7 April 2000

QUALITY FOR CALVERS…

FEEDING high quality silage before cows calve improves milk composition, but care must be taken to limit calf growth in early pregnancy, concludes research undertaken at IGER, Aberystwyth.

MDC and MAFF-funded research examined the effects of silage quality on feed intake, weight change and milk performance of dry cows. This demonstrated that feeding high quality silage could boost intakes and improve milk fat and protein composition, said Richard Dewhurst.

During the trial, two silage qualities were compared; a high D-value grass silage of 72 and ME 11.7, ensiled on May 9; the other a low quality silage of 60 D-value and ME of 10.3, ensiled on June 15.

He said that this research stemmed from earlier premises that feeding concentrates in late pregnancy didnt stop pre-calving drop in feed intake.

However, feeding high quality silage throughout a cows dry period benefited milk composition and late pregnancy intakes. But it also led to excessive weight gains in both cow and calf, causing calving difficulties.

"This is the big downside of feeding high quality, first cut silage during the early dry period, when it seems there is potential to affect calf weights."

But it is possible to rectify this, said Dr Dewhurst. Feeding lower quality silage in the early dry period, followed by high quality silage three weeks before calving will increases intakes and benefit milk composition without causing calving difficulties.

He said this principle was possible to adopt on farm, even when differing silage quality was unavailable.

"When using a silage/straw forage mix and a protein supplement, remove straw from the diet about three weeks before calving." &#42