The Montana Department of Livestock has sent this letter to some area cattle producers.

Dear <CattleProducerName>:

You are receiving this letter as notification that open cows sold from your herd were purchased by a herd that tested positive for trichomoniasis (trich) in May of 2016. As part of Montana’s state program aimed at eradication of the disease, Montana Department of Livestock (MDOL) provides notification to potential source herds so they can assess their risk and conduct trichomoniasis testing.

The affected herd purchased open females from various sources in Montana and other states. It is possible that the source of trich introduction into this herd was an open cow and, therefore, this letter is being sent to all herds that may have provided cattle to the affected herd in the year prior to the positive diagnosis.

We recommend that you consult with your local veterinarian to evaluate the potential risk of having trichomoniasis present. If you already trich test your bulls or if you pregnancy check your cows, your risk is likely low. If you are unsure of the reproductive health of your cattle or have other reason for concern, such as a history of high rate of opens, we recommend that you test your entire bull battery for trichomoniasis.

Fortunately, the risk of trichomoniasis can be mitigated with the following best-management practices:

  • Use virgin bulls or bulls <4 years old with an annual test.
  • Define your breeding season; limit to 60-90d if possible.
  • Pregnancy check females.
  • Work with your veterinarian to determine the reproductive health of your herd.
  • Test all bulls for trich and other reproductive diseases, in particular, if you are experiencing herd-fertility problems.
  • Avoid purchasing open or short bred cows (less than 120d) to mix with your herd.
  • Know the disease status and herd-health programs of all herds mixing with yours.

If you have any questions, please feel free to contact me at (406) 444-5214 or Additional information on trichomoniasis can be found on our website at

As a quick refresher, trichomoniasis, commonly referred to as “trich,” is a venereal disease of cattle caused by a protozoa organism, tritrichomonas foetus. This small, motile organism is found only in the reproductive tract of infected bulls and cows. Trich can cause infertility, low pregnancy rates, and abortion, all of which can have long-ranging effects on herd health and cattle producers’ livelihoods.

If you received this letter and have questions about its implications for you and your herd, please contact Bridger Vet at 406.663.3335. We’ll be happy to help you understand trichomoniasis and how it can affect your cattle.