Silage prospects are looking better for this winter’s rations

She says: “This is indicative of the rapid growth at the start of the season resulting in a more mature crop despite an earlier harvest. The consequence is that this will affect how silages will perform in the rumen.

“The combination of increased dry matter and lignin means that both rapidly and slowly fermentable carbohydrates are lower than in 2018.

"Overall, fermentable carbohydrate averages are low when compared to fermentable protein. This means that there is an excess of rumen fermentable protein which could impact on rumen balance in the total diet.

“To balance this, it may be necessary to increase the proportion of rapidly fermentable energy sources in supplementary feeds, possibly feeding more cereals to optimise rumen energy and microbial protein levels.

“The good news is we are seeing lower acid loads than in 2018 and are generally seeing a higher fibre index than last year. Together these mean it should be possible to formulate diets containing more cereals safely, without increasing the acidosis risk.”

Dr Homer says the overall picture is that the average silage has a Dynamic Energy content down from 6.7MJ/kg DM to 6.2MJ/kg DM. While this still indicates a good energy level, the reduced fermentability could affect milk production potential.

A cow eating 10kg DM/day would be expected to produce M+8.1 litres from silage provided the total diet is correctly balanced in terms of rapidly and slowly fermentable carbohydrate and protein.

”Encouragingly we are seeing higher intake potential, up from 97.3g/kg metabolic liveweight in 2018 to 106.4g/kg metabolic liveweight this year.

"This means cows should be enthusiastic about eating higher quantities which could be good news given that in many parts of the country first and second cuts have been good, and with some heavy third cut crops in the field farmers may be able to increase the proportion of grass silage in the diet this winter.

“As in any other year, the average masks a considerable variation in actual crops. While they indicate a trend, they cannot take the place of regular analysis of the clamps on the farm,” she says.