Extending the grazing season into earlier spring and later autumn is the primary grazing management practice which can simultaneously increase pasture utilisation per hectare and the proportion of grazed grass in the diet of spring calving dairy herd. This project proposes to quantify the biological effects of alternative stocking rate and grazing season length combinations on animal and pasture productivity and overall farm business economic performance in the Border Midlands and Western Region (BMW) region.
In 2017, 120 animals (consisting of 50% Holstein-Friesian and 50% Holstein-Friesian Jersey crossbred) were assigned to 1 of 4 grazing treatments before calving based on breed, parity, calving date, and Economic Breeding Index. The 4 experimental groups were comprised of 2 grazing season lengths: average (205 days; March 15th to October 20th) and extended (270 days, February 15th to November 20th) and 2 stocking rate treatments: medium (2.5 cows/ha) and high (2.9 cows/ha). Each experimental group has its own farmlet that is managed separately depending on grazing season length and stocking rate requirements.