6 MASS. EXPERIMENT STATION BULLETIN 321 



The composition of the feeds as set forth in Table 5 has been used together with 

 average digestion coefficients to obtain the intake of nutrients as recorded in 

 Table 6. It will be rioted that the intake was slightly higher on the tankage 

 ration than on the soybean-cottonseed ration. This was unintentional, and was 

 due chiefly to the fact that the grain mixture which contained the tankage proved 

 to be somewhat higher than the other mixture in ash, protein, and fat. Prelim- 

 inary calculation when the formulas of the mixtures were decided on had indicated 

 the composition of the two to be in theory nearly identical. The tankage analyzed 

 somewhat above its guarantee for protein, which accounts in part for the dis- 

 crepancy. 



RESULTS OF THE FEEDING TRIAL 



Palatabilty of the Tankage 



No difficulty was experienced in getting the cows to eat the grain mixture 

 which contained tankage. One cow refused her grain on the first day of the trial 

 but not thereafter. The herdsman states that in general the cows did not clean 

 up the tankage mixture as quickly as they did the soybean-cottonseed; but, 

 as already stated, they did not refuse it. The amount of tankage in the grain was 

 17 percent. 



Changes in Live Weight 



The cows were weighed when the trial was started and thereafter at the end 

 of each forty-day feeding period, just previous to the change of rations. 



Table 7 shows that there was a slightly superior gain in weight on the tankage 

 ration, but calculation of the probable error of the average values given shows 

 that the difference in favor of the tankage is not significant. 



General Appearance of the Cows 



All animals in the experiment were graded for condition twice during the 

 season. The average grade was "good" tending toward "excellent" as the ex- 

 periment and the barn feeding season drew to an end. No differences were appar- 

 ent to the eye in the condition of the animals on the two rations. 



Milk Production 



A summary of milk production on the two rations appears in Table 8. The 

 figures given have been corrected to a uniform fat basis of 4 percent according 

 to the usual formula (.4M + 15F), in which M equals actual milk production 

 and F equals calculated fat production based on the fat test of the milk and the 

 actual milk production. Due to a close agreement between the butterfat tests 

 for the two groups of cows, the corrected values in Table 8 do not differ greatly 

 from the actual milk production. 



Table 8 shows a slight difference in milk production in favor of the tankage 

 ration, but calculation of probable error shows that this difference is not sig- 

 nificant. 



Composition of the Milk 



Composite milk samples were taken from each group of cows about midway 

 of each feeding period. The sampling period was two days in length and samples 

 from individual cows in a group were pooled to make a group sample. Table 9 

 shows that there was no significant difference between the rations in this respect. 



