Measurement of Grassland Management Practice on Commercial Dairy Farms

Abstract

Visual assessment (>4 cm) was found to be the preferred method of pasture mass estimation. Grass budgeting with the use of grass cover measurement, was found to be the most effective aid to good grazing management. Closing farm grass cover in late November/early December should be 350 to 450 kg DM/ha with a range in covers of 200 to 900. Target farm grass covers of 550 to 600 kg DM/ha at turnout at stocking rate of 2.75 cow/ha. Pre-grazing yields at turnout should not be less than 1000 kg DM/ha, giving daily grass allowance of not less than 5 kg DM/cow. The available grass supply in Spring should be budgeted so as to finish the first grazing rotation between the 10th-20th April (grass supply equal grass demand). During the main grazing season (May to August), grazing grass cover should be maintained at 900 to 1000 kg DM/ha or 200 to 240 kg DM/cow. Pre-grazing yield should be maintained at 1800 to 2000 kg DM/ha, with post-grazing residuals at 150 to 200 kg DM/ha (5.5 to 6.5 cm post-grazing height). Stocking rates of greater than 4.5 cow/ha on the grazing area in May/June mostly resulted in inadequate grass supply at some periods over that time. Rotation length can be increased from 21 days in mid/late August to 35 days in late September, allowing grass cover to increase to 1100 to 1300 kg DM/ha. Last rotation should be 25 to 35 days, with first paddocks rested from the 10th to 15th October. Greater use of grass measurements at farm level will allow dairy farmers to obtain a greater proportion of the dairy herd’s feed demand from grazed grass, and higher cow performance.