654 



STATE BOARD OF AGRICULTURE. 



TABLE II.— SHOWING THE AGE AT WHICH INFECTION FIRST APPEARED IN THE 



UDDERS OF COWS UNDER OBSERVATION. 



The animals in this table are in a herd which has been under observa- 

 tion the past three years during which time an average of about 20 per 

 cent of the udders have been infected. The percentage of cows present 

 with infected udders would have greatly increasd but for the fact that 

 a number of the animals have been sold while others have died during 

 this period. It will be noticed that the age of the animals apparently 

 has no connection with the first appearance of the infection. 



SUMMARY AND CONCLUSIONS. 



Part I. 



There is apparently no connection between the Bact. abortus antibody 

 content of the blood and that of the milk. 



The Bact. abortus antibody content of milk may vary from quarter to 

 quarter indicating that the antibodies present are due to local infection 

 and do not come from the blood stream. 



The agglutination test as compared with the complement fixation test 

 for Bact. abortus infection when using milk instead of the blood serum 

 gives the higher percentage of positive reactions, and is apparently more 

 reliable. 



A pure culture of Bact. abortus introduced into the milk cistern of a 

 cow's udder caused the appearance of agglutinins in the milk. 



In every case in which Bad. abortus was found present in the milk 

 by animal inoculation the agglutinins for this organism were also 

 found, but this bacterium w^as not found in every case in which agglut- 

 inins were demonstrated. 



The agglutinins may be present in the milk of cows that have aborted 

 and in the milk of cows that have never aborted. 



The antibodies may be present in one or more quarters, may spread 

 from quarter to quarter, and may gradually die out. 



As high or a higher antibody and cellular content in the strippings 

 than in the fore milk seems to indicate active infection and the presence 

 of Bact. abortus in the milk in sufficient numbers to produce the typical 



