Sexual receptivity and reproductive performance of rabbit does administered exogenous GNRH, Ovaprim^tm

Abstract

Twenty-seven (27) nulliparous rabbit does aged 6 - 7 months were subjected to a study to evaluate the effect of Ovaprim^TM, an exogenous gonadotropin-releasing hormone (GnRH) on their sexual receptivity and reproductive performance. The animals were randomly selected and assigned into three treatment groups in a completely randomized design; each treatment consisting nine animals divided into three replicates with 3 animals per replicate. The GnRH was injected intramuscularly at the rates of 0.0ml, 0.5ml and 1.0ml /kg body weight respectively, across the 3 treatment groups. Ovulation in the control experiment was induced using vasectomized bucks. The does were inseminated using freshly collected and diluted semen, 3 hours after administration of the GnRH. Parameters measured were sexual receptivity, conception rate (%), litter size, stillbirth (%), pre-weaning mortality rate and body weight of does and litter (g) at birth and at weaning (42 days). Sexual receptivity was measured and scored on a graded scale of 1 - 5. Results showed significant differences (P<0.05) between the treatments on sexual receptivity, conception rate, and litter weight at weaning. Litter size, litter weight at birth and pre-weaning mortality were not significantly different (P>0.05) among treatments. Sexual receptivity and conception rate were shown to improve after administration of 0.5ml of Ovaprim^TM per kg body weight. In conclusion, exogenously added GnRH, Ovaprim^TM had minimal effects on body weight index and reproductive performance of rabbit does. However, a higher dose of 1.0ml/kg body weight led to a decline in performance suspected to be associated with a negative feedback mechanism.