Supplementary biotin for sows: effect on reproductive characteristics.

Eighty female pigs were fed from 25 kg liveweight either basal diets calculated to provide 32 micrograms available biotin/kg (control diet) or basal diets supplemented with 350 micrograms biotin/kg. Reproductive performance was studied over four parities. Sows receiving supplementary biotin returned to oestrus 2.9 +/- 1.7 and conceived 6.1 +/- 1.4 days sooner than controls (P less than 0.05). Of those sows receiving supplementary biotin, more returned to oestrus and conceived within 10 days of weaning (83.2 per cent v 74.6 per cent and 80.6 per cent v 71.8 per cent respectively) and fewer were treated for anoestrus (7.3 per cent v 17.0 per cent) than those on the control diet. Supplementing diets increased the annual productivity of sows completing four parities by 1.42 +/- 1.02 pigs/sow/year (P less than 0.05) and increased the total weight of weaner produced/sow/year by 17.3 +/- 7.4 kg (P less than 0.05). It was concluded that the majority of commercial dietary formulations would require supplementation with biotin in order that sows may express their full reproductive potential.