EFFECTS OF INDUCED OR DELAYED PARTURITION AND SUPPLEMENTAL DIETARY-FAT ON COLOSTRUM AND MILK-COMPOSITION IN SOWS

Two experiments were conducted to evaluate the effects of inducing pre mature parturition on the composition of colostrum and milk and the ef fects of dietary fat supplementation on colostrum and milk composition from premature and delayed farrowing sows. In Trial 1, eight sows wer e allowed to farrow naturally (d 114, NF sows) and eight sows were ind uced to farrow (IF sows) prematurely by injection of prostaglandin Fa, on d 112 of gestation. Average fat content of sow's milk during the f irst 12 h postpartum was lower for IF than for NF sows (P < .05), as w as overall mean fat percentage(P < .05). In Trial 2, 53 sows were rand omly assigned in a 2 (diets) x 5 (parturition treatments) factorial ex periment. Dietary treatments fed during the last 2 wk of gestation and throughout lactation were control diet and added fat diet (control di et plus 10% corn oil). Parturition treatments included 1) natural farr owing (d 114), induction of parturition with prostaglandin F-2 alpha o n 2) d 110, 3) d 111, or 4) d 112 of gestation, and 5) delay of partur ition with progesterone followed by injection of prostaglandin on d 11 5. The added fat diet increased milk fat percentage compared with the control diet (P < .01). Colostral fat percentage was reduced by induct ion of premature farrowing (d 110 or 111) in sows fed the control diet but was unaffected in sows fed added dietary fat (interaction, P < .0 5). Mean fat content of colostrum was not reduced in groups receiving the added fat diet that were induced to farrow prematurely. In sows wi th delayed parturition, colostral immunoglobulin G concentrations were lower for the group fed the added fat diet than for the group fed the control diet (P < .05). Addition of fat to sow diets during late gest ation and lactation may help maintain high colostral energy for newbor n pigs when sows are induced to farrow prematurely.