Kinetics of Intravenously Administered Lactose in Cows

Four adult Norwegian Red cows were employed in an experiment designed to study the kinetics of lactose. The cows were given 50 g or 60 g of lactose by rapid intravenous injection of a 10 % lactose solution. Blood samples were taken at different intervals after injection, and lactose concentrations in the samples determined by an enzymatic/spectrophotometric method. The mean half-time for lactose elimination was 85.7 min, and for distribution 8.4 min. The mean apparent volume of distribution was calculated to be 0.189 1/kg, and total body clearance 1.55 ml min−1 kg−1. There was evidence to suggest that lactose mainly is eliminated renally from its distribution volume by glomerular filtration in the cow.