Objective—To estimate prevalence of canine hip dysplasia
(CHD) in Golden Retrievers and Rottweilers and
identify sources of bias in published reports.
Animals—200 clinically normal Golden Retrievers and
140 clinically normal Rottweilers between 24 and 60
months of age referred for hip evaluation (group 1) and
93 clinically normal dogs evaluated for Orthopedic
Foundation for Animals (OFA) hip certification (group 2).
Procedure—Hip-extended pelvic radiographs from
group 1 dogs were screened for CHD. Radiographs
were evaluated twice; the first interpretation used an
OFA-type subjective 7-point scoring system, and the
second included the caudolateral curvilinear osteophyte
as an additional sign of degenerative joint disease.
The OFA submission rate of group 2 dogs was
determined from the number of official reports
returned from the OFA.
Results—Prevalence of CHD in Golden Retrievers
ranged from 53% to 73% and in Rottweilers ranged
from 41% to 69%. Among dogs referred for OFA evaluation,
radiographs from 49 (53%) were submitted to
OFA. Of submitted radiographs, 45 (92%) were normal;
of radiographs not submitted, 22 (50%) were
normal. Radiographs with normal-appearing hips
were 8.2 times as likely to be submitted to the OFA.
Compared with Golden Retrievers, Rottweiler radiographs
were significantly more likely to be submitted
for OFA certification.
Conclusions and Clinical Relevance—Prevalence of
CHD in these 2 breeds may be much higher than previously
reported in the United States. Results suggest
substantial bias in the OFA database, which causes
lower estimates of prevalence of CHD. (J Am Vet Med
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.