The timing of weaning calves is an important decision in any beef herd, but during drought the timing is more important due to future impacts on herd fertility.

Early weaning is a cost-effective means of maintaining cow condition and aiding herd fertility by greatly reducing the demands on cows, while well cared for early weaned calves are still able to meet their future potential for growth, carcase yield and quality.

As a general rule it is better to wean earlier, rather than later as there is a large economic cost to leaving calves on the cows.

Factors which need to be considered when deciding to wean calves include feed availability, cow fat score, calf age and calf weight.

Feed availability and cow fat score are closely linked.

In seasons when feed in the paddock is plentiful, cows are able to milk well, while still maintaining body condition.

During periods of limited feed availability, lactating cows can quickly loose condition and rapidly fall in fat score.

The weaning of calves instantly reduces the nutritional stress of lactation on the cow.

Weaning allows the cows to transfer nutrients that were previously going into milk production to normal body functions, including improving condition and preparing for the next calf.

The important aspects of herd fertility - calving percentage, calving pattern and calving span - are strongly affected by cow condition.

The better the condition of a cow at calving, the better her milk supply and the sooner she will return to oestrus after calving.

Ultimately, cows should not be allowed to fall below fat score 2, before the calves are weaned.

In severe situations calves can be weaned as early as six weeks of age, but it is preferable to wait until the calves have reached 12 weeks or around 100 kilograms live weight.

Calves of this age require less protein and are easier to feed than six week old calves.

Once weaned, calves need to be provided with a quality diet high in both energy and protein.

Calf diets may be in the form of calf pellets, or four parts cereal grain to one part protein meal.

Some roughage - preferably long chopped - is also required for calves; pasture hay or good cereal straw are adequate.

Weaner diets are expensive, but it is critical that weaned calves are provided with a diet that will keep them growing.

Research from the CRC for Cattle and Beef Quality has shown that calves should grow at more than 0.6 kg/day until they reach 250 kg, otherwise they may suffer significant stunting which will reduce their potential to grow out, and eventually result in fatter, lower yielding carcases.

Any periods of growth below 0.6 kg/day could have permanent detrimental effects.

Female calves to be retained as future breeders may suffer reduced pelvic size if not fed enough.

Contact: Jeffrey House, Forbes, (02) 6850 2925.