Effect of diluent and storage time of rabbit semen on the fertility of does reared under two different lighting schedules

Abstract

Using a 3-factorial design, the effect of two commercial diluents (IMV vs Minitüb), two storage times (fresh vs 6h storage at ambient temperature) and a lighting schedule was studIed on artificial inseminated does. During a 10 month experimental period 140 (nulliparous and multiparous) does were randomly divided in two production groups and submitted to a 16h r :8hD continuously lighting schedule or to a 10hL:14hD schedule. In order to synchronize the oestrus, the lighting period was suddenly increased till 16hL from 5 days before the insemination (alternative lighting). Both production groups were inseminated every a weeks with an interval of 3 weeks between them. In total 988 inseminations were performed with an average conception rate (CR) of 56.5 %. The CR with both diluents was comparable, 55.6 % and 57.5 % for IMV and Minitüb, respectively. There was no decrease observed n CR when semen was stored during 6 hours into the insemination straws. CR was respectively 56.6 % (fresh semen) and 56.4 % (stored semen). The difference in CR between lighting schedules was small (2 %) and also not significant. Differences in litter size were not significant and could not be relatad to the treatments used. The overall low CR (56.5 %) is partly explained by the physiological status (vulva colour) of the does, indicating that 67 % of the does were not receptiva (white or rose vulva) at the 1 st insemination. However, on does showing a red or purple vulva a CR of 70.3 % was obtained. â–¡tter size of does inseminated with white vulva was significantly (P<0.001) lower, and amounted only 3.9 (nulliparous does) and 5.8 (multiparous does) live youngs instead of 6.9 (nulliparous, rose vulva) to 8.9 (multiparous, purple vulva) when inseminated with coloured vulva.