576 ANNUAL REPORT! OF THE Off. Doc. 



tuiH's, Jiiul lowt'i' prices than are fixed for liij^li-grade products, to 

 oucourage their wide use. There may be, aud undoubtedly are, 

 conditions where the use of tliese mixed products wouhl be desirabh', 

 as, for example, where farmers do not have a considerable quantity 

 of bulky material, and where the necessity is for bulk, as well as for 

 actual nutrition. On most dairy farms, and also upon grain farms, 

 there is usually an abundance of material of this sort, and for 

 these farmers the purchase of oat feeds cannot be regarded as 

 economical in any particular. In many cases, more or less of the 

 concentrated feeds, as cottonseed meal, linseed meals, gluten meals, 

 etc., have been added to the oat hulls, in order to increase the pro- 

 tein content, and consequent nutritive value, and that some returns 

 may be obtained in their use. 



These various feeds naturally fall into two general groups, one 

 in which the protein is the chief constituent, and the other in whicli 

 the carbohydrates are largely in excess, or into protein and carbo- 

 hydrate feeds. In the case of the protein feeds, there is a wide 

 range in the amount of this substance which may be obtained for 

 a given sum from the different groups, malving it a matter of the 

 very greatest importance for the farmer to ascertain the character 

 of the feed that he desires, and that he should carefully study the 

 relation between che content of nutrients and the selling price. 



The carbohydrate group includes many of the oat feeds, and feeds 

 prepared from refuse waste products, and wliile there is not so 

 great a variation in the content of carbohydrates or in the content 

 of protein as in the other class, they as a rule supply the farmer with 

 this substance, which he already has in excess, and their purchase 

 cannot be regarded as economical. 



Investigations as to the functions of the various groups of nu- 

 trients, protein, fat and carbohydrates, have clearly established cer- 

 tain general principles, among w^hich is, that of all of the groups of 

 substances protein is the most important, because it is the only one 

 from wliich the protein substances of the body may be derived, and 

 because it may also contribute to the building up of the body in 

 fat. It must, therefore, exist in all rations, whether fed for main- 

 tenance only, or for increase of animal product, and the amount of 

 protein in reference to other substances exerts an important infiu 

 ence upon the production of animal product, whether of meat, milk 

 or fat. Investigations, however, have not yet clearly indicated the 

 exact relation that protein must sustain to the other substances in 

 the rations, though that it shall be in greater excess in those rations 

 intended for the building up of animal product than for those for 

 simple maintenance, has been clearly indicated. 



Studies of the composition of the ordinary home-grown products, 

 for example, the cereal grains, have also made clear the fact that 

 they are as a rule deficient in protein. Hence in the preparation of 

 rations for dairy cows, for young stock, and for the making of beef or 

 mutton, the purchase of feeds resolves itself into a purchase of 

 protein, provided economy in the use of nutrients is desired. It 

 must not be understood, however, that economy in the use of 

 nutrients is identical with economy in feeding, as it may very fre- 

 quently happen that economy in the use of nutrients may not be 

 economical feeding; conditions may be such that the feeder can 



