CATTLE PRODUCTS 347 



EXERCISE. Bad Flavor in Milk. Some farmer's son 

 may be able to tell the class some of his own experience in 

 getting bitter milk when cows have been in weedy pastures 

 when the grass is poor. 



Cabbages, wet brewers' grains, and spoiled ensilage may 

 flavor the milk if fed only a few hours before milking. To 

 avoid such bad effects from those feeds, if used at all, they 

 should be fed to the cows when their udders are empty, 

 just after milking. 



EXERCISE. Composition of Milk. Prepare a set of bot- 

 tles containing the proper amounts of different materials to 

 show approximately the composition of one pint of milk. 

 Preserve these with a few drops of formalin in each. Use 

 the following: 



14 oz. water in a pint bottle. 



YL oz. melted butter in Y* oz. vial. 



YZ oz. cheese (protein) in Y* oz. vial. 



#J oz. milk sugar in 1 oz. bottle. 



Y% oz. salt (mineral matter) in smallest vial. 



These should be neatly labelled and kept for future reference. 

 The set will resemble Figure 208. 



Difficulty in Obtaining Pure Milk. Healthy milk cows 

 naturally produce a pure product, but much of the milk 

 used for food is not as pure as it should be. There are many 

 chances for the milk to become dirty or infested with bac- 

 teria before it is used. Careless and improper methods in 

 barns or on the part of those who handle the milk before and 

 after it reaches the home are the chief causes of impure milk. 

 Milk may be kept pure and free from harmful contamination. 

 Poor and unclean milk should not be used for food. 



Bacteria in Milk. The bacteria in milk are classed as 

 either good or bad. Those which cause milk to sour are 

 useful when the milk or cream is to be used for making 

 butter or cheese. There are many bad forms of bacteria 



