6 MASS. EXPERIMENT STATION BULLETIN 406 



the relatively large amount of cornstarch used as a source of energy ; or whether 

 the regular mixture was more palatable because of the presence of such materials 

 as cottonseed meal and soybean meal, remains an open question. If either of 

 the last two reasons is the correct one, the difficulty could be readily overcome in 

 feeding practice. It seems doubtful that the relatively small amount of urea 

 present (3 percent as a maximum) could have had any substantial effect, either 

 favorable or adverse, on pelatability. 



Table 5. — Average Grades* for General Condition of Cows 



Regular Urea 



Ration Ration 



"Double Reversal" Groups 



At start Good Good + .50 



During first year Good + .31 Good - .06 



During second year Good + .42 Good + .50 



"Continuous" Groups 



At start Good + .25 Good + .25 



During first year Good + .30 Good - .08 



During second year Good + .36 Good — .09 



*The numerical expression of the grade is based on a unit difference of 1.00 between one grade 

 class and the next; thus, very good has been assigned a rank of 1, good a rank of 2, and so on down. 

 In other words. "Good + .31" represents an average grade tending definitely toward very good, 

 while "Good — .06" represents an average grade tending slightly towards /air. 



General Condition of the Cows 



All cows were graded for condition at the beginning of the experiment and 

 twelve times during its course at intervals of two to three months. The data in 

 Table 5 are based on 265 observations made jointly by the author and the farm 

 manager at the hospital. Without exception, the condition of the cows on the 

 regular ration tended to improve as the feedmg trials progressed, while with one 

 exception in the cows on urea the trend was in the other direction. This was 

 especially true in the groups kept continuously on one type of ration and was 

 evident to any but a casual observer. This may have been due not to the pres- 

 ence of urea, but to removal from the ration of some desirable conditioner when 

 the cottonseed meal and soybean meal were purposely excluded. The grades 

 were not based solely on condition as indicated by texture of hair and hide, but 

 also on degree of fleshing. In the continuous groups, some of the cows on the 

 urea ration were rather thin all through the trials, while those on the regular 

 ration almost without exception maintained themselves in good to excellent flesh. 



"Double Reversal" Groups 



Regular ration • 62 76 



Urea ration 45 64 



"Continuous" Groups 



Regular ration 239 274 



Urea ration 229 266 



The reason for the much larger net gains by the "continuous" groups is that they represent a 

 much longer period; viz., from just after calving to just preceding the next calving. The interval 

 for the "double reversal" groups was eight weeks in the first year and seven weeks in the second 

 year. 



