Lactating Cow
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Calculating Metabolisable Energy (ME) needs is important for dairy cows. You adjust for feed quality by adding or subtracting 4% per MJ ME/kg DM from the standard 11.0 MJ ME/kg DM. Consider factors like maintenance, milksolids production, walking, weight change, and feed wastage to work out daily requirements. These calculations are important to keep your cows healthy and maximise milk production. Make sure you adapt the guidelines to your farm's specific conditions for best results.
The requirements are calculated for pasture at 11.0 MJ ME/kg DM. For different pasture quality make the following adjustments to calculate the ME requirements.
- ME requirements with increasing feed quality: subtract 4% per MJ ME above 11.0 MJ ME/kg DM
- ME requirements with decreasing feed quality: add 4% per MJ ME below 11.0 MJ ME/kg DM
Note: The feed requirement figures are 'eaten' feed demand plus 6% to allow for feed wastage observed under good feeding conditions of pasture in farmlet trials. Where feed (pasture or supplement) wastage rates are higher than those stated, requirements for feed offered need to be increased.
Maintenance MJ ME/day (Lwt kg)
| 300 | 350 | 400 | 450 | 500 | 550 | 600 |
| 40 | 45 | 50 | 54 | 59 | 63 | 68 |
Milksolids MJ ME/kg MS by breed
| MJ ME/kg DM | Jersey (kg MS) | J X F (kg MS) | Friesian (kg MS) |
| 10 | 81 | 84 | 86 |
| 11 | 77 | 80 | 82 |
| 12 | 74 | 77 | 79 |
Walking MJ ME/km
| Flat | Rolling | Hilly/steep |
| 2.0 | 3.0 | 6.0 |
Pregnancy MJ ME/day
| 12 wks prior to calving | 8 wks prior to calving | 4 wks prior to calving | 2 wks prior to calving | Annual total | |
| Jersey | 11 | 18 | 32 | 42 | 1,848 |
| Kiwicross | 12 | 21 | 37 | 48 | 2,114 |
| Kiwicross | 13 | 23 | 41 | 54 | 2,338 |
| Fresian | 14 | 24 | 44 | 57 | 2,478 |
Lactating cow liveweight MJ ME/kg Lwt change
(Diet ME required or saved)
- Lwt gain 50
- Lwt loss -37
Example: Daily requirements of a 450 kg JXF cow, producing 2.0 kg MS/day and losing 0.5 kg/day Lwt at 12.0 MJ ME/kg DM.
- Maintenance = 54
- Walking on flat (3 km a 2 MJ ME/km) = 6
- Milksolids (2.0 kg MS x 80 MJ) = 160
- Lwt loss (0.50 kg Lwt x -37 MJ) = -19
- Total MJ ME at 11.0 ME = 201
- ME requirements reduced by 4% as 12.0 ME fed = 201 x 96% = 193
- Total kg DM Eaten (193 divided by 12.0 ME) = 16.1 kg DM
Note: Diet ME required reduced by 19 MJ ME from loss of Lwt
Total daily dry matter requirements lactating cows (kg DM/cow/day); for daily milksolids production
Daily milking cow requirements: kg DM/cow/day at 10.5 MJ ME/kg DM
| Breed | kg Lwt | 0.8 | 1.0 | 1.2 | 1.4 | 1.6 |
| J | 350 | 10.4 | 11.9 | 13.4 | 14.9 | 16.4 |
| J | 400 | 10.9 | 12.4 | 13.9 | 15.4 | 16.9 |
| J x F | 450 | 11.6 | 13.1 | 14.7 | 16.3 | 17.8 |
| Fr | 500 | 12.1 | 13.7 | 15.3 | 17.0 | 18.6 |
| Fr | 550 | 12.6 | 14.2 | 15.8 | 17.4 | 19.0 |
Daily milking cow requirements: kg DM/cow/day at 11.0 MJ ME/kg DM
| Breed | kg Lwt | 1.0 | 1.2 | 1.4 | 1.6 | 1.8 |
| J | 350 | 11.1 | 12.5 | 13.9 | 15.3 | 16.7 |
| J | 400 | 11.5 | 12.9 | 14.3 | 15.7 | 17.2 |
| J x F | 450 | 12.2 | 13.7 | 15.2 | 16.6 | 18.1 |
| Fr | 500 | 12.8 | 14.3 | 15.8 | 17.3 | 18.8 |
| Fr | 550 | 13.3 | 14.8 | 16.3 | 17.8 | 19.3 |
Note: No walking or Lwt loss or Lwt gain included
Daily milking cow requirements: kg DM/cow/day at 12.0 MJ ME/kg DM
| Breed | kg Lwt | 1.4 | 1.6 | 1.8 | 2.0 | 2.2 |
| J | 350 | 12.2 | 13.5 | 14.7 | 15.9 | 17.2 |
| J | 400 | 12.6 | 13.9 | 15.1 | 16.3 | 17.6 |
| J x F | 450 | 13.3 | 14.6 | 15.9 | 17.2 | 18.5 |
| Fr | 500 | 13.9 | 15.2 | 16.5 | 17.8 | 19.1 |
| Fr | 550 | 14.3 | 15.6 | 16.9 | 18.2 | 19.5 |
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