FEEDING STANDARDS— CALCULATING RATIONS 



85 



sented later in this chapter. The Wolff-Lehmann standards are, how- 

 ever, briefly explained first on account of their historical and founda- 

 tional importance. 



The Wolff-Lehmann standards are given in full in Appendix 

 Table IV. From this the following examples are taken for purposes of 

 study : 



Digestible nutrients required daily per 1,000 lbs. live ireight 



The table shows that according to the Wolff-Lehmann standards a 

 1,000-lb. ox at rest, neither gaining nor losing in weight, requires 

 for 1 day's maintenance 18 lbs. of dry matter containing the follow- 

 ing digestible nutrients: 0.7 lb. crude protein, 8.0 lbs. carbohydrates, 

 and 0.1 lb. fat, with a nutritive ratio of 1 :11.8. When the animal is 

 growing, fattening, giving milk, or doing external work, a larger 

 quantity of nutrients must be supplied than for maintenance, as the 

 table shows. 



Careful experiments carried on since the Wolff-Lehmann standards 

 were proposed have conclusively shown that dairy cows, work horses, 

 and fattening cattle, sheep, and pigs all need considerably less crude 

 protein than is recommended in these standard. As protein-rich feeds 

 are usually the highest in price over much of our country, following 

 these standards is frequently decidedly uneconomical. The authors 

 have therefore drawn up the "Modified Wolff-Lehmann standards," 

 which are discussed later in this chapter and given in Appendix 

 Table V. As these are based upon the many feeding trials carried 

 on in recent years, they furnish more accurate information on the 

 requirements of farm animals than the original standards. 



Altho it is advisable in the actual feeding of stock to follow one of 

 the more recent feeding standards described later in this chapter, both 

 students and stockmen should, first of all, familiarize themselves with 

 the Wolff-Lehmann standards because of their historical interest and 

 the great help they have been to animal husbandry in the past. Hav- 

 ing considered the Wolff-Lehmann standards, one is prepared for the 

 study of other more accurate standards now in the process of formation. 



