Grazing Management in Spring and Subsequent Dairy Cow Performance

Two levels of grazing intensity were unposed on pasture durtng a spring-time pre-treatment period in two years at Massey University’s Dary Cattle Research Urut. The two grazing intensws were lax (L), 2000-2500 kg DMlha residual herbage mass (RHM) and intense (I) 1000-1500 kg DM/ha RHM. imposed for 2 grazmg rotations. Durmg this period, net herbage accumulation (NHA) on the L wards was approximately twce that on I wards. However, by early summer, NHA was greater on the I than L wards. Subsequently, during the experimental feeding period I” early summer, herbage on the I wards contalned lower percentages of reproductive tillers, grass stem, and senescent maner, and was of higher digestrbllity than herbage on the L wards. Durmg the feedlng period, cows grazing the I wards had greater yields of milk and milk fat than cows on the L wards when offered both generous and restricted daily herbage dry matter allowances. The effect of ward type on dry matter intake (DMI) was dependent on dry matter allowance. However, when a common allowance of leaf was offered, DMI. milk and milk fat yield were not significantly affected by ward type on offer. The results emphasise the importance of mamtaining green, leafy wards into late spring and summer in order to maximlse milk yvald per cow at this time. This was achwed by maintammg a RHM of no more than 1500 kg DMlha throughout spring by Imposing sufficiently high stocking rates.