If pasture cover is left too long (pre- or post-grazing), pasture digestibility deteriorates. Subsequently, the dead and/or older plant material builds up, decreasing pasture quality. This in turn creates issues at subsequent grazings.
When post-grazing residuals rise above target levels, immediate action needs to be taken. Mowing pre-grazing or immediately post-grazing can regain control and maintain subsequent pasture quality.
When grazing pre-mown pastures, cows' eating behaviour changes as they can be less selective and there is less opportunity to reject stem.
In addition, small high-quality leaves like clover can be mown and will drop below grazing height, decreasing the quality of pasture eaten at that grazing.
Pre-grazing mowing is not a strategy to increase immediate dry matter intakes, unless used when increasing the daily area offered (a faster rotation) during periods of rapid pasture growth.
Mowing after grazing lets animals be more selective and choose what they eat. The herd can be moved on to a fresh pasture and the mower used afterward to control the uneaten, lower-quality, pasture.
The best way to mow is to cut as close as possible to 7-8 clicks on the rising plate meter, which will set the following post-grazing residual.
Spring-summer transition
During the transition from spring to summer, pastures need sufficient nitrogen to convert from their reproductive phase back to vegetative production of high quality leaf. While pastures are still actively growing and before soil moisture is limited, strategic use of early summer nitrogen can help establish strong pastures for summer.
Nitrogen promotes vegetative tiller growth and reduces tiller population decline in summer.
These are both important for summer production and improving pasture persistence by ensuring pasture is in a good, healthy state before the summer stresses arrive.
Mark Brown is a Pasture Improvement Leadership Group member and Agricom representative
