Table 4.
Energy requirements for beef cows in different stages of pregnancy and milk yield calculated based on BR-CORTE (2016) and NASEM (2016) systems
| Item | System | |
|---|---|---|
| BR-CORTE (2016) | NASEM (2016) | |
| BW, kg | 500 | 500 |
| SBW, kg | 491 | 480 |
| EBW, kg | 418 | 428 |
| CBW, kg | 32 | 32 |
| Requirements | ||
| NEm, Mcal/d | 9.04 | 9.48 |
| MEm, Mcal/d | 12.5 | 16.5 |
| NEp, Mcal/d | ||
| 180 d pregnant | 0.16 | 0.18 |
| 210 d pregnant | 0.26 | 0.32 |
| MEp, Mcal/d | ||
| 180 d pregnant | 1.35 | 1.37 |
| 210 d pregnant | 2.14 | 2.43 |
| NEl, Mcal/d | ||
| 5 kg milk | 3.75 | 3.60 |
| 8 kg milk | 6.00 | 5.76 |
| MEl, Mcal/d | ||
| 5 kg milk | 5.21 | 6.25 |
| 8 kg milk | 8.33 | 10.0 |
| Efficiency of use of ME to NE | ||
| Km | 0.72 | 0.58 |
| Kp | 0.12 | 0.13 |
| Kl | 0.72 | 0.58 |
CBW = calf birth weight; MEp = metabolizable energy requirement for pregnancy; NEl = net energy requirement for lactation; MEl = metabolizable energy requirement for lactation; Km = efficiency of use of MEm to NEm; Kp = efficiency of use of MEp to NEp; Kl = efficiency of use of MEl to NEl; MEl = metabolizable energy for lactation.