S<'IENTIFl(' SWINK FEEDlNc; 



241 



(Mght months of age seems to develop in the pig a factor of 

 waste which since it is more or less permanent becomes a 

 hindrance to a pig that is being grown and developed for breed- 

 ing purposes, because it checks its growth, brings it to early 

 maturity, makes the pig a less econom.ical feeder later, and 

 seems also to produce a tendency in the pig to transmit to its 

 offspring the same characteristics. 



In a certain experiment, a bunch of pigs fed a ration of corn 

 and water in a dry lot attained a live weight of approximately 

 80 pounds at eight months of age. This was owing to a de- 

 ficiency of both protein and mineral matter. In another ex- 



Fig. 6.3. — Protein requirement of breeding pigs. 



periment where mineral matter was supplied in the form of 

 charcoal, salt, air-slacked lime, bone meal, and hard wood 

 ashes, the pigs attained a live weight of 140 pounds. Pigs 

 that were fed a balanced ration attained a weight of 290 pounds 

 at eight months of age. Still another bunch, fed exactly as 

 those mentioned just preceding, except that they received more 

 protein, made only 170 pounds of total live weight at the same 

 age. They had an excess of protein. 



Illustration.— To illustrate further: Suppose a field of wheat 

 in the shock is to be threshed with a steam thresher and sheaves 

 of wheat are to be used with which to fire the engine. The 

 wheat used in the engine for fuel represents the feed used by 

 the pig for maintenance and energy for digesting and assimi- 

 lating its feed and for excreting w^aste products. The grain 

 that goes into the sack represents the gains made; the grain 

 that blows over, the waste; and the straw, the feces. When 

 the machine is run empty the wheat used as fuel in the engine 

 represents the actual quantity of feed used for maintenance. 



16 



