

.'. : : : ••: -•. '•. 



-•-. •' .' . ♦.' :: ..:.••'. 4/ 



Tlie work has been carried on for the most part from the point 

 of view of a laboratory man cooperating with clinicians. No 

 attempt is made in this paper to give detailed clinical data, methods 

 for physical examinations, etc. There are included many state- 

 ments "and some data given in a preliminary article on the sub- 

 ject. While the subject is broad in its scope, in fact too broad for 

 great detail, it is hoped that a start has been made toward future 

 and more detailed investigations. 



History 

 References to, and investigations relating to, the part played by 

 the bull in the process of reproduction in the herd, and in the 

 spread of genital infections, have been limited largely to those 

 phenomena caused by Bad. ahortum. Bang (1) originally called 

 attention to the possibility of the male transmitting the organism 

 discovered by him, but he reached no definite conclusion on the 

 subject. James Law (2) writing on contagious abortion in cows, 

 early suspected this possibility when stating under " casual infec- 

 tions," that — " In a case which came under the observation of the 

 Avriter recently, a family cow, kept in a barn where no abortion 

 had previously occurred, was taken for service to a bull in a herd 

 w^here abortion was prevailing, and though she Avas only present 

 at the latter place for a few minutes, she aborted in the sixth 

 month." Jansen, as quoted by Sand, reports the case of a cow 

 from an aborting herd having been taken into a herd that had 

 been previously quite free from the disease. Soon after her arrival 

 she aborted, and later cow after cow of the original herd aborted. 

 The owner kept the matter a secret, and sent his cow to a neigh- 

 bor's bull for service, with the result that for two years abortion 

 prevailed among cows served by this bull. McFadyean and Stock- 

 man (3) later, in experimental work, attempted but failed to in- 

 fect cows by using a soiled bull for service. Hadley and Lothe 

 (4) state: "A large number of stockmen hold that the bull is an 

 important factor in the transmission of contagious abortion in 

 herds. A smaller number believe that the bull merely acts as a 

 passive carrier of the abortion disease and is not actively concerned 

 in the transmission." In a subsequent bulletin, Hadley (5) re- 

 marks : ' ' The abortion organisms may enter the body 



during sexual intercourse." In an experiment carried on by the 

 same author and co-workers, abortion-free virgin heifers were mated 

 to abortion-infected bulls, infection being evidenced by positive 

 reactions to the complement fixation and agglutination tests. His 

 results indicate, he believes, " that the bull is not so important a 

 factor in transmitting abortion as many believe." The con- 

 clusions are: "Bulls may become infected with abortion bacilli. 

 Bulls that reacted to the blood tests were incapable of dissemi- 

 nating the abortion disease to the abortion-free heifers with which 

 they were mated. Bulls appear to possess a sexual or individual 

 immunitv to abortion infection that renders them less susceptible 



