CHAPTER IV 



FEEDING STANDARDS AND THE EFFECT OF DIFFERENT 

 NUTRIENTS 



Measuring Feed Values for Animals. The usefulness 

 of different feeds for animals is measured by determining 

 the per cent of total crude protein, nitrogen free extract, 

 fiber, and fat digested by the animals. Feeding tests have 

 been made, and quite complete feeding standards have 

 been prepared for animals to determine the amount of 

 digestible nutrients required to maintain the life processes 

 and in addition to provide for work, for the production 

 of milk, for growth and for fattening. The first feeding 

 standard was based on total rather than digestible nu- 

 trients and was proposed in 1859, and the first complete 

 standard based on digestible nutrients was proposed by 

 Dr. Wolff in 1864 which resulted later in the Wolff- 

 Lehman feeding standards. 



Numerous feeding experiments conducted since that 

 time have led to the use of several other standards which 

 are more accurate. Experiments with a respiration ap- 

 paratus and calorimeter by Kellner and Zuntz and also by 

 Armsby show that the energy required in eating and di- 

 gesting feed must be subtracted from the total available 

 digestible energy to secure the true net value of the feed. 

 These tables show the amount of total dry matter, diges- 



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