DRIED BLOOD AS A SOURCE OF PROTEIN 

 FOR DAIRY COWS 



J. G. Archibald 



Assistant Research Professor of Animal Husbandry i 



INTRODUCTION 



A year ago Bulletin No. 321 of this station was published setting forth the 

 results of feeding high grade tankage to milking cows. Since the results were 

 entirely favorable the question arose as to whether other by-products of the 

 meat packing industry might also be utilized to advantage for this purpose. 

 Dried blood was chosen for a trial since it is the only other abattoir by-product 

 of considerable volume, which is low enough in price to compete as a possible 

 source of protein with the commonly used protein concentrates. 



Dried blood is just what the name indicates. According to Morrison 2 , "the 

 blood is collected . . . and heated in large vats until it is thoroughly coagu- 

 lated. The excess water is drained off and more moisture is removed in a 

 hydraulic press. The solid residue is then dried and ground to form blood meal 

 or dried blood." The protein content is very high, usually between 80 and 

 85 percent. Dried blood should not be confused with ''soluble blood flour," 

 a specially prepared article which has been used considerably as an ingredient 

 of calf meals, and which commands a somewhat higher price. 



METHOD OF CONDUCTING THE INVESTIGATION 



A feeding trial of dried blood similar to that conducted for tankage in 1934-35 

 was carried on during the winter of 1935-3B, lasting from November 18 to 

 April 25. Twenty-two cows in the State College herd were available for the 

 experiment. These were divided into two groups of eleven each, as nearly 

 alike as possible with respect to breed, age, live weight, stage of lactation, 

 amount of milk being produced, and fat test of the milk. Table 1 shows the 

 similarity in these respects. 



The dried blood used in the experiment was the usual commercial article. 

 It was compared with a mixture of equal parts of soybean meal and cottonseed 

 meal, 10 percent of it being included in the experimental grain mixture. The 

 groups of cows were fed by the double reversal method, one group receiving 

 the dried blood for forty days while the other received the soybean-cottonseed 

 ration. At the end of that time the rations were reversed and the reversal was 

 repeated three times throughout the season, so that each group received each 

 ration for two different periods of forty days each. As is customary, results 

 have been reckoned from the last thirty days of each period, the first ten days 

 being considered preliminary, to allow the cows to become accustomed to the 

 change in feed and to take care of any lag in the effect of the previous ration 



■The author desires to make the following acknowledgments: To Wilson & Co., Chicago, who 

 supplied the dried blood used in the experiment; to C. H. Parsons, farm superintendent for his 

 cooperation in the conduct of the work; and to Thomas Muir, herdsman, who had immediate 

 charge of the animals and the details of feeding. 



'Morrison, F. B. Feeds and Feeding. 20th Edition. 1936. 



