Bloat occurs when the fermentation gases produced in the rumen can not be evacuated and cause an overdistention of the rumen. There are two forms of bloat. The frothy bloat (called primary bloat) is due to a persistent foam mixed with the ruminal contents. The free-gas bloat (called secondary bloat) is due to free gas separated from the ingesta that cannot go out of the rumen because of mechanical obstruction. Bloat mainly occurs in cattle but may also be seen in sheep. There are individual (genetically determined) susceptibilities to bloat (Kahn, 2005).