Objective—To describe effects of lifetime food
restriction on causes of death and the association
between body-mass characteristics and time of death
Animals—48 dogs from 7 litters.
Procedures—Dogs were paired, and 1 dog in each
pair was fed 25% less food than its pair mate from 8
weeks of age until death. Numerous morphometric
and physiologic measures were obtained at various
intervals throughout life. Associations of feeding
group to time and causes of death were evaluated,
along with important associated factors such as body
composition components and insulin-glucose
Results—Median life span was significantly longer
for the group that was fed 25% less food, whereas
causes of death were generally similar between the 2
feeding groups. High body-fat mass and declining
lean mass significantly predicted death 1 year prior to
death, and lean body composition was associated
with metabolic responses that appeared to be integrally
involved in health and longevity.
Conclusions and Clinical Relevance—Results were
similar to results of diet restriction studies in rodents
and primates, reflecting delayed death from species-
and strain-specific intrinsic causes. Clinicians should
be aware that unplanned body mass changes during
mid- and later life of dogs may indicate the need for
thorough clinical evaluation. (J Am Vet Med Assoc 2005;226:225–231)
Objective—To determine the relationship between
the caudolateral curvilinear osteophyte (CCO) and
osteoarthritis associated with hip dysplasia in dogs.
Design—Longitudinal cohort study.
Animals—48 Labrador Retrievers from 7 litters.
Procedure—In each of 24 sex- and size-matched pairs
fed the same diet, a restricted-fed dog was fed 25%
less than a control dog for life. The dogs' hips were
evaluated in the standard ventrodorsal hip-extended
radiographic projection at 16, 30, and 52 weeks of age
and then yearly for life. Histologic examination of hip
joint tissues was performed on 45 dogs.
Results—Median age at death was 11.2 years.
Adjusting for feeding group, dogs with a CCO were
3.7 times as likely to develop radiographic signs of
osteoarthritis than those without a CCO. Stratified by
diet, 100% of the control dogs with a CCO developed
radiographic signs of osteoarthritis and 55% of
restricted-fed dogs with a CCO developed radiographic
signs of osteoarthritis. The CCO was the first
radiographic change seen in 22 of 29 (76%) dogs with
osteoarthritis. Overall, 35 of 37 (95%) dogs with a
CCO had histopathologic lesions of osteoarthritis.
Conclusions and Clinical Relevance—Results indicate
a relationship between a CCO on the femoral neck
and subsequent development of radiographic signs of
osteoarthritis in Labrador Retrievers evaluated over
their life span. A CCO is an important early radiographic
indication of osteoarthritis associated with canine hip
dysplasia. (J Am Vet Med Assoc 2004;225:233–237)