While early harvested maize crops are analysing well and should help support good milk yields, a significant number of crops have been harvested late and may present nutritional challenges, according to Trouw Nutrition GB who have already analysed over 1,000 samples this year.
Ruminant technical development manager, Dr Liz Homer says early crops have produced a similar quality feed to 2014 which suggests some well-made, good quality forages.
“The average 2015 maize silage is 30.1 per cent dry matter which is 1.4 per cent lower than last year, meaning that 0.7kg more freshweight will need to be fed to achieve a 5kg dry matter intake.
"However, the average ME is higher at 11.6MJ, which is combined with marginally higher starch, lower NDF and lignin. Intake potential is virtually identical to last year too.
“Starch degradability is higher than last year, already as high now as for the whole 2014/2015 season average. Degradability significantly increases with time in the clamp, and coupled with lower NDF content means farmers will need to balance rapidly and total fermentable carbohydrate supply to reduce the risk of acidosis.”
Dr Homer says the early maize crops should support good levels of milk production provided they are well-balanced. However, she stresses there is a considerable range in the samples analysed and advised farmers to get clamps analysed and to repeat the analysis regularly during the winter so changes in starch degradability can be reflected in diet formulation.
She also comments that this year a significant proportion of crops have been harvested late which can have consequences for feeding value so these crops will need to be analysed and diets formulated carefully.
“Where crops have been harvested late because they were slow to mature, it is likely overall starch levels will be increased as more sugars are converted to starch. This will lead to a higher potential ME level provided crops do not get over ripe. However, if the stalk becomes increasingly lignified, the crop will have lower digestibility, impacting on both energy content and intakes.
“If crops are harvested late due to the weather, increased lignification will be a serious risk and starch content may be reduced as a result of a higher proportion of vegetative material in the crop. The other threat in this situation will be the increased risk of soil contamination which will make it difficult to achieve a stable fermentation.
“With farmers looking to maximise contribution from forage and to ensure all litres are produced as efficiently as possible, maize silage will have a large role to play. Regular analysis of quality and close attention to diet formulation to maximise rumen health will be essential to exploit the potential this winter,” said Dr Homer.