Profitability for most livestock enterprises is strongly linked to pasture growth and utilisation.
Yet one of the key tools for maximizing growth is under-utilised in Western Australia.
While pasture growth is heavily influenced by nutrient availability, farm consultant Martin Staines says grazing management is just as important, and one way to significantly improve pasture growth is to implement a basic rotational grazing plan.
Introducing Dr Staines
Dr Staines was one of the original consultants supported by South West NRM back in 2017 to develop the Grazing Matcher Program. Support for the program was also provided by Western Beef Association Inc. and Meat and Livestock Australia Profitable Grazing Systems Initiative.
His emphasis on rotational grazing is based on a sound understanding of how pastures grow, how they recover from grazing and when quality is highest.
“Ryegrass, which is our dominant pasture [in the South West of WA], only carries three live leaves, so if you don’t graze when your plants reach this stage you will lose biomass. And the quality of ryegrass peaks at the three-leaf stage.”, Dr Staines said.
While grazing shouldn’t be left too late, grazing too early when plants have fewer than two new leaves is likely to stunt growth.
“After grazing, ryegrass will use its sugar reserves in the stem to develop its first two new leaves. When those leaves have developed its sugar store will be replenished. So it’s best to delay grazing until at least two leaves have developed, otherwise plants won’t have a ‘full sugar tank’ to recover from grazing and growth will be slower.”
For paddocks with a clover component, grazing when ryegrass has two to three leaves will also suit clover growth. Other grasses vary in the number of live leaves, with fescue having two and kikuyu four to five.
It takes approximately 24 days in spring to 54 days in winter for ryegrass to get to optimum growth stage, as it is most dependent on temperature. Ideally, farmers should rotate stock to match growth rates, but this complicates management and can reduce uptake of rotational grazing.
The Dr Staines formula
So Dr Staines has come up with a basic formula for farmers who want a simpler process.
“If farmers graze a paddock every 35 days or five weeks throughout the year, they will be grazing at the two to three and a half leaf stage. That’s not a bad compromise,” he said.
Stock should be shifted at least twice a week to avoid plants getting grazed twice in the one rotation. So to achieve a five week rotation with two shifts per week, farmers will need 11 paddocks. The number of grazing days can vary depending on paddock size.
Dr Staines believes the closer farmers can get to this model, the better pasture growth and utilisation will be.
Consider height too
Besides rotational grazing, another key consideration for pasture management is to ensure that it is grazed to four to six centimetres in height. Leaving too much height or residue can result in low utilisation, feed quality and pasture density. Leaving less than four centimetres residue risks delayed plant recovery, reduced feed intake and weed invasion.
But the height of pasture residue can’t affect the rotation speed. If that is allowed to happen, it’s likely that paddocks will be grazed at the wrong leaf stage.
“You have to stick to your rotation plan. If there’s not enough pasture in a paddock and the next paddock isn’t ready, feed hay or silage to cover the gap. This can be done in a holding paddock if need be,” he said.
“If on the other hand the next paddock is ready too early, before you are ready to move stock into it, drop that paddock out for hay or silage and move to the next paddock instead.
“So the key to good grazing management is to implement a basic rotational grazing plan, leave the correct residue after grazing, and fill feed gaps when required.”
