Resumen de Effect of a systematic PMSG treatment 48 hours before artificial insemination on the productive performance of rabbit does
A total of 148 multiparous rabbit does were distributed into two equal groups. Two days before insemination, the animals of the treated group received 25 IU of PMSG (Ciclogonine PROCHENA). The animals of the control group received no injection. At the end of the 9-month experiment, the does went on breeding according to the same protocol (artificial insemination (Al] 10-11 days after each kindling), except injections of PMSG, in order to study the possible remanent effects of the treatment. This postexperimental stage lasted for 7 months. During the experiment, PMSG improved the percentage of receptive does (72.0 vs 38.4 %, P = 0.001) and its efficiency was not reduced with time; the percentage of kindling through Al was however improved only far the first tour inseminations (78.7 vs 66.2 %, P = 0.024), PMSG treatment was without significant effect far the following inseminations. Moreover, PMSG significantly improved the fertility of the lactating does at the time of insemination (+ 18.4 %) but did not improve the fertility of the non lactating does (+ 1.3 %). PMSG treatment improved the number of total born young per kindling by 7.4 % but, for a similar level of receptivity, the treatment did not improve the numerical productivity but decreased the mean weight at weaning (658.4 vs 674.9 g, P = 0.044). PMSG treatment made it possible to improve the global productivity of the rabbit does (number of weaned young per insemination) by + 28.4 % following the first tour inseminations; there was no improvement far the following inseminations. The improvement of this criterium depended on the physiological stage of the does at the time of insemination. In lactating does indeed the increase in the number of weaned young per insemination in the treated does persisted throughout the trial (beginning: + 44.6 %, end: + 48.0 %) while the molecule had no effect on the non lactating does whatever the experimental stage. The use of PMSG in non lactating does is thus unjustified. lt was also demonstrated that when treatment was over the productivity of the does which were previously treated was identical to that of the control group.
