220 A FEEDERS' GUIDE. 



bran, or 2.5 pounds of hay of average quality, can be substituted 

 to a limited extent for a pound of grain in ordinary dairy rations, 

 without changing appreciably the yield or the composition of the 

 milk produced by the cows, or influencing their live weights or 

 general condition. These quantities of the different feeds are, 

 therefore, considered of similar value and equivalent to one feed 

 unit. If a cow ate 750 pounds of hay, 150 pounds of bran, and 90 

 pounds of ground corn during a certain month, she received 750 

 divided by 2.5, or 300 feed units, in the hay eaten, 150 divided by 

 1.1 or 136 in the bran, and 90 in the ground corn, making a total 

 of 526 feed units eaten. 



If she yielded one pound of butter-fat a day in her milk on 

 this feed, or 30 pounds for the month, she produced 30 divided 

 by 5.26, or 5.70 pounds of butter-fat per 100 feed units consumed 

 in her feed. There are great differences among cows in the 

 returns made per unit of feed, and data obtained as given above 

 show in a striking manner whether a cow is an economical pro- 

 ducer or whether she required an excessive amount of feed to 

 make her production. 



Through this information, along with that as to the capacity 

 of the cow for dairy production furnished by a milk scale and a 

 Babcock tester, a farmer can find out definitely the rank of the 

 different cows in the herd as dairy producers and may thus know 

 which ones, if any, are not profitable animals and should be sent 

 to the butcher. 



Feeding Standards. 



Investigations by scientists have brought to light the fact that 

 the different classes of farm animals require certain amounts of 

 food materials for keeping the body functions in a regular healthy 

 activity; this is known as the maintenance ration of the animal, 

 an allowance of feed which will cause him to maintain his live 

 weight without either gaining or losing, or producing animal 

 products like milk, wool, meat, eggs, etc. If the animal is expected 

 to manufacture these products in addition, it is necessary to supply 

 enough extra food to furnish materials for this manufacture. The 

 food requirements for different purposes have been carefully 

 studied, and we know now with a fair amount of accuracy how 

 much food it takes in the different cases to reach the objects 



