Farmers-led research proves red clover doesn’t affect sheep fertility

Intro

Red clover is a key component of sward mixes for agri-environment payments. For farmers, it offers fast growth, high protein, and superior nitrogen fixation over white closer, cutting fertiliser costs. It boosts soil health, drought resilience, and biodiversity. However, farmers often avoid grazing breeding ewes on it due to fertility concerns.

In this project, four farmers wanted to challenge conventional guidance by working with Innovative Farmers and ADAS to monitor scanning rates on a diverse forage mix containing red clover.

The Challenge

Conventional advice discourages farmers to include use red clover in swards grazed before and during breeding. The is based on research from the 1960’s and 70’s on 100% red clover swards. It has limited relevance to UK systems, where red clover is grown in mixed swards.

Phyto-oestrogens in red clover mimic oestrogen and can affect sheep fertility. Modern varieties are bred with lower phyto-oestrogen levels, but no practical research has confirmed whether modern varieties are safe to graze during mating.

The Solution

Four farmers across the West Midlands and Wales put their observations to the test through a controlled trial with expert support to see if they could benefit from red clover without compromising sheep fertility.

Through the Innovative Farmers programme, they worked with Gillian Preece, a senior agricultural consultant at ADAS and first-generation sheep farmer. She coordinated the trial, assisted with data collection and compiling the results.

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The Trial

Each farmer had 100+ breeding ewes, randomly split into two sub-flocks
Before and during the mating period, one group grazed a diverse ley containing red clover and plants including chicory, plantain and wildflowers.
The control group grazed a sward without red clover.
The groups merged afterwards to ensure consistent management for the rest of pregnancy.
Scanning results for both groups were recorded to track fertility.
The group also assessed the proportions of red clover in each sward, dry matter and nutritional content.

The Results

Ewes on diverse leys containing red clover had a higher scanning percentage (av. 181%) than ewes grazing on non-red clover leys (av. 170%).
This suggests that grazing diverse leys containing red clover may enhance fertility.
The improved fertility likely results from better forage availability, diversity, and quality.
The farmer group hopes this trial encourages others to use red clover to cut costs, lower carbon footprints, and benefit from SFI payments like CSAM3 (£382/ha) for herbal leys.
Phyto-oestrogen tests are expensive but will be necessary to shift formal industry advice.

Farmer Insights

“The more red clover we can use, the better – it’s helped us to really cut back on nitrogen costs and it’s also good for drought resistance. Without legumes we would be looking at paying huge costs this year – fertiliser costs would have gone from £35,000 last year to £90,000 this year”. Marc Jones, Powys.
“We now finish as many lambs as possible on it and tup on it too. 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.” Tim Teague, Shropshire.