gums, etc.) The latter two (crude fiber and nitrogen-free extract) 

 are often called carbohydrates. In compounding rations, protein, 

 carbohydrates and fat are the main nutrients to be considered. 



The main function of protein is to form flesh. It may under some 

 circumstances form fat, produce heat and furnish material for energy 

 production. It seems to be a milk stimulant. The functions of the car- 

 bohydrates and fat are to produce heat, muscular energy, body, and, 

 perhaps milk fat, and to protect ths protein from over-consumption. 



The digestibility of food is variously affected by sundry conditions 

 of the animal and its feed. The several nutrients are assimilated in 

 quite different proportions when in different combinations. The deter- 

 mination of these proportions is the aim of digestion experiments- — 

 Pages 5-14. 



III. Feeding standards. These are of three sorts, the physiological, 

 the practicable and the average standards. The first are not absolute 

 rules but average estimates based on the present knowledge of the 

 physiological needs of farm stock. They consider maximum yield only. 

 The second are variables, take cognizance of costs of raw material and 

 of product, and are the result of the experience, observation and study 

 of the individual feeder. The third are simply the expression of aver- 

 age feeling practice, apart from considerations of adaptation or profit. 



The standards are many in number and have been proposed by 

 sundry German and American investigators. They are useful as 

 guides rather than as rules. Any standard is better than none Choice 

 will vary in accordance with sundry considerations. They may be 

 made use of in calculating a ration or in planning a season's feeding 

 campaign— Pages 14-29. 



IV. Sundry economic considerations. A classification of the more 

 common roughages and concentrates aids in indicating their values in 

 ration making. In making sales and purchases the main point to bear 

 in mind is to sell so far as practicable carbon, hydrogen and oxygen, 

 air-given elements, and to buy nitrogen, phosphoric acid and potash, 

 soil-derived ingredients readily lost through cropping. A second 

 point hardly less important is to make one's farm a carbohydrate fac- 

 tory and to seek supplementary protein at the feed store. 



While the exact expression of the money values of sundry grain 

 feeds on any common basis is impossible, an approximation to such 

 an expression may be made. The results are not absolute and have on 

 the whole a somewhat doubtful value. The percentage of digestible 

 protein is the primal consideration in dairy feeding. Pages 29-37 . 



V. Appendix contains a glossary and tables showing the sundry 

 standards, the composition and digestible ingredients of the several 

 fodders and feeds fed in New England and a convenience table which 

 simplifies the mathematics of calculating a ration.— Pages 37-56. 



