IMMUNO-CASTRATION BY IMMUNIZATION WITH GnRH IN BLACK BENGAL BUCKS (CAPRA HIRCUS)

The present study was carried out to elucidate the castration effects of immunization against GnRH (Gonadotropin releasing hormone) in Black Bengal bucks. Thirty (30) Black Bengal bucks under study were divided into three groups, viz. Group I (control animals), Group II (surgical castrates) and Group III (immunized bucks). Anti-GnRH antibody titer was measured from the blood samples collected from Group III animals on days 0, 1, 3, 5, 7, 15, 30, 45, 60, 85, 100, 115. Plasma testosterone and cortisol level were also measured for all blood samples collected (during the said period) from all the animals. The increased antibody titer in bucks about 45-50 days after primary immunization coincided with the decreasing plasma testosterone level during the same period. No significant anti-GnRH activity was observed in the control as well as surgically castrated bucks. Plasma testosterone level increased progressively during the experimental period in the control group, whereas surgical castrates showed a marked reduction in testosterone level soon after the castration. The immunized bucks were under less stress condition than the surgically castrated ones as indicated by their plasma cortisol concentration. Both the surgical and immuno-castrates were easily handled and managed during the experimental period due to a marked reduction in sexual behavioral measures than the control group. So, the immunization against GnRH may be a non-invasive, convenient alternative to the surgical castration.