138 AGRICULTURE. 



not alone upon the food, but upon the breed, 

 individuality, and condition of the animal fed. 



These standards are excellent as a basis for 

 feeding and for comparison. No stockman 

 should omit the results of his own experience — 

 if he has kept an accurate record of feeds and 

 their results — as an element in deciding upon a 

 suitable ration for different animals at different 

 stages of development or different requirements 

 of work. 



4. Nutritive Ratio. — The ratio between the 

 protein and the heat-producing elements (car- 

 bohydrates and ether extracts) for any kind of 

 food, or combination of foods, is called the nu- 

 tritive ratio. For example, in the daily food 

 required — 20 pounds dry matter — for a horse 

 doing light work, the amount of digestible pro- 

 tein is 1.5 pounds; carbohydrates, 9.5 pounds; 

 ether extract, .4 pounds. Multiplying the num- 

 ber of pounds of ether extract, .4, by 2.4, or its 

 heat value, the result is .96 pounds ; this, plus 

 the carbohydrates, 9.5 pounds, is equal to 10.46 

 pounds. Dividing the 10.46 pounds of heat- 

 producing elements by the number of pounds of 

 protein, 1.5, the result is 7:; therefore, the nu- 

 tritive ratio of this food is 1:7. 



Exercise 6. — (<?) What is llie nuiriiive ratio of a food 

 containing .7 pounds of protein, 8 pounds of carbohy- 

 drates, and .1 pound ether exti'acl ? 



{b') If the nutritive ratio of a food is 1:7.7, ^^d tlie 



