Effect of feeding protected lipid to dairy cows in early lactation on the composition of blood lipoproteins and secretion of fatty acids in milk.

摘要: Effects of 0, 1·7, 3·3 or 5·0 kg/day a protected soya bean – tallow supplement, incorporated into hay:concentrate diet (25:75) and fed ad libitum to Friesian cows, on intake digestion fatty acids, output milk acids blood lipoprotein composition were measured. Most the increased approximately 1 kg/day, was accounted for by intakes C 16:0 , 18:0 18:1 . At low intakes, amounts all apparently digested linearly related their respective intakes. high C16 C18 curvilinear relationships established. Yield total fat positively dietary acid carbohydrate negatively live-weight change. Yields short intermediate chain in milk, synthesized within mammary gland, correlated yields 18 with these acids. Decreased proportions 4–16 associated diet. 16:1 corresponding outputs saturated weeks lactation. The proportion resulted concentrations very density lipoproteins (VLDL, d + LDL 2 1·019 1·060 g/ml) serum free increase large whose from 17 75% (2 22% lipid). triglyceride combined fraction decreased 11 2% whilst phospholipids 29 36%. These changes attributed present. VLDL taken up gland averaged 0·79 0·34 respectively. VLDL+LDL digested. tended be apparent uptakes but triglycerides It is suggested that utilization formation. Protected lipid feeding 14:0 14:1 jugular triglycerides. Similar observed Differences compositions across either selective uptake interchange between