Influence of ruminal degradable intake protein restriction on characteristics of digestion and growth performance of feedlot cattle during the late finishing phase

Table 5 Treatment effects on metabolizable protein and amino acid supply ¹ versus requirements ²

	Urea fermentation potential
Item	0	0.6	1.2
Metabolizable protein, g/d
Supply	688	600	565
Requirement	613	574	493
Metabolizable methionine, g/d
Supply	12.4	10.6	9.9
Requirement	12.3	11.5	9.9
Metabolizable lysine, g/d
Supply	39.2	32.9	30.1
Requirement	39.3	36.7	31.5

¹Metabolizable protein supply estimated as 80% undegraded intake crude protein and microbial crude protein entering small intestine (Trial 1), adjusted for level of intake. Metabolizable amino acid supply based on diet composition and corresponding tabular amino acid composition of undegradable intake protein for individual feed ingredients and average amino acid composition of ruminal bacteria (NRC, [17]).
²Metabolizable protein and amino acid requirements based on average body weight and daily weight gain (Trial 2; NRC, [17], Level 1).

ISSN: 2055-0391