and field breed, was also genetically intermediate between the conformation and performance breeds. The number of DLA‐DRB1 alleles varied from 3 to 10 per breed with extensive sharing. SNPs across the wider DLA region were more frequently homozygous in all pure breeds than in village dogs. Compared with their village dog relatives, all modern breed dogs exhibit reduced genetic diversity. Genetic diversity was even more reduced among breeds under selection for show/conformation.     

FC‐24 Risk factors for atopic dermatitis in a Swedish population of insured dogs

Studies into the epidemiology of canine atopic dermatitis (CAD) are in great demand. Estimates of the prevalence and incidence of CAD are commonly based on hospital studies where no reference population is defined. Such studies tend to overestimate the disease frequency due to referral bias and a higher proportion of complicated cases at secondary care centres than in the general population. The aim of this paper was to present better estimates of the incidence of CAD. The Swedish dog population offers unique opportunities to study the epidemiology of CAD due to several characteristics: a large proportion of dogs are purebred, fleas and flea allergies are rare, and a secondary database of disease records is available through an insurance company that covers approximately 30% of all Swedish dogs. By accessing insurance‐claims records for the years 1995–2000, the true incidence rate of CAD was estimated as 10 cases per 10,000 dog years at risk. Univariate analysis showed that the incidence was the same across genders. Additionally, large differences in the risk of being diagnosed with CAD existed among breeds. In this study, breeds with the highest risk were the bull terrier (88 cases/10,000 dog years at risk), Staffordshire bull terrier (58/10,000), West Highland white terrier (51/10,000), Welsh terrier (50/10,000) and boxer (50/10,000). Decreased risk was observed among sighthounds; no cases were recorded among the Borzoi, Saluki and Whippet breeds. A proportional hazards (survival) model was developed in order to take sex, breed, age and geographical region into account in a multivariate analysis. Funding: Swedish University of Agricultural Sciences, The Foundation for Research.