44 



MAINTENANCE RATIONS OF FARM ANIMALS. 



Both the averages and the range of the results obtained by Kellner and by 

 Armsby and Fries for thin cattle on coarse fodder show a remarkably close 

 agreement. The results upon fat cattle will be considered on subsequent pages. 



In addition to the respiration experiments just considered, a num- 

 ber of live-weight experiments upon the maintenance ration of cattle 

 have been reported. 



Such trials were made by the writer at the Pennsylvania Experiment Sta- 

 tion 1 in 1S92 to 1897, the feed being either chiefly or entirely coarse fodder. 

 The live weight was taken daily during relatively long periods and the nitrogen 

 balance was also determined, and from these data an approximate computation 

 of the loss of fat was attempted. The amount of methane excreted, and the 

 corresponding loss of metabolizable energy, was calculated from the total carbo- 

 hydrates digested. Computing the final results on the same assumptions as in the 

 Moeckern experiments, 2 the results of 4 experiments each on 3 animals weighing 

 from 400 to 500 kilograms, computed per 500 kilograms live weight, were : 



Metabolizable energy in maintenance rations of steers — Armsby. 





Per 500 kilograms live weight. 



Ration. 











Steer 1. 



Steer 2. 



Steer 3. 



Chiefly or entirely coarse fodder: 



Therms. 



Therms. 



Therms. 



Experiment I, 1892-93 



14. 23 



[17.09] 



13.69 



Experiment II, 1892-1894 



13.61 



13.56 



12. 40 



Experiment VI, 1894-95 



12.92 



12.87 



12.73 



Experiment VII, 1894-95 



13.03 



12.76 



[17-77] 





13.45 



13. 06 



12.94 



Largely grain: 









Experiment VIII 



11.72 



9.15 



10. 70 



Assuming, as before, that about 57 per cent of the metabolizable energy was 

 available, and omitting the two apparently exceptional results, the maximum, 

 minimum, and average results are: 







Metabolizable energy. 



Available energy. 





Ration. 



Per 500 



Per 1,000 



Per 500 



Per 1,000 







kilograms 



pounds 



kilograms 



pounds 







live weight. 



live weight. 



live weight. 



live weight. 



Coarse fodders: 





Therms. 



Therms. 



Therms. 



Therms. 







14. 23 



13. 34 



8.11 



7.60 



Minimum 





12. 40 



11.62 



7.07 



6.62 





:::. 



13. 15 



12. 32 



7.50 



7.02 



Largely grain 





10. 52 



9:86 



6.00 



5.62 



The results on coarse fodders are materially higher than those of the respira- 

 tion experiments just cited, but the method is, of course, much less accurate. 



Haecker 3 reports determinations of the maintenance rations of dry cows made 

 in three successive 3^ears and in which three different animals were used. In 

 these experiments the nutrients digested were determined directly and the 

 sufficiency of the ration judged of from the live weight and appearance of the 

 animals. Results obtained by Kellner 4 and by Armsby and Fries 5 show that 



1 Pennsylvania Experiment Station, Bulletin 42. 



2 This differs somewhat from the method of computation followed in the original report 

 of the experiments. 



3 Minnesota Experiment Station, Bulletin 70. 



4 Die Landwirtschaftlichon Versuchs-Stalionen, vol. 53, pp. 440-445. 



5 Bureau of Animal Industry, Bulletins 51, 74, 101, and 128. 



