Table 5.
Descriptive statistics for BW, predicted body composition, energy requirements, and energy budgets for the 59 Angus steers and heifers1 in the feedlot RFI test, and their correlations with midparent RFIP-EBV and with feedlot-test DMI and RFI
| Correlations | ||||||||
|---|---|---|---|---|---|---|---|---|
| Trait | Units | Mean | SD | Min. | Max. | RFIp-EBVmp2 | DMI | RFIf |
| Start-WT | kg | 410 | 36 | 342 | 499 | −0.04 | 0.68*** | 0.00 |
| Start-EBP | kg | 62.5 | 5.9 | 50.8 | 80.7 | −0.28* | 0.50*** | −0.17 |
| Start-EBF | kg | 60.8 | 11.4 | 34.8 | 90.8 | 0.47*** | 0.62*** | 0.41** |
| End-WT | kg | 504 | 42 | 417 | 600 | −0.14 | 0.64*** | 0.00 |
| End-EBP | kg | 70.1 | 6.2 | 57.8 | 88.1 | −0.40** | 0.44*** | −0.21 |
| End-EBF | kg | 106 | 13.6 | 77.8 | 137 | 0.40** | 0.75*** | 0.44*** |
| Maintenance: MER lit | MJ/d | 40.5 | 2.6 | 34.6 | 46.0 | −0.14 | 0.62*** | 0.04 |
| Maintenance: MER test | MJ/d | 40.4 | 3.7 | 33.1 | 49.8 | −0.36** | 0.33* | −0.11 |
| MER test WT | MJ/kg | 0.089 | 0.006 | 0.075 | 0.102 | −0.33* | −0.37** | −0.15 |
| MER test Protein | MJ/kg | 0.611 | 0.038 | 0.511 | 0.686 | −0.07 | −0.21 | 0.10 |
| Activity lit | MJ/d | 6.8 | 0.6 | 5.7 | 8.2 | −0.09 | 0.67*** | 0.00 |
| Activity test | MJ/d | 7.6 | 0.6 | 6.4 | 9.2 | −0.05 | 0.67*** | 0.03 |
| ME for gain | MJ/d | 75.7 | 10.5 | 52.8 | 102 | 0.55*** | 0.93*** | 0.84*** |
| ME for gain ADG | MJ/kg | 55.1 | 11.2 | 30.7 | 79.3 | 0.56*** | 0.47*** | 0.55*** |
| ME for gain Protein | MJ/kg | 793 | 357 | 327 | 1948 | 0.35** | 0.32* | 0.27* |
| ME requirement: MEI lit | MJ/d | 122 | 13 | 92 | 155 | −0.16 | 0.42** | 0.09 |
| ME requirement: MEI test | MJ/d | 123 | 14 | 91 | 156 | −0.21 | 0.37** | 0.05 |
| Actual ME intake | MJ/d | 124 | 11 | 98 | 150 | 0.41** | 1 | 0.74*** |
1Comprising 29 steers and 30 heifers.
2Midparent EBV for postweaning RFI.
RFI = residual feed intake; RFIp = RFI measured postweaning; EBP = empty body protein weight; EBF = empty body fat weight; MER = maintenance energy requirement; MER lit = MER calculated based on literature equations; MER test = MER calculated using data from this current test; MER test WT=MER test/midtest BW; MER test protein=MER test/midtest EBP; Activity = energy used for activity; Activity lit = Activity calculated based on literature equations; Activity test = Activity calculated using data from this current test; ME for gain = ME for energy retained and heat production for gain in body protein and fat; ME for gain ADG=ME for gain/ADG; ME for gain Protein=ME for gain/gain in body protein; MEI = ME intake; MEI lit = MEI calculated based on literature equations; MEI test = MEI calculated using data from this current test; RFIf = RFI measured in the feedlot.
*P < 0.05; **P < 0.01; ***P < 0.001.