Follicular dynamics in Plains zebra (Equus burchelli): preliminary results

Abstract

The current knowledge on reproductive biology of zebras is very vague and based primarily on observations of free roaming animals in nature or captivity, or obtained from genital tracts collected after culling. Information regarding zebra estrous cycles and ovarian follicular dynamics is lacking [Nunez et al., In: Equine Reproduction, 2nd Edition, 2011, v. 2, 2851-65]. A preliminary report on slaughtered mountain zebras (Equus zebra hartmannae) showed the presence of 20-40-mm follicles during the proestrus phase and corpora lutea in pregnant females [Lilian et al., J Reprod Fertil 1988;84:505-11]. Ovum pick-up from follicles 25 mm performed in captive reared or slaughtered animals produced high quality oocytes from Plains zebras (Equus burchelli) and Mountain zebras [Meintjes et al., J Zoo Wildl Med 1997;28:251-59]. Embryo transfer from zebras to mares has produced viable, healthy foals as a method of genetic preservation and production of high quality individuals [Bennett et al., Equine Vet J 1985;17:78-9; Summers et al., J Reprod Fertil 1987;80:1320]. These assisted reproductive techniques have been carried out utilizing just the beginning and end of estrus dates for calculating the day of embryo flushing [Allen et al., J Heredity 1997;88:384-92]. The objective of this study was to characterize follicular dynamics during spontaneous (Experiment 1) and induced (Experiment 2) estrous cycles