Effects of Buserelin acetate and semen extension on fertility in rabbit does under artificial insemination

Abstract

The productivity of rabbit farms can be increased and become more homogeneous through the use of Artificial Insemination (AI). However, this possibility is limited with low conception in artificially inseminated does without ovulation induction. This study aimed at determining the conception rate of rabbit does induced with buserelin acetate and inseminated with extended semen at varied dilution ratio. A total number of Twenty eight multiparous non-lactating rabbit does were randomly allotted into four treatments housed individually in a completely randomised design. Rabbits were used as a teaser for semen collection using an artificial vagina and after semen collection and evaluation; ejaculates from ten bucks with more than 60% motility were pooled and extended. Forty eight hours before the AI, the does were hormonally synchronized (i.m) for oestrus with 20IU PMSG. Does in treatment 1(control) were inseminated with unextended semen without buserelin but injected with normal saline, while does on treatments 2, 3 and 4 were inseminated with extended semen in ratio 1: 1, 1:2 and 1: 3 (semen: extender), respectively and were all intramuscularly induced using 0.8µg of buserelin after insemination. Results showed that some of the does induced with buserelin acetate intramuscularly (treatments 2, 3 and 4) were pregnant, while none of the control rabbits was pregnant. The ratio 1: 1 extended semen (treatment 2) recorded the highest percentage conception (85.71%) followed by treatment 3 (71.43%) and treatment 4 (57.14%). There was significant (P<0.05) difference in gestation length (32.50, 31.00 and 32.75), litter size (4.83, 8.60 and 3.25), live kits at birth (3.50, 6.60 and 1.75) for treatments 2, 3 and 4 respectively and the average litter weight was not significantly different among the treatments. This study suggests that diluting semen in ratio 1: 1 produced highest conception rate with intramuscular administration of 0.8µg buserelin acetate than extending semen in ratios 1: 2 and 1: 3.