Milk secretion in relation to blood composition. The urea contents of blood and of milk-serum

Abstract

Expts. showed that in the cow, whole blood and the fat-free serum of milk have the same urea content irrespective of the rate of milk secretion. Mammary venous blood is not significantly different from arterial blood in this respect. During lactation milk may be used as an alternative to blood for determination of blood-urea. A method is suggested for estimating the volume of blood which participates in the formation of a given volume of milk and for determining the approximate rate of blood flow through the mammary gland.