The benefits of herbal leys

See our information on the benefits of herbal leys for livestock and the environment. You will find tips on managing bloat and the anthelmintic properties of herbal leys.

• Improves soil structure and health
• Provides resilience in dry periods
• Nitrogen fixation from legume species – so requires little fertiliser
• Extends the grazing season
• Benefits carbon sequestration
• Good livestock growth rates when rotationally grazed
• Improves biodiversity of bird and insect species
• Some species have anthelmintic properties – so less need for wormers

Studies have shown that there can be no difference in average growth rate between cattle grazed on herbal leys and ryegrass swards. Growth rates of 0.7–1.6 kg/day can be achieved, and rotational grazing can support a good growth rate.

Herbal leys can extend the grazing season, and improve feed quality for livestock, thereby reducing purchased concentrates.

Some species have tannins and therefore have some anthelmintic properties. However, the mechanism for reducing worm burden is less understood in some species. Species that are considered to have anthelmintic properties include:

• Sainfoin
• Chicory
• Birdsfoot trefoil

Their direct anti-parasitic activity is related to a reduction in nematode egg hatching, larval development and mobility of larval stages. They are also thought to have an indirect effect mediated through an increase in host resistance by reducing the microbial breakdown of protein in the rumen. Research suggests that the level of condensed tannin required in feed/grazed forage is 20–40 g/kg.

Bloat is a risk on high legume swards, particularly in the spring, due to fast, lush growth. Tannins can aid in reducing bloat, as well as applying salt to pasture, or including chicory in the sward. For further advice, consult your vet.

• Deep rooting encourages soil resilience through structure and fertility – including soil drainage channels which reduce surface water
• High legume content in a sward can fix 180 kg N/ ha – reducing fertiliser costs and emissions
• Improves soil carbon sequestration
• Can reduce grass weeds by 10% compared to a ryegrass and white clover sward, also useful for blackgrass control
• Improves biodiversity of birds and insects – increased resources for pollinators
• Increases number of worms
• Can reduce nitrate leaching

• Success can vary with soil type and management
• Species diversity will decline over time
• It can be challenging to manage
• P and K require monitoring