The effects of natural mating and artificial insemination using cryopreserved buck semen on reproductive performance in Alpine goats

Abstract

This study compared the effects of natural mating and artificial insemination using frozen buck semen on reproductive performance in Alpine goats. Sixty reproductive Alpine goats were grouped according to natural mating ( $n=30$ ) and artificial insemination ( $n=30$ ) breeding methods. Oestrus was synchronised in experimental goats using a vaginal sponge impregnated with 20 mg of progestogen FGA (fluorogestone acetate) for 11 days. At the time of sponge insertion, 150 $\mu$ g of prostaglandin F ${}_{2\alpha }$ (PGF ${}_{2\alpha }$ ) analogue was injected intramuscularly. Forty-eight hours prior to vaginal sponge withdrawal, 500 IU equine chorionic gonadotropin (eCG) was injected into the animals. At the end of synchronisation protocol, goats were fertilised using frozen semen or mated with a well-performing buck (ratio: 1 male to 5 females). The pregnancy (pregnant/synchronised goats) and mortality rates ( $P<0.05$ ) were higher (93 % vs. 70 %; 2 % vs. 4 %) in the naturally mated goats than the artificially inseminated group. Kids' live weight at birth was similar ( $3.83\pm 0.23$ and $3.15\pm 0.11$ kg) in both groups. The oestrus synchronisation followed by natural mating achieved better reproductive performance than the goats artificially inseminated using frozen semen. However, the artificially inseminated animals displayed an acceptable twinning rate.