Bovine Genital Campylobacteriosis, caused by Campylobacter fetus subsp.venerealis is associated with production losses due to herd infertility and sporadic abortions. The aim of this study was to compare abortifacient properties between C. fetus subsp. venerealis strains. Four groups of 10 pregnant guinea pigs (4 vaccinated (Vibrovax^TM twice, five weeks apart prior to mating) and 6 non-vaccinated) were challenged intraperitoneally at week five of gestation with four different strains at a concentration of 10⁷ cfu/ml. Tissues from dams and foetuses were examined by culture. Proportions were compared using Fisher’s Exact test. Strain 76223 resulted in 8/10 abortions (6/6 non-vaccinated, 2/4 vaccinated), strain 924 2/10 (2/6 non-vaccinated, 0/4 vaccinated), strain 635 0/10 and strain B6 2/10 (1/6 non-vaccinated, 1/4 vaccinated), within 12 days (p=0.007). C. fetus subsp. venerealis was reisolated from peritoneum, uterus horns, placenta, amniotic fluid and foetal stomach contents in aborting and non-aborting animals. Reisolation was unsuccessful in five of the vaccinated animals. Virulence variation was present with differences in abortion rates and culture results. Intra-peritoneal administration of C. fetus subsp. venerealis to pregnant guinea pigs is a promising small animal model for investigation of C. fetus subsp. venerealis strain variation and abortion mechanisms.