86 A STUDY OF FARM ANIMALS 



In this 91.4 pounds, of the digestiljle material of use to an 

 animal, we find 10.6 pounds of protein, 39 pounds of car- 

 bohydrates, and nine tenths of a pound of fat. The nutritive 

 ratio is also 1:3.9. Let us now look further and learn how 

 such figures have a practical value to the feeder of animals. 



The kind and amount of food required by an animal very 

 naturally depend on the class to which it Ijelongs, its age, 

 and use. No one would expect to feed a calf the same as a 

 horse, or a sheep like a milch cow. Each must be fed so as 

 to supply its needs as completely as possible. As might be 

 expected, scientists were a long time getting the necessary 

 information to enable men to understand how to feed so as 

 to get the best results. 



What we know as feeding standards in the beginning 

 were very simple and did not have an3' real value. The 

 working out of useful standards began in Germany, and 

 German chemists have done more than any one else to furnish 

 us knowledge on this subject. The first plan attempted was 

 to give meadow hay a fixed value, and then measure up other 

 feeds with that as the standard. That plan originated about 

 1810. Some fifty years later, another German chemist sug- 

 gested that animals l)e fed special amounts of protein, car- 

 bohydrates, and fat, according to certain conditions. His 

 plan was not good, however, because he did not take into 

 account the digestibility of the food. He was able to analyze 

 a food, but he knew nothing of how much of each nutrient 

 the animal digested. At that time there was considerable 

 information of the chemical composition of feeding stuffs, 

 but the digestibihty of the foods had not been figured out. 

 Then about 1864, another German chemist, by the name of 

 Wolff, proposed that animals be fed daily certain amounts of 

 digestible protein, carbohydrates, and fat, such as were actu- 

 ally required by the animals. Wolff was able to make this 

 proposal because he had conducted many feeding tests with 

 different animals, and had learned much of the digestibility 



