Factors Influencing Percentage of Fat in Milk

Abstract

Summary The feeding of prickly pear lowers the percentage of fat in the milk. The outstanding characteristics of prickly pear analyses are the high water and mineral contents. The mineral matter is especially high in calcium and magnesium. Much of the work reported above was done with the idea of finding what particular constituent was responsible for the decrease in percent of fat. The quantity of water consumed does not affect the test. Calcium either in the form of bone meal or limestone has no definite influence on the test. A combination of high water and high mineral feeding as compared with low water and low mineral has no influence on the percentage of fat in the milk. The carbonate and sulphate of magnesium do not lower the per cent of fat. The feeding of 7 to 11 pounds per cow per day of cottonseed meal and linseed oil meal caused an increase in the fat content of the milk. Gluten feed at the rate of 6 to 7 1 2 pounds per day did not affect the test. Linseed oil has the same effect as linseed oil meal. Small quantities (2 or 3 pounds) of linseed oil meal do not seem to affect the test. Apparently the influence of the linseed oil meal feeding on the percentage of fat in milk is temporary. Since linseed oil exerts the same effect as the meal, and since gluten feed which is low in oil does not affect the test, the conclusion is that the results observed are due to the oil rather than the protein. Exercise by walking three miles a day increases the test slightly but unmistakably. Hot weather lowers the test. The decrease is greater with those breeds yielding naturally a milk high in fat.