Maternal control of oocyte quality in cattle "a review"

The oocyte is a central regulator of multiple aspects of female fertility, including ovarian follicular development and early embryogenesis. During its prolonged diplotene arrest, the oocyte is subjected to endogenous (i.e., reactive oxygen species from metabolism) and exogenous (i.e., heat stress, malnutrition) sources of damage-inducing factors, which may lead to a progressive deterioration of oocyte quality. A deficit in oocyte competence can lead not only to a failure of fertilization but also to a lower developmental rate after fertilization. Thus, an appropriate environment for growth and maturation of the oocyte, in vivo and in vitro, is critical to ensure optimal oocyte quality. The objectives of the current review are to give an overview of some maternal key factors that influence oocyte quality in cattle and describe some of the findings to date in the hope of obtaining competent oocytes that could be used for clinical and applied purposes.