With the first silage harvest of the season already started, Germinal’s David Little stresses the importance of aiming for the highest possible quality by cutting grass at the optimum time.
“When making silage, it is usually the case that as quantity increases, quality decreases,” he says. “This is because the more mature (stemmy) crop will have a higher fibre content and therefore be less digestible and of lower nutritional value.
“There will always be the inevitable temptation to allow crops to ‘bulk up’ to ensure maximum clamp fill, but for the best outcome the advice is usually to cut the crop approximately one week before the grass comes into head.”
Quality is measured by D-value, which is directly correlated with energy (ME). So if the D-value is falling, so is the energy value of your silage, he adds.
“D-value declines as the grass becomes more mature, with the biggest and most significant drop-off occurring after ear emergence (heading), so you really want to avoid cutting stemmy grass with a lot of seed heads.”
When planning ahead for future silage leys, David Little says that ensuring mixture selection takes account of quality – as well as yield and other traits – is an important starting point.
“Firstly, select mixtures that contain varieties that are on the Teagasc Pasture Profit Index (PPI) and Recommended Lists, and ensure the varieties are highly rated for conservation D-value.
“Secondly, look at the heading date range across the varieties included, as these should ideally be as close as possible to ensure the majority of the crop is at optimum maturity simultaneously.
“It will pay to maximise the D-value of your silage, as this equates to higher energy and reduces your reliance on bought-in concentrates.”