FOOD AND FEEDINa 685 



maehme, in so far do the proteids aid the work of the 

 machine by keeping it in good repair and workiug order. 

 From this point of view the proteids represent the mechan- 

 ism by which the work is done ; the carbohydrates the fuel 

 necessary for its performance. It must be kept in mind 

 that this is but a general statement, since muscular work is 

 also done by protein, and may be wholly done by it, as 

 shown by dogs living on lean meat. The exact relative 

 value of carbohydrates and proteids in the production of the 

 vital forces is still subjudice. 



The classes of food stuffs for the larger animals em- 

 brace both green and dry fodder, consisting of the whole 

 plant minus the roots ; parts from which the more valuable 

 portions have been removed, as straw; tubers and roots 

 containing a large percentage of water ; the seeds or grains, 

 constituting the most concentrated food ; and the seed 

 coverings or chaff. 



Bef use and bye-products of manufacture are extensively 

 used, as bran, cottonseed meal, linseed meal, and brewers' 

 grains. In addition, animal matter, as flesh meal, bone 

 meal, and dried blood, are sometimes of value. Pasture 

 grass may be taken as a standard of comparison for green 

 fodders. In 100 lbs. of grass there are approximately 

 digestible : 



Protein 1.04 lbs. 



Fat 0.5 " 



Carbohydrates.... 10.34 " 



Green clover contains considerably more, green rye 

 slightly more, and green oats somewhat less protein ; while 

 in green corn fodder there is only about half as much pro- 

 iein. Roots, as compared with green pasture grass, possess 

 only one-third the quantity of protein and solids. Potatoes, 

 however, have double the nutritive value of roots. Com- 

 parison is made in reference to protein, as that is by far the 

 most valuable nutrient, and the amount of carbohydrates 

 and fat do not vary much in similar kinds of fodder. 



Meadow hay, including such common varieties as timo- 

 thy and red top, may be taken as a standard of comparison 



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