NUTRIENT METABOLISM AND UTILIZATION IN THE MAMMARY-GLAND

Before dairy cow feed evaluation can progress from systems based on em pirical measurement to those based on mechanistic modelling the essent ial components of the model have to be defined. This review describes those elements which pertain to the mammary gland itself, briefly desc ribing the major metabolic events within the gland before considering the supply of substrates to the udder and the uptake of those substrat es across the capillary endothelium and basolateral membrane of the se cretory cell. A level of complexity is revealed which throws into ques tion our ability to construct adequate mechanistic models without cons iderably more input into understanding the fundamental biology of the mammary gland.