Folic acid and reproductive performances of sows.

Two-hundred nine sows were used in a 2 X 2 split-plot unbalanced design to measure the effect of folic acid against control, and flushing against a normal level of feeding, between weaning and mating on the following variables: serum folates at weaning and at 60 d of gestation, blood hemoglobin (Hb) and hematocrit (Ht) after 15 wk of gestation and reproductive performance at farrowing. Folic acid was administered im according to a schedule that maintained serum folates at approximately the same level between weaning and 60 d of gestation. The treatments had no effect on Hb or Ht after 15 wk of gestation. Average live litter size was 12.0 piglets/litter for sows receiving the folic acid and flushing treatments as compared with 10.5 for sows without any treatment; the main effect of folic acid was significant (P less than or equal to .04). Intralitter variation in birth weight and total litter weight tended to be increased by folic acid administration. Results showed that the administration of folic acid during gestation could appreciably improve the reproductive performance of sows.