Supplementation of Milk Replacers Containing Soy Protein with Threonine, Methionine, and Lysine in the Diets of Calves

Abstract

An attempt was made to improve the protein quality supplied in milk replacers containing soy protein by supplementing Thr, Met, and Lys to the milk replacers fed to calves. Six Holstein x indigenous male calves were fitted with single cannulas at the end of the ileum. Calves were fed milk replacers containing skim milk (86%) and whey (14%) proteins or skim (43%), whey (14%), and soy (43%) proteins either with or without amino acid (AA) supplementation according to a double 3 x 3 Latin square design. Average daily gain, N retention, and ileal digestibilities of dry matter, N, and AA were significantly higher for calves fed the milk replacer containing skim milk protein than for calves fed the milk replacer containing soy protein. Average daily gain, N retention, and ileal digestibilities of dry matter, N, and AA were significantly higher for calves fed the milk replacer containing soy protein plus AA supplementation than for calves fed the milk replacer containing the soy protein without AA supplementation. Therefore, supplementation of a milk replacer containing the soy protein without AA supplementation. Therefore, supplementation of a milk replacer containing soy protein with limiting AA that correspond to the AA found in milk protein can considerably improve the protein quality of that milk replacer for the preruminant calf.

The Limiting Sequence and Proper Ratio of Lysine, Methionine and Threonine for Calves Fed Milk Replacers Containing Soy Protein

“…Previously, both Jenkins and Emmons (1983) and Kanjanapruthipong (1998) reported that supplementing Lys, Met, Thr, and Ile could increase ADG in calves fed MR containing milk and soy proteins. Improved ADG was also observed when supplementing Lys and Met (Hill et al, 2007) but with no change in ADG when adding Thr in all milk sources formulas (Hill et al, 2008a).…”

“…However, recent estimations of the AA requirements were conducted in calves fed milk solely with no starter or hay (Williams and Hewitt, 1979; van Weerden and Huisman, 1985; Toullec, 1989; Gerrits et al, 1997; Hill et al, 2008a). Kanjanapruthipong (1998) found that supplementation of a MR containing soy protein with Lys, Met, and Thr that corresponds to the AA found in milk protein considerably improved the protein quality of that MR for the preruminant calf. However, no attempt was made to establish the sequence of these limiting AAs or to determine the AA requirements in his experiment.…”

“…However, no attempt was made to establish the sequence of these limiting AAs or to determine the AA requirements in his experiment. All the practices in the studies previously mentioned (Williams and Hewitt, 1979; van Weerden and Huisman, 1985; Toullec, 1989; Gerrits et al, 1997; Kanjanapruthipong, 1998; Hill et al, 2008a) for feeding young calves did not conform to commercial conditions in China, where calves are fed not only MR containing milk sources and soy protein but also starter and hay ad libitum . The limiting sequence and relative ratio of these AAs have not been established for calves fed MR containing soy protein under commercial conditions in China.…”

Performance and nitrogen metabolism of calves fed conventionally or following an enhanced-growth feeding program during the preweaning period

“…Thus, the efficiency of utilization of absorbed amino acids (AA) could be improved by lowering the CP content of MR, and adjusting its amino AA profile. In fact, Kanjanapruthipong (1998) reported that calves fed MR (concentrated at 13% DM and 21% CP) containing soy protein and supplemented with AA presented a greater ADG and N retention (g/day) than calves receiving an MR without AA supplementation.…”

Asynchronous Supply of Indispensable Amino Acids Reduces Protein Deposition in Milk-Fed Calves3

“…In rapidly growing animals, such as milk-fed calves, effects of a suboptimal timing of AA supply on N balance will likely be more pronounced. To date, vegetable proteins have replaced substantial amounts of dairy proteins in milk replacer for calves, with subsequent addition of crystalline AA to reach ideal AA patterns (19,20); hence, asynchronous absorption kinetics of indispensable AA may occur.…”