Differing rearing strategies will be appropriate on different farms. This will depend on the nature of the individual dairy enterprise, land availability, land quality, land accessibility to cows, labour available etc. Within any farm the strategy adopted may also be different for animals born at different times of the year.

The options range from the conventional approach (based on diets of grass silage over both Winters and grazing over both Summers) through to systems which provide more controlled nutrition in which the major part of the rearing period (Winter and Summer) is based on straw or silage + concentrate. Experience has shown that these systems (especially using straw) are much easier to implement and be assured of meeting target performance. Indeed they are almost essential for late Spring and Summer born calves if 24 month calving is to be successfully achieved.

THERE ARE ADVANTAGES AND DISADVANTAGES FOR EACH APPROACH:

The conventional system has positive advantages, and reduces the variable costs of rearing, but:-

• It can compete for land with the profit making cow enterprise.

• The variation in the quality of silage and grass necessitates frequent monitoring of heifer performance.

• Supplementation of animals at pasture can present management problems.

• Grazing land away from the main farm may present additional bio-security risks to the dairy herd.

• It is not appropriate for rearing late Spring - Summer born calves for 24 month calving.

More controlled systems using straw can increase feed costs but:-

• Less land area required (less conflict with cows for land).

• Much greater precision in meeting target growth rates.

• Reduces bio-security risk associated with off-farm grazing.

• Maximises the use of young stock housing.

•  Extremely suitable for late Spring - Summer born calves.

Systems based on straw for at least part of the rearing period are being increasingly adopted by farmers to provide much easier control of growth rates - especially during the first Winter and Summer. Total housing systems using silage can also be appropriate.

The keys to a good straw/silage based total housing system are:-

Ensure straw or silage is of good quality.

• Ensure the overall diet is nutritionally balanced.

• Allow animals access to grazing during some stage of the rearing programme (enables animals to develop their grazing skills).

• Remember that animals housed during the rearing period are susceptible to intestinal parasites when put to pasture for the first time - irrespective of their age.

Monitor heifer growth rates, through the Thompson growth plan, throughout the rearing period.

FEED PLAN TO ACHIEVE 560 - 580 KG AT 24 MONTH CALVING (TOTAL HOUSED SYSTEMS)