manure, not including the amount dropped while at work. This quan- 

 tity, which would be worth about ^13.50 as fertilizer, would require 

 the use of about 2,500 pounds of straw for bedding. According to 

 the author's calculations a ton of wheat straw economically used for 

 bedding horses may result in 6 tons of fresh manure, although in gen- 

 eral practice the amount is not likely to exceed 5 tons and may be 

 much less if few animals are kept or the manure is infrequently 

 removed. 



RATIONS ACTUALLY FED AND FEEDING STANDARDS. 



The amount of the different feeding stuffs required and hence the 

 quantity of nutrients supplied to horses may be learned by observa- 

 tion or experiment or a combination of the two methods. Doubtless 

 all practical horse feeders supply rations which they believe are suited 

 to their horses' needs, and in stables where horses are fed in any con- 

 siderable number economy demands that the amount fed shall be fixed 

 and not vary according to the whims of the feeder. When the feed- 

 ing stuffs used are weighed and the condition of the horses is noted, a 

 feeding experiment results. Using average values obtained from 

 many more or less complicated feeding experiments and other investi- 

 gations, so-called feeding standards have been devised which are 

 designed to show the amount of protein, fat, and carboh3^drate£ 

 required per day for various conditions of work and rest. For the 

 sake of uniformity, the standards arc usually calculated on the basis of 

 1,000 pounds live weight. They often show in addition the nutritive 

 ratio; that is, the ratio of protein to the sum of the carbohydrates 

 and 2.25 times the fat. It is also possible to express the feeding stand- 

 ards in terms of protein and energy, since the functions of food, as 

 previously stated, are to build and repair tissue and suppl}^ energy, 

 protein alone serving for the former purpose, while all the nutrients 

 ^deld energy. The best known feeding standards for horses and other 

 farm animals are those computed by Wolff and revised by Lehmann. 



Very frequently so-called standards for horses have been proposed 

 which have shown the quantities of feeding stuffs required; for in- 

 stance, the pounds of oats and ha}^ needed per da}^ per 1,000 pounds 

 live weight. Such standards, or more properly standard rations, have 

 been aVlopted in many countries for army horses, and in other cases 

 where large numbers of horses are fed under uniform conditions. The 

 digestible nutrients furnished by such standard rations can be calcu- 

 lated by the aid of figures showing the average composition and diges- 

 tibility of the feeding stuffs. 



The table following shows the amount of nutrients and energy fur 

 nished per 1,000 pounds live weight by rations supplied the IT. S. 

 Army horses, by those fed to a number of farm horses at the stations, 



170 



