FEEDS AND FEEDING 121 



The available energy is the fuel value of any food after deducting the 

 losses due to the evacuation of undigested food, the fermentations of 

 foods, the excretion of urea and other protein bodies. Besides the energy 

 yielding foods, there are a few substances like the vitamines which in 

 minutely small quantities are necessary for the maintenance of health 

 besides certain mineral substances, such as those which control the life 

 processes. 



As a result of the knowledge of feeds and feeding given above, scien- 

 tists have drawn up tables showing the amount of each class of nutrients, 

 which are known as the feeding standards. Thus, Haecker of the Min- 

 nesota Station found that the i,ooo-lb. dry, barren cow can be maintained 

 on 0.6 Ib. of crude protein, 6 Ibs. of carbohydrates and o.i Ib. of fat, all 

 digestible. A i,ooo-lb. milk-producing cow should be allowed 0.7 Ib. of 

 crude protein, 7 Ibs. of carbohydrates and o.i Ib. of fat, all digestible. 

 These feeding standards are at variance with the Wolff-Lehmann feeding 

 standards where a cow yielding 22 Ibs. of milk requires 29 Ibs. of dry 

 matter, 2.5 Ibs. of protein, 13 Ibs. of carbohydrates, 0.5 Ib. of fat. The 

 nutritive ratio is 1 15. 7. A horse at medium work, according to the Wolff- 

 Lehmann feeding standard requires 24 Ibs. of dry matter, 20. Ibs. of crude 

 protein, n Ibs. of carbohydrates, 0.6 Ib. of fat with the nutritive ratio i :6.2. 



. BIBLIOGRAPHY 



ALLEN, E. W. : The Feeding of Farm Animals. Farmers' Bulletin 22, U. S. Department 



of Agriculture, 1895. 

 ARMSBY, HENRY P.: The Maintenance of Rations of Farm Animals. Bulletin 143, 



Bureau of Animal Industry, 1912. 

 GARDNER, FRANK D. WITH COLLABORATORS: Successful Farming. Ready Reference 



on all Phases of Agriculture for Farmers of the United States and Canada. The 



John C. Winston Company, Philadelphia, 1916, pages 562-572. 

 HALL, A. D.: The Book of Rothamsted Experiments. E. P. Dutton and Company, 



New York, 1905, pages 240-259. 

 HENRY, W. A. and MORRISON, F. B. : Feeds and Feeding. A Handbook for the Student 



and the Stockman. The Henry-Morrison Company, Madison, Wisconsin, 



Fifteenth Edition, 1915. 

 LUSK, GRAHAM: Science of Nutrition. W. B. Saunders Company, 3d edition, 1918. 



LABORATORY WORK 



The laboratory period corresponding to this lesson may be devoted to an oral or a 

 written test, which should be given occasionally as a matter of review and to try out 

 the proficiency of the different members of the class. 



