PRODUCTION AND UTILIZATION OF MILK measure, a high-yielding mammal is subservient to the needs of its mam mary gland to which it must supply not only the precursors for the synthesis of milk constituents but also an adequate level of high-energy-yieldin substrates(ATP, UTP, etc. ) required to drive the necessary synthetic reactions. In addition, minor constituents(vitamins and minerals )must be sup 1.7 Biosynthesis of milk constituents The constituents of milk can be grouped into four general classes according to their source organ-(mammary gland) and species-specific (e.g. most proteins and lipids); organ- but not species-specific(lactose); species- but not organ-specific(some proteins) neither organ- nor species-specific(water, salts, vitamins) The principal constituents(lactose, lipids and most proteins)of milk are synthesized in the mammary gland from constituents absorbed from blood However, considerable modification of constituents occurs in the mammary gland; the constituents are absorbed from blood through the basal mem rane, modified(if necessary) and synthesized into the finished molecule (lactose, triglycerides, proteins) within the mammocyte (mainly in the endoplasmic reticulum) and excreted from the mammocyte through the apical membrane into the lumen of the alveolus We believe that it is best and most convenient to describe the synthesis of the principal constituents in the appropriate chapter. 1.8 Production and utilization of milk Sheep and goats were domesticated early during the agricultural Revo- lution, 8000-10000 years ago. Cattle were domesticated later but have become the principal dairying species in the most intense dairying areas, although sheep and goats are very important in arid regions, especially around the Mediterranean. Buffalo are important in some regions, especially in India and Egypt. Mare's milk is used extensively in central Asia and is receiving attention in Europe for special dietary purposes since its compo- sition is closer to that of human milk than is bovine milk ome milk and dairy products are consumed in probably all regions of the world but they are major dietary items in Europe, North and South America, Australia New Zealand and some middle eastern countries. total milk production in 1996 was estimated to be 527 x 10 tonnes, of which 130,PRODUCTION AND UTILIZATION OF MILK 11 measure, a high-yielding mammal is subservient to the needs of its mam￾mary gland to which it must supply not only the precursors for the synthesis of milk constituents but also an adequate level of high-energy-yielding substrates (ATP, UTP, etc.) required to drive the necessary synthetic reactions. In addition, minor constituents (vitamins and minerals) must be supplied. 1.7 Biosynthesis of milk constituents The constituents of milk can be grouped into four general classes according to their source: 0 organ-(mammary gland) and species-specific (e.g. most proteins and 0 organ- but not species-specific (lactose); 0 species- but not organ-specific (some proteins); 0 neither organ- nor species-specific (water, salts, vitamins). The principal constituents (lactose, lipids and most proteins) of milk are synthesized in the mammary gland from constituents absorbed from blood. However, considerable modification of constituents occurs in the mammary gland; the constituents are absorbed from blood through the basal mem￾brane, modified (if necessary) and synthesized into the finished molecule (lactose, triglycerides, proteins) within the mammocyte (mainly in the endoplasmic reticulum) and excreted from the mammocyte through the apical membrane into the lumen of the alveolus. We believe that it is best and most convenient to describe the synthesis of the principal constituents in the appropriate chapter. lipids); 1.8 Production and utilization of milk Sheep and goats were domesticated early during the Agricultural Revo￾lution, 8000-10000 years ago. Cattle were domesticated later but have become the principal dairying species in the most intense dairying areas, although sheep and goats are very important in arid regions, especially around the Mediterranean. Buffalo are important in some regions, especially in India and Egypt. Mare’s milk is used extensively in central Asia and is receiving attention in Europe for special dietary purposes since its compo￾sition is closer to that of human milk than is bovine milk. Some milk and dairy products are consumed in probably all regions of the world but they are major dietary items in Europe, North and South America, Australia, New Zealand and some Middle Eastern countries. Total milk production in 1996 was estimated to be 527 x lo6 tonnes, of which 130