Effect of date and length of closure and post grazing residual on pasture quality for silage

Abstract

The nutritional value of pasture silage made in New Zealand is often sub-optimal for lactating dairy cows. As farming systems require more pasture silage to be used in an attempt to increase lactation lengths and milksolids production per cow, the quality of this silage becomes more important. In spring 1995, pastures were closed for silage at weekly intervals from 11 September to 17 October, representing six distinct closure dates, to determine the effect that date and length of closure has on pasture quality. In spring 1997 pastures were grazed to different residuals (1.2- 1.4, 1.8-2.0, 2.1-2.4 and 2.5-2.9 t DM/ha) and then closed for silage to determine the effect that post grazing residual has on pasture quality. In both experiments pasture dry matter (DM) yield and chemical and botanical composition was monitored over the 63 day closure. Pasture closed on 11 or 17 September had higher metabolisable energy (ME) (P