Herbage and milk production from a grass-only sward and grass-white clover swards in an intensive grass-based system

摘要

White clover {Trifolium repens L.; clover) can increase the sustainability of grass-based dairy systems and has the potential to increase milk production. This experiment compared milk production from a perennial ryegrass (PRG) sward receiving 250 kgN ha1 yr"1 (Gr250), a PRG-clover sward receiving 250 kgN ha~(-1) yr~(-1)(C1250) and a PRG-clover sward receiving 150 kg N ha~(-1) yr"1 (C1150) in a rotationally grazed system in 2013 and 2014. Three groups of cows were allocated to graze each sward in 2013 and 2014 (n=14 and 19, respectively). Clover inclusion into PRG swards had no effect on the total herbage production. There was a treatmentxweek interaction on sward clover content; C1150 had greater clover content in the second half of the grazing year.Treatment had an effect on cumulative milk yield (MY) and milk solids (MS) production. The C1150 had lower cumulative MY compared to C1250 (6,055 and 6,343 kg milk cow~(-1), respectively); there was no significant difference between C1150 and Gr250 (6,055 and 5,912 kg milk cow~(-1), respectively); and C1250 had greater cumulative MY than Gr250 (6,343 and 5,912 kg milk cow~(-1), respectively). The MS yield of the clover treatments were significantly greater than the Gr250 and were similar between both clover treatments.