FACTORS INFLUENCING MILK PRODUCTION 305 



objectionable flavor. These flavors are due to the volatile 

 oils in these feeds, whereby they impregnate the milk while 

 in the body of the cow. The effect of some feeds is to pro- 

 duce hard butter-fat, while others make it soft. Butter 

 made from milk from cows fed cottonseed meal has a high 

 melting point, while corn meal has the opposite effect on 

 the butter-fat, although not in any serious degree. The fat 

 in the milk takes on a more yellow hue when the cows are 

 turned on pasture or when they are fed carrots, bright green 

 alfalfa hay, or new silage. This yellow color is due to what 

 is known as carotin, which is more abundant in carrots and 

 green feeds than elsewhere. 



The effect of the different kinds of food on the milk 

 yield may be quite marked, cows responding more with 

 some foods than others. The yield will fall off with the use 

 of coarse, dry, unpalatable foods, and increase with those 

 of finer quality that are succulent and palatable. The kind 

 and character of the feed, however, can not materially change 

 the quality of the milk. A cow fed rye straw, a very low 

 grade food, may fall off in her milk flow, but there will be 

 no essential change in the character of her milk. If it were 

 possible to change the composition of milk by feeding, then the 

 individuality of the milk of the Jersey or the Ayrshire might 

 be changed, thereby seriously affecting its character and value. 



Frequency of milking no doubt has a bearing on the 

 yield. Under most conditions cows are milked twice daily. 

 As the official testing of dairy cows has progressed, however, 

 the custom has developed of milking three or four times 

 daily, as conditions justify. Heavy milkers, such as Hol- 

 stein-Friesians, are milked at least three times and in many 

 cases four times. In Holland in common practice the cows 

 are usually milked three times daily. If there is the same 

 period of time between each milking, the milk will show 

 quite uniform tests of total solids and butter-fat. If, how- 

 ever, there is a considerable difference in the number of hours 



