‘It’s no good growing grass if it can’t be grazed clean’

There is an increasing demand for varieties that are most suited to grazing. Traditionally, grass variety traits have been high digestibility – to drive animal performance – and high dry matter production to carry high stocking rates.

Varieties that can be cleaned out easily can reduce workload, as they do not require the extra time and cost of topping. These varieties continue to drive animal performance at each grazing in the rotation.

Ultimately, this means varieties that don’t need mechanical intervention – varieties that are grazed more often – produce more milk and meat and leave more profit in the farmer’s pocket.

Unfortunately, to date, this kind of grazing information is not included in the Pasture Profit Index (PPI). The PPI is only derived from cutting trials conducted by the Department of Agriculture and no animal effects are currently factored into the PPI.

New grazing trials

Thankfully, this kind of information is now streaming in from the Teagasc on-farm grass variety evaluation study. In this experiment, varieties are being sown in full paddocks, on commercial farms, across the country.

These varieties are subjected to all of the rigours of actual grazing pressure that swards experience on normal Irish farms. Post-grazing sward height is measured and this clearly shows how easy it is to graze out a variety.

Even small amounts of grass, which animals may choose to leave behind, can build up over several grazings. This grass material, which has been left behind, will be of poor quality in the following rotation and, as a result, will hamper animal performance. Forcing cows to clean out paddocks definitely hits milk performance.

Source: Teagasc

Management plays a massive part as well. It is essential to have the correct soil fertility and pH. Grazing covers at less than 1,500kg/ha will improve graze out. However, some varieties are more forgiving than others.


Figure one shows the post-grazing sward height of all the varieties tested. When it comes to easy-care varieties, AstonEnergy comes to the top of the pile.

AstonEnergy grazed out to the lowest height of all the varieties tested, meaning more of the grown grass was turned into meat or milk. This also means that the sward can regrow from a clean starting point without topping.

AstonEnergy also achieved the most grazings in the season, along with one of the best results for digestibility, spring growth and total growth over the four-year period (2013-2016). This is in slight contrast to the spring growth figure on the PPI; but, of course, findings reported from grazing swards are likely to be most applicable to Irish farms.

Dr. Patrick Cashman from Goldcrop commented: “AstonEnergy is being grazed more often, producing high yields of highly-digestible grass. It is being grazed cleanly in every grazing and is ultimately leaving more money in the farmer’s pocket.

When you look across all the important traits, AstonEnergy really does tick all the boxes when it comes to grazing.

“While AstonEnergy looks good on the PPI, where AstonEnergy really excels is under actual animal grazing.

“Paddocks of AstonEnergy at the Greenfield Farm are unique in that they have only ever been grazed since sowing eight years ago; they’ve never seen a topper or mower due to the exceptional graze out.”

Higher spring growth varieties could prove critical in a late spring

Even in a good spring, most highly-stocked farms will have a grass deficit to feed animals. This requires more expensive supplementation of conserved feeds or concentrates. Including high spring growth varieties in grazing mixtures is a logical step, to set up new reseeds, to meet the high spring demand.

Moira, an intermediate heading variety, has the highest spring growth on the 2018 PPI. However, Moira is likely to be unsuitable for intensive grazing, as intermediate heading varieties tend to be difficult to graze clean in mid-summer; meaning it would be more suitable for silage production.

In the late heading category, Meiduno is the top variety for spring growth. Meiduno has over double the euro value for spring growth on the PPI compared to the average late heading variety; 200kg/ha of extra spring growth was recorded by Department of Agriculture’s trials. For more information on AstonEnergy click here