Health problems in a feedlot are most commonly associated with diet followed by diseases related to high stocking rates and stress. It is most common at the start of feeding but can occur whenever there is a change in diet or disruption to continuous feeding, for instance if grain or hay are allowed to run out or are spoilt by wet weather. Acidosis is due to the rapid fermentation of starch in the rumen and over-production of lactic acid. Lactic acid is produced by bacteria that tolerate acidic conditions whereas the bacteria involved with the breakdown of the lactic acid do not tolerate acidic conditions. A gradual increase in starch allows the bacterial populations to multiply and utilise the lactic acid as it is produced whereas a rapid change creates an imbalance and results in acidosis.
Careful management can reduce the incidence of acidosis.
A gradual introduction to grain and gradual changes to the cereal component of the ration are vital. If a feed supply does run out, ensure sheep have a full rumen of good quality hay before reintroducing grain. Ensuring palatable roughage is always available to livestock is very important. Affected animals may scour, appear listless with rapid respiratory rates and a broad stance. They may kick or bite at their stomachs.