Composition and Output of Lipid in the Thoracic Duct Lymph of the Newborn Calf

The composition and output of lipid in thoracic duct lymph has been studied in unanaesthetized calves during the first 6 days after birth. Recirculating lymphatico-venous shunts were established in a total of six calves within 3 hr of birth. The calves recovered quickly from the operation and were able to suck strongly within 1-2 hr of its completion. The concentration of lipid in lymph collected from calves before the first feeding was very high, ranging from 164 to 694 mg/l00 ml. Triglyceride comprised 54% of this lipid with free fatty acid, phospholipid, free cholesterol, and esterified cholesterol comprising, respectively, 6'4, 25'6, 2'5, and 2·5%. Despite the very high output of triglyceride in lymph at this time (mean value O' 86 g/hr), there was no visual evidence of chylomicrons.