Effects of dietary spray-dried plasma protein on sow productivity during lactation.

Seventy-two primiparous and multiparous sows (36 per dietary treatment) farrowed in 4 groups were used to evaluate the effects of spray-dried plasma protein (SDP) on sow and litter performance during lactation. Dietary lactation treatments consisted of a corn-soybean meal control and a corn-soybean meal diet containing 0.5% SDP. Both diets were formulated to contain 1.0% total Lys and 3.46 Mcal/kg of ME and were fed from d 107 +/- 1.2 of gestation to weaning. Sows were allotted to dietary treatment based on breed, parity, and the date of d 107 of gestation. Litters were standardized within diet, and pigs were weaned at an average age of 19 +/- 2.1 d. Sows were fed 3 times daily during lactation. After weaning, sows were fed a common gestation diet and checked twice daily for estrus. Sows were grouped by parity (young sows, <or=3; mature sows, >3) for statistical analysis. The data were analyzed as a 2 x 2 factorial arrangement of treatments; the factors were parity (<or=3 or >3) and SDP (0 or 0.5%). Treatment differences were considered significant at P < 0.10. Mature sows had a greater BW on d 107 of gestation, on d 1 postfarrowing, and at weaning; greater lactation ADFI; and greater litter BW after cross-fostering, but pig survival to weaning was decreased. Sows fed SDP had a greater gestation interval, litter BW at weaning, and litter ADG, with 1 less lactation day. The effect of SDP addition was dependent on sow parity, as noted by numerous SDP x parity interactions. The addition of SDP increased lactation ADFI in mature sows but decreased ADFI in young sows. Mature sows fed SDP had a greater number of pigs weaned per litter, litter and pig weaning weights, pig survival to weaning, and number of pigs weaned per litter weighing more than 3.6 kg, but the SDP diet had little to no effect on these responses in young sows. Subsequent farrowing data were collected, but no dietary treatment effects (P > 0.10) were observed. The results of this research indicate that SDP increased productivity of sows in parity 4 or greater.