Estimating reproduction ability of Hungarian Merino rams

Scrotal circumference, testosterone content of blood serum, libido and sper m quality parameters of Hungarian Merino breeding and young rams were exami ned according to seasons by the authors in a farm. In the case of matured rams a seasonal effect was observed both in scrotal circumference and testosterone content of blood serum (measured two hours l ater after exogenous GnRH treatment) and sperm quality. In the case of youn g rams no seasonal effect was observed. It was found that the scrotal circu mference of young rams and the testosterone content of blood serum (two hou rs after exogenous GnRH treatment) are determined by the maturity of the ra ms. A medium connection could be observed between scrotal circumference and testosterone content of blood serum induced by GnRH treatment. In the case of matured rams there is a loose and not significant correlation between s crotal circumference and sperm quality (r = 0.39). They have come to the co nclusion that libido shows medium correlation with scrotum circumference (r = 0.56), while the correlation with testosterone content of blood serum is tight (r = 0.78), and the correlation with sperm quality proves to be a lo ose one. According to the results scrotum circumference can be used as one of the po ssible markers for selection of rams for reproduction purposes.