Effect of protein and(or) carbohydrate fractions of dried whey on performance and nutrient digestibility of early weaned pigs.

One hundred eighty 3-wk-old pigs (initial weight 4.8 kg) were utilized in a 35-d growth trial to determine the effects of the carbohydrate and(or) protein fraction of dried whey on pig performance. In addition, 30, 3-wk-old pigs (initial weight 4.9 kg) were used in two digestion trials to study the effects of the whey fraction on nutrient digestibility. Dietary treatments included a corn-soybean meal diet (control), control + 20% dried whey, control + 14.4% lactose, control + 2.1% lactalbumin, control + 14.4% lactose + 2.1% lactalbumin, and control + 8.4% whey protein concentrate. Pelleted diets containing equal lysine concentrations were fed. Lactose and lactalbumin were added at the same levels as provided by a 20% dried whey diet. Pigs fed diets containing milk products exhibited superior (P less than .05) ADG and efficiency of feed utilization and greater (P less than .05) apparent digestibilities for DM, energy and N compared with pigs fed the control diet. Including either lactose or lactalbumin in the diet for the early weaned pig resulted in similar gain, feed efficiency and nutrient digestibility. These results indicate that both the carbohydrate (lactose) and protein (lactalbumin) fractions of dried whey are important in explaining the beneficial response to dried whey elicited in the weanling pig.