47 



feedinj^- experiment results. Using averag-e values obtained from 

 many more or less complicated feeding- experiments and other investi- 

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

 designed to show the amount of the different nutrients required per 

 day for various conditions of work and rest. For the sake of uni- 

 foruiity, the standards are usually calculated on the uniform basis of 

 1,000 pounds live weight. The feeding standards show the amount of 

 protein, fat, and carbohydrates required daily, and often the nutritive 

 ratio also; 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 standards 

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

 viously stated, are to build and repair tissue and supply energy, 

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

 yield 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 instance, 

 the pounds of oats and hay needed per day per 1,000 pounds live 

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

 been adopted 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. Such calculations have been often made, 

 especially by earlier investigators, on the basis of data secured by 

 digestion experiments with ruminants. However, this method can not 

 give the most satisfactory results. If possible, coefficients of digesti- 

 bility obtained in experiments with horses should be used. 



Standard rations and feeding standards have been proposed by 

 Grandeau and Leclerc, LaA'alard, and others. These French investi- 

 gators based their recommendations chiefly on investigations with the 

 horses of the Paris cab companies and the French army. The work 

 extended over a number of years and thousands of horses were 

 included. In connection with the work the digestibility of the ration 

 was determined. 



In compiling this bulletin letters were addressed to express com- 

 panies, cab companies, fire companies, and other organizations in dif- 

 ferent cities of the United States using large numbers of horses, 

 requesting information regarding the rations fed. Information was 

 also secured regarding the average weight of the horses. Similar 

 values regarding horses fed by a number of cab companies, etc., in 

 foreign countries were compiled from available published data. The 

 rations fed army horses in the United States and other countries were 

 also learned by correspondence and by compilation from various 



