Farming Talk: Three-leaf rule crucial to get grazing right
With some areas having experienced the wettest April since 1910 and unseasonably cold temperatures, grazing management has thrown up some challenges in the last few weeks.
With some areas having experienced the wettest April since 1910 and unseasonably cold temperatures, grazing management has thrown up some challenges in the last few weeks.
Speaking at a recent DairyCo discussion group, Dr John Roche of Dairy NZ said "If you find yourself with a hole in your grazing wedge because land had been taken out for silage earlier in the season it is important to remember that the three-leaf rule is crucial and not get tempted to enter paddocks too early.
"Provided soil temperatures are the same, each leaf on the grass plant should appear at the same rate, but if you are going in at the two leaf stage you could be reducing potential pasture grown by 15-20 per cent.
Approximately 15 per cent of the pasture is grown in the 1st leaf
35 per cent in the second
50 per cent in the third leaf
"A longer rotation means more grass by default. You are allowing the grass time to grow that valuable third leaf.
"With a lower stocking rate it is harder to manage that all important three-leaf stage," Dr Roche explained.
"You can either get tempted to go in too early to keep on top of things or wait until the three-leaf stage to enter a pasture, and the grass can get away from you. You won't leave the right residuals (1500) and canopy closure will happen faster. A higher stocking rate means many of these decisions are made for you.
"Walk the pasture, pull out a few plants and check leaf emergence. Use it as another piece of information about your grazing.
"It is better to reduce grass to the cows now to extend the grazing season grass allocation and offer supplements. This allows grass to recover.
"If you've had heavy rain and the paddock looks poached up, don't panic. In reality if the grass root is still in the ground and there is plenty of moisture the grass should come back. Give it a week and maybe then think of doing something later in the season."
Ways to graze fields better in order to reduce poaching:
Graze from the far side of the field first. So cows never walk over bare ground, where they do most damage.
Dont feed buffer before the cows go out. Let the cows go out hungry, let them concentrate on eating and then get them in afterwards if you need to.
Remember how much water there is already in cows feed when there are wet conditions, and bear this in mind when looking at access to the water trough. One farmer in the group said his cows had drunk an average of 4 litres of water on a very wet day and 48 litres the day before that.
Think about a sacrifice track it doesnt have to be that wide as cows will walk in single file. It may take more time when they are coming in for milking but it is worth it.
Hugh Black, DairyCo extension officer
