Effects of feeding whey protein on growth rate and mucosal IgA induction in Japanese Black calves

Data from 63 Japanese Black calves were collected to clarify the effects of feeding whey protein on the growth rate and mucosal IgA induction in calves. Dietary treatments in milk replacers were 1) 26% CP as in skim milk (control), 2) 26% CP as whey and skim milk and 3) 26% CP as whey. Diets were offered from 3 to 63 days of age in calves. Feeding whey protein had no effects on growth rate, fecal consistency and fecal water in calves. Compared with 2 days of age, fecal IgA concentration in calves decreased at 14 days of age, while fecal water increased. Feeding whey protein increased fecal IgA in calves after 14 days of age, which was thought to be the increased mucosal IgA induction in the gut. Serum cholesterol concentration tended to be lower in calves fed whey than in control group, but feeding whey protein had no clear effects on serum glucose, NEFA, total protein and urea-N concentrations. These results suggest that feeding whey protein enhances mucosal IgA induction in calves, but feeding whey protein has little effect on growth rate and fecal consistency in calves.