Table 7.

Least squares means for the effect of sex on growth performance, carcass characteristics, and NH₃ gas emissions in beef cattle over a 91-d period

	Sex			Dose × sex	Sex
Variable	Steers	Heifers	SEM	P-value1	P-value1
Growth performance2
Unshrunk initial BW, kg	475	432	9.2	0.996	<0.001
Unshrunk final BW, kg	601	556	18.9	0.916	<0.001
DMI, kg	9.1	8.6	0.53	0.980	0.038
ADG, kg	1.38	1.38	0.12	0.724	0.875
G:F, kg:kg	0.151	0.159	0.0065	0.856	0.064
Carcass characteristics
HCW, kg	376	346	11.3	0.865	<0.001
Dressing percentage2	62.5	62.2	0.30	0.738	0.078
Adjusted fat thickness, cm	1.13	1.30	0.110	0.994	0.024
LM area, cm2	14.7	14.5	0.26	0.063	0.216
Marbling score3	567	592	11.8	0.979	0.156
Calculated yield grade4	2.39	2.46	0.137	0.816	0.582
KPH, %	1.65	2.10	0.049	0.802	<0.001
Lean maturity5	164	164	3.3	0.731	0.854
Skeletal maturity5	167	175	1.7	0.585	<0.001
Overall maturity5	166	171	2.4	0.639	<0.001
14-d WBSF6, kg	2.80	2.67	0.100	0.620	0.142

¹If the dose × sex interaction was not significant (P > 0.05), the main effect of sex was evaluated for the pooled doses. Statistical significance for sex was declared when P ≤ 0.05 and tendencies were declared when 0.05 ≤ P ≤ 0.10.

²Growth performance and dressing percentage were based on unshrunk initial and final BW.

³500, Small⁰⁰; 600, Modest⁰⁰.

⁴Yield Grade = 2.50 + (0.98 × adj. fat thickness, cm) + (0.2 × KPH, %) + (0.0084 × HCW, kg) – (0.05 × LM, cm²) (USDA, 1997).

⁵100, A⁰ maturity; 200, B⁰ maturity.

⁶WBSF, Warner–Bratzler shear force, measured after a 14-d aging period.