Comparison of Whey Protein Concentrate and Spray-Dried Plasma Protein in Diets for Weanling Pigs1

Two experiments were conducted to evaluate the effects of whey protein concentrate (WPC) and spray-dried plasma protein (SDPP) on growth performance of weanling pigs. In Exp. 1, 180 weanling pigs (initially 6.3 kg) were fed 1 of 5 experimental diets containing 0, 2.5, or 5.0% WPC or SDPP. Pigs were fed the experimental diets from d 0 to 14 after weaning, with all pigs fed a common diet from d 14 to 27 after weaning. Overall (d 0 to 27 after weaning), increasing SDPP from d 0 to 14 linearly increased ADG (P < 0.03). Also, pigs fed diets containing SDPP had improved ADG (P < 0.03) compared with pigs fed WPC. In Exp. 2, a total of 228 weanling pigs (initially 6.8 kg) were used to evaluate the effects of WPC source on growth performance of weanling pigs. Pigs were fed 1 of 7 experimental diets, which included a negative control with no WPC, a positive controlwith 5% SDPP, or the negative control diet with 5% WPC from 1 of 5 sources. Pigs were fed the experimental diets from d 0 to 14 after weaning, with all pigs fed a common diet from d 14 to 28 after weaning. Overall (d 0 to 28), there was a significant difference (P < 0.05) in ADG between WPC sources. There were no differences in average daily feed intake and gain:feed for the overall treatment period, or between pigs fed WPC and SDPP. Whey protein concentrate can potentially be fed as a replacement for SDPP in diets for nursery pigs only if using a high-quality source.