PARENT SESSION
COMPARATIVE ASPECTS OF REPRODUCTION
Harborside C
7:30 AM-10:00 AM

(398) REPRODUCTIVE SURVEY OF THE AFRICAN ELEPHANT POPULATION IN NORTH AMERICA.

Freeman, Elizabeth¹, Weiss, Emily², Brown, Janine¹, ¹ Conservation & Research Center, Front Royal, VA² Sedgwick County Zoo, Wichita, KS

ABSTRACT- The population of African elephants currently held in North American zoos (n=206) is not self-sustaining, and reproductive rates are low. One problem, identified through long-term weekly serum progesterone analyses, is that many reproductive-age elephant females are not cycling normally. To better understand this problem, a survey was conducted to determine how many elephants are being reproductively monitored and of those what proportion are not cycling. Of those surveyed (n=150), 95 were bled weekly for hormonal analysis to assess reproductive cyclicity. Nearly a third (n=32) were not cycling, demonstrating low concentration or undetectable progesterone profiles. The remaining females exhibited normal progesterone cycles of ~16 week duration. Neither age, body weight nor social rank (female status within the herd hierarchy) were related (P>0.05) to cyclicity status. Furthermore, analysis of serum samples collected longitudinally for 6- to 24-months from normal cycling (n = 22) and non-cycling (n = 26) elephants suggested that ovarian acyclicity was not related (P>0.05) to altered pituitary (LH, FSH), adrenal (cortisol) or thyroid (TSH, T3, T4) hormone secretion. Hormone concentrations in acyclic females were similar to baseline levels in cycling animals. The exception was prolactin, where overall mean concentrations were elevated (P<0.05) in 8 of the non-cycling African elephants. In sum, data reveal that ovarian inactivity is a significant reproductive problem in African elephants held in zoos. Early observations suggest that acyclicity in elephants is not related to social status, although other socio-environmental factors cannot be excluded. The role of hyperprolactinemia as a cause of elephant infertility also needs to be further investigated.

KEY WORDS: estrus, hormones, acyclicity, elephant