BIOREC PhD Project 3: Response of reproductive function (spermatogenesis, steroidogenesis) to environmental challenges in the stallion.

PhD student: Carlos HERRERA LUNA, Artificial Insemination and Embryo Transfer

Supervisors: Christine AURICH, Ingrid WALTER

Abstract: Species that are naturally frequently exposed to stress (e.g. equids in their natural habitat) have to be able to reproduce despite a frequent fluctuation of glucocorticoid concentrations. This suggests a low responsiveness of their gonads to cortisol. Due to domestication and selection, the gonadal responsiveness might change and increase. Under natural conditions, stallions strictly live in social groups with mares or other stallions. We will test the hypothesis that stress caused by isolated housing of domesticated stallions under the conditions of the modern horse breeding industry may contribute to low fertility.  The endocrine response to a controlled stress situation in adult stallions will be investigated and the influence of glucocorticoids on reproductive testicular functions will be characterized. Mechanisms will be compared between stallions of a wild-type and a domesticated breed to investigate possible phaenotypic changes caused by domestication. The study will help to investigate an involvement of stress in the pathogenesis of sub- and infertility in stallions kept under the conditions of the modern horse breeding industry.