TY - JOUR
T1 - Metabolizable protein and amino acid requirements of growing cattle.
AU - Wilkerson, V. A.
AU - Klopfenstein, T. J.
AU - Britton, R. A.
AU - Stock, R. A.
AU - Miller, P. S.
PY - 1993/10
Y1 - 1993/10
N2 - Metabolizable protein and amino acid requirements for growing cattle were estimated using data from 11 research trials. A total of 543 steers were individually fed a high-roughage diet supplemented with protein at several levels above a urea supplement control. The mean weight for all animals was 253 kg, with a range in mean initial to final weights of 200 to 316 kg, respectively. Daily gain ranged from -.04 to .89 kg. Metabolizable protein for each treatment group was calculated at the point at which the protein requirement was met. The sum of dietary escape protein (basal and supplemental) and calculated microbial protein represented metabolizable protein supplied per test protein source analyzed in each trial. Daily gain was regressed against calculated metabolizable protein flow using weighted regression analysis (r2 = .69, n = 45) to determine the metabolizable protein requirements for maintenance (3.8 x BW.75 g/d, where BW is expressed in kilograms) and growth (305 g/kg of live weight gain). Calculated metabolizable amino acid requirements as a percentage of metabolizable protein for a 253-kg animal gaining .49 kg/d were as follows: methionine, 3.0%; total sulfur amino acids, 5.8%; lysine, 8.0%; tryptophan, 1.0%; threonine, 5.2%; valine, 5.7%; isoleucine, 5.6%; leucine, 6.9%; phenylalanine, 3.9%; and histidine, 1.6%. The proposed requirements were based on live animal gain and intake of metabolizable protein and should represent the needs of the growing beef animal.
AB - Metabolizable protein and amino acid requirements for growing cattle were estimated using data from 11 research trials. A total of 543 steers were individually fed a high-roughage diet supplemented with protein at several levels above a urea supplement control. The mean weight for all animals was 253 kg, with a range in mean initial to final weights of 200 to 316 kg, respectively. Daily gain ranged from -.04 to .89 kg. Metabolizable protein for each treatment group was calculated at the point at which the protein requirement was met. The sum of dietary escape protein (basal and supplemental) and calculated microbial protein represented metabolizable protein supplied per test protein source analyzed in each trial. Daily gain was regressed against calculated metabolizable protein flow using weighted regression analysis (r2 = .69, n = 45) to determine the metabolizable protein requirements for maintenance (3.8 x BW.75 g/d, where BW is expressed in kilograms) and growth (305 g/kg of live weight gain). Calculated metabolizable amino acid requirements as a percentage of metabolizable protein for a 253-kg animal gaining .49 kg/d were as follows: methionine, 3.0%; total sulfur amino acids, 5.8%; lysine, 8.0%; tryptophan, 1.0%; threonine, 5.2%; valine, 5.7%; isoleucine, 5.6%; leucine, 6.9%; phenylalanine, 3.9%; and histidine, 1.6%. The proposed requirements were based on live animal gain and intake of metabolizable protein and should represent the needs of the growing beef animal.
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U2 - 10.2527/1993.71102777x
DO - 10.2527/1993.71102777x
M3 - Article
C2 - 8226380
AN - SCOPUS:0027682650
SN - 0021-8812
VL - 71
SP - 2777
EP - 2784
JO - Journal of animal science
JF - Journal of animal science
IS - 10
ER -