50 MANUAL OF FARM ANIMALS 



reject sweet clover, and why weeds, which often impart a bad 

 flavor to the product, are sometimes readily eaten. 



MAINTENANCE RATIONS AND PRODUCTIVE RATIONS 



A ration may be defined as the quantity of food that will 

 be consumed by an animal weighing one thousand pounds in 

 twenty-four hours. In forming rations, it is necessary to take 

 into account the purpose for which the animal is intended. For 

 a given purpose an animal will require a given amount and 

 kind of food. Thus a one-thousand-pound cow yielding 

 twenty pounds of milk per day will require a certain kind and 

 a certain amount of food. This is called a standard ration. For 

 convenience of study, rations are divided into two general 

 classes, — rations for maintenance and rations for production. 



Maintenance rations. — A maintenance ration is one that sup- 

 plies the needs of a resting animal without producing any 

 kind of labor and with no loss or gain of body substance. We 

 have already seen that a certain amount of the food consumed 

 by the animal goes to support life, maintain body temperature, 

 repair waste tissue, and to provide muscular activity of vital 

 processes. Since the demands on the body for maintenance 

 are largely for the production of muscular energy and heat, 

 nine-tenths or more of the maintenance ration may consist of 

 carbohydrates. This fact has much significance in the winter- 

 ing of idle animals. Strictly speaking, no farm animal should be 

 fed only a maintenance ration. Animals receiving maintenance 

 rations are yielding no product. All farm animals should be 

 producing something at all times. 



Productive rations. — Productive rations may be looked upon 

 as made up of two parts: that which is needed to maintain the 

 animal, and that which may be applied to production after the 

 bodily needs have been supplied. It is the food consumed in ex- 

 cess of the amount required for maintenance that enables the 

 animal to produce. The question, then, is as to the quantity of 



