The Flow and Composition of Lymph from the Mammary Gland of Lactating and Dry Cows

Abstract

A technique is described for the collection of lymph from the mammary gland of conscious cows. Lymph was collected from the half-udders of 5 cows for periods up to 26 days. Lymph flowed at rates which varied between 7 and 120 ml. per hour in dry cows and as much as 1300 ml. per hour in cows just before parturition and in early lactation. There was a marked increase in lymph flow when the cows were lightly exercised, but milking did not produce any consistent alteration in the rate of lymph flow. Protein leakage from the capillaries of the mammary gland was much greater in the cow immediately before parturition and in early lactation than at later stages in lactation. The rate of transfer of T-1824 labelled albumin between plasma and mammary lymph was also studied and the results of these experiments are discussed in relation to the variation in size of the tissue-fluid pool and rate of protein filtration at different stages of lactation. The composition of mammary lymph from the cow resembled lymph collected from the mammary gland of sheep and goats. In lactating cows the glucose concentration of the lymph was about 10% higher than that in the plasma from the subcutaneous abdominal vein.