Ongoing research at University College Dublin (UCD) is pointing to the very real benefits of including a range of grasses, legumes and herbs in the leys grazed by breeding sheep and their lambs.
“Our work is showing that such an approach can deliver real benefits in terms of overall dry matter yields, seasonality, persistency and lamb output,” said Dr. Tommy Boland, one of the scientists involved in the appropriately named SmartGrass project.
“We know that swards containing a mix of grass, legume and herb varieties can yield up to 20t of dry matter per hectare without a requirement to spread nitrogen (N) fertiliser.”
Boland was one of the speakers at the seminars hosted as part of the recent sheep event in Ballymena, Northern Ireland. He pointed out that a combination of factors will contribute to the yield potential of multi-species sward mixes.
He added: “In the first instance, traditional grass varieties can piggy-back on the N fixing capabilities of legumes, such as red clover. Adding to the growth potential of these mixes is the deep rooting growth profile of herbs, including plantain and chicory.
“This helps break up the soil but it also ensures that swards remain productive during dry spells, as was the case last summer across all of the UK and Ireland.
Where grass is concerned, Cocksfoot has been shown to be a valuable contributor to grazing swards for sheep. Taking a multi-species approach has undoubted advantages where both biodiversity and environmental protection are concerned.
The research at UCD has been developed in two primary directions. The first of these is to identify which is the best combination of species to include in specialised sheep swards; the second is to quantify the performance of ewes and lambs on such pastures.
Boland admitted that more work is required to develop species of clover and a range of herbs which are more persistent under Irish conditions.
However, in initial SmartGrass research, results are strongly suggesting that significant lamb growth rate gains can be achieved by using multi-species pastures, as opposed to single variety perennial ryegrass swards.
“The real driver here is the improved performance that can be achieved from birth to six weeks-of-age,” said Boland.
We believe this is a direct result of the improved milk output achieved by the ewes and the enhanced nutritional value of that milk. What’s more, these improvements are maintained right through to finishing.
Boland also referred to research carried out in other countries, which points to the improved eating value of lamb, produced from animals maintained on herb-rich pastures.
He added: “We hope to verify this potential attribute under Irish grazing conditions courtesy of the SmartGrass project.”