Trial could see more breeding sheep benefit from grazing red clover

A group of farmers grazing their flocks on leys containing red clover as part of a trial could overturn old fears about the legume’s impact on sheep fertility. If successful, it is hoped to encourage other farmers to make use of the many environmental and business benefits of using red clover.

The four farmers, who are based in the West Midlands and Powys are working with ADAS as part of a field lab run through the Innovative Farmers programme which is managed by the Soil Association. They plan to graze a selected group of their ewes on herbal leys containing at least 10% red clover, before and after tupping, to test the impact on pregnancy rates.

A growing number of sheep producers are beginning to reap the benefits of mixed red clover leys, but the majority are still reticent due to research conducted 50-60 years ago in Australia and New Zealand.

Gillian Preece, a sheep farmer and senior consultant at ADAS, who is coordinating the field lab trial, says this research now badly needs updating to reflect how UK farmers actually use red clover.

You can follow the latest updates from the field lab here. 

Why farmers want to measure fertility of sheep on red clover

“We know there are UK sheep producers using red clover successfully in their grass leys, but the science hasn’t caught up with them, and the research that exists has relevance issues,” says Mrs Preece.

“Red clover contains phyto-oestrogens, which when fed in large quantities, can trick the ewe’s body into thinking she’s pregnant, thereby stopping her from cycling. In previous studies, ewes were grazed on leys containing 100% red clover, so they would have got a big hit of oestrogen.

“But most farmers in the UK would hardly ever do this and would be much more likely to include red clover in smaller quantities as part of a mixed herbal ley,” explains Mrs Preece.

“Without up-to-date research on this, many sheep farmers are missing out on the multiple benefits of red clover, including for soil fertility, drought resistance, environmental stewardship payments, and reduced feed and fertiliser costs.”

One of the farmers taking part in the trial is Tim Teague, a Romney sheep producer who farms around 500 acres of mainly grass in Shropshire. Mr Teague is expecting to lamb 1,800- 2,000 ewes next Spring and has selected 360 of them for the field lab.

“I’d read lots of conflicting advice about grazing breeding ewes on red clover,” says Mr Teague. “I asked everyone I could about it and everyone who was experienced in using it said they hadn’t had any problems with fertility.”

Last year, before the field lab began, Mr Teague tried his breeding ewes on a ley containing about 25% red clover, with successful results. “The ewes took the tup really well – we had a very high scanning percentage at 188%,” he says.

Mr Teague says he hopes the trial will confirm what he has already found and give other farmers the confidence to use red clover.

“Red clover really opens up a lot of opportunities,” says Mr Teague. “It provides a really high-quality feed, and so we now finish as many lambs as possible on it and tup on it too. It also helps deal with drought. Thanks to red clover, we now don’t buy in any nitrogen fertiliser or feed other than a bit of fodder beet, and my business is as resilient as it could be as a result.”

Benefits of grazing sheep on red clover

Red clover offers a host of benefits, which many sheep producers are currently missing out on, says Mrs Preece. These include:

  • Soil fertility: Red clover is a nitrogen-fixing legume, and so helps improve soil fertility for the next crop in the rotation.
  • Drought resilience: With deep roots, red clover helps with soil structure and creates a pasture more resilient to drought.
  • Protein source: Red clover offers an alternative source of protein to bought-in feeds.
  • Lower input costs: By helping to build soil fertility naturally, red clover reduces reliance on nitrogen fertilisers.
  • Greater flexibility: Being able to graze livestock on mixed red clover leys throughout the year offers greater grazing flexibility to the farmer and lowers the risk of running out of grass.
  • Farm income: Legume and herb rich swards are currently part of Countryside Stewardship schemes (e.g. GS4 £309/ha) and are likely to be part of Environmental Land Management Schemes (ELMS) due to their many environment benefits.
  • Increased biodiversity: Flowering red clover leys encourage pollinating insects and other wildlife which depend on them.
  • Lower emissions/carbon footprint: Less use of nitrogen fertilisers and bought-in feed lowers green-house-gas emissions, and helps build a circular economy on farm.

How the field lab will work

Four farmers, who have flocks of between 500 and 2,000 breeding ewes each, have selected at least 160 of their ewes for the trial, which will then be split in half on their farms. One group will graze the leys containing red clover, and the other (the control group) will graze grass lays with no clover. The two groups of ewes will contain a similar mix of ages, body conditioning scores and breeds.

Both groups will be grazed for three weeks before tupping and throughout the mating season. They will then be scanned, and pregnancies recorded. The swards will be assessed for clover content when the sheep are initially put on the fields, when the rams are put in, and when the mating period ends. Samples of both swards will also be sent off for nutritional analysis.

“Our hypothesis is that if farmers can use red clover in mixed leys then they can have all the benefits without any negative consequences,” says Mrs Preece. “There might even be a positive effect on fertility because such leys offer high feed quality.

“We hope that by updating the science we can give farmers the confidence to use red clover again, and vets the confidence to encourage it,” says Mrs Preece.

“These sorts of practical questions are exactly what farmer-led research is designed to answer,” says Innovative Farmers Manager, Rebecca Swinn. “By giving sheep farmers the scientific support to robustly test red clover leys, this field lab is helping the knowledge and technical understanding in this area develop in real time. We look forward to seeing the results, which hopefully will give farmers confidence in agroecological farming practices that can improve their bottom line, build farm resilience, and protect the environment.”

The first results are expected in early January 2022.

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