10 July 1998

Forages a boost to growth levels

UTILISING alternative forages and managing sward heights to boost intakes could see deer achieve their genetic potential, say New Zealand researchers.

Tom Barry, researcher at Massey University, New Zealand, told delegates that lactating hinds fed forages, including red clover and chicory, achieved up to 70% higher growth rates than hinds grazing perennial ryegrass swards.

Grazing height was a key consideration, said Mr Barry. In a New Zealand study the average sward height of grazed grass was below the optimum 10cm (4in) required to maximise intakes. For chicory, optimum grazing height was 10-30cm (4-12in), he said.

"If producers manage swards to maximise intakes it has a dramatic effect on stag growth and the number that achieve the target of finishing at 92kg liveweight or 50kg carcass-weight by 12 months old."

Analysis of New Zealand units had shown 21% of young stags were capable of achieving these finishing targets when grazing 5cm (2in) perennial ryegrass swards. That increased to 50% with sward heights of 10cm (4in), while rotational grazing on annual ryegrass swards increased it to 60%.

However, up to 73% of young stags had potential to finish off perennial ryegrass and white clover swards within 12 months because of higher intakes and nutritive value, said Mr Barry. Between 90-100% of stags could finish off crops such as red clover and chicory for the same reason.

Alternative forages can help extend grazing through the periods when grass growth slows, he added. It could also cut the cost and need for anthelmintics to control worms.