Livestock are of growing importance in agriculture. Global populations of livestock have increased significantly in recent decades, and East Asia has recorded major increases in its livestock numbers. Thailand’s stocks of poultry, cattle and pigs have expanded with its economic development. Per capita consumption of red meat and milk by Thais shows an upward trend and its livestock industry is becoming more commercialised. Nevertheless, most cattle are still present in Thai villages and village poultry still account for around one third of Thailand's poultry. The type of animal husbandry practised in Thai villages influences the incidence and spread of livestock diseases. The economics of private decisions about livestock health interventions are discussed. Vaccination of livestock against foot-and-mouth disease is taken as an example and the private economics of treating a sick animal is considered. Methods for measuring the social economic benefits from control of livestock diseases (and their distribution) are outlined along with some of their policy implications. The usefulness of using the price of livestock as a guide to the value of maintaining their healthiness is examined. It is suggested that increases in the healthiness of livestock be looked upon as an addition to livestock capital, as in the case of human capital.