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is evident, therefore, that if it be possible to determine just how 

 much of each of the three remaining classes of nutrients protein, 

 carbohydrates, and fat is needed, and if it be known how much of 

 each the various feeding stuffs contain, it will not be a difficult 

 matter to compute the ration. 



Meaning of 'Ration' 



By ' Ration ' is meant (1) the total amount of food of all kinds 

 fed to an animal in each or any 24-hour or day-long period, and 

 (2) in a general way, the mixture of feeds being fed any given herd 

 or individual. 



Digestible Constituents. 



By the use of reagents, the chemist can determine the exact 

 percentage of any given substance in a food. The digestive organs 

 of the cow, while able to utilize or digest certain proportions of the 

 different substances, are seldom or never able to dissolve the whole 

 of any food or of any particular constituent, as protein, carbohydrates 

 or fat, contained in that food. 



By careful experimental work it has been possible to determine 

 just what percentage of any given substance in a food is digestible 

 by cattle. 



The quantity so digestible is called ' digestible protein,' 

 'digestible fat 7 or 'digestible carbohydrates/ as the case may be. 



Nutritive Ratio. 



The proportion existing between the digestible protein and the 

 sum of the digestible carbohydrates and the fat multiplied by 2 in 

 any particular feed or in any mixture of feeds, is known as the 

 nutritive ratio of the feed or of the mixture. Thus in the case of 

 wheat bran there is about 11 -9 pounds digestible protein to 47 -6 

 pounds of digestible carbohydrates plus fat x 2. If the number 

 47-6 be divided by 11 '9 it will be found to go 4 

 times. It is then said that the nutritive ration of wheat bran is 1 

 to 4. This is usually written : N.R. 1 : 4. 



A ration where the amount of carbohydrates and fat is large 

 in proportion to the amount of protein is said to have a 'wide' 

 nutritive ratio. A ration where the proportion was 1 of protein 



