CHAPTER VII 



FEEDING STANDARDS— CALCULATING RATIONS 



I. Early Feeding Standards 



To guide the farmer in selecting rations for his stock, scientists 

 have drawn up feeding standards. These are tables showing the 

 amounts of each class of nutrients which, it is believed, should be pro- 

 vided for farm animals of the various ages and classes for the best 

 results. 



Early feeding standards. — At the beginning of the last century 

 almost nothing was known about the chemistry of plants and animals, 

 and the farmer gave his stock hay and grain without knowing what 

 there was in this feed that nourished them. In 1859, when chemistry 

 had thrown some light on the composition of feeds, Grouven, in Ger- 

 many, proposed the first feeding standard for farm animals. This 

 was, however, very imperfect, for it was based not on the amount of 

 digestible nutrients required, but on the total crude protein, carbo- 

 hydrates, and fat in feeding stuffs. 



In 1864 Wolff, a famous German scientist, presented the first table 

 of feeding standards based on the digestible nutrients contained in 

 feeds. These set forth the amounts of digestible crude protein, carbo- 

 hydrates, and fat required daily by the different classes of farm 

 animals. The "Wolff standards were brought to the attention of 

 American farmers 10 years later and were further introduced by 

 Armsby's "Manual of Cattle Feeding," which appeared in 1880. 

 The value and importance of these standards were soon recognized 

 and with their adoption came the first wide-spread effort toward the 

 rational feeding of farm animals. In 1896 the Wolff standards were 

 modified by Lehmann, as scientific trials had then thrown further 

 light on stock feeding. 



The numerous feeding experiments which have been carried on since 

 the Wolff -Lehmann standards were presented have given us more com- 

 plete knowledge of the nutrients required by the various classes of farm 

 animals than was possessed by these pioneers in the field of animal 

 nutrition. Naturally such results show that these early standards 

 are in some respects inaccurate. Taking these facts into considera- 

 tion, later scientists have drawn up other standards which are pre- 



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