title: Effects of induction versus prevention of hibernation on reproduction in captive male and female woodchucks (Marmota monax).
abstract: Reproductive performance and gonadal function were studied in two groups of woodchucks containing 16 females and 8-9 males each. The control group was maintained indoors under conditions that do not induce hibernation, including fluctuating temperature of 6-12 degrees C, ad libitum feed, and exposure to natural and incandescent light. The hibernaculum-housed group was, in addition, provided conditions that do induce hibernation, including temperature reduced to 5.6 +/- 1.7 degrees C, no food, and no light from 19 November to 21 February. Hibernaculum housing caused 67% of males and 94% of females to hibernate with reduced body temperature for significant periods of times. Compared to control conditions, hibernaculum housing caused (p less than 0.05) a delay in testis recrudescence, a reduction in mean peak testis size (1.8 vs. 3.0 cc) and its mean date of occurrence (14 March vs. 15 February), a reduction in mean testosterone concentrations in February, and a reduced incidence of fertile matings (22 vs. 88%). In females, hibernation resulted (p less than 0.05) in a greater loss in body weight and a reduced pregnancy rate (31 vs. 82%), which was related to post-hibernation body weights that, in turn, were related to prehibernation body weights. Among hibernaculum-housed females, the pregnancy rate was lower in smaller females (0%; 2.0 +/- 0.1 kg) than in the larger ones (63%; 2.9 +/- 0.1 kg). The results demonstrate that the experimental imposition of hibernation-inducing conditions for 3 mo prior to the expected breeding season can alter subsequent reproductive performance in laboratory-maintained woodchucks, whereas a reproductive rate of 88% can be obtained in animals prevented from hibernating during their first year in captivity.
authors: Department of Physiology, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853.
authors: P W
authors: PW
authors: Concannon
authors: L A
authors: LA
authors: Fullman
authors: B H
authors: BH
authors: Baldwin
authors: B C
authors: BC
authors: Tennant
mesh_terms: D000818:Animals; D003080:Cold Temperature; D005260:Female; D005298:Fertility; D006605:Hibernation; D006799:Housing, Animal; D007036:Hypothermia, Induced / Q000662:veterinary; D008297:Male; D008392:Marmota / Q000502:physiology*; D012098:Reproduction; D012589:Sciuridae / Q000502:physiology*; D013737:Testis / Q000502:physiology