Dried skim milk as a replacement for soybean meal in growing-finishing diets: Effects on growth performance, apparent total-tract nitrogen digestibility, urinary and fecal nitrogen excretion, and carcass traits in pigs1,2

Two trials were conducted to determine the replacement nutritive value of dried skim milk for growing-finishing pigs. In a three-phase feeding trial, 180 growing composite barrows (40.8 ± 2.9 kg BW) were allotted to three dietary treatments. Each phase lasted 28 d. Treatment 1 comprised a basal corn–soybean meal diet supplemented with crystalline AA to contain true ileal digestible concentrations (as-fed basis) of 0.83, 0.66, and 0.52% Lys; 0.53, 0.45, and 0.40% Thr; and 0.51, 0.45, and 0.42% sulfur amino acids (SAA; Met + Cys) in Phases 1, 2, and 3, respectively. Treatments 2 and 3 were the basal diets with 5 and 10% (as-fed basis) dried skim milk added. The three diets at each phase were formulated to have the same quantities of DE, true ileal digestible Lys, Thr, Trp, SAA, Ca, and available P. Pigs were housed 10 per pen (six pens/treatment), allowed ad libitum access to feed, and slaughtered at 121.6 ± 9.3 kg BW. No differences were detected between pigs fed the basal diet and the dried skim milk diets or between pigs fed the 5 and 10% dried skim milk diets, respectively, in 84-d ADG (P = 0.84 or P = 0.71), ADFI (P = 0.54 or P = 0.91), and G:F (P = 0.80 or P = 0.97), in hot carcass weight (P = 0.66 or P = 0.74),