Bloat is the accumulation of excess gas in the rumen and can develop in less than one hour after introduction to a high-risk paddock, but more often after one day.
Conditions when bloat is likely to occur
- Lush rapidly growing legume pastures. More likely with legume pasture in rapidly growing vegetative stage and in highly digestible pasture with low percentage of dry matter. The highest risk is with lucerne, followed by white clover, then subterranean clover.
- Intensive ration feeding (mainly in feedlot or drought feeding) with low fibre component (where greater than 80% of ration is grain).
Identifying and diagnosing bloat
Clinical signs for bloat in a group of animals grazing high risk pastures or on grain include sudden death, distension in the left upper flank if still alive or others in mob showing mild signs. The condition is painful and affected cattle will be agitated and may vocalise or rub their sides against objects such as tree stumps.
Pasture can be assessed to determine the risk of bloat. Producers should consider pastures with a high proportion of legumes and with lush and vegetative growth as a high bloat risk.
Prevention strategies for bloat
- Avoid grazing high-risk pastures with a high proportion of actively growing legumes in vegetative growth by use of grazing management.
- Slowing the rate of rotational grazing so cattle graze more mature pastures.
- Daily application of bloat oil on pasture may be cost effective in some situations (bloat oil in water troughs may be considered if water availability is controlled).
- Ensuring livestock have access to roughage such as hay (which can also have bloat oil applied).
- Using bloat capsules if grazing high risk pastures for extended periods. Use the Health Cost Benefit Calculator to determine the cost-benefit of using bloat capsules.
- Incorporating bloat resistant legumes, such as Lotus corniculatis, into pasture mixes.