EFFECT OF EXOGENOUS GONADOTROPHIN-RELEASING HORMONE ON SEMEN CHARACTERISTICS AND LIBIDO OF RABBIT BUCKS

Résumé

Twenty-seven (27) New Zealand White rabbit bucks aged 6 — 8 were used to evaluate the effect of Ovaprim, an exogenous gonadotropin releasing hormone (GnRH), on their seminal characteristics and libido. The rabbits were randomly selected and assigned to three treatment groups designated as T_l, T₂ and T₃ in a completely randomized design (CRD). The exogenous hormone was administered by intramuscular injection at the rate of 0.00ml, 0.20ml and 0.40ml per kilogram body weight for T₁, T₂ and T3 respectively, with T_l serving as the control experiment. Semen samples were collected at the beginning of the experiment to determine the baseline and after 48 days of administration of the hormone. Libido was measured 3 hours after administering the GnRH. Results obtained from the baseline study showed no significant difference (P>0.05) in the various treatments for semen volume, mass motility, sperm concentration, live sperm proportion, number of spermatozoa per ejaculate, total viable spermatozoa, normal sperm proportion, semen viscosity, semen colour, libido score and reaction time. At the end of the study, semen volume, sperm concentration, live sperm proportion, number of spermatozoa per ejaculate, total viable sperm, semen viscosity and libido were found to differ significantly (P<0.05) between the treatments. It was concluded from this study that the administration of 0.2ml/kg exogenous GnRH (Ovaprim) used for this experiment led to enhanced reproductive performance with respect to libido and semen quality and had little or no deleterious effect on the rabbit bucks.