22 



PROTEIN REQUIREMENTS OF CATTLE: MITCHELL 



very largely due to differences in fat content, as Murray (*2) and later 

 Moulton(*^) have shown. The more rapidly an animal increases in 

 weight on a given ration the more rapidly will it fatten. These two 

 considerations, therefore, appear to justify the conclusion above stated, 

 and hence as the initial step in the analysis of the chemical data of the 

 Missouri experiments, the age of each of the slaughtered animals was 

 corrected in accordance with the weight attained, by the use of equations 

 (2), (3), and (4). In other words, by substituting the weight of the 

 animal, W, in the age-weight equation for its group, the corrected age, t, 

 was determined. The observed ages and the corrected ages of the animals 

 slaughtered are compared in Table 8. 



TABLE 8 



The Observed and Corrected Ages of the Missouri Steers Submitted 

 TO Chemical Analysis 



Group I 



Group II 



Group III 



The only great discrepancies between observed and corrected ages 

 relate to Steers 509 and 500 in Group III, which for some unexplained 

 reason do not fit in well with the growth data given for this group of 

 animals in Missouri Eesearch Bulletin 62. The corrected ages given 

 in Table 8 are the ages at which the steers would have attained their 

 slaughter weights if they had increased in weight at the average rate 

 for their group. 



In obtaining mathematical functions describing satisfactorily the rela- 

 tions between corrected age and the content of the steers in moisture, 

 nitrogen, fat and ash, Brody's equation was found generally applicable 



