Diseases of Cattle: PASTURE BLOAT

Bloat is a form of severe indigestion marked by a collection of gas in the rumen that the animal is unable to expel. Normal digestive processes create gases consisting chiefly of carbon dioxide and methane in the rumen.  Most of the gases are eliminated by belching.  Gases that are trapped may form a foam or froth in the rumen which further prevents their elimination.  Froth formation can be caused by many factors resulting from interactions between the animal, rumen microorganisms, and differences in plant biochemistry.  The main causes of bloat are an inherited tendency for bloat, certain proteins in forage (particularly in legumes), the coarseness of the roughage and the type of rumen microbial population.  Pasture bloat usually occurs in animals grazing wheat pasture, lush legumes (alfalfa, Ladino, red clover) or fed green-chopped legumes.  To prevent pasture bloat in cattle you should plant pastures so that no more than 50 percent of the forage mixture is alfalfa or clover, fill cattle on dry roughage or grass pastures before turning to legume pastures, provide grass hay or graze in a rotation using grass pastures.

Visual signs of bloated cattle include distension of the left side of the animal, discomfort as indicated by stomping of feet or kicking of belly, labored breathing, frequent urination and defecation, and sudden collapse.