CHAPTER XVIII 



THE COMPUTATION OF RATIONS 



i. FEEDING STANDARDS 



790. Origin. As the hay values described in Chapter XVI 

 (700) gradually gave place to new methods of comparing the 

 values of feeding stuffs based upon improved methods of chemi- 

 cal analysis and upon investigations into the general laws of 

 nutrition, an attempt naturally followed to express the nutritive 

 requirements of animals in a similar manner instead of in terms 

 of gross weight of feed or of hay values. Thus originated the 

 feeding standards for different species of farm animals which 

 later came to be popularly regarded more or less in the light of 

 prescriptions or recipes for successful feeding. 



791. Early standards. The earliest suggestion along this 

 line seems to have originated with Haubner J about 1840. 

 Lingethal, 1 in 1857, amplified the suggestion, but Grouven 2 in 

 1858 was the first to formulate specifically the requirements 

 of farm animals, expressing them in terms of dry matter, 

 total protein, total fat (ether extract), and " carbohydrates " 

 (total material soluble in acids and alkalies). In other words, 

 the crude nutrients were the basis of Grouven's standards. 



Wolff took the next step in advance by making the digestible 

 nutrients as determined by the methods of Henneberg and 

 Stohmann (707-710) the basis for comparisons of feeding stuffs 

 and for expressing feed requirements. His feeding standards 

 were first published in 1864 in Mentzel and von Lengerke's 

 Landwirtschaf tlicher Kalender and were also incorporated in his 

 widely read book, Die landwirtschaftliche Fiitterungslehre, in 

 1874. These standards attempted to formulate the amounts 

 of digestible protein, carbohydrates and fats which should be 



Quoted by Grouven ; Kritische Darstellung aller Fiitterungs-Versuche. Kas- 

 sel, 1863, p. 327. 



2 Vortrage iiber Agricultur-Chemie, 1858. 

 2 Y 689 



