58 



digestible protein and 19,560 calories. It would be going too far to 

 propose the adoption of these average values as standards in the place 

 of those which have been commonly accepted. It is undoubtedly true 

 that a feeding standard should be based on other data than the results 

 of feeding experiments; however, in so far as the results represent 

 the average practice of successful feeders they are worthy of con- 

 sideration, and certainly emphasize the importance of undertaking 

 investigations with a view to revising the standards. It should be 

 remembered that the amounts of digestilile nutrients in the rations 

 actually fed were calculated with the aid of coefficients of digestibility 

 obtained with horses and are, therefore, considerably lower than would 

 be the case if average values obtained with ruminants had hcen used, 

 a method of calculation which has been often followed in the past, but 

 which does not seem desirable. 



METHOD OF CALCULATING RATIONS. 



The feeding value' of any ration may be readily calculated and com- 

 pared with the standards. Suppose a horse at moderate work and 

 weighing 1,200 pounds is fed 11 pounds of oats and 10 pounds of tim- 

 othy hay dail3\ The Wolff-Lehmann feeding standard for horses at 

 moderate Avork calls for 1.8 pounds of protein and 20,700 calories per 

 thousand pounds live weight. A horse weighing 1,200 pounds would 

 therefore require 1.2 times as much, or 2.2 pounds protein and 32,000 

 calories. Oats contain 9.39 pounds of digestible protein and 122,100 

 calories per hundred pounds. Eleven pounds would therefore furnish 

 1 . 03 pounds of protein (9. 39 X 0. 11 = 1. 03), and 13,430 calories (122, 100 X 

 0.11 = 13,430). Timothy hay furnishes 1.25 pounds protein and 69,850 

 calories per hundred pounds. Ten pounds would therefore furnish 

 0.13 pounds protein (1.25X0.10 = 0.13) and 6,985 calories (69,850X 

 0.10 = 6,985). The sum of the nutrients furnished by 11 pounds of 

 oats and 10 pounds of ha}^ would therefore be 1.16 pounds protein and 

 20,115 calories, or 1.01 pounds protein and 11,585 calories less than 

 the standard calls for. This may be made up by adding more oats, 

 hay, or other feeding stutf. The amount of oats required to furnish 

 the necessary protein maj^ be learned from the proportion 10(» : 9.39 : : 

 a: 1.01; or, in other words, by dividing 1.04 b}' .0939, which gives 

 11.07. This quantity of oats would also furnish 13,517 calories, mak- 

 ing the total protein of the ration 2.2 pounds and the total fuel value 

 33,932 calories. The fuel value of the ration is in excess of the stand- 

 ard, though the agreement is close enough for all practical purposes. 



As previously stated, it is not necessary that the amounts furnished 

 in a ration shall exactly equal those called for by the standard, but 

 rather that they appi-oxiniate them, being greater rather than less 

 through a long period. Rations which will furnish the amounts called 



