COLOUR OF MILK

Waikato Times, Volume 124, Issue 20740, 25 February 1939, Page 11 (Supplement)

COLOUR OF MILK

BREED CHARACTERISTIC The colour of milk and cream is essentially a breed characteristic and Guernseys produce the deepest shade of all cows, with Jerseys a close second. The Guernsey tint is deeper than that of the Jersey, even when the Guernsey fat percentage is lower. The milk of the Friesian cow is generally the lightest colour when it is oompared with the milk of other breeds, and that of the Red Poll, Ayrshire and Shorthorn next. With these breeds, as well as with the Channel Island cattle, the order of oolour is not necessarily the order of richness.

Another important factor is the cream rising power, and it is not always the richest milk that throws up cream best. Breed differences seem to be as firmly established as

other racial features, and. so far as the colour of milk is concerned, may have been influenced by breeders in the past who have sought to avoid the production of yellow fat in beef cattle. Pigment the Same Apparently the pigment that makes the fat of Guernsey and Jersey beef so yellow is exactly the same as that which tints the milk and cream, and so it may be impossible to combine in one animal white beef fat with deeptinted milk. Milk also varies in colour with individual cows. For a short while after calving the milk is deeper in colour than it is for the rest of the lactation, which may be partly explained by the fact that colouring matter is stored up in the cow’s body during the 8 or 10 weeks she is dry before calving. Cows over 10 years of age have often been noticed to yield lighter tinted milk them younger members of the same herd. Various shades of yellow and bluish milk are sometimes met with and their discolouration is attributed to certain bacteria, acting either upon the fat or the casein, according to their variety. Blue discolouration is said to occur only in milk that is definitely acid. A reddish tinge in milk and cream may also be due to the presence of germs which cause tiny red dots to form on the surface when the liquid has been standing. The reddish sediment sometimes found at the bottom of the milk vessel is due to an inflamed udder, and the sediment consists of particles of blood. No milk that shows discolouration or any other abnormal feature should be used for human consumption. but should at once be submitted to test. The natural colouring matter is only

utilised by the eow in proportion io the percentage of butterfat in the milk, and more especially to the size of the fat gloubles. Milk that Is rich in fat and is composed of large globules (which make churning easier) will always be deeper coloured than milk of any quality with smaller fat globules.