THE EFFECT OF IMMUNONEUTRALIZATION OF PMSG NEAR A GONADOTROPIN-INDUCED ESTRUS ON THE REPRODUCTIVE-PERFORMANCE OF GILTS

In four experiments, 189 gilts either received PMSG antiserum around t he time of a PMSG- (experiments 1, 2 and 3) or PMSG/hCG-induced (exper iment 4) oestrus or served as controls. Ovulation rates were not affec ted by treatment. There was no treatment effect on pregnancy rate (exp eriments 2, 3 and 4). In experiment 2, numbers of embryos in PMSG-trea ted control gilts were quite low and were higher (P < 0.05) in those g ilts subsequently receiving anti-PMSG treatment. In experiment 3, the mean number of embryos in control gilts were higher than in experiment 2 and there was no effect of immunoneutralization of PMSG. No treatme nt effect was evident in PMSG/hCG treated gilts (experiment 4). These data indicate that the immunoneutralization of PMSG is unlikely to imp rove the reproductive performance of gilts following a gonadotropin-in duced oestrus except in gilts that otherwise would have poor performan ce.