A review of quality and processing suitability of milk from cows treated with bovine somatotropin

Abstract

This paper reviews recent literature concerning whether cows injected with BST still give milk of good quality and processing characteristics. Fat, protein, and lactose contents of the milk are negligibly affected by bST when the cow is in positive energy balance. This state is an important prerequisite when bST is administered. When bST is given by a sustained-release system, some cyclic effects in fat and protein contents are found. Bovine somatotropin may cause an increase in the relative amount of long-chain fatty acids, and the SCC is sometimes increased. Protein composition is usually not negatively affected, nor is the theoretical cheese yield calculated from the total protein content. The available information on the effect of bST on various milk minerals and enzymes, freezing point, pH value, and milk flavor gives no cause for concern. Relatively little is known about the effect on the various vitamins. Heat stability of the (condensed) milk and cheese-making properties were generally not affected, but further experiments with milk from the same farm trials are recommended. The concentration of bST in the milk is not affected by normal doses, but the effect on insulin-like growth factors needs additional study.