How managing winter grass residuals can increase first cut D-value
If producing high D-value silage is the objective on farm, then good grazing management this winter and spring has an important role to play. Good grazing conditions have allowed fields to be grazed to the desired residual, without causing too much damage to the sward.
Grazing down to a residual of 5cm from late autumn into early spring – is the key to ensuring that re-growth is of a high D-value. Longer residuals can lead to dead vegetation accumulating and therefore the quality of the sward will be reduced significantly.
Although weather conditions are favourable at the moment, if soil conditions deteriorate and livestock begin poaching then they should be removed or this will also affect 1st cut yields and quality. Weather conditions can make grazing difficult and the desirable height a challenging target to hit during early spring. It might be an option to graze fields now that are intended for 1st cut silage.
Research has shown that fields un-grazed from late autumn into early spring will produce lower D-value silage compared to those that were grazed. Un-grazed fields during this period that are harvested for silage in late May will have an estimated D-value that is on average 7% lower than if they were grazed.
However, there was no difference in silage D-value if grass was grazed in late autumn/winter versus early spring and harvested in late May. The quality of silage also depends on harvest date, growth stage at harvest and fertilisation.
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