The effect of abomasal infusion of casein on acetate, palmitate and glucose kinetics in cows during early lactation.
Four mature Friesian cows were used in a Latin square design experiment to measure the effects of abomasal casein infusion on milk production and the kinetics of glucose, acetate and palmitate in jugular venous blood. The basal ration contained 110 g crude protein/kg dry matter and was offered at the rate of 4 kg hay, 3 kg alkali-treated straw cubes plus 9 kg concentrates/d. Treatments were infusion of casein into the abomasum at the rate of 0, 240 or 460 g/d. The experiment started 1 week post partum. Experimental periods lasted 21 d. [6-3H]glucose, [9, 10-3H]palmitate and [U-14C]acetate were continuously infused into one jugular vein for measurements of whole-body flux rates. The yield of milk protein was increased significantly (P less than 0.05) by the first increment of casein infusion, with no further increases. Casein infusion had no effect on blood concentrations of glucose, acetate, palmitate or growth hormone. Mean flux rate of glucose increased with each increment of casein. The effect at 460 g/d was higher (P less than 0.1) than with no infusion. Flux rates of palmitate and acetate were increased (P less than 0.1) by the first increment of casein. The proportion of blood bicarbonate derived from acetate increased (P less than 0.05) with the first increment of casein. Protein status of cows early in lactation influences the dynamics of glucose and fatty acid metabolism.
D000018:Abomasum; D000085:Acetates / Q000378:metabolism*; D019342:Acetic Acid; D000818:Animals; D002364:Caseins / Q000008:administration & dosage / Q000494:pharmacology*; D002417:Cattle; D005260:Female; D005947:Glucose / Q000378:metabolism*; D013006:Growth Hormone / Q000097:blood; D007263:Infusions, Parenteral; D007700:Kinetics; D007774:Lactation / Q000187:drug effects; D008892:Milk / Q000378:metabolism; D008894:Milk Proteins / Q000378:metabolism; D019308:Palmitic Acid; D010169:Palmitic Acids / Q000378:metabolism*; D011247:Pregnancy
D000085:Acetates; D002364:Caseins; D008894:Milk Proteins; D010169:Palmitic Acids; D019308:Palmitic Acid; D013006:Growth Hormone; D005947:Glucose; D019342:Acetic Acid