The term indigestion is used to refer to alteration in the rumen environment as a result of dietary changes. The change in quantity and quality of feed disrupts rumen microflora, pH is altered and the result is temporary ruminal atony, inappetence and change of faecal consistency.
It is the most common cause of diarrhoea in shipboard cattle, and is usually associated with the sudden feed change from hay in assembly points to pellets at sea. Indigestion may also result in constipation in assembly points when cattle come from lush grass pastures on to coarse hay. It may also occur when a new batch of hay or pellets with a different concentration of nitrogen, starch or fibre, is introduced into the diet.
Cattle have fluid to watery faeces but otherwise appear healthy with normal to slightly depressed appetite. Multiple animals in multiple pens will be affected. The diarrhoea usually resolves in a few to several days as rumen flora adapt.
The main differential diagnoses are ruminal acidosis and salmonellosis.
Substituting chaff or hay for part of the pellet ration speeds recovery.
Avoid uneven feeding regimes and introduce new diets gradually over several days. It is recommended that cattle be adapted to the shipboard ration before the voyage is recommended to avoid wet pen conditions from diarrhoea.