Conditions when likely to occur:
Lush rapidly growing legumes. More likely with legume pasture in rapidly growing vegetative stage, in highly digestible pasture with low percentage of dry matter.
Highest risk lucerne > white clover > subterranean clover.
Intensive feeding ration (mainly in feedlot or drought feeding) with low fibre component (>80% of ration as grain).
Pasture assessment (proportion of legume in pasture is high, lush and in vegetative growth). May develop bloat in less than one hour after introduction to a paddock but often after a day.
Clinical signs (mob not just individual): Sudden death, distension in the left upper flank if still alive or others in mob with mild signs.
Management strategy to prevent disease:
Avoid grazing high-risk pasture with a high proportion of actively growing legumes in vegetative growth by use of grazing management.
For producers adopting intensive rotational grazing slowing rotation so cattle graze more mature pasture may reduce risk but not eliminate it in all situations.
In intensive grazing/strip grazing situations, daily spraying bloat oil on pasture may be cost effective. This strategy will not be cost effective or practical in all other situations. Bloat oil in water troughs may be considered if water availability is controlled. Bloat blocks are less reliable.
Consider incorporating bloat resistant legumes, such as Lotus corniculatis, into pasture mixes.
More information on bloat including causes, prevention and treatment can be found on the primefacts factsheet provided by the NSW Department of Primary Industries.