88 



A STUDY OF FARM ANIMALS 



feeds, and made use of the standards that came to us from 

 Europe. To-day we are able to use a table of digestible 

 nutrients which is based on the composition of American 

 feeds as studied by chemists of our own country. The Wolff 

 standards as improved by Lehmann were introduced to 

 America and for some years had extensive use. Wolff used 

 1,000 pounds as the standard of weight for animals, and 

 assumed that a certain amount of dry matter, and of digesti- 

 ble protein, carbohydrates, and fat, were needed for that 

 weight under given conditions. The animals were classified 

 in groups, as oxen, fattening cattle, milch cows, sheep, horses, 

 etc. Then those in a group were classified according to their 

 purpose; as, for example, horses into light, medium, and heavy 

 work; and dairy cows in four classes, according to the amount 

 of milk made per day. The following figures, taken from 

 the Wolff-Lehmann feeding standard, illustrate its arrange- 

 ment: 



Pounds required daily for each 1,000 Ibs. live weight. 



This table means, for instance, that a horse at light work 

 weighing 1,000 pounds requires 20 pounds of dry matter 

 daily, containing 1^ pound of protein, 9J/2 pounds of carbo- 

 hydrates, and 0.4 pound of fat, the ration having a nutritive 

 ratio of 1:7. These exact standards of daily require- 

 ments did not stand the test in American feeding operations, 

 and our scientists sought to improve them. As a result of 

 the studies of Professors W. A. Henry and F. B. Morrison, 

 of Wisconsin University, new standards were introduced. 



Modified Wolff-Lehmann standards. These investiga- 

 tors recognized "that feeding standards are but approxima- 



