CONDITIONS INFLUENCING DIGESTION 129 



cooking feeding-stuffs by steaming or otherwise renders 

 them more palatable, and thereby makes possible the 

 consumption of material otherwise wasted, the influence 

 upon digestibility is a minor consideration. 



189. Influence of grinding foods. — ^Few points are 

 more frequently questioned than the profitableness of 

 grinding grain. There seem to be only two ways in which 

 such preparation can enhance the nutritive value of a 

 feeding-stuff, viz., by diminishing the energy needed for 

 the digestive processes and by increasing the digesti- 

 bility. While not many experiments bearing upon the 

 digestion side of this question are on record, their evi- 

 dence is quite emphatic. In three trials with horses, with 

 corn and oats, grinding caused an increase of digesti- 

 bility varying from 3.3 to 14 per cent. A single experi- 

 ment with maize kernels gave a greater digestibility of 

 about 7 per cent from grinding, and with wheat, in one 

 trial, the increase was 10 per cent. In one test with 

 sheep, the unground kernels were as completely utilized 

 as the ground. It is reasonable to expect that with 

 ruminants the danger of imperfect mastication is less 

 than with horses and swine, although whole kernels of 

 grain are often seen in the feces of bovines. The profita- 

 bleness of grinding grain tiu-ns, in part at least, upon the 

 relation of the cost of grinding to the loss of nutritive 

 material from not grinding. If the miller's toU amounts 

 to one-tenth the value of the grain the economy of grind- 

 ing it may be doubtful, especially with ruminants. The 

 utihzation of the undigested kernels of grain by pigs is a 

 business point to be considered. 



190. Effect of common salt. — It is the custom of 

 many feeders to allow their animals an unlimited supply 

 of salt, and others furnish it in definite and regular quan- 



