278 



Feeds and, Feeding. 



437. Feed requirements for work. The manner of calculating 

 the amount of feed necessary for the performance of a certain 

 amount of work may be illustrated by an example cited by 

 Wolff. 1 If a riding horse in average condition, weighing 937 

 pounds, and 1,157 pounds with rider and saddle, travels 20.5 

 miles daily, he performs the amount of work shown in the table, 

 which calls for corresponding quantities of nutrients. 



Nutrients required for work of varying degrees Wolff. 



To the digestible nutrients given in the last column must be 

 added the quantity necessary to maintain the animal, aside from 

 the performance of any work, which will amount to 6. 70 pounds 

 per 1,000 pounds weight (7.39 for 1,100 pounds), so that ordi- 

 narily the supply of digestible matter in the ration would be re- 

 spectively 9. 13, 11. 97 and 20. 17 pounds. The two amounts in the 

 last column are larger than any horse will be able to assimilate, 

 but a continuous canter or even slow trot for the whole distance 

 of 20 miles represents an amount of work rarely performed by 

 the horse. If we assume that one-third of the distance was 

 traveled in a walk, one-third in a slow trot, and one-third in a 

 canter, we find that the total time required would be 14,960 

 seconds, the total energy used 11,874,000 foot-pounds, and the 

 corresponding feed requirements 4.25 pounds of digestible 

 matter. This added to the feed required for maintenance 

 amounts to 10.52 pounds of digestible matter. A horse walking 

 20 miles will require seven hours and twenty minutes. If equal 

 distances are traveled in walk, trot and canter, it will take four 

 hours and nine minutes. The total energy spent in the former 



1 Landw. Jahrb., 1887, Suppl. Ill, p. 120. 



