57 



different conditions and by a large number of feeders whose opinions 

 regarding what constituted a proper ration naturally differed. Taken 

 as a whole it does not seem unfair to assume that the figures are rea- 

 sonably trustworthy, since it is highly probable that the private firms 

 fed their horses rations which experience had shown were satisfactory 

 and in the case of the farm horses, which were without exception fed 

 at the experiment stations under controlled conditions, the rations 

 were undoubtedly adequate, since the only results included are those of 

 feeding tests in which the horses maintained their weight. As will be 

 seen, the average values for the protein and energy in the rations of 

 the horses performing light work are considerabl}^ less than similar 

 values for horses performing moderate work. The data for the for- 

 mer group is much more limited than for the latter, but the relation is 

 in accord with the commonly accepted theories. The farm mules con- 

 sumed a ration furnishing less protein and practicall}" the same amount 

 of energy as horses performing similar work, though the tests with 

 mules are too few for general deductions. The rations of the truck 

 and draft horses performing severe muscular work furnished less pro- 

 tein and energj" on an average than the rations of the horses with mod- 

 erate work. This is not in accord with commonly accepted theories 

 and may be explained in part perhaps by the fact that the data for the 

 group performing severe work is much less extended than that for 

 the group performing moderate work. There is every reason to sup- 

 pose that the truck and draft horses received rations sufficient for 

 their needs, as the firms owning them are known to make the effort to 

 maintain their horses in good condition. Such truck and draft animals 

 are often employed at work which is performed at a slow pace, and 

 undoubtedly this has a bearing on the fact that they were able to per- 

 form a large amount of work on a comparatively small ration, as the 

 speed at which work.is performed has a marked effect upon the food 

 requirements. 



It will be seen that the average values, representing the amounts 

 which w^ere fed to American horses performing light, moderate, and 

 severe work, differ somewhat from the commonly accepted feeding 

 standards. The average values for horses at moderate work (express 

 horses, cab horses, and farm horses), namely, 1.49 pounds digestible 

 protein and 22,710 calories per 1,000 pounds live weight per day are 

 considerably less than those called for by the Wolff- Lehmann standard 

 or by Grandeau's estimates. The agreement with Lavalard's figures 

 is much closer, the protein being a little larger and the energy very 

 nearly the same. The average values for horses at light work, namely, 

 0.99 pound digestible protein and 1-4,890 calories per 1,000 pounds 

 live weight, are also less than the values called for b}'^ the Wolff' 

 standard. The greatest difference, however, is observed in the values 

 for horses wdth severe work, the American average being 1.12 pounds 



