JOURNAL OF AGMCCLTP1CAL MARCH 
Vol. XI Washington, D. C., December 3, 1917 No. 10 
INFLUENCE OF THE DEGREE OF FATNESS OF CATTLE 
UPON THEIR UTILIZATION OF FEED 
By Henry Prentiss Armsby, Director , and J. August Fries, Assistant Directory 
Institute of Animal Nutrition of The Pennsylvania State College 
COOPERATIVE INVESTIGATIONS BETWEEN THE BUREAU OE ANIMAL INDUSTRY 
OF THE UNITED STATES DEPARTMENT OF AGRICULTURE AND THE INSTITUTE 
OF ANIMAL NUTRITION OF THE PENNSYLVANIA STATE COLLEGE 
INTRODUCTION 
In the fattening of cattle it is a common experience that the gain in 
live weight secured per unit of feed consumed diminishes as the fattening 
progresses. Little reflection is required to make it evident that this 
phenomenon may be the combined result of a variety of causes. A 
supposed lower utilization of feed by the fattened as compared with the 
thin animal has been regarded not uncommonly as one such cause. It 
has been supposed that with the progress of the fattening the body cells 
become less efficient in the manufacture of fat from other nutrients or 
that the cells of the adipose tissue, as they become loaded with fat, offer, 
as it were, an increasing resistance to the deposition of added fat, to 
overcome which requires an expenditure of energy. In either case a 
unit of a resorbed nutrient, such as dextrose for example, would yield 
less fat than in the thin animal, while the heat production of the body 
would be correspondingly increased and the net energy value of the feed 
reduced. 
The investigation here reported was undertaken to test this view by 
means of a direct comparison of the utilization of feed energy by the 
same steer in ordinary condition and when well fattened. Although it 
includes only a single comparison on one animal, the results appear of some 
interest in view of the paucity of experimental evidence on this point. 
OUTLINE OF EXPERIMENT 
The subject of the experiment was a pure-bred Shorthorn steer about 
2 years and 9 months old at the beginning of the experiment. He was 
a very quiet and docile animal. During the winter of 1912-13 he was 
the subject of a series of respiration calorimeter trials (unreported). 
During the following summer he was on pasture and gained some 240 
(451) 
Journal of Agricultural Research. 
Washington, D. C. 
kw 
Vol. XI, No. 10 
Dec. 3, 1917 
Key No. Pa. —4 
