DRIED BLOOD FOR DAIRY COWS 7 



Flavor of the Milki 



The composite samples taken for analysis were also scored for flavor, pre- 

 servative having been purposely omitted with this in mind. The samples were 

 kept in a cool milk room and scored on the same day on which the final aliquots 

 were taken. 



Insofar as the rations were concerned there was no difference in flavor of 

 the milk. The product from one group of cows without exception scored 

 slightly higher than that from the other group, but it was always the same 

 group irrespective of which ration they were receiving. 



Curd Tension of the Milk 



This factor was determined on two occasions on the samples used for analysis 

 and flavor. No difference could be detected between the samples in this respect. 



SUMMARY AND CONCLUSIONS 



Dried blood has been compared as regards its suitability for dairy cows with 

 a mixture of soybean meal and cottonseed meal. The comparison has been 

 made by means of the double reversal method using twenty-two cows in the 

 State College herd, divided into two groups of eleven each. The feeding period 

 extended over 160 days, each group of cows being on each ration at two different 

 times for periods of 40 days in length. Dried blood made up 10 percent of the 

 experimental grain ration, and supplied digestible protein equal in amount to 

 that in the 10 percent each of soybean meal and cottonseed meal which the 

 control ration contained. 



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

 which contained the dried blood. 



There was a slightly significant difference in gains in weight in favor of the 

 control ration, but there were no significant differences between the two rations 

 in any of the following respects: general appearance of the cows, milk produc- 

 tion, composition, flavor, and curd tension of the milk. 



Insofar as these results are concerned, it seems evident from the standpoint 

 of palatability and the absence of any unfavorable effects on the animals that 

 dried blood can be safely used as a component of grain mixtures fed to dairy 

 cows to the extent of at least 10 percent of the mixture. 



Also, in view of our general knowledge of the subject of the protein require- 

 ments of milking cows and the fact that there was not a significant difference 

 in milk production on the two rations, it seems a reasonable conclusion that 

 the blood was a satisfactory source of protein as a substitute for a mixture of 

 soybean meal and cottonseed meal. 



Acknowledgment is made to M. J. Mack and H. G. Lindquist of the Department of Dairy- 

 Industry of Massachusetts State College who made the tests for milk flavor; and to W. S. Mueller 

 of the same department, who determined the curd tension of the samples. 



Publication of this Document Approved by the Commission on Administration and Finance 

 4M,10-'36. No. 9010. 



