The donkey and horse are closely related, and many of the conditions that affect them are very similar. However, the detection of sickness or disease in the donkey can be made more difficult by its stoical nature. Dullness and depression may be the only symptoms exhibited. These subtle behavioural changes may also be accompanied by anorexia. Subtle changes in performance that can be early indicators of disease in sporting or racehorses are frequently impossible to detect in the donkey, as most UK donkeys lead a sedentary lifestyle as companion animals. This can unfortunately mean that the donkey may be in the advanced stages of a disease before a diagnosis is reached. The attending veterinary surgeon should therefore regard the call to a dull donkey as a call to a potentially very sick animal.
This chapter will focus on the approach to the diagnosis of the cause of the dullness. The treatment of specific conditions that affect donkeys are considered in more detail in later chapters.