As of this date, no efficacy for bulls has been shown, i.e., the vaccine has not been shown to protect bulls from becoming infected. Do not keep these females. They should not be mingled with the normal, pregnant cows, nor should the same bulls breed these two different groups of cows. Alternatively, these open cows could be culled. Additionally, in some herd situations, artificial insemination can be used to clear up an infected herd and heat synchronization can be helpful in this regard.
Good fences make good neighbors.
Culture new bulls and old bulls prior to the breeding season at the semen exam time. This is also a good time to vaccinate bulls for Vibrio, another venereal disease. Be very suspicious of new cows or bulls, especially somebody else s cull. Do not loan, rent, or borrow bulls. Trichomoniasis is a complex disease problem, and your veterinarian should always be consulted regarding decisions about preventing, controlling, or diagnosing this disease.