FEEDING STANDARDS: ORIGIN AND USE 87 



of feeds. His studies resulted in what are now known as 

 The Wolff feeding standards for farm animals. Two 

 things were shown by this great scientist. One was the 

 digestibility of the nutrients in different feeding stuffs, and 

 the other was the amount of each of these required by farm 

 animals under certain conditions. Wolff found that ani- 

 mals that were doing no labor, that were not being fattened, 

 neither gaining nor losing in weight, required only sufficient 

 food to keep the body and the internal organs healthy and 

 vigorous. Such an animal required what he called a main- 

 tenance ration. A young animal needed a growing ration, 

 and cattle intended for meat required a fattening ration. 

 A cow producing a large amount of milk must be fed, first 

 to supply the ordinary needs of the body, such as might be 

 found in a maintenance ration, and, besides this, she must be 

 fed still more to enable her to produce the milk of which the 

 food is the source. The dry cow may be satisfied on a 

 maintenance ration consisting of some form of roughage only, 

 such as clover hay, for example; but, if she is yielding a 

 good supply of milk, then rich concentrates must be fed, if 

 the increased demands of milk production are to be met. 



The standards of Wolff were not entirely satisfactory to 

 the Germans, so in 1896 Dr. Lehmann, of the Berlin Agri- 

 cultural High School, introduced some improvements which 

 became known as the Wolff-Lehmann Feeding Standards. 



Since Wolff first made known this most important dis- 

 covery, many other chemists have experimented in the same 

 field. Both European and American agricultural chemists 

 have extensively studied the science of feeding, so that now 

 we know much more than did the student or farmer in the 

 days of Wolff. Animals have been carefully studied, and 

 the invention of the respiration calorimeter has resulted in 

 some wonderful investigations in the fields of chemistry and 

 animal nutrition. The work of Wolff was that of a pioneer. 

 For many years Americans relied on analyses of German 



