Breeding ewes using natural service or artificial insemination

Extract

Artificial insemination of ewes has become commercially available in Britain on a small scale over the last few years. It allows the farmer to benefit from MLC recorded rams which have been selected for growth rate and more recently for carcass quality. However, proximity to an A.I. centre is an important consideration as A.I. of ewes requires the use of fresh semen. Frozen semen has not vet achieved the quality and reliability necessary on a commercial scale. Insemination is carried out at a fixed time after the removal of Intra-vaginal pessaries and an injection of Pregnant Mare Serum Gonadotrophin (PMSG). Synchronisation of oestrus using sponges and PMSG adds to the cost of using a commercial A.I. service. If A.I. is not used then one ram per ten ewes is necessary for a synchronised mating which either requires a ram sharing group or considerable financial investment if rams of equivalent quality to those used in A.I. centres are to be purchased.