CAUSES OF DISEASE

Although we often think of infectious agents as the cause of disease, in fact many of the ailments we see in farm livestock are nothing to do with infection. Lameness must be the best example of this. For example, simple physical trauma to the foot has a major role in the aetiology of many hoof problems. Poisoning, or, at the other extreme, trace element deficiency, can also lead to major health problems. Overall the major causes of disease or ill health in farm livestock may be listed as follows:

• Infectious agents

• Nutritional deficiency and excess

• Metabolic disorders

• Poisoning

• Physical injury

• Congenital disorders