SECRETION OF MILK

Ellesmere Guardian, Volume XLV, Issue 3174, 6 December 1927, Page 8

SECRETION OF MILK

QUESTION OF CONTINUITY

A remarkable experiment was carried out at a United States dairy experiment farm recently, when the udders of two cows killed were removed immediately after slaughter and mounted in a position.for post-mortem milking in a recent test to determine whether milk is manufactured during the few minutes required for the milking process, as is generally taught, or whether it is secreted continuously and collected in the udder previous to milking. It is generally held that the capacity of a cow's udder is not more than a half pint to each quarter, and, therefore, that the milk must necessarily be manufactured during the milking operation. In these tests it was found however, that a cow's udder is capable of holding from 11 to 20 quarts of milk. One of the cows had normally been giving about 121b. at a milking. When her udder was milked after being completely severed from all body connexions a total of 10.271b. of milk

was obtained, or more than 85 per cent, of her normal production, indicating that this amount had been collected and stored as milk previous to her slaughter.

The postmortem milking of the second cow yielded 50 per cent, of her normal production., A considerable quantity of milk still remained, due to the difficulty with which it was released. Mr W. W. Swett, Bureau of Dairy Industry, United States Department of Agriculture, has expressed the opinion that these tests indicate that milk secretion is to a considerable extent a continuous process, and that a large proportion of the milk secured at any milking is collected and stored within the mammary gland before milking is commenced; also that the liberation of the milk from the gland is not dependent either upon a nervous or mechanical stimulation or upon internal muscular contraction. It is understood that extensive studies of the mammary gland are now being made by the bureau in connexion with the project dealing with the relation of a dairy cow's conformation and anatomy to her milk and butter-fat producing capacity.