Colitis in donkeys

There are many companion or pet donkeys kept in the UK. Donkeys have certain behavioural and physiological nuances that render their clinical presentation of disease, subsequent treatment and management to have differences from horses and ponies. This article discusses the specific presentation of colitis in donkeys, acknowledging the current ‘unknowns’ that continue to perplex case management while providing guidelines for diagnosis, treatment and prevention, based on the author's experience. This article will focus on acute colitis but reference is made to chronic presentations.

Colitis refers to inflammation of the colon but in many affected donkeys, the caecum may be the only part of the intestine affected (typhlitis) or more commonly a combined typhlocolitis is seen. The reader should be aware that the clinical presentation does not always allow for easy differentiation of colitis from typhlocolitis. ‘Colitis’ is used in this article as a general term and encompasses typhlocolitis.

The initial presentation of acute colitis or typhlocolitis in the donkey is usually vague. Owners may notice that the donkey's demeanour is less bright than usual, appetite may be reduced or completely anorexic. This is classically known as the ‘dull’ donkey. It is vital that a veterinary assessment of the donkey is performed without delay. As a prey species, donkeys have evolved with the behavioural characteristic of stoicism – the ability to mask outward signs of pain or illness likely conferred an evolutionary advantage (Burden and Thiemann, 2015). Unfortunately, this ability to avoid signifying weakness to predators can manifest as owners not recognising that their donkey is unwell until pathophysiology is advanced (McClean et al, 2019). The donkey is unlikely to demonstrate clear evidence of abdominal pain, such as rolling or kicking at the abdomen, and diarrhoea is not commonly seen in acute cases of donkey colitis (Du Toit et al, 2010). It is hypothesised that this may be related to the ability of the donkey hindgut to conserve water retention (Barrio et al, 2019), which is another evolutionary advantage for a species that evolved in dry, arid environments. However, there is little scientific proof that this is indeed the reason for the lack of diarrhoea in colitis presentations.