Table 1. Effects of zilpaterol on feedlot performance and carcase characteristics.
Outcome | Number of studies (n) | Raw mean difference 95% CI | Effect Size and 95% CI | Weighted mean difference and 95% CI | I2 estimated hetero-geneity | Significant meta-regression effects |
Final Body weight (kg) | 31 | 6.562 | 0.449 | 8.150 | 0.0 | |
4.229 to 8.895 | 0.277 to 0.621 | 5.627 to 10.674 | ||||
Dry Matter Intake (kg/d) | 26 | −0.160 | −0.470 | −0.118 | 0.0 | |
−0.243 to −0.077 | −0.676 to −0.264 | −0.167 to −0.070 | ||||
Average Daily Gain (kg/d) | 29 | 0.210 | 0.884 | 0.153 | 29.1 | |
(0.0)1 | ||||||
0.141 to 0.278 | 0.656 to 1.113 | 0.111 to 0.194 | ||||
Gain:feed (kg/kg ratio) | 28 | 0.024 | 1.336 | 0.024 | 54.1 | |
0.017 to 0.031 | 1.002 to 1.671 | 0.018 to 0.030 | ||||
Hot Carcase Weight (kg) | 35 | 15.383 | 1.323 | 15.179 | 55.9 | |
12.937 to 17.829 | 1.034 to 1.611 | 13.615 to 16.743 | ||||
Ultimate pH | 5 | 0.022 | 0.102 | −0.002 | 0.0 | NA |
−0.033 to 0.077 | −0.411 to 0.616 | −0.017 to 0.013 | ||||
Longissimus muscle area (cm2) | 35 | 8.147 | 2.302 | 8.006 | 70.8 | Unit (0.022) period (0.165) Multivariate2 |
7.115 to 9.180 | 1.898 to 2.705 | 7.052 to 8.959 | ||||
Objective measurement of ‘redness’ (Colour) | 18 | 0.012 | 0.098 | 0.03 | 15.0 | |
−0.122 to 0.098 | −0.174 to 0.371 | −0.004 to 0.066 | ||||
Fat thickness at the 12th rib (cm) | 35 | −0.106 | −0.697 | −0.11 | 47.8 | Fat of control(0.120) and period (0.186) Multivariate2 |
−0.139 to −0.073 | −0.940 to −0.453 | −0.158 to −0.080 | ||||
Standardised USDA marbling score | 34 (28)* | −23.004 | −0.861 | −22.947 | 37.3 | Unit (0.030) period (0.050) Multivariate2 |
−31.245 to −14.763 | −1.100 to −0.621 | −30.330 to −15.564 | ||||
Dressing Percentage (%) | 27 | 1.657 | 2.205 | 1.706 | 71.5 | |
1.319 to 1.996 | 1.669 to 2.741 | 1.510 to 1.902 | ||||
Warner-Bratzler Shear Force (kg) | 47 | 1.022 | 1.212 | 0.840 | 61 | Age (0.001) unit (0.001) Multivariate2 |
0.854 to 1.191 | 1.024 to 1.401 | 0.720 to 0.960 |
CI – Confidence interval.
Sensitivity with removal of Avendano-Reyes et al.
NA – insufficient studies to attempt.
Higgins and Thompson (2004) method.
*6 trials removed with different units for Raw mean and weighted mean differences.