IMMUNIZATION OF MATES TO CONTROL ENDOMETRITIS CAUSED BY STREPTOCOCCUS-ZOOEPIDEMICUS

Normal mares were immunised by the intramuscular and intrauterine admi nistration of an antigen with adjuvant and they and unimmunised contro l mares were later challenged by the intrauterine instillation of path ogenic Streptococcus zooepidemicus; the response of all the mares was monitored clinically and bacteriologically for seven days. Significant ly fewer S zooepidemicus were present in cervical swabs taken from the immunised mares than from the control mares (P<0.01) and the degree o f inflammation in the genital tract of the immunised mares was also si gnificantly less (P<0.001). This protective effect of immunisation was associated with the specific IgG response in the serum, and an IgG an d IgA response in the uterine secretions. These results are the first demonstration that a previous immunisation with a suitable antigen can reduce an infection of the reproductive tract of mares.