FEEDING STANDARDS CALCULATING RATIONS 121 



1.61 Ibs. Fat in cereals and factory and mill by-products had a starch 

 value of 2. 12 Ibs., nearly as high as in oil-bearing seeds. 



Kellner also found that the net nutritive value of certain concentrates, 

 such as grains and seeds, oil cakes, roots, and slaughter-house by-products, 

 was about the same as that obtained when the several pure nutrients in 

 them were fed separately. It was therefore possible to calculate the 

 approximate starch values of such feeds from the amounts of each class of 

 digestible nutrients they contained. However, it was not possible to 

 compute the starch values of feeds high in fiber with any degree of exact- 

 ness whatsoever. From the few typical feeds which he actually studied 

 in respiration experiments, Kellner found that with such feeds it was 

 necessary to make deductions from the starch values computed as before, 

 ranging all the way from 5 to 30 per ct. with mill and factory by-products 

 and from 50 to 70 per ct. with straw, to get their true starch values. 

 By making arbitrary deductions in this manner he computed the starch 

 values for a long list of feeding stuffs. Owing to the great amount of 

 labor involved, he determined the starch values by actual experiment for 

 but sixteen feeds. Moreover, he ascertained the starch values for these 

 feeds only when fed in a moderate ration to steers. As will be pointed 

 out later, the values for other classes of stock may differ considerably 

 from these. 7 We must therefore regard these starch values as approxi- 

 mations which are helpful until further data are secured. 



170. Kellner's feeding standards. Kellner then formulated feeding 

 standards for the various classes of animals in which the requirements 

 are expressed in dry matter, digestible protein, and starch values. For 

 example, his standard for the maintenance of the mature steer per 

 1,000 Ibs. live weight calls for 15 to 21 Ibs. dry matter, 0.6 to 0.8 Ib. 

 digestible protein, and 6 . Ibs. starch values. 



Fraps of the Texas Station 8 has computed in a manner similar to 

 that of Kellner what he terms " productive values " of feeds. These are 

 the amounts of body fat which it is estimated 100 Ibs. of various feeds will 

 produce when fed in addition to a maintenance ration. Neither the 

 Kellner starch values and feeding standards nor the Fraps productive 

 values are given here in detail, but instead Armsby 's recently revised 

 tables of net energy values and of feeding standards, which are chiefly 

 used in this country by those desiring to compute rations according to 

 the net energy system. 



V. THE ARMSBY ENERGY VALUES AND FEEDING STANDARDS 



171. The Armsby energy values. With the first and only respiration 

 calorimeter used in the study of farm animals in America, Armsby 

 determined at the Pennsylvania Station 9 the net energy values for 



T Eckles, Mo. Res. Bui. 7; Woods, Jour. Agr. Sci., 5, 1914, p. 248. 

 8 Tex. Buls. 185, 203. 



U. S. Dept. Agr., Bur. Anim. Indus., Buls. 51, 74, 101; Farmers' Bui. 34(5; Dept. 

 Bui. 459; The Nutrition of Farm Animals, 1917. 



