CHAPTER IV. 



ESTIMATION OF THE REAL NUTRITIVE VALUE 

 OF FOODSTUFFS. 



It may at once be stated that the market price of a 

 foodstuff is by no means a reliable index to its true 

 feeding value. This statement is even truer in relation 

 to the feeding of horses than in feeding cattle and sheep, 

 for the question of the manurial value of the residue of 

 the food does not concern the majority of horse owners. 

 It is necessary, then, to determine the criteria by which 

 to judge of the real value of any foodstuff in order to 

 compare its cost with that of other similar foods for 

 which it might be substituted. 



As we have seen, for nutritive purposes the important 

 constituents of a food are the proteins (albuminoids), 

 fats, and carbo-hydrates. Amides and the digestible part 

 of the crude fibre must also be considered nutritive in 

 a limited degree. For maintenance and repair of mus- 

 cular tissue proteins are indispensable, whilst for the 

 purposes of producing energy and work the other con- 

 stituents are all useful, but have widely different values. 

 Thus a chemical analysis to determine the amount 

 and proportion of these nutrient constituents is the first 

 requirement in estimating the value of any foodstuff 

 (see Table I., p. 22). 



Next it is necessary to know the comparative values 



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