276 MILK, BUTTER, AND CHEESE [chap. 



than would otherwise be the case. Nor do particular 

 foods have any permanent effect upon the richness of 

 the milk. It is generally found that a slight change of 

 food exerts a stimulating action for a short time upon 

 the milk yield, though drastic changes may have the 

 reverse effect and temporarily reduce the yield and 

 quality of the milk ; in any case the effect does not 

 persist for many days. Certain classes of succulent 

 foods which are very rich in a-proteins, such as brewer's 

 grains, green fodder, and especially fresh grass at its 

 first shoot in the spring, have an exciting effect in 

 promoting the flow of milk. Particularly does the first 

 grass, after the cows are turned out, give rise to an 

 abundant production of comparatively poor milk. Lack 

 of green food is also apt to result in a falling-off both in 

 the yield and the quality of the milk, and a large 

 quantity of watery foods eventually results in thin and 

 poor milk. 



The quality of the butter is, however, considerably 

 affected by the nature of the food, because the composi- 

 tion of the butter fat varies with the material out of 

 which it is manufactured by the cow; in some cases 

 indeed the fatty acids contained in the food can again 

 be identified in the butter fat. An excess of fibrous 

 foods — hay and straw or over-ripe forage crops — gives 

 rise to hard, tasteless butter ; peas and beans and cotton- 

 seed meal or cake also harden the butter. On the other 

 hand, linseed cake gives rise to a soft and oily butter, 

 and maize and gluten feeds, oats and rice, also tend to 

 soften the butter. The feeding of turnips and swedes, 

 except some time before milking, communicates a 

 characteristic and disagreeable flavour to the butter, 

 while it is well known that the flavour of certain strongly 

 smelling plants like wild garlic is carried over to the 

 butter. 



