Symposium: disease prevention in calves. Factors affecting susceptibility of calves to disease.

Enteric and respiratory disorders are the main hazards to successful calf rearing. The many interrelated factors in the etiology of these disorders are reviewed, and an attempt has been to classify the factors into those of a microbiological, immunological, nutritional, genetic, physical, or psychological nature. No one would dispute that enteric and respiratory disorders are the two main hazards to calf health, but many would argue about the relative importance of specific pathogens and other predisposing factors in the etiology of these disorders.