The welcome news of some high-quality maize silage needs to be tempered by the continued impact of this year’s forages on rumen health. So says Trouw Nutrition GB and its nutritionists are also warning producers against opening clamps too early.
“The 2018 maize season was unusual with late planted crop following the wet spring having to cope with a significant drought in the summer,” says the company’s Liz Homer. “Slow growing crops then matured quickly with the first maize reportedly cut before the end of August.
Reflecting the season, analysis samples have been coming in earlier than usual. But Dr Homer adds that, worryingly, more than 15% of samples were inadequately fermented: “Which suggests a rush to get the feed into diets driven, in part, by reduced overall forage stocks.
“It is important that maize is correctly fermented in order to optimise milk yields and cow health,” she explains. “Feeding incompletely fermented crops should be resisted. The fermentation will be unstable, increasing the risk of spoilage. And any analysis will not be representative of the final feed.”
Overall, the results for the first 500 samples analysed by the company show good feed values. Dry matter averages 32.8% with a higher proportion of drier crops, which is a consequence of the excellent weather at harvest. Energy measures are good at 11.7MJ/kgDM and 31% starch. NDF and lignin levels are lower. Starch degradability is the same as in 2017 but, as starch content is higher overall, there is an increase in bypass starch.
“The headline figures show that some good maize silage has been made and, in crops that have completed fermentation, the characteristics of the fermentation are good,” says Dr Homer. “However, when we look at how the forage may perform in the rumen it is clear careful balancing will be needed to maintain good rumen health.”