Blood Lipids of Cows at Different Stages of Lactation

Abstract

The levels and uptake by the mammary gland of blood lipid components, acetate, ketone bodies, and glucose during early or late lactation were compared to the values during the dry period. During the dry period, levels of plasma phospholipids, cholesterol esters, and free cholesterol dropped to 38.0, 51.7, and 63.9%, respectively, whereas plasma triglycerides rose to 146% of the late-lactation levels. The only positive arteriovenous difference observed consistently during the dry period was for plasma acetate. During early lactation, levels of total plasma triglycerides were lower, whereas those of phospholipids and cholesterol esters were similar to levels of the same components during the dry period. The arteriovenous differences for blood glucose and ketone bodies during early lactation were higher than during any other period. No consistent arteriovenous differences for plasma phospholipids, cholesterol esters, free cholesterol, or free fatty acids were observed during any period, except for the large and consistently positive arteriovenous differences for free fatty acids in two out of three cows during early lactation.