Diarrhoea of nutritional origin

DefinitionFor the purpose of this paper, diarrhoea will be defined as the condition in which faeces containing less than 12% dry matter are produced.It may be the result of poor absorption of water from, or increased secretion of water into, the alimentary tract, or in certain cases a reduced excretion of faecal dry matter. Economic importanceT h e economic importance of diarrhoea in the ruminant animal is mainly of relevance in the nutrition at the pre-ruminant stage.In a recent survey of calf wastage (Leech, Macrae & Menzies, 1968) 8.9% of 40 ooo calves were affected with diarrhoea on some occasion during the 1st year of life.The cause of death in 44'9% of 350 post-mortem cxaminations was classified as being due to gastrointestinal disorders, with a further 24.8% resulting from septicaemia.Since an earlier survey of 2046 post-mortem examinations showed that Escherichia coli was associated with 46% of deaths up to 6 months of age and Salmonella with 24:/0 (Veterinary Investigation Service, I 964), the great majority of the gastro-intestinal disorders are clearly associated with colibacillosis.Most of the mortality from diarrhoea occurs at a young age and, in the survey of Leech et al. (1968), the probability of death at any time in home-bred calves was about equal to the reciprocal of age, and percentage mortality up to age W (in weeks) was equal to log, W+ 1.72.