Development of hormonal profiles of Nubian bucks at puberty in Sudan

Abstract

This study was designed to monitor the development of the hormonal profiles of the Nubian bucks at puberty. Thirty two (32) Nubain male kids between 1 day and 24 weeks having body weights of 2.3 to 13.5 kg were utilized in this study. All kids were injected with human chorionic gonadotropin (hCG). Blood samples were collected from the jugular veins of the animals immediately before hCG injection and 1 h after the injection. Plasma was separated from the samples and stored at 20°C until it was assayed for determination of hormonal levels. After hCG injection, the plasma level of testosterone was significantly higher (p< 0.01) than the level of the hormone before hCG treatment. Significant increase was also observed in luteinizing hormone (LH) values after hCG injection (P≤ 0.01). Plasma follicles stimulating  hormone (FSH) had one peak in week 8 in samples taken before hCG injection. This was followed after two weeks by the first elevation of LH. Plasma prolactin (PRL) concentration showed a gradual increase with age, reaching the peak in week 18. Based on the first appearance of spermatozoa in the lumina of the seminiferous tubules, penile separation and attainment of maximal levels of testosterone, LH, FSH and PRL, pubertal age was reached between 18 to 20 weeks.  Key words: Nubian bucks, hormonal profiles, puberty.