Does mowing before grazing increase dry matter intake and milk yield?

Abstract

Mowing pasture before allocation of herbage to dairy cows is one management strategy suggested to improve feed quality, increase herbage dry matter (DM) intake and increase milk solids yield. To test these hypotheses, pasture at either a three or four week regrowth interval was offered to dairy cows 3 hours after pasture had been mown or as standing pasture. Forty-eight late lactation, Friesian x Jersey dairy cows were blocked into four groups and randomly allocated to each treatment. There was no effect of mowing or regrowth interval on botanical composition of the pasture on offer. Composition of herbage above 3.5 cm varied in DM content which was increased by mowing (13.2 versus 18.4% DM, P<0.05). For pastures with a three week regrowth interval, crude protein content was higher in the mown compared with standing herbage. At a similar herbage allocation, apparent DM intake was lower in mown (14.9 kg DM/cow/day) than in standing (15.5 kg DM/cow/day) treatments (P<0.05). This resulted in lower milk solids yield (P<0.05) in mown (1.24 MS/cow/day) compared with standing pasture (1.40 kg MS/cow/day). There was no apparent advantage in mowing ryegrass pastures in late lactation to improve herbage utilisation, DM intake or milk yield.