Potentially exposed bulls include all of the bulls that have been in contact with any cows or bulls from a breeding pasture that contained a test positive animal.  You may have opted to sell all of the potentially exposed bulls, in which case you may only have potentially exposed cows to manage.

Potentially exposed cows and bulls should be managed as a separate herd for the next breeding season.  These animals must be permanently identified and appropriate herd records must be kept so that these animals can be identified later in the year (or coming years) and returned to their management group if they get out.  The bulls should be removed from the breeding pasture after 90 days, or less, and housed as a separate group from the rest of the bull battery. 

To evaluate the success of removing Trich from your herd, the bulls should be tested for Trich shortly after the breeding season (they will need at least 1 week of sexual rest prior to testing) and the cows should be examined for pregnancy in a timely fashion.  If the pregnancy rate of this group is acceptable and the Trich tests come back negative then it will no longer be necessary to manage and maintain these animals as a separate herd.

There is a Trich vaccine on the market that may be of some benefit in reducing the number of abortions if Trich is still in the herd.  If you chose to keep any cows that are at high risk for having Trich you may want to consider vaccinating. Please discuss the economics of using this vaccine with your veterinarian.   

Alexander et. al., Aus Vet J, 1953. Christensen et. al., Aus Vet J, 1977. Clark et. al., Aus Vet J, 1983. Cobo et. al., Therio, 2007. Gault et. al., Am Vet Res, 1995. Gooder et. al., JAVMA, 1986.  Kvasnicka et. al., Therio, 1989.  Kvasnicka et. al., Am J Vet Res, 1992.  Mancebo et. al., Vet Parasit, 1995.  Schnackel et. al., Ag Pract, 1989.  Skirrow et. al., AM J of Vet Res, 1990. Skirrow et. al., JAVMA, 1987.