Influence of the male effect on the reproductive performance of female Payoya goats implanted with melatonin at the winter solstice

Abstrct esearch addressed the effect on reproductive performance of melatonin implants inserted at the winter solstice in Payoya goats. Female goats (n = 100) were divided into two experimental groups, one subjected and the other not subjected to the male effect. Half of each group was implanted with melatonin at the winter solstice; the remaining animals received no such hormone treatment. Oestrous activity, as detected by visual observation, was recorded daily using melatonin implanted bucks. Trans-rectal ultrasonography was used to estimate of time of ovulation. Corpus luteum activity was confirmed by plasma concentrations of progesterone greater than 0.5 ng/mL. Fecundity, fertility, prolificacy and productivity were calculated. Neither the male effect nor melatonin treatment alone influenced reproductive performance. The greater fecundity and fertility: 91.7% (P < 0.05) was obtained with melatonin implantation plus the male effect. Greater productivity occurred when melatonin was used (1.02 ± 0.10 compared with 0.76 ± 0.66 mean number of kids per female for melatonin and non-melatonin treated groups, respectively, P < 0.05). The present results show that the fertility of female Payoya goats implanted with melatonin at the winter solstice can be improved by subjecting females to the male effect. Moreover, productivity of does is enhanced when melatonin implants are used in comparison to productivity of non-treated females.