372 Tlie Feeding of Animals 



needed to furnish these quantities of digestible nu- 

 trients, when consisting of a mixture in equal parts 

 of corn and oats would be approximately 11.5 lbs., 15 

 lbs., and 2) lbs. for the three conditions of labor. 

 Lavalard, who made observations covering a period of 

 a number of years for 32,000 omnibus, army, and draft 

 horses, has reached the conclusion that "a horse per- 

 forming ordinary work requires 115 grams of diges- 

 tible protein and 1,100 grams of digestible carbohy- 

 drates per 100 kilograms live weight." This is at the 

 rate of 1.215 lbs. of digestible nutrients per 100 lbs. of 

 live weight. This observer bases the ration upon the 

 weight of the animal, but practically concedes that 

 "somewhat larger amounts of protein and carbohy- 

 drates are considered necessary with small horses," 

 a conclusion which is entirely consistent with obser- 

 vation and related facts. Lavalard 's formula would 

 furnisli a 1,000-pound horse, doing ordinary work, 

 with 12.1 lbs. of digestible nutrients daily, a quantity 

 not inconsistent with the German standard. 



It seems to the writer that the results of the mas- 

 terly and extensive metabolism investigations which 

 Zuntz has carried on with a horse under various con- 

 ditions may properly be cited in this connection. This 

 investigator determined the oxygen consumption, which 

 is equivalent to ascertaining the food use, by a horse 

 at rest, when walking on a smooth level without load, 

 and when performing both light and heavy work. 

 First of all, it appears from his observations that 31.6 

 per cent, or about one-third, of the total food energy 

 can be converted into useful work. This is much less 



