INTRODUCTORY. 13 



ing for the food they eat. It is all consumed in sustaining 

 the vital functions. 



A well-bred Shorthorn has been made to weigh 1,200 

 Ibs. by the time it was a year old. On the other hand, an 

 ox is sometimes kept five years before it attains this 

 weight. The Shorthorn was fed a considerable amount 

 of food over and above that required to sustain life, while 

 the other had little more than was necessary for this pur- 

 pose. Let us assume that the latter ate 4 tons of hay a 

 year, and that 80 per cent of it was used merely to sus- 

 tain life. At the end of five years he would have con- 

 sumed 20 tons of hay, 16 tons of which have been used 

 merely to sustain the vital functions, and' 4 tons have been 

 converted into 1,200 Ibs. of animal matter. 



The Shorthorn accomplished the same result in one 

 year; and we may reasonably suppose that in this case 

 also, 4 tons of hay or its equivalent, were sufficient to fur- 

 nish the material necessary for the formation of this 

 amount of animal growth. We may further assume that 

 at any rate no more food was required to sustain the vital 

 functions in the Shorthorn than was required by the other 

 animal. This we have estimated at 3 tons 4 cwt. a year. 

 It follows, therefore, that the Shorthorn, by eating 7 tons 

 4 cwt. of hay or its equivalent, in a single year was ena- 

 bled to produce as much beef as the other steer produced 

 by the consumption of 4 tons a year for five years. The 

 consumption of less than twice as much food enabled the 

 Shorthorn to increase five times as rapidly as the other. 

 Seven tons 4 cwt. of hay, or its equivalent, produced as 

 much growth (and probably more beef and fat), when fed 

 to the animal capable of eating and assimilating it. 



These considerations will show why a pig, that can eat 

 so much more food than a sheep or an ox, in proportion 

 to size, is enabled to grow so much faster, in proportion to 

 the food consumed. 



The fact that the pig has greater powers of assimilating 



