Reseeding: What grass varieties should I use?

After identifying poor-performing paddocks, the next step is to choose a grass variety which will best suit the system on the farm. Farmers need to identify which paddocks will be predominately used for grazing.

Farmers can choose varieties that are suited to an extended grazing season and that have the potential to produce a quality sward.

On the other hand, if there is a possibility that paddocks may be taken out for silage, farmers can look at varieties that are better suited for silage quality and yield; but which are also suited for grazing.

Speaking at the recent Irish Grassland Association (IGA) grazing infrastructure event, UCD’s Bridget Lynch outlined that farmers must pick a mix for end use.

She said: “Farmers can pick their own mixes or go to their local co-ops and choose a ready-made mix. However, they need to know what they are looking for; it is important to focus on the variety traits.”

Perennial ryegrass traits:
  • Spring growth;
  • Autumn growth;
  • Sward quality;
  • Silage production;
  • Heading date range – early, intermediate, late;
  • Pasture Profit Index (PPI) – €/ha/year.

Bridget added: “Keeping an eye on the heading date range is important. Farmers need to keep it at five and seven days.

“If it’s wider than that, farmers will have paddocks that are heading out ahead of others and it’s more difficult to manage with regard to the timing of grazing and the timing of silage cutting,” she explained.

Diploids or tetraploids?

The UCD lecturer touched on the inclusion levels of tetraploids and how they are growing in popularity among farmers.

“It is recommended to keep tetraploids to about a 30-40% inclusion rate. If it’s grazing ground and if it’s dry, farmers can afford to up the tetraploid level.

“Teagasc research where farmers have been sowing one variety has indicated that farmers love the tetraploids and some of them are happy enough to include all tetraploids.”

She added: “I think overtime we will see the use of tetraploids increase in the mixes as we go forward. That’s because they have a high sugar content, a high intake level and a good graze out ability.”

Bridget explained that keeping different variety inclusion levels to two can be beneficial. On this, she said: “In recent years, in UCD, I’ve been picking two varieties – a diploid and a tetraploid.

“I find if I’m going to pick a third or fourth variety, this might dilute the beneficial effects of two very good varieties; I think this is key,” she explained.

The Pasture Profit Index (PPI) can be described as the ‘EBI’ for grass varieties; it can indicate the economic merit of an individual variety.

White clover

Clover has an important role to play on drystock farms. Teagasc research has shown that dairy animal performance increased by 12-15% with the inclusion of white clover in grazing swards.

In addition, Teagasc – in Grange, Co Meath – is currently looking at the benefits of including white clover under livestock production systems.

White clover:
  • Leaf size – small, medium and large;
  • >25% inclusion rate in established swards;
  • Seed rate – 3-4kg/ha;
  • Nitrogen fixing;
  • Increased sward quality;
  • Increased intake;
  • Increased average daily gain (ADG).

White clovers are listed on leaf size – small, medium and large. The small-leaf varieties tend to be more suitable and are more resilient for sheep grazing, while the medium and large-leaf clovers are used for beef and dairy enterprises.

Bridget added: “From speaking with a researcher in Moorepark, it seems we can get a little bit obsessed with nitrogen (N) application and clover.

“One of the biggest issues with white clover is that it is absent in the first round of grazing; it starts to come with the increase of soil temperatures.

“Farmers can front load their N application and put more N on at the first fertiliser round to encourage the grass proportion of the sward; it can be decreased later in the year if clover is present in the sward,” she concluded.

To view the recommended list of grass varieties for 2018, just Click here