FEEDING OF FARM STOCK. 191 



for each pound of digestible protein. The reason for mul- 

 tiplying the fat by 2.25 is because it has two and a quarter 

 times the fuel value of the carbohydrates and before add- 

 ing must be brought to a carbohydrate basis. For example, 

 let us find the nutritive ratio of clover hay, which has been 

 found to contain 6.8 per cent, digestible protein, 35.8 per 

 cent, digestible carbohydrates, and 1.7 per cent, digestible 

 fat. 



1.7 X 2.25= 3.82 The nutritive ratio of clover hay 



3.82+35.9 =39.72 then is 1 to 5.8, the protein being 



39.72-r- 6.8 = 5.8 expressed as 1. 



When the proportion of carbohydrates and fat to the 

 protein is large, the ration is said to be "wide," and when 

 it is small the ration is "narrow." Timothy hay, for ex- 

 ample, has a ratio of 1 to 16.7, which is wide; gluten feed 

 has a ratio of 1 to 2.6, which is narrow; while clover hay 

 has a ratio of 1 to 5.8, which is medium. The feeds or 

 rations with a narrow nutritive ratio are as a rule more 

 expensive than those with a wide one, because protein or 

 nitrogen, whether purchased as a feed, a fertilizer or as 

 beef steak, always commands a high price. 



FEEDING STANDARDS. 



Besides having the results of the chemical analyses of 

 feeds and the digestion experiments, we have also the deter- 

 minations which actual feeding trials have given regarding 

 the amount of protein, carbohydrates and fat which the 

 different classes of animals require under various condi- 

 tions. An expression of these amounts constitutes what is 

 called a "feeding standard," and is to be used as a guide 

 in computing the rations and their nutritive ratio for ani- 

 mals doing a certain amount of work. These standards are 

 merely the results of experiments and practical experience 

 condensed into a brief statenient of what in general, and 

 under average conditions, constitutes a good ration for the 

 purpose in view. They may not be absolutely exact and 

 reliable for each individual animal, neither may they be 



