Amino acid supplementation of calf milk replacers containing bovine plasma protein
Traditionally milk replacer formulations for preweaned calves use milk protein sources (now principally whey proteins) because of their high digestibility, desirable amino acid profile, and lack of anti-nutritional factors. Over the course of the past five years the price of milk-based proteins has continued to increase. As a result research has focused on finding more cost effective alternative protein sources to incorporate into milk replacers that result in similar performance compared to milk-derived protein formulations. Therefore, the objective of this experiment was to determine the effects of calf milk replacers containing 0, 5, or 10% bovine plasma protein, either without or with supplemental Ile and Thr, on growth and health of Holstein bull calves (n = 104) for 56 d. The milk replacers were formulated to contain 22% crude protein (CP), 20% fat, and 2.0% Lys. Treatments were as follows (M): control, all milk protein MR, with Met added to achieve a Met:Lys ratio of 0.31; (5P): 5% addition of PP (plasma protein; 18% CP), with Met added to equal the ratio in treatment M; (5PA): 5% PP addition as in treatment 5P, but with Ile and Thr added to equal the amount in treatment M; (10P): 10% addition of PP (36% CP), with Met added to equal the ratio in treatment M; and (10PA): 10% PP addition as in treatment 10P, but with Ile and Thr added to equal amount in treatment M. Calves were fed the treatments twice daily at 12.5% solids at a rate of 10% of arrival body weight (BW) for the first 2 d, 12% of arrival BW for the remainder of the first week, and 14% of BW, adjusted weekly, until week seven. During the eighth week calves were fed once a day at 7% of BW and then weaned. Starter was not fed until the sixth week for ad libitum intake. Intake, health scores, and fecal scores were measured daily. Body weight and growth measures were taken weekly and blood serum samples were taken during week 4. There was no effect of treatment on crude protein or metabolizable energy (ME) intake during the first five weeks. There tended (P = 0.08) to be an effect of treatment on dry matter (DM) intake and during week 6 to 8, calves fed 10P tended (P = 0.09) to have decreased MR and ME intake relative to the other treatments. Starter and total intake was not different among treatments. The interaction of treatment by time was significant (P = 0.03) for body weight of calves with calves fed treatment 10P having the lowest BW during weeks 6 and 8 compared with the other treatments and lower BW than treatments 5P and 10PA in week 7. Additionally, average daily gain (ADG) was lowest for calves fed treatment 10P. There was a significant difference among treatments for gain:feed (kg/kg) with calves fed treatment 10P having the lowest efficiency. There was no difference in withers height, hip height, body length, and hip width among treatments. Heart girth and heart girth ADG had treatment by time interactions with calves fed treatment 10P having the smallest heart girth compared to the other treatments in week 7. In the first 21 d, scours occurrence was higher in the control than for the milk replacers containing the higher inclusion of plasma protein both without and with supplemental Ile and Thr, and scours occurrence was also higher for the lower inclusion of plasma protein compared with the higher inclusion of plasma protein when amino acids were included. Throughout the 56-d trial, the chance of antibiotic treatment was greater in the control milk replacer then all treatments except the higher level of plasma inclusion without supplemental amino acids and greater for the higher inclusion of plasma protein without supplemental amino acids compared with the other milk replacers with plasma protein. Calves on treatments with the higher inclusion of plasma protein had fewer days of scours compared to the control and all of the milk replacers with plasma protein except the higher plasma protein without supplemental amino acids had fewer days of treatment with antibiotics compared to the all milk control. With inclusion of plasma protein there was no difference in performance and improved health was observed as long as formulations were balanced for Ile and Thr.
Amino acid, plasma protein, milk replacer
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign