for feed

8 December 2000

Home-grown protein

for feed

CONCENTRATE costs for many beef rearing systems could be reduced through the use of home-grown proteins, BGS delegates were told.

Researchers at the Institute of Grassland and Environmental Research, Aberystwyth are looking at a range of protein crop options in the on-going Alternative Forage Programme. This included red clover, lucerne, lotus, sainfoin and legumes such as kale, forage peas and beans, said IGERs Maiecia Fraser.

"The latest edition of Nix Pocketbook puts concentrate costs for 18-month beef at £134, grass silage beef at £168 and 24-month beef at £105-£120. But concentrate costs also apply to proteins we can grow in this country. After grass many producers are at the mercy of imports – mainly soya – and whether we like it or not many have links with GM crops," said Dr Fraser.

The trials hope to establish which crops have the greatest potential. Legumes are popular, but the reduced need for nitrogen – saving £87/ha (£35/acre) over grass – has to be offset by liming costs, phosphorus and herbicide applications totalling £36/ha (£14.57/acre).

Poor winter survival of lotus and sainfoin has made redrilling necessary. Red clover and lucerne had competed well against grass with a yield of 14.3t DM/ha (5.78t DM/acre) after applications of 250kg/ha a year of nitrogen (200 units/acre). For legumes, researchers suggest cutting peas by 12 weeks, beans at 14 weeks and kale up to 20 weeks or crude protein levels begin to fall.

Ensiling trials had shown the better crops had preserved 50% of the true nitrogen content, but that fell to just 20% in the poorest. Lotus, sainfoin, peas and beans all contain tannins which protect protein in the rumen increasing the supply to the intestine. Red clover contains an enzymes which does a similar task, but levels vary between varieties.

Results from a trial on growing lambs had been encouraging, with most crops out-performing grass silage, but nitrogen losses through the digestive tract had been high for both lucerne and sainfoin. &#42


&#8226 Saves on concentrate costs.

&#8226 Reduces fertiliser needed.

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