Influence of maternal nutritional factors on ovarian folliculogenesis in cattle

Assisted reproductive technologies, such as artificial insemination and embryo transfer, have produced significant outcomes in cattle. These technologies are useful not only for improving fertility but also for increasing the rate of genetic change in beef and dairy livestock. Today, embryo transfer in cattle is both practical and commercially viable. However, bovine embryo transplantation still remains suboptimal under on-farm conditions, one of the main reasons for which may be inefficient nutritional management. The role of nutrition in modulating reproduction and particularly in ovarian function remains unclear. Considerable effort has been made to elucidate the nutritional factors regulating the development of follicles in either a direct or an indirect manner. Moreover, evidence indicates that bovine folliculogenesis is modulated by gonadotropins as well as by metabolic hormones, including growth hormone, leptin, insulin and insulin-like growth factor-1. In addition, metabolites – such as glucose, urea and non-esterified fatty acids – are considered to play a role in regulating ovarian follicular development. Nutrition affects folliculogenesis indirectly by altering the activity of reproductive hormones. Furthermore, nutrition has local impact on the development of follicles at the ovarian level. As a result, nutrition is possibly decisive to the fate of bovine oocyte development, since oocyte quality influences reproductive outcomes such as fertilization and pregnancy rates. Although numerous reviews in the published literature describe nutritional roles in reproduction, the primary focus of this paper is the effect of nutritional factors on folliculogenesis in cattle. A greater understanding of this influence may facilitate nutritional manipulation in order to enhance fertility in cattle in a cost-effective yet very efficient way.