Defining the range for plasma protein incorporation in milk replacer for dairy calves

The objective of this study was to determine the effects of calf milk replacer containing from 0% to 100% of the total protein from porcine plasma protein, with or without isoleucine balanced, on calf growth and health. Four groups of 31 male Holstein calves were blocked by initial BW and plasma protein concentration and assigned to one of seven treatments. Treatments were as follows: A: control, all-milk protein milk replacer, B: 33% plasma protein addition, C: 33% plasma protein addition plus isoleucine, D: 67% plasma protein addition, E: 67% plasma protein addition plus isoleucine, F: 100% plasma protein addition, and G: 100% plasma protein addition plus isoleucine. Calves were fed milk replacer only, twice daily for 5 wk. During wk 1, calves were fed at a rate of 10% of BW (reconstituted to 12.5% solids). During wk 2 to 5, calves were fed at a rate of 12% of BW (12.5% solids). Body weight, body length, heart girth, withers height, hip height, and hip width were measured once weekly. Blood was sampled during wk 4 and serum was analyzed for urea N, total protein, total globulins, and albumin. Calf growth decreased with increasing addition of plasma protein in the diet. Supplementation with isoleucine lessened the negative effects of increasing plasma protein. We observed no negative health effects with the addition of plasma protein in the diet, but neither did plasma protein improve measures of health status. Provided that amino acid balance is maintained, porcine plasma protein can replace substantial amounts of whey protein in calf milk replacer with minimal effects on calf growth