Effect of prepuberal and postpuberal gonadectomy on heat production measured by indirect calorimetry in male and female domestic cats.
OBJECTIVE
To use indirect calorimetry to compare heat production between gonadectomized and sexually intact male and female cats.


METHODS
Male (n = 6) and female (n = 6) kittens were gonadectomized at 7 weeks or 7 months of age, or left sexually intact. Body heat production was measured by indirect calorimetry in all cats at 12, 18, and 24 months of age.


METHODS
18 male and 18 female clinically normal domestic shorthair cats.


METHODS
Heat production was measured, using an open-circuit, respiratory, indirect calorimeter. All cats underwent calorimetry at 12, 18, and 24 months of age. The heat coefficient, a measure of resting metabolic rate, was calculated for each cat at each test; heat coefficient is defined as logarithm of heat (kcal/h) divided by logarithm of body weight (kg).


RESULTS
Heat production did not vary with age in male or female cats. Heat coefficient was higher in sexually intact male and female cats than in gonadectomized male and female cats at 12, 18, and 24 months of age (12 months, females, P < 0.01, males, P = 0.04; 18 months, females, P < 0.01, males, P = 0.02; and 24 months, females and males, P < 0.01).


CONCLUSIONS
These data suggest that resting metabolic rate in cats decreases after gonadectomy.


CONCLUSIONS
A decrease in metabolic rate is synonymous with a decrease in caloric requirements. Gonadectomized animals fed in a manner similar to sexually intact animals may be predisposed to obesity and its sequelae.
Root
M V
MV
Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St Paul 55108, USA.
Johnston
S D
SD
Olson
P N
PN
D000704:Analysis of Variance; D000818:Animals; D002153:Calorimetry, Indirect / Q000379:methods / Q000662:veterinary; D002415:Cats / Q000502:physiology*; D004285:Dogs / Q000502:physiology*; D004734:Energy Metabolism; D005260:Female; D006358:Hot Temperature; D008297:Male; D009919:Orchiectomy; D010052:Ovariectomy; D015203:Reproducibility of Results; D012741:Sexual Maturation