Impacts of multi-species swards on livestock health

Multi-species swards provide highly nutritious forage for grazing livestock. However, they also present unique management challenges, including the risk of bloat and fertility issues due to phytoestrogens.

Multi-species swards can play an important role in supporting livestock health by influencing rumen function, immune resilience, parasite management and mineral balance. Their value lies not just in what animals eat but in how the diet functions within the animal. 

When managed carefully, they can support healthier, more resilient livestock while reducing reliance on chemical and purchased inputs.

Sward mixes can support rumen function by providing a balanced supply of fibre and protein compared with monocultures. This reduces the risk of acidosis and supports steady energy release, improving overall digestive health and animal performance.  

Herbs such as chicory and sainfoin may also moderate fermentation and support a more stable rumen environment.

Swards with a high proportion of legumes, particularly clovers, are more prone to causing bloat due to their high protein and carbohydrate content, especially during wet, humid conditions.

• Maintain species diversity 

• Introduce stock gradually to clover-rich swards 

• Feed hay or straw before turnout 

• Avoid hunger-driven paddock moves 

• Use anti‑bloat supplements when required 

• Monitor stock closely when grazing high-legume swards 

• Remove animals on that pasture immediately 

• Contact your vet 

• Provide a high‑fibre diet 

• Rest the pasture for at least 10 days

Implement rotational grazing and rest periods between grazing cycles to break the life cycles of internal parasites.

Regularly perform faecal egg counts (FEC) to monitor and manage parasite burdens. This allows for targeted worming based on actual parasite presence.

While some herbs are a good source of micronutrients (e.g. chicory as a source of selenium), additional mineral supplements, such as copper, selenium and cobalt, might be needed. 

• Regularly test soil and forage  

• Request blood tests where deficiency risk is known 

• Supplement grazing when required

Phytoestrogens are naturally occurring compounds found in some red and white clover varieties. 

They can mimic the effects of oestrogen and can disrupt reproductive processes in female livestock. 

Red clover silage has not been shown to negatively affect cattle fertility, but sheep are more sensitive. 

To mitigate fertility risks: 

• Use multi-species swards rather than pure red clover leys 

• Keep breeding ewes off high red clover for six weeks before and after tupping 

• Select appropriate clover varieties with advice from seed suppliers