CHEMISTRY OF THE FEEDING OF ANIMALS. IQl 



it requires about 2| parts of starch to form 1 of fat, it may be said 

 that at least 165 lbs. of the non-nitrogenous substance consumed 

 contributed pretty directly to the formation of the QQ lbs. of fat. 

 Lastly, in reference to the increase : of the 11 lbs. of mineral mat- 

 ter consumed, only about | lb. were stored up in the increase of 

 the animal. 



It is observed, then, that a comparatively small proportion of 

 either the nitrogenous substance or the mineral matter of the food, 

 is retained in the increase ; the manure, on the other hand, retains 

 a very large proportion of the former, and nearly the whole of the 

 latter. 



Of 100 parts of gross dry substance consumed, 1*7 parts of 

 nitrogenous substance, 15'7 of fat, and 0'2 of mineral matter — in 

 all 17 '6 parts — are stored up in the increase ; 14" 3 parts, consist- 

 ing of highly nitrogenous organic matter, and 2*4 parts of mineral 

 matter, making a total of 16'7 parts, are retained in the manure ; 

 and 65*7 parts, consisting chiefly of carbon, hydrogen and oxygen, 

 are lost by respiration, &c. Or, if we reckon the proportion of 

 each class of constituents consumed which is stored up in the in- 

 crease, the last column of the table shows that of 100 of nitro- 

 genous substance consumed, lo"5 parts; of 100 non-nitrogenous 

 substance consumed, 18'5 parts; and of 100 mineral matter con- 

 sumed, 7 '3 parts are retained in the increase. 



It will not be necessary to follow so closely the figures in the 

 table relating to the sheep and oxen. It will suffice to direct 

 attention to the chief differences of result obtained with the three 

 descriptions of animal. 



Whilst the pig required only 420 lbs., the sheep required 912 lbs., 

 and the oxen 1109 lbs. of dry substance in food to produce 100 

 lbs. increase in live weight. In other words, the sheep consumed 

 more than twice as much, and the oxen more than two and a half 

 times as much, to produce a given amount of increase, as the pig. 

 But the food of the pig was of a much higher character than that 

 of the other animals. Whilst it consisted entirely of highly 

 elaborated grain, closely resembling human food, the food of the 

 other animals contained a large amount both of woody fibre and of 

 crude succulent roots ; the dietary of the ox containing the larg- 

 est proportion of hay, with its high percentage of indigestible 

 woody matter. 



Turning to the columns giving the composition of 100 parts of 

 the increase, they show that whilst that of the pig contained 73'8 



