122 Feeds and Feeding. 



The table shows that a 3-months-old calf weighing 275 Ibs. re- 

 quires 1.10 Ibs. of digestible protein and 5 therms of net energy 

 value, the latter including the 1.10 Ibs. of protein. When the calf 

 has grown to 1100 Ibs., or quadrupled in weight, it requires but 

 0.55 Ib. more protein and 3 more therms than before. This rela- 

 tive lessening in feed requirement is due to the fact that the larger 

 animal requires relatively less for maintenance, as explained elsewhere 

 in the discussions on maintenance requirements. (96, 123a) For the 

 1000-lb. steer Armsby allows 1.75 Ibs. of digestible protein, and but 

 1.65 Ibs., or 0.10 Ib. less, for the same animal when weighing 1100 Ibs. 

 This is because at the higher weight the steer has practically ceased 

 muscular growth and therefore needs less protein than earlier in 

 life. A comparison of the maintenance and growth requirements 

 of animals, as here set forth, reveals the fact that a large por- 

 tion of all the feed the animal consumes is used for the support 

 of the body, and that the additional requirements for growth are 

 not relatively large. 



145. Standards for milch cows and fattening steers. Armsby 

 supplements the foregoing partial standards with the following: 



1. For milk production, add to the maintenance standard 0.05 Ib. of diges- 

 tible protein and 0.3 therm for each pound of 4 per ct. milk to be produced. 



2. For mature fattening cattle, add 3.5 therms to the maintenance stan- 

 dard for each pound of gain to be made. 



For the milch cow Armsby provides additional food, both pro- 

 tein and therms, as noted in the foregoing, because milk is rich 

 in complex protein compounds, and also contains carbohydrates 

 and fat. Furthermore, the cow is usually growing a calf. For 

 the fattening steer Armsby holds that, after providing the pro- 

 tein set forth in the ration for growth, the steer will fatten sat- 

 isfactorily without any additional protein, provided there are sup- 

 plied sufficient carbohydrates and fat to meet the standard. Hence 

 there is no provision for additional protein during fattening as in 

 the Wolff standards. 



Armsby recommends that: 



1. A 1,000-lb. ruminant should receive 20 to 30 Ibs., or an average of 25 Ibs., 

 dry matter per day. 



2. The horse should receive somewhat less dry matter than ruminants. 



146. Ration for dairy cow. The following illustrates the method 

 of using the Armsby tables and standards in computing rations. 

 The digestible protein in the tables is true protein; that is, it does 

 not include the amids. 



