title: Endocrine patterns of the estrous cycle and pregnancy of wildebeest in the Serengeti ecosystem.
abstract: Despite the importance of the western white-bearded wildebeest (Connochaetes taurinus mearnsi) to the Serengeti-Mara ecosystem, surprisingly little is known about the reproductive physiology of this keystone species. A longitudinal, non-invasive endocrine study was conducted on female wildebeest captured from the Serengeti-Mara migration and maintained for approximately 16 months in large fenced enclosures within the species' natural range. An intact bull was introduced to a female subgroup (n=5), while remaining females (n=10) were unexposed to a male. Fecal progestagen patterns reflected ovarian activity and pregnancy. In non-pregnant animals, luteal and inter-luteal baseline progestagen values differed (p<0.001) over time, thereby allowing identification of recurrent estrous cycles. The average durations of the luteal phase, estrous cycle, gestation, and post-partum anestrus were 14.3+/-0.5, 22.6+/-1.0, 240.8+/-11.7, and 104.1+/-15.6 d, respectively. Annual reproductive patterns indicated a distinctive period of ovarian activity that extended from 13 May through 3 December (203.5+/-29.9 d) with all unmated females displaying from one to 14 estrous cycles. Progestagens were higher (p <0.001) in pregnant (n=4) than non-pregnant (n=10) cows. These data (1) reveal the value of fecal hormone monitoring for establishing the first ever endocrine profiles of female wildebeest in semi-free-living conditions in their native range, and (2) indicate that the species is a seasonal breeder that is polyestrous and a spontaneous ovulator.
authors.affiliation: Conservation & Research Center, National Zoological Park, Smithsonian Institution, 1500 Remount Road, Front Royal, VA 22630, USA. amossvan@hotmail.com
authors.forename: A Moss
authors.initials: AM
authors.lastname: Clay
authors.forename: R D
authors.initials: RD
authors.lastname: Estes
authors.forename: K V
authors.initials: KV
authors.lastname: Thompson
authors.forename: D E
authors.initials: DE
authors.lastname: Wildt
authors.forename: S L
authors.initials: SL
authors.lastname: Monfort
mesh_terms: D000818:Animals; D001947:Breeding; D017753:Ecosystem; D030762:Estrous Cycle / Q000378:metabolism*; D005243:Feces / Q000737:chemistry; D005260:Female; D007630:Kenya; D007774:Lactation; D008183:Luteal Phase / Q000378:metabolism; D008297:Male; D036801:Parturition; D011247:Pregnancy; D011372:Progestins / Q000032:analysis / Q000378:metabolism*; D012098:Reproduction / Q000502:physiology*; D012418:Ruminants / Q000378:metabolism*; D012621:Seasons; D013636:Tanzania
chemical_list: D011372:Progestins