Feeding Standards. 233 



and wheat bran. However, when cooking or steaming the feed 

 renders it more palatable, and secures a larger consumption of 

 material which otherwise would be wasted, the influence on di- 

 gestibility is of less importance. 



Grinding increases the digestibility of feeds. Mechanical divi- 

 sion is an important factor in the rate and completeness of solu- 

 tion of material in the digestive tract. A single experiment with 

 corn, fed to the horse, showed about 7 per cent increased digesti- 

 bility from grinding, and with wheat, in one trial the increase 

 was 10 per cent. With ruminants, the danger from imperfect 

 mastication is less than with horses and swine. Whether it will 

 pay to grind the grain will depend upon the cost of grinding 

 and the loss of nutritive material from not grinding. 



Influence of one. feed on the digestibility of another. It is 

 generally stated that the addition of a considerable quantity of 

 protein to a ration of hay and straw consumed by a ruminant, 

 is completely digested, without affecting the digestibility of the 

 original feed. Pigs have been fed potatoes to which variable 

 quantities of meat flour were added. The proteins of the meat 

 were completely digested, while the proportion of potatoes di- 

 gested remained unchanged. 



It is also claimed that the addition of fat or oil to a basal 

 ration of hay and straw was without influence on their digesti- 

 bility. 



On the contrary, Dietrich and Koenig state that if a carbo- 

 hydrate, as starch or sugar, is added to the extent of more than 

 10 per cent of the dry substance of a basal ration, or if roots or 

 potatoes, equivalent in dry matter to more than 15 per cent, are 

 fed, a diminution of digestibility occurs. It is further stated 

 that the depression of digestibility is reduced, when, accompany- 

 ing the high starch intake, there is a corresponding increase in 

 protein consumption. Prom these considerations, it is stated 

 that highly nitrogenous feeds may be given with hay and straw 

 without affecting their digestibility; but feeds rich in carbohyd- 



