Table 2.
Least squares means and 95% confidence intervals of performance variables of low (feed efficient, HE; n = 12) and high (feed inefficient, LE; n = 12) residual feed intake (RFI) mid-lactation dairy cows.
| Variable 1 | HE | LE | p-Value | ||
|---|---|---|---|---|---|
| RFI, kg | −1.73 | [−2.16, −1.30] | 1.72 | [1.17, 2.27] | - |
| DMI, kg | 29.5 | [28.5, 30.6] | 33.5 | [32.5, 34.6] | <0.01 |
| Milk Production | |||||
| Milk, kg | 50.7 | [46.7, 54.8] | 51.2 | [47.2, 55.2] | 0.87 |
| Milk energy, Mcal | 33.4 | [30.9, 36.0] | 34.4 | [31.8, 37.0] | 0.59 |
| ECM, kg | 49.7 | [46.0, 53.3] | 51.0 | [47.3, 54.6] | 0.61 |
| FCM, kg | 48.4 | [44.7, 52.2] | 50.0 | [46.3, 53.7] | 0.54 |
| Fat, kg | 2.7 | [2.2, 3.2] | 3.0 | [2.5, 3.5] | 0.32 |
| Protein, kg | 1.6 | [1.4, 1.7] | 1.6 | [1.4, 1.7] | 0.94 |
| Lactose, kg | 2.4 | [2.2, 2.6] | 2.4 | [2.2, 2.6] | 0.92 |
| Fat, % | 3.20 | [2.95, 3.45] | 3.37 | [3.12, 3.62] | 0.32 |
| Protein, % | 3.06 | [2.94, 3.17] | 3.06 | [2.94, 3.17] | 0.98 |
| MUN, mg/dL | 14.6 | [13.7, 15.6] | 15.3 | [14.4, 16.2] | 0.32 |
| Body Size | |||||
| BW, kg | 768 | [733, 802] | 784 | [750, 819] | 0.49 |
| Metabolic BW | 146 | [141, 151] | 148 | [143, 153] | 0.50 |
| BW change, kg/d | 0.32 | [0.12, 0.53] | 0.26 | [0.06, 0.47] | 0.69 |
| BCS | 3.22 | [3.07, 3.37] | 3.15 | [3.00, 3.30] | 0.48 |
1 DMI = dry matter intake; ECM = energy-corrected milk; FCM = fat-corrected milk; MUN = milk urea nitrogen; BW = body weight; BCS = body condition score.