120 PRINCIPLES OF FEEDING FARM ANIMALS 



and they may vary considerably. If an animal is fed a 

 light ration for a considerable period of time, it is probable 

 that its requirements are lessened. It is a matter of com- 

 mon-observation that a quiet, lazy animal requires less 

 feed than a nervous, energetic one, and that animals do 

 better in certain kinds of weather than in other kinds. In 

 the third place, there are characteristics of feeds other than 

 their chemical composition and energy values which must 

 be considered in formulating rations. Theoretically, one 

 might satisfy the requirements of a feeding standard by 

 using feeds which in actual practice would not give satis- 

 factory results. In the fourth place, individual feeds often 

 vary considerably from the average chemical composition and 

 energy value as given for that feed in the generally accepted 

 tables. Consequently, then, one must not look upon the 

 feeding standard as a hard and fast rule to be followed at 

 all times, but only as a guide to be adapted to varying condi- 

 tions and to be used in connection with one's practical knowl- 

 edge of the amounts, proportions, and combinations of 

 feeds which are used in stockfeecUng. Although a knowl- 

 edge of feeding standards is not essential to being a suc- 

 cessful feeder of live stock, yet such a knowledge enables the 

 inexperienced stockfeeder to learn the art more quickly, at 

 less expense, and more thoroughly than when he depends 

 upon experience as his only teacher. There have been a 

 large number of feeding standards proposed, all of them 

 having more or less value. The most important of these 

 will be taken up and discussed. 



The Wolff-Lehmann Standard. — Probably the best 

 known and most widely used standards, at least until re- 

 cently, are the Wolff-Lehmann standards given in Table 



