14 



CANADIAN FARM YEAR BOOK. 



pound of protein equals 1,860 cal- 

 ories, 1 pound of fat 4,220 calories, 

 and 1 pound of carbohydrates 1,860 

 calories. 



Nutritive Ratio. 



The relation existing between the 

 nitrogenous and nitrogen-free nutri- 

 ents in the ration is termed the nutri- 

 tive, or nutrient ratio. In calculat- 

 ing this ratio it is necessary to arrive 

 at a factor which will represent the 

 total value of the fat and the carbo- 

 hydrates. As will be seen by refer- 

 ence to the preceding values for the 

 production of energy, fat has a value 

 which is 2.25 times as great as an 

 equal weight of carbohydrates. So 

 that the nutritive ratio is actually 

 the relationship existing between the 

 protein in the ration and a factor 

 obtained by multiplying the fat by 

 2.25 and adding to the carbohydrates. 

 The nutritive ratio may be concisely 

 stated as follows: Protein (fat x 2.25 

 plus carbohydrates.) 



As has been seated, one of the 

 chief functions of food was to supply 

 material to build and repair the 

 body. The different constituents of 

 which feeding stuffs are composed 

 differ in their ability to serve this 

 purpose. All the organs and tissues 

 jf the body contain nitrogen. Pro- 

 tein is the only nutrient which sup- 

 plies this element, and is therefore 

 essential in building up and restoring 

 body tissues. It Is plain, therefore, 

 that the demands of the animal for 

 material with which to renew the 

 tissues of the body and to provide for 

 growth of the different parts, must be 

 satisfied by the protein contained In 

 the ration. 



Heat and Energy. 



The heat and energy which is re- 

 quired in the animal body may be 

 supplied by any one of the three con- 

 stituents — protein, fat or carbo- 

 hydrates. If the cost of raising or 

 procuring protein was about the same 

 as It is for carbohydrates, it would 

 be of little Importance to do more 

 then assure a sufficient supply of this 



ingredient. If the ration contained 

 decidedly more protein than was ne- 

 cessary, the feeder would not be In- 

 curring any loss, for this substance 

 is able to supply all of the require- 

 ments of the body which may be sup- 

 plied by carbohydrates or fats. But 

 at the present time protein is very 

 considerably dearer than carbohy- 

 drates. Foods rich In protein always 

 command the highest prices. It is 

 essential, therefore, to be as economi- 

 cal as possible in the use of this nu- 

 trient, and to limit the quantity as 

 far as practicable. It thus becomes 

 necessary to find what this limit is 

 for the different species of animals, 

 and for the different conditions under 

 which they may be keptf Large num- 

 bers of feeding experiments have been 

 made under varying conditions with 

 this end in view. From the results, 

 feeding standards have been worked 

 out, which show the amount of di- 

 gestible protein, fat, and carbohy- 

 drates supposed to be best adapted 

 to different animals when kept for 

 different purposes. 



Since certain of the nutrients can 

 replace one another, it often trans- 

 pires that the physiological standard 

 does not correspond with the stand- 

 ard for most economical production 

 in a given locality. This applies more 

 especially to the protein, which is the 

 most expensive nutrient; but, as a 

 matter of fact, it has often been 

 found in practical experience, that 

 production has been increased and 

 cheapened by making the rations con- 

 form more nearly to those suggested 

 by the physiological standard. 



To Balance a Ration. 



After reading the paragraph on 

 "Nutritive Ratio," and with a definite 

 understanding of the value of sucn 

 take an inventory of the feeds at your 

 disposal and then read the paragraph 

 in this chapter on "Selection of Feed- 

 ing Stuffs." Now say that you wish 

 to balance a ration for a steer. In 

 the table on feeding standards we 

 find the total dry matter to be about 

 30 lbs., protein 2.5 lbs., carbohydrates 

 16.0 lbs., fat .5 lbs. Now turn to your 

 feeding and computation table and 



