Table 3.

Nitrogen metabolism of bulls fed on experimental diets with different levels of crude protein

Parameters	Dietary treatments			SEM	p-value
	LCP	MCP	HCP		Linear	Quadratic
Total N
N intake (g/d)	123.47b	138.09a	148.35a	3.833	0.004	0.774
Total N losses (g/d)	94.00b	99.22ab	102.32a	1.660	0.011	0.706
% of intake	76.17a	71.88ab	69.10b	1.403	0.011	0.767
Urinary N
Urinary N (g/d)	26.82	27.01	28.04	2.494	0.746	0.886
% of total excreted	28.48	27.18	27.41	2.309	0.747	0.806
% of intake	21.68	19.51	18.82	1.295	0.166	0.697
Faecal N
Faecal N (g/d)	67.18	72.21	74.29	2.187	0.059	0.654
% of total excreted	71.52	72.82	72.59	2.309	0.747	0.806
% of intake	54.50	52.38	50.29	2.579	0.293	0.972
N balance (g/d)1)	29.47b	38.86ab	46.02a	0.051	0.009	0.877

LCP, low crude protein; MCP, medium crude protein; HCP, high crude protein; SEM, standard error of mean; N, nitrogen.

¹⁾N balance = N intake–urinary N–faecal N.

^a,bWithin the same row with different superscripts means significant difference (p<0.05).