Objective—To determine quantitative values for components
of body composition in clinically normal dogs
of various breeds by use of dual energy x-ray absorptiometry
(DEXA) and validate the precision and accuracy
of DEXA technology in dogs.
Animals—103 clinically normal sexually intact adult
Procedure—In a cross-sectional study, Beagles,
Pembroke Welsh Corgis, Golden Retrievers, Great
Danes, Pointers, Rottweilers, and nonpurebred dogs
received total body DEXA scans. For the validation
portion of the study, the results of DEXA scans of 6
dogs were compared with values obtained by chemical
analyses of tissues from euthanatized dogs to
determine the accuracy of this modality in dogs.
Results—Results (coefficient of variation) of the precision
tests ranged from 0.10% for lean tissue to
5.19% for fat tissue, whereas accuracy tests revealed
a difference between percentage bone mineral content
and ash values. Body composition differed by
sex, such as higher lean tissue and bone mineral content
in males within some breeds, and among
breeds. Regardless of body size or weight, the percentage
of body weight that was bone mineral ranged
from 3 to 4.0%.
Conclusions and Clinical Relevance—Results of
this cross-sectional study provide valuable body composition
data for clinically normal adult dogs, which
may have research and clinical applications. (Am J Vet
Objective—To determine the earliest day of gestation at which relaxin could be detected in pregnant queens by use of a commercially available point-of-care test designed for use in dogs, and to calculate sensitivity and specificity of the test for pregnancy detection on any specified day of gestation.
Animals—162 female cats (24 queens from a breeding colony, 128 stray and feral queens undergoing ovariohysterectomy, and 10 ovariohysterectomized cats).
Procedures—24 queens were monitored for pregnancy. Blood samples were collected daily and tested for relaxin until 2 consecutive positive test results were obtained. The earliest day of pregnancy detection was estimated by counting backward from the day of parturition to the day of the first positive test. The uteri, ovaries, and any fetuses of 128 stray and feral queens undergoing ovariohysterectomy were examined grossly, and gestational day in pregnant queens was determined on the basis of fetal crown-rump length. Blood samples from these queens and from 10 cats ovariohysterectomized prior to the study were collected for relaxin testing.
Results—Pregnancy was detected by use of the relaxin test kit as early as gestational day 20; sensitivity of the test was 100% on and after gestational day 29. False-positive results were detected in 3 queens, 2 of which had large (approx 2 × 3-cm) ovarian cysts, resulting in a specificity of 95.9%.
Conclusions and Clinical Relevance—A commercially available relaxin test kit designed for use in dogs can be used to reliably detect pregnancy in cats.
Objective—To study the musculoskeletal development
of Great Dane puppies fed various dietary concentrations
of calcium (Ca) and phosphorus (P) in
fixed ratio by use of dual energy x-ray absorptiometry
(DEXA), determination of serum insulin-like growth
factor I and parathyroid hormone concentrations,
radiography, and blood chemistry analysis results.
Animals—32 purebred Great Dane puppies from 4 litters.
Procedure—At weaning, puppies were assigned randomly
to 1 of 3 diets. Blood was collected for biochemical
analyses and hormone assays, and radiography
and DEXA were performed through 18 months of
age. Changes in body weight, bone mineral content, fat
tissue weight, lean mass, result of serum biochemical
analyses, hormonal concentrations, and radius lengths
were analyzed through 18 months of age.
Results—Bone mineral content of puppies correlated
positively with Ca and P content of the diets fed.
Significant differences between groups in bone mineral
content, lean mass, and body fat were apparent
early. The disparity among groups increased until 6
months of age and then declined until body composition
was no longer different at 12 months of age.
Accretion rates for skeletal mineral content, fat, and
lean tissue differed from each other and by diet group.
Conclusions and Clinical Relevance—Ca and P concentrations
in the diet of young Great Dane puppies
are rapidly reflected in the bone mineral content of
the puppies until 5 to 6 months of age, after which
hormonal regulation adjusts absorption and excretion
of these minerals. Appropriate Ca and P concentrations
in diets are important in young puppies < 6
months of age. (Am J Vet Res 2002;63:1036–1047)