29 September 1995

– the risks

High DMfeed

Producer confidence and a willingness to invest prevailed at the European Dairy Farming Event, despite concern over limited forage stocks

DAIRY producers feeding cows high dry matter silage this winter could see disappointing herd performance and reduced production a forage hectare.

This has been the case in Holland where high dry matter silages (40%-45%) achieved by harvesting after two to three days wilting have been lower in feed value than expected.

Speaking at the Event, Dutch researcher Dr Ate Bosma of the Institute of Agricultural Engin- eering, Wageningen, said a two- to three-day wilt reduced silage quality rather than improving it. "Extended wilting loses nutrients and lowers feed value," he said.

Dutch producers were now reducing wilting to improve silage quality. He advises that grass is wilted for 24 hours to achieve dry matters of 30%.

He warned that producing high dry matter silage presents greater scope for management mistakes than producing wet silage. Extended wilting led to delayed re-growth, loss of silage quality and increased risk of aerobic spoilage.

"It is better to make good quality wet silage than bad quality high dry matter silage," he said.

Prof Roger Wilkins of the Institute of Grassland and Environmental Research said: "There is a view that the higher animal intakes achieved with dry grass silage will increase production, but this is not backed up by trials," he said. "In most cases research shows a depressed performance a hectare from animals fed dry silage (35% DM) compared with unwilted crops (21% DM).

Prof Wilkins cited results of Eurowilt studies carried out at the former Grassland Research Institute, Hurley, to compare high and low dry matter systems.

"Losses were slightly lower with the wilted silages and they gave higher dry matter intake," he said.

"But digestibility was reduced, giving similar milk yields and dairy liveweight gains to unwilted systems."

Dr Ate Bosma:"Extended wilting leads to nutrient loss and reduced feed value."