Non-nutritional (novel) techniques for manipulation of milk composition

摘要

Abstract This review considers the control of milk composition by endocrine factors and local mechanisms operating within the udder, and the impact of management systems and the environment on these control systems. Much less is known about control of milk composition than yield, although one can propose that prolactin is more concerned with control of lactose and protein secretion whilst growth hormone has a bigger role to play in fat secretion. Molecular biological approaches have the potential to increase understanding and, in the distant but foreseeable future, to manipulate milk composition on a commercial scale. The feedback inhibitor of lactation (FIL), which is responsible for local control of milk yield, has equal effects on lactose, fat and protein secretion, so changes in milking frequency do not alter gross milk composition. During the course of lactation the processing properties of milk gradually deteriorate as a consequence of proteolytic degradation of caseins, but new research shows that this can largely be prevented by milking thrice–daily. This has significant implications for future milking strategies such as robotic milking and extended lactation.