BUREAU OF AXIMAL INDUSTRY. 109 



was 5,980 pounds; buttorfat, 240 pounds; butterfat test, 4.11 per cent ; 

 income over cost of feed, $55.69; returns for $1 expended for feed, 

 $2.11. The records show that in those associations where the work 

 has been continued for a long period the production has generally 

 increased from jear to 3'ear. xVs production increased, the income 

 over cost of feed increased rapidly, and for each increase of 51) pounds 

 in butterfat there was an increase of $15 in income over cost of 

 feed. Cows that freshened in the fall produced more milk and but- 

 terfat and greater average income over cost of feed than those 

 which freshened in the spring or summer. Large cows excelled small 

 cows of the same breed in production of milk and butterfat and 

 in income over cost of feed. As the butterfat test increased, the 

 average production of butterfat advanced and average production 

 of milk declined. These records also indicate that cows remain in 

 the herd an average of about 4.7 years. 



COOPERATIVE BULL ASSOCIATIONS. 



The number of active bull associations increased from 78 on July 

 1. 1919, to 120 on June 30, 1920. This is the largest increase since 

 the work began, and is partly due to the momentum gained during 

 the preceding year, when the first real effort was made to ex! end 

 the work. Eighteen of the new associations are in South Carolina, 

 Alabama, and Mississippi, where a large part of the active field 

 worJv has been done by the cooperative extension men. Reports 

 from the associations which have been in operation for a fairly long 

 time show that the bull association is fulfilling its purpose of im- 

 proving the herds, and that the daughters of association bulls have 

 generallv excelled their dams in milk and butterfat production. 

 In one Maryland association 21 daughters of association bulls ex- 

 celled their dams in yearly production by an average of 963 pounds 

 of milk and 44 pounds of butterfat. 



Plans drawn in the division for a bull barn and pen that will 

 permit safe handling of the bull have been used extensiA'ely and have 

 given general satisfaction. 



COMBATING INFECTIOUS DISEASES IN DAIRY HERDS. 



On account of the supposed danger of spreading disease by means 

 of bull associations, and because of the opportunity for cooperation 

 in cow-testing and bull associations, some preliminary work has been 

 done in connection with these organizations, looking toward sys- 

 tematic efforts at a later period for the eradication of tuberculosis 

 and contagious abortion. Assistance w^as given in controlling abor- 

 tion in Virginia and Mississippi and in combating tuberculosis and 

 abortion in South Carolina. 



UTILIZATION AND IMPRO\'EMENT OF DAIRY PRODUCTS. 



Successful campaigns to promote the increased consumption of 

 dairy products in cities, towns, and rural districts have been carried 

 on by the Dairy Division and the States Relations Service of the 

 department in cooperation with State agricultural colleges and local 

 agencies. 



