7 November 1997

Rape diets save cash

FEEDING rape-only protein sources instead of fishmeal and soya to early lactation dairy cows will lift margins by 1p/litre.

Thats the finding of Milk Development Council funded work at ADAS Bridgets which sought to design feeding strategies to maximise use of home-grown proteins for milk production.

Diets, fed as total mixed rations, were based on high quality grass silage, and included a high protein wheat alongside various protein sources.

These were soya and rape, linseed and rape, lupins and rape (heat treated) and all rape, plus the control of fish, soya and rape.

Researcher Rosemary Mansbridge told a MGA sponsored College Network meeting at Seale Hayne (more on p36), that fishmeal and imported soya bean meal could be replaced in the diet of high yielders by linseed and rape or lupins and heat treated rape, with no adverse effect on intake, milk quality or yield of solids.

Rape-only diets gave lower milk yields, but the yield of fat and protein was similar. Margin/litre at 15.3p was highest on this diet – reflecting the lower cost of the rape. The control diet resulted in the lowest margin at 13.9p/litre.

(Feed prices calculated for October, and based on a 20p/litre milk price, with grass silage costed at £75/t dry matter.)

Diets containing linseed, lupins, and rape only as protein sources, increased milk ureas. These might give rise to an increased risk of reduced fertility, warned Ms Mansbridge.

&#8226 Results from a similar trial comparing different protein sources fed mainly maize based diets will soon be available.