22 March 1996

DUP – yield effect?

SUPPLEMENTING dry cow diets with digestible undegradable protein may not change milk yields and intakes in the next lactation.

This is the finding of studies by the Institute of Grassland and Environmental Research reported at the BSAS meeting.

IGERs Richard Dewhurst said previous studies had shown that supplementing grass silage with DUP during the dry period could increase yields of milk protein and lactose.

"These studies involved limiting forage intake either by restricting access or through feeding straw," said Dr Dewhurst.

The IGER study allowed free access to forage and compared grass silage with grass silage and barley straw, and grass silage plus 0.5kg maize gluten meal a cow a day.

"No significant effect was recorded in milk yield, protein or fat content in the next lactation. This is possibly because the ad lib forage caused cows to put on too much condition.

"The study serves as a warning to producers who have been encouraged to feed dry cows extra DUP and may have added it to ad lib diets. It is important that condition score at this stage is heeded for the benefit in the next lactation to be realised," he said. &#42