684 
Journal of Agricultural Research 
Vol. XXXI, No. 7 
Table XIII .—Breeding data on experimental cows during period of experiment 
COWS TREATED WITH BACTERIUM ABORTUS BACTERIN 
Cow 
No. 
Data 
247 
409 
432 
435 
439 
442 
468 
Nonpregnant following 12 services. 
Calved May 1,1923 (282 days); pregnant; due to calve May 19,1924. 
Calved Feb. 28, 1923 (278 days); pregnant; due to calve Apr. 29,1924. 
Calved July 6, 1923 (272 days); pregnant; due to calve July 6, 1924. 
Aborted Sept. 20, 1923 (178 days); calved Dec. 13, 1924 (278 days). 
Calved Apr. 30,1923 (272 days); pregnant; due to calve June 14, 1924. 
Served 10 times; calved Jan. 5, 1924 (276 days). 
CONTROLS 
17 
71 
84 
223 
254 
441 
465 
466 
Calved June 15,1922 (calf vigorous); calved Jan. 8,1924 (265 days). 
Calved July 17,1923 (278 days); served Feb. 27,1924 (probably pregnant). 
Aborted July 29,1922 (243 days); aborted Dec. 31, 1923 (252 days). 
Calved June 19,1922 (calf vigorous); calved Mar. 9,1924 (286 days). 
Calved Jan. 28,1923 (281 days); pregnant; due to calve May 7,1924. 
Calved Oct. 29, 1923 (280 days); served Jan. 23, 1924 (probably pregnant). 
Calved Jan. 20,1923 (277 days); served 10 times; last service Jan. 22,1924. 
Calved Oct. 21,1922 (282 days); calved Sept. 28, 1923 (278 days). 
The results from the guinea-pig inoculations failed to indicate that 
the infective properties of the milk of different cows was influenced 
greatly by the quantity produced. It was also noted that unless 
the cows were no longer being milked daily, the quantity of milk pro¬ 
duced seemed to have no marked influence on the agglutinin titer of 
the whey. It was observed, however, that the milk of certain cows, 
whether they were practically dry or producing from 35 to 40 pounds 
daily, infected guninea pigs with marked regularity when injected in 
5 c. c. quantities. Cows 71 and 466 illustrate this point. * The milk 
of other subjects produced less uniform results in this respect. 
Whether such variations were due to differences in virulence of 
strains, numbers of organisms contained in the milk samples, or to 
the resistance of different pigs was not determined. 
SUMMARY 
Repeated injections of Bad . abortus bacterin, in which the organ¬ 
isms had been killed by heat, did not prove to be of practical value 
in overcoming Bad . abortus udder infection in cows. 
Eight of a group of fifteen cows with udders infected by Bact. 
abortus produced milk capable of infecting guinea pigs for approxi¬ 
mately two years. 
Variations in the quantity of milk produced by a Bact abortus 
udder-infected cow, provided the animal is milked daily, did not 
markedly affect the agglutination reaction of the milk whey. 
The blood serum of cows which have acquired infectious abortion 
may react strongly to the agglutination test for at least a year after 
the disappearance of the infection from the udder, as indicated by 
guinea-pig inoculation tests. 
