The use of clover in grass swards has become increasingly popular on Irish farms. But, bloat can be an issue in swards with high white clover content.

Many farmers have seen the benefits clover offers in terms of production, along with providing a decrease in the need for chemical fertiliser.

The main concern with clover swards is bloat. It can occur at any time of the year, but it is more likely to occur in the second half of the year when white clover content in the sward is at its highest.

Having good grassland management can minimise and prevent the risk of bloat to the animals grazing these swards.


There are two main forms of bloat: gassy, caused by a blockage in the gullet and frothy, which is associated with high clover content in swards.

Bloat occurs when the eructation mechanism is inhibited and gas production exceeds the animals ability to expel the gas.

It typically happens within the first hour after turnout onto new pasture and is a common cause of sudden death.


To mitigate the risk within your herd, avoid switching between grass-only and grass-white clover swards – where possible.

It is important to keep post-grazing sward height at 4cm and not below.

You should provide a small area in the paddock for the first two to three hours after turn-out to prevent gorging on white clover.

You should also provide an anti-bloating agent in the water supply; this should start the day before entering, what is considered a ‘risky’ paddock.

It is important to check cows after turnout and regularly, for the first three hours of grazing during high risk periods.