Estimating reproduetion ability of Hungarian Merino rams*

Abstract

Abstract. Scrotal circumference, testosterone content of blood serum, libido and sperm quality parameters of Hungarian Merino breeding and young rams were examined 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 later after exogenous GnRH treatment) and sperm quality. In the case of young rams no seasonal effect was observed. It was found that the scrotal circumference of young rams and the testosterone content of blood serum (two hours after exogenous GnRH treatment) are determined by the maturity of the rams. 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 scrotal circumference and sperm quality (r = 0.39). They have come to the conclusion 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 loose one. According to the results scrotum circumference can be used as one ofthe possible markers for selection of rams for reproduetion purposes.