Dairy cows

• Target the best quality roughage towards freshly calved cows and those with a sustained high yield.
• Target restricted diets towards cows in late lactation, dry cows and young stock. Dry cows and those in late lactation can sustain some condition loss without serious detriment to performance. Young stock fed restricted roughage along with moderately high concentrate, convert concentrate relatively efficiently.

• Extending the grazing season has become popular in many areas of Northern Ireland in recent years because of reductions in feed cost and savings in silage requirement.
• Research at the Agricultural Research Institute for Northern Ireland (ARINI) Hillsborough has shown that extending the grazing season in late autumn/early spring by grazing cows for 2-3 hours/day can reduce silage requirements by up to 36% while cows are at grass. This will increase milk yield by up to 2.1 litres/day and improve protein. The technology programme at Greenmount College has also demonstrated this.
  Aim for an early turnout by not grazing dry, southerly facing fields after the end of October. Apply urea fertiliser to these fields in the last half of February when 2-3 dry days are forecast.
  Turnout cows in the early spring for 2-3 hours/day when grass cover reaches two tonnes of dry matter/hectare (7cm high) and when ground conditions are sufficiently dry.
• ·Feeding high levels of a low protein supplement (based on barley or wheat) is an option if you have insufficient silage.
  Research at ARINI Hillsborough has shown that even with ad libitum access to grass silage, autumn calving dairy cows require as little as 4.5 tonnes of fresh silage (at 18 percent DM) for a six month winter if they are also receiving 12 KG/day of a low protein concentrate.
  Note: Feeding such diets requires considerable care and further advice should be sought from your DARD Development Adviser.
• ·Where silage is poor-moderate quality then increased levels of supplementary feeding will be required to maintain milk yield (Table 7). This can be fed in the parlour or alternatively can be given as a mid-day feed.

• To obtain 30 litres of milk/cow/day, 10kg of silage/head/day can be saved (180 tonnes of silage on 100 cows over the winter) by feeding additional meal or by substituting some straw.
• If silage is costing more than £19/tonne then restrict silage and feed extra supplement. Based on the rations in Table 8 if straw is costing £65/tonne (£1/small bale) then silage purchased at up to £30/tonne (£15/big bale) is better value than a straw based diet. Straw at £65/tonne is unlikely to be economic.