A COMPARISON OF MILK PROTEIN-SOURCES IN DIETS OF CALVES UP TO 8 WEEKSOF AGE

Four dietary ratios of dried skim milk and whey protein concentrate as the primary protein sources in milk replacers were evaluated using di gestibility, growth performance, health characteristics, and blood mea surements of calves that were 12 to 36 h of age to 8 wk of age. Sixtee n Holstein bull calves, housed individually within an environmentally controlled facility, were randomly allotted to diets. Protein sources in the milk replacer were expressed as ratios (percentages) of dried s kim milk to whey protein concentrate in diet 1, 100:0; diet 2, 67:33; diet 3, 33:67; and diet 4, 0:100. There were no significant difference s in the mean number of days that calves scoured. Apparent biological value and N retention differed among diets over all weeks. Apparent di gestibilities and biological values (percentages) over all weeks were diet 1, 82.50 and 67.71; diet 2, 82.85 and 70.15; diet 3, 83.82 and 67 .46; and diet 4, 84.03 and 72.25, respectively. Diets varying in the r atio of dried skim milk to whey protein concentrates had no effect on health, growth, or apparent digestibilities in Holstein calves up to 8 wk of age.