Synchronisation of the reproductive cycle in pigs

An outline of procedures to synchronise oestrus and ovulation in pigs is described. The oestrus cycle of pigs can be synchronised depending on the stage of the reproductive cycle of these animals. Non-cyclic gilts shortly before puberty, can easily be synchronised by treatments with a mixture of 400 i.u. eCG and 200 i.u. hCG. A more accurate timing of ovulation can be obtained by starting the follicular phase with eCG and inducing ovulation 3 day later with hCG or GnRH. Reproductive disturbances might be induced if animals in reality are cyclic. A similar treatment is possible for sows at weaning (especially in primiparous sows, which may otherwise show extended weaning to oestrus intervals). Cyclic gilts can be synchronised by synchronisation of the luteal phase by means of a progestagen (Regumate?) treatment during approximately 18 days. This permits spontaneous luteal regression but prevents follicular development until end of treatment. In weaned sows the follicular phase can be postponed by Regumate? treatment for 3 or more days, offering time to recover from lactational stress. An alternative, but still experimental, procedure may be induction of luteolysis in pregnant animals after Day 12 of insemination (breed and abort) or induction of pseudo-pregnancy followed by induced luteolysis. In general the oestrus of non-cyclic animals can be regulated effectively with gonadotropins, inducing the follicular phase, while the oestrus of cyclic animals can be regulated by progestagen treatment to postpone the follicular phase