How Behavioral Stress Disrupts the Endocrine Control of Reproduction in Domestic Animals

Behavioral stress can prevent animals from achieving normal reproductive success. Stressors associated with intensive livestock management may be responsible for reduced reproductive efficiency. However, before appropriate management decisions can be made to alleviate the effects of behavioral stress on reproduction, it is necessary to identify the mechanisms by which stress disrupts normal reproduction. The neuroendocrine regulation of follicular development and ovulation requires a complex and delicate interplay between the pituitary gonadotropins and the feedback actions of the major follicular steroid, estradiol. Because of this complexity, the regulation of the follicular stage of the estrous cycle and ovulation is especially vulnerable to the effects of stress. Although the pathophysiological mechanisms by which stress disrupts reproduction are not fully understood, the stress-induced secretion of adrenal glucocorticoids seems to be of special significance because these steroids can effect both the synthesis and secretion of gonadotropins. Of additional importance may be the role of corticotropin-releasing hormone and adrenocorticotropin on the regulation of the hypothalamic-pituitary-gonadal axis.