|Beneath the surface
with David Law
Having a spring rotation planner has long been a helpful tool for farmers to navigate grazing management in the two months after calving, in order to maximise available feed and the resulting production they achieve between calving and Christmas.
From dry-off on June 1, most herds start on a 100-day rotation that becomes exponentially shorter until October, when they reach a 20-day rotation.
So why don’t we do the same for summer? By March, most farms are on a 20-30-day rotation and are suffering in the heat. Paddocks have been grazed so hard that the pasture has all but disappeared, exposing the soil to the baking hot sun.
If farmers implemented a 100-day rotation during summer – starting December 15 – by the end of February the herd would have only been around the farm once.
As there is a mental challenge to overcome – between preparing for summer and trying to get the most production in spring – most farmers would cringe at the thought of a 100-day round in summer. But it’s important to understand the idea in a greater context.
First, we need to appreciate the importance of diversity in our paddocks; ryegrass grown with synthetic nitrogen no longer cuts the mustard if you want to take care of your farm during summer.
A major component of diversity is clover. A biologically balanced farm produces a great deal of clover, which fixes nitrogen naturally from the air and reduces the need for synthetic nitrogen. The biology in the soil also increases, releasing nutrients and trace elements to the plant roots.
On our Total Replacement Therapy demonstration farm we have not only witnessed pasture cover increase during the summer, but as we reach the end of Phase One we’ve seen clover increase from under 10 per cent visible clover at the start of the programme to more than 50 per cent at our last farm walk.
What started as ground cover, filling the gaps in pasture and protecting soil from the sun, is now standing tall, lush and radiantly green while the ryegrass around it is dry, stalky and brown.
Clover is like fruit salad and ice-cream to cows; it doesn’t lose palatability in the summer heat and, as a leafy plant, helps cows produce more milk than dry ryegrass because cows use less energy to digest clover.
On our demonstration farm we haven’t planted any clover; it is always present under the soil, waiting for the right conditions to thrive.
However, the next step for us is to enhance the role of clover by making the most of the cultivars that are now available.
Variety of seeds
We will be looking at sowing a variety of seeds – chicory, plantain, clovers, cocksfoot and ryegrass – for a good, varied diet in the paddock.
Ryegrass is certainly part of a balanced diet – even as standing hay, as it is a valuable fibre source for cows – but it cannot be relied upon to carry the herd through the summer dry.
Summer crops also have their place, but again, they cannot be prioritised at the expense of neglected pasture.
I believe introducing a summer rotation planner, encouraging the growth of clover, and sowing a variety of seeds to increase diversity is the way forward in navigating our increasingly dry summers without sacrificing animal health, production and profitability.
We know farmers whose cows are still producing 1.6-2kgMS/day in the height of summer because they’re using a long round to keep cover to protect their soil and stop it from drying out, and are providing cows with a varied diet that allows them to keep producing milk.
A 100-day rotation in summer is certainly worth a discussion.