Dairy Notes September 2011
Plan winter feeding now!
Fodder quantity and quality will be major issues on many farms this winter. Buffer feeding during the summer, early housing and lower than normal yields from first cut grass silage and forage maize will all put pressure on fodder supplies this year. In particular County Down producers growing open established forage maize crops are facing a major shortfall in forage stocks. While first cuts are generally of good quality, high dry matters may be a problem with regards to heating at the face and restricting cow intakes.
Now is the time to plan forage use this winter.
- Measure up stocks now to see what forage is in store - compare this with likely winter demand.
Table 1: Conversion factors to convert silage volume to tonnes of silage
| Silage dry matter % | Conversion factor (tonnes of silage per m3) |
|---|---|
| Grass 20% | Multiply by 0.77 |
| Grass 25% | Multiply by 0.68 |
| Grass 30% | Multiply by 0.60 |
| Whole crop 40% | Multiply by 0.67 |
| Forage maize 30% | Multiply by 0.75 |
Worked example
The silage in a silo measures 28 metres long, 10 metres wide and 2.7 metres deep.
Volume of silage = 28 x 10 x 2.7 = 756 m3
For a 25 percent dry matter silage there is 756 m3 x 0.68 = 514 tonnes of silage.
Table 2: Estimated monthly feed requirement of stock (assuming silage is 25 percent dry matter)
| Silage (tonnes/month) | |
|---|---|
| Dairy cows in milk | 1.4 |
| 200-250 kg heifer | 0.6 |
| 350-400 kg heifer | 0.9 |
Dry cow management
Many cow health problems in early lactation are avoidable with good dry cow management. Good management ensures fresh calved cows spend little time in negative energy balance, show signs of heat within 50 days and potentially hit a calving index of 390 days.
It sounds simple, but not getting the dry period right sees everything thereafter fall apart. Cows should be dried off 50-60 days before calving, allowing time to adjust feeding to achieve a target body condition score of three when fresh calved. Cows need a low energy, high fibre ration in the dry or transition period. Aiming for 14-15 kg dry matter intake to supply just 110-115 MJ of energy a day for maintenance and the developing calf can be a challenge, but is possible. Anything over ends up as body fat.
Dry cow housing
Accommodation is key. It should be clean, airy and social. Clean water must always be available to cows. Water is the most understated nutrient we have. Farmers using bore holes should have supplies tested for pH. All water should be clean enough for you to consider drinking. A dry cow drinks 50-60 litres daily and milkers up to 100 litres, so it is important.
Dates to remember
Remember under the Nitrates Action Programme 14 September is the last day for sowing fertiliser on grassland.
