28o MILK, BUTTER, AND CHEESE [chap. 



records of the milk yield of each cow from day to day, 

 and by occasional analyses, he will be enabled to obtain 

 the most profitable returns from his cows. Cases are 

 on record where the milk yield of a herd has been 

 raised by lOO or 200 gallons per cow per year by the 

 keeping of careful records and the weeding out of the 

 poorer animals. If the farmer is selling milk it will be 

 sufficient for him to obtain occasional analyses of the 

 mixed milk in order to see that it keeps above the legal 

 standard ; but if he finds it is falling too low, it may be 

 necessary to examine into the composition of the milk 

 of the single cows, in order to weed out those who are 

 reducing the percentage of fat to a dangerous degree. 

 When, however, a farmer is making butter from his 

 milk he is less concerned with the total amount of milk 

 yielded than with the amount of butter fat itself, and it 

 is to such a farmer that a knowledge of the average 

 composition of the milk yielded by each animal is of the 

 first importance. As regards the feeding, we have seen 

 that this should be liberal but not excessive, if either too 

 high or too low the cow will begin to fall off in both yield 

 and quality after a certain time. Perhaps the best test 

 that the food is being maintained at a right level, is to 

 weigh the cows from time to time. If they are slightly 

 gaining in weight we may be sure that the food is at 

 about the right level. Very often in this country cows 

 are fed excessively and wastefully owing to the mistaken 

 idea that the greater and richer the amount of food the 

 better will be the production of milk. Perhaps the 

 greatest economy in feeding cows can be effected by 

 roughly adjusting the amount of food to the weight of 

 the cow and the yield of milk. Properly speaking, a 

 cow's rations should be made up of the amount of food 

 required for maintenance, which will vary simply 

 with the weight of the cow, together with the 



