JOmAL OF ACRiaiTIIAL RESEARCH 



Voiv. XXII Washington, D. C, October 15, 192 1 No. 3 



INFLUENCE OF THE PLANE OF NUTRITION ON THE 

 MAINTENANCE REQUIREMENT OF CATTLE' 



By F. B. MuMPORD, Dean of the College of Agriculture, A. G. Hogan, of the Depart- 

 ment of Animal Husbandry, and W. D. Salmon, Graduate Student in Animal Hus- 

 bandry, College of Agriculture, University of Missouri. 



In 19 1 4 an investigation was begun at the University of Missouri to 

 study some of the effects of underfeeding. Calves of beef-breeding 

 stock were secured, and they were placed on three planes of nutrition. 

 Group I was fed to grow rapidly, but not to become fat. Group II was 

 placed on a lower nutritive plane and was fed to gain about }4 pound per 

 day. Group III was placed on a still lower nutritive plane and fed to 

 gain about V3' pound per day. At the present time three animals remain 

 that were started on the investigation in 19 14. Seven others were added 

 in 191 7. The older animals, therefore, have been under observation for 

 seven years and the younger animals for four years. Under these cir- 

 cumstances it seemed desirable to make a study of the maintenance 

 requirement of steers at different ages and on different planes of nutrition.^ 



The ideal method of conducting an investigation of this kind would 

 require a respiration calorimeter. Since that was impossible, the alter- 

 native was to calculate the energy value of the feed consumed and cor- 

 rect this for the estimated value of the gains or losses in body weight. 



The net energy of the feed consumed was calculated in accordance 

 with procedures developed by Armsby.^ The energy value of the changes 

 in body weight were calculated from the composition of steers that had 

 been analyzed at this Station by the Department of Agricultural Chemis- 

 try. So far as possible steers were selected as controls for this purpose 

 that were of similar age, measurements, and weight and that had received 

 similar treatment. 



' The data for this paper were taken from the thesis of W. D. Salmon, presented at the University of 

 Missouri, as partial fulfillment of the requirements for the degree of Master of Arts. The investigation 

 was initiated by F. B. Mumford, Dean of the College of Agriculture, and by P. F. Trowbridge, at that 

 time Chairman of the Department of Agricultural Chemistry. Since September 1918, E. A. Trowbridge, 

 Chairman of the Department of Animal Husbandry, has had general supervision of the project. This 

 article was prepared by A. G. Hogan, who has been in immediate charge since September, 1920. A large 

 number of workers have contributed to the success of the experiment. 



' The original data will be reproduced in detail in a subsequent publication. 



8 Armsby, H. p., and Fries, J. A. net energy values for ruminants. Pa. Agr. Exp. Sta. Bui. 

 142, 20 p. 1916. 



Journal of Agricultural Research Vol. XXII, No. 3 



Washington, D. C. Oct. 15, 1921 



zv Mo. -J 



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