Estrous Cycle of Induced Ovulators: Lesson From The Camel — A Review

Camel, rabbit, cat, ferrets, minks, koala and meadow moles are induced ovulators requiring copulation to trigger the ovulatory process and the estrous cycle differs from that of other domestic animals. The estrous cycle in these animals composed of follicular recruitment, follicular growth, follicular maturity and follicular regression phase. These animals are variously reared as companion, fur-bearing and meat animals. Among these, the camel is the most valuable and classical induced ovulator which is rear not only for milk and meat, but as work animal and contributes effectively to the welfare of people in harsh and difficult environments. As a classical induced ovulatory, camelid has cycling receptivity with distinctive estrus but requires mating in order to ovulate. The other classes of induced ovulators like cats and ferrets require both the presence of male to achieve behavioral estrus and actual copulation to ovulate. The camel has good prospects of survival as a suitable livestock for projects of sustainable agriculture and animal production under harsh desert or arid conditions. However the reproductive nature of camels presents a huge challenge to camel husbandry. The natural constraints include the long period of attaining puberty, limited breeding season, difficulties in induced ovulation, long gestation period and inter-calving intervals. Efforts to improve the reproductive efficiency of the female camel are closely related to a better understanding of the folliculogenesis or follicular wave pattern. Many investigators might not be aware of the peculiar reproductive information available about this animal species. A working knowledge of ovarian function or estrous cycle will be of immense importance to the application of assisted reproductive technologies (ARTs) and enhancements of reproduction in camelids. This work presents the overview of estrous cycle in camel as a classical example of induced ovulators with the aim of providing current knowledge to the reader and to stimulate wider research interest in camel research and reproduction.