INITIAL ANALYSIS may show good feed potential, but don’t overestimate the quality of your maize silage this winter, warns Frank Wright’s ruminant specialist Cara Freeston-Smith.

“Overestimating the value of forage could lead to cows failing to meet their potential and possible problems with fertility,” she says.

“We are getting a number of reports of cows failing to milk as well as expected and believe it could be because they are using the winter diet to regain weight rather than produce milk.”

Miss Freeston-Smith believes some producers expected too much from grass grazed late in the season resulting in mid and late lactation cows losing condition.

“While the average maize crop should help boost feed intakes, producers shouldn”t be too optimistic about its production potential. Watch what happens in practice and adjust rations accordingly.”

The company’s results, from more than 1000 maize silage samples, reveal average dry matters are 3% lower than last year at 29.7%, while starch and nutrient detergent fibre (NDF) contents are both slightly higher.

“The average energy content is 11.2MJ/kg DM, but there is a significant range from 9.7MJ to 12.3MJ/kg DM,” she adds.

David Bright of Wilts-based David Bright Seeds reports maize silages seem to be pretty reasonable and no worse than other years. However, many crops were cut too dry.

“When it turned wet, crops were ready, but producers either couldn”t get on the land or contractors weren”t booked early enough,” he says.

Producers whose maize harvest was caught by wet weather from mid-October onwards could be dealing with silage that is too dry, agrees The Dairy Group’s nutritionist Chris Savery.

“The crop had lost its green by then, the grains were hard and it was more difficult to harvest,” he says. As long as the clamp wasn’t contaminated by mud, producers should pay attention to face management to avoid spoilage and good feed practice.

“A lot of grass silage was good, so it’s a case of weighing up the combination of analyses, and what cows think of it and make changes accordingly,” adds Mr Savery.

Suffolk-based independent consultant Bruce Woodacre has also seen maize that is drier than expected. “Once dry matter rises above 35%, the level of soluble starch falls off rapidly meaning there is less fermentable energy available to rumen bacteria. This may result in poorer performance from silage,” he says.

Mr Woodacre warns that drier silages, being more open, are not as well preserved. Once clamps are open, aerobic deterioration soon leads to the presence of mycotoxins.

“The mistake would be to assume all herds have the same problem caused by maize silage, but they require different solutions. Maize lacking in soluble starch should be balanced with another starch source such as wheat.”