There are many possible infectious causes of abortion, including the viruses of infectious bovine rhinotracheitis (IBR) and bovine viral diarrhea (BVD). There are also bacterial infectious agents such as brucellosis, vibriosis and leptospirosis, as well as the protozoans of trichomoniasis and neosporosis. Abortions may also be caused by feed toxins such as nitrates. Prevention is directed against the specific causes of abortion and can be decided upon with discussion from your private veterinarian.