The effect of managed boar contact in the post-weaning period on the subsequent fertility and fecundity of sows.

This study demonstrates, in the artificial insemination of weaned sows, the advantage of isolating sows from contact with boars from weaning until the fourth day after weaning and then introducing a boar to elicit the estrous display before insemination. Weaned sows were isolated from boar stimulation during the immediate post-weaning period (Day 0 = weaning) until Day 4, when they were introduced to full boar contact. Sows were inseminated immediately upon display of oestrus shown by back pressure test (0 h) and 24 h later. Fertility data were collected after parturition. This "segregated service management" (SSM) resulted in significantly improved farrowing rate and litter size (P < 0.001) compared with the results in the group that had conventional continuous contact with the boar. All other measured performance indicators were similar between the groups. The benefit of SSM is believed to be due to artificial insemination being timed more closely to ovulation or to a more certain identification of true oestrus and/or improved sperm transport in the sow. SSM is recommended for enhancing the efficiency of boar-sow interaction to maximise fertility and fecundity at artificial insemination.