8 MASS. EXPERIMENT STATION BULLETIN 321 



better flavor. On the samples taken in January and March the decision was 

 unanimous that the milk from the cows receiving the tankage ration was slightly 

 the better as regards flavor. 



The decision was also evenly divided as regards the groups of cows, which rules 

 out individuality of the animals as a factor in influencing the flavor. It may be 

 concluded that the tankage did not affect the flavor of the milk in any way. 



Whipping Quality of the Cream 



The entire production of each group of cows for one milking was kept separate 

 on two occasions, the cream was separated, and a representative portion of each 

 lot was submitted to the whipping test. To quote the statement of the member 

 of the Department of Dairy Industry who made the test, — "the cream obtained 

 from samples A and B was found to be equal in whipping rate, degree of stiffness 

 and overrun. No objectionable flavor was detected." 



SUMMARY AND CONCLUSIONS 



High-grade, dry-rendered tankage has been compared as regards its suitability 

 for dairy cows with a mixture of soybean meal and cottonseed meal. The com- 

 parison has been made by means of the double reversal method using twenty- 

 four cows in the State College herd, divided into two groups of twelve each. 

 The feeding period extended over 160 days, each group of cows being on each 

 ration at two different times for periods 40 days in length. Tankage made up 17 

 per cent 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 ration which 

 contained the tankage. 



There was no significant difference in the effect of the tankage ration as com- 

 pared with the soybean-cottonseed ration in any of the following respects: Gain 

 in weight, general appearance of the cows, milk production, composition and 

 flavor of the milk, and whipping quality of the cream. 



Insofar as these results are concerned, it seems that high-grade tankage can be 

 safely added to the list of protein feeds for dairy cows, provided the usual pre- 

 cautions for feeding protein concentrates are observed. In addition to its protein, 

 tankage carries a considerable amount of bone, which can take the place of the 

 bone meal so often added as a mineral supplement to mixed feeds. 



Publication of this Document Approved by Commission on Administration and Finance 

 1\1 B "85. No. 5389. 



