Choke occurs due to a blockage of the oesophagus or throat, meaning that the cow cannot swallow or eructate to release gas from the rumen. It occurs when the animal eats too greedily, eats large solid objects (apples, potatoes etc.) or dry feeds that get lodged in the throat. It may also occur following treatment of Hypoderma lineatum (Warble flies) in the oesophageal larval stage, which releases dead larvae and leads to a severe reaction. The obstruction may be partial or complete.