Donkeys are not small horses, and their natural environment is not the temperate conditions of the UK but a more semi-desert like environment where food is scarce and of a poorer quality. In the UK donkeys live a pasture lifestyle, and many of the clinical problems which arise are the result of too much food and not enough exercise. These are problems which are exacerbated as a donkey reaches old age. Donkeys frequently live into their thirties, so are a long term undertaking and need regular veterinary and dental care throughout their lives.
Donkeys have evolved to live in arid, mountainous, desert areas where feed is sparse and of poor quality. As a consequence, they are excellent at digesting very fibrous plants and can feed off woody shrubs and trees as well as grass. Replication of this natural environment can be very difficult in the UK where donkeys are commonly kept as companion or leisure animals on lush, grass-rich pastures. Every donkey should be fed according to their body condition, age, underlying health issues, time of year and grazing availability. Inappropriate feeding can lead to boredom, obesity and the potentially serious health issues that occur as a consequence of this.
Donkeys (and small pony breeds) are at particularly high risk of developing hyperlipaemia - abnormally high levels of triglycerides (fat) circulating within the blood. This occurs when the body’s energy supplies are limited (e.g. off feed) or nutritional demands are increased (e.g. pregnancy, disease) coupled with a metabolic abnormality called insulin resistance (donkeys are inherently insulin resistant). Hyperlipaemia can be a primary condition or secondary to anything which causes a donkey to go off its food. Hyperlipaemia is associated with a high mortality (death) rate due to organ failure and therefore recognition of ‘at risk’ animals is essential. Prompt and aggressive intensive care treatment of affected animals is essential to optimise their chances of survival.
The term ‘colic’ describes the symptoms displayed when a horse or donkey is suffering from abdominal pain. Donkeys are very stoical by nature and therefore rarely display the same clinical signs as horses; instead they tend to present as dull and off their feed. Monitoring a donkey’s demeanour and normal bowel habits can be helpful in identifying those affected before the condition deteriorates. The causes of colic in donkeys are very varied and commonly include blockage with partially digested food material (impaction), muscle cramps of bowel wall (spasmodic) or a build of gas within the bowel. Investigation of colic is aimed at identifying the patient’s physical status and the cause of the colic so that medical or surgical treatment can be tailored accordingly.
Castration of donkeys requires special care because donkeys have a larger blood supply to the testicles compared with horses and as such are at greater risk of bleeding post-surgery. For this reason most donkey castrations are performed under general anaesthesia (GA), to allow a ligature (secure suture) to be placed around the blood vessels. This reduces the risk of post-operative bleeding and intestinal prolapse through the surgical incision. Due to the need for GA and the technique required, castration is best performed at the clinic.
The donkey is very stoical in nature, which can make detection of sickness and disease very difficult. Dullness and depression are frequently the only symptoms exhibited for a number of conditions, including severe and life threatening illness. Donkeys are affected by many of the same conditions as horses, but may present in a different way e.g. colic presenting as dullness only. Any dull donkey should be promptly examined by a vet to prevent development of hyperlipaemia, a potentially fatal condition.
Donkeys are particularly prone to foot problems because in captivity in the UK they are managed in a damp environment with a temperate climate. They frequently have access to lush grazing, contrasting vastly with the desert conditions and fibrous diets where they evolved to survive and thrive in the wild. These differences increase the risk for the development of poor quality horn, laminitis and white line separation and disease.