AbstractThe nature of endogenous enzymes in the alimentary tract of cattle is examined and their functions in digestive processes discussed. The main digestive enzymes in cattle are salivary and pancreatic lipase, rennin, pepsin, trypsin, lactase and amylase. Maltase and isomaltase, celliobiase, trehalase, elastase and carboxypeptidase are also present. There is no evidence that cattle secrete sucrase. Most of the enzymes secreted by the gut of cattle are present at birth, although peak activities are not always reached until animals reach 2‐3 weeks of age. These activities often persist through to maturity and are generally unaffected by rumen development. The amounts of enzymes secreted are affected by several factors including the nature of the diet, the method of feeding and age. There is also appreciable variation in the secretion of individual enzymes between animals of similar age and receiving the same diet.