Amino Acid Supplementation of Calf Milk Replacers Containing Bovine Plasma Protein
Plasma protein (PP) is an effective alternative protein source for young calves, but utilization at higher amounts may be limited by Ile and Thr content. We determined the effects of PP and supplemental AA in milk replacers (MR) on calf growth and health. Male Holstein calves (n=104) were blocked by BW and randomly assigned to 1 of 5 MR formulated to contain 22% CP, 20% fat, and 2.0% Lys. Treatments (trt) were: all milk protein (A); 5% PP plus Met to equal trt A (B); 5% PP plus Met, Ile, and Thr to equal A (C); 10% PP plus Met to equal A (D); or 10% PP plus Met, Ile, and Thr to equal A (E). Treatments (12.5% solids) were fed twice daily at 10% of BW for d 1-2, 12% of BW for d 3-7, and 14% of BW for d 8-35, adjusted weekly. No starter was fed. Calves were housed in individual hutches bedded with straw and offered water ad libitum. Health data were recorded daily and growth measured weekly. Serum obtained on d 28 before and 4 h after feeding was analyzed for total protein (TP), urea nitrogen, albumin, and globulin. Data were analyzed using the MIXED and GLIMMIX procedures of SAS. Initial BW (41.9±4.38 kg) and serum TP (5.7±0.09 g/dL) were similar among groups. Intakes of DM, CP, ME, and Lys did not differ (P>0.35) among trts. Average daily gain tended (P=0.08) to be decreased by 10% PP (D), but not when AA were supplemented (E). Gain:DMI (P=0.10) and gain:Lys intake (P=0.08) tended to be lower for trt D. The Logistic model revealed that during the first 21 d, scours occurrence was higher in trt A than trt D and E (odds ratio [OR]=1.35, P=0.07 and 1.61, P=0.01, respectively), and trt C tended to be higher than trt E (OR=1.41, P=0.08). The chance of antibiotic treatment was greater in trt A than trt B, C, and E (OR=3.55, P<0.0001; 3.39, P=0.0002; 2.48, P=0.001) and lower in trt B and C than trt D (OR=0.31, P=0.0003; 0.32, P=0.0006). Serum albumin was highest (P=0.02) for trt B and urea nitrogen tended (P=0.10) to be higher for trt A; TP and globulin did not differ (P>0.11). Inclusion of PP in MR improved health of young calves; when AA were balanced, growth and efficiency were similar to all milk protein.
Keywords: amino acid, plasma protein, milk replacer