Liveweight gain for lambs in multi-species grazing trials

Monday 25.04.2022 , event , news

To measure the impact of increasing sward diversity on animal performance, Germinal is supporting researchers undertaking multi-species grazing trials at University College Dublin (UCD) Lyons Farm.

Researchers set up four swards and nitrogen plans; a perennial ryegrass monoculture at 163 kg N/ha/year; a perennial ryegrass and white clover mix at 90 kg N/ha/year; a six-species mix at 90 kg N/ha/year; and a nine-species mix at 90 kg N/ha/year. Swards were stocked at 12.5 ewes/hectare and raised to a post-grazing sward height of 4 cm. Each ewe reared twins.

Professor Tommy Boland from UCD said, “The team began their research hoping multi-species sward performance would match that of perennial ryegrass, or not be too far below it. What we discovered was quite different.”

Liveweight gain for lambs 

“Anytime we used a sward more complex than a monoculture, we saw lamb performance benefits,” explains Professor Boland. “These benefits were carried through to the point of slaughter.”

Lambs suckling ewes grazing the six-species sward had a 2.4 kg higher liveweight gain at weaning. All mixed-sward lambs reached slaughter two weeks earlier than those on the monoculture sward.

“Quicker finishing times is a big benefit to sheep farms, as you can move the lambs off earlier when you’re prioritising grass resources and flushing ewes coming into the breeding season,” says Professor Boland. “Environmentally it is potentially beneficial too as shortening the lifetime of the animal reduces methane emissions.”

Anthelmintic benefits for lambs

The team also recorded anthelmintic use during the trial, as antimicrobial resistance to parasites remains a big problem for the sheep industry. They found, using faecal egg counts, the multi-species grazed animals required fewer drenches, with the interval between doses increasing to almost double that of the monoculture.

“These results are exciting for animal production, and I would also stress a need to take a holistic view of multi-species use. It’s not just about animal performance; multi-species leys benefit soil health, water infiltration and biodiversity.”

Beef performance also improved

Professor Boland and his team have also studied the effects of multi-species swards on beef animal performance. They established three swards with a stocking density of 2.5 livestock units per hectare; one monoculture, one perennial ryegrass and clover mix, and a six-species mix. The steers grazing the multi-species sward had a 20% higher growth rate during their second year at grass.

“It’s exciting to be able to say positively that offering animals swards consisting of more than a single species improves their performance. It isn’t a ‘silver bullet’ for all the challenges on-farm, but I’m confident in saying multi-species swards form part of a farmer’s toolbox for the future,” concludes Professor Boland.

For more detailed information on the research, methodology and findings, watch the multi-species webinar on our Knowledge Hub.

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