Invagination of the caecum into the colon in a Welsh pony

A chronic wasting disease in a 16 month old Welsh pony filly is described. The animal died 26 days after the onset of illness which commenced with a sub-acute colic and was characterised by progressive loss of appetite and weight. Post-mortem examination revealed a total invagination of the caecum into the colon and it seemed logical to assume this invagination occurred at the start of the illness. A review of the literature showed that total caecal invagination produces 2 distinct clincal syndromes. It can occur either as an acute illness characterised by severe colic and death after about 10 days, or as a chronic wasting disease, such as the case presented here, which may not result in death for several weeks or even months.