202 BEEF PRODUCTION 



right proportion. While the ration, as in this case, may 

 possess sufficient digestible nutrients in proper propor- 

 tion, it may still need revision on account of a lack of 

 palatability, or the proportion of roughage to concen- 

 trates may be too large. For the more advanced stages 

 of fattening, this ration should be revised, so that less 

 roughage and more concentrates are used. 



1 The "Nutritive Ratio'.' of a food-stuff or a ration is 

 the relation that exists between the quantity of digestible 

 protein and the quantity of digestible carbohydrates and 

 fat which it contains. Thus, if 100 pounds of brewer's 

 grains contain 15 pounds of digestible protein and 45 

 pounds of digestible carbohydrates and fat, the nutri- 

 tive ratio is expressed thus: 



Protein is to Carbohydrates and Fat as 15 is to 45, 

 or, Protein is to Carbohydrates and Fat as 1 is to 3. 



Or, written mathematically, Protein: Carbohydrates 

 + Fat : : 1 : 3. 



To find the nutritive ratio, then, of a feeding-stuff — 

 that is, to find how many pounds or what fraction of a 

 pound of digestible carbohydrates and fat it contains 

 for each pound of digestible protein — divide the sum of 

 its digestible fat X 214 and its digestible carbohydrates 

 by its digestible protein. The medium ratios lie between 

 1 part protein to 5y 2 parts carbohydrates and fat 

 (1 : 5.5) and 1 part protein to 8 parts carbohydrates 

 and fat (1:8.0). If the carbohydrates largely predom- 

 inate, the ratio is said to be wide ; if the proportion of 

 protein is above the medium, the ratio is said to be 

 narrow. Thus, timothy hay, with a nutritive ratio of 

 1:16.6, makes a wide ration; vetch hay (1:3.2), a 

 narrow one. 



Narrow Nutritive Ratio. — The following common and 

 commercial food-stuffs are relatively high in digestible 

 protein and low in digestible carbohydrates: 



Concentrates. — Wheat bran, linseed oil meal, wheat 



1 By the author, in " Practical Farming and Gardening." Rand. 

 McNally A Co., Chicago. 



