236 



Agricultural Chemistry. 

 For 1000 Pounds Live Weight Daily. 



In formulating standards for ruminants it is better to start 

 with two kinds of roughage, furnishing from 16 to 20 pounds of 

 dry matter, and about 10 pounds of carbohydrates (nitrogen 

 free-extract) , and then add concentrates, which will on first cal- 

 culation bring the total digestible protein somewhat under the 

 standard. The additional requirements can then be easily com- 

 puted. The term "fat" is identical with the "ether extract." 



It is not necessary that a ration agree mathematically in all 

 nutrients with the standard. To attempt to do this is to avoid 

 the individual possibilities of the animal. The tables of digestion 

 co-efficients and feeding standards are but averages and approx- 

 imations. They are not to be followed blindly and absolutely, 

 but if taken as guides, they can become extremely helpful. For 

 example, the Wolff standards are quantities to be fed per thou- 

 sand pounds of live weight. It is known that the food demands 

 of an organism are not proportional to its size, but rather to its 

 surface. This is because of a difference in demand on the heat 

 producing function of a food. A small animal has a propor- 

 tionately greater suface to its weight than a larger animal. Con- 

 sequently it does not require the same proportional amount of 

 digestible food to maintain a 1700 pound steer as one weighing 

 ] 000 pounds. For instance, Kuhn of the Mockern Station, found 

 that a 1900 pound ox could be maintained on 0.7 pound of di- 

 gestible protein and 6.6 pounds of digestible carbohydrates. 



