38 



SUCCESSFUL FARMING 



The Armsby Standards express the requirements of farm animals in 

 pounds of digestible protein and in therms of energy. Instead of giving 

 separate standards for all the different classes of farm animals, Armsby 

 gives standards for maintenance and growth. Inasmuch as any excess 

 of feed above maintenance may be used for fattening or milk production, 

 he gives the amount of nutrients above the maintenance requirements 

 necessary to produce a pound of gain or a pound of milk. Thus, the stand- 

 ards for fattening and for milk production vary with the amount of gain 

 or with the amount of milk produced. To determine the standard for a 

 fattening animal, one adds 3.5 therms per each pound of daily gain to the 

 energy requirement for maintenance, as all the energy above the mainte- 

 nance requirement may be used for the production of flesh and fat. Armsby 

 recommends that a 1000-pound ruminant should receive 20 to 30 pounds, 

 or an average of 25 pounds of dry matter per day. A horse should have 

 somewhat less. The amounts of digestible protein and of energy in the 

 common feeding-stuffs as presented by Armsby are given in Table II. 

 His feeding standards are given in Table IV. For example, if one desires 

 to calculate a ration for a 1000-pound steer gaining two pounds per day, 

 the first step is to determine the requirements. From Table IV it is seen 

 that the requirements of a 1000-pound steer gaining two pounds per day 

 are 1.8 pounds of digestible protein and 13.0 therms of energy. As the 

 second step, we will assume a trial ration consisting of 10 pounds of corn 

 and 8 pounds of clover hay. Referring to Table II, it is found that the 

 digestible protein and energy in this ration are as follows: 



Comparing the trial ration with the standard, we find that it is low 

 in both protein and energy. As the third step, we will add 2 pounds of 

 cottonseed meal, as it is high in both protein and energy. The ration then 

 contains the following nutrients: 



This ration, although a trifle low in dry substance, fulfils the requirements 

 of the Armsby standard. 



