Montana Department of Livestock

Here to serve the people of Montana and its livestock industry.

Animal Health Bureau

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Department of Livestock
Animal Health Bureau
PO Box 202001
Helena, MT 59620-2001
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Bovine Trichomoniasis

Trichomoniasis in Montana

Disease Information

Additional Information


 Trichomoniasis in Montana

In 2007 Montana implemented a trichomoniasis program based upon industry feedback. The primary focus of the program has been ongoing surveillance of Montana’s bull population through required testing.

Current Montana regulations require an official trich test for all non-virgin bulls that are:

  • Moving out of any county designated as a trichomoniasis epizootic area (Big Horn, Glacier, Pondera or Yellowstone county).*
  • Sold, loaned or leased within a trichomoniasis epizootic area.
  • From multiple sources going to a common pasture for breeding.
  • Imported into Montana.
  • From herds adjacent or exposed to a confirmed positive herd.

 *Bulls leaving the epizootic area for change of pasture only where adequate testing facilities are not available may complete testing within 45 days after movement.

All bulls must have official identification at the time the test sample is taken. This may be an official USDA tag (USDA silver metal clip or RFID tag) or a Montana trich tag. Montana trich tags are on a five-year color rotation, which changes on September 1st of each year.

  • Sep 1, 2020 – Aug 31, 2021 Green
  • Sep 1, 2021 – Aug 31, 2022 White
  • Sep 1, 2022 – Aug 31, 2023 Orange
  • Sep 1, 2023 – Aug 31, 2024 Blue
  • Sep 1, 2024 – Aug 31, 2025 Yellow

Historical Test Data


Trichomoniasis Testing Data

The map below represents Montana trichomoniasis tests for FY23 (7/1/2022-6/30/2023) by county.  Click the map to display the interactive map with more in-depth detail.

MT Trichomoniasis Cases by County - FY2023 


To view testing data for specific years, select a year below:


Disease Information

What is Trichomoniasis?

Trichomoniasis (trich) is a sexually transmitted disease of cattle caused by the parasitic protozoan, Tritrichomonas foetus. The resulting abortions and infertility associated with infection can be economically devastating to affected producers. Economic losses to the U.S. beef industry from reduced conception rates, lower weaning weights and increased culling are estimated to exceed $100 million annually. Trichomoniasis has worldwide distribution and is a major cause of infertility in naturally bred cattle in many countries.

Signs & Symptoms
Infection with the trich organism is generally inapparent in cows and bulls, but can cause serious reproductive problems in cows, including early and occasional late-term abortion, and repeat breeding that results in an extended calving season and a high percentage of open cows (20-50 percent or more). Most cows will clear an infection within a few weeks to a few months with an unknown duration of immunity, and therefore may be reinfected. A small percentage of animals will fail to clear the infection and are typically animals that come up open at pregnancy checking.
Bulls can be tested for trich by obtaining a preputial scraping from suspect animals and submitting to an approved AAVLD laboratory. Montana recognizes the following as official tests:
  • Three negative weekly cultures
  • Single PCR
  • Pooled PCR (Pooled testing is not accepted for positive, adjacent, or exposed herds.)
Testing of cows is not routinely performed.
Treatment & Vaccination
There are no effective, FDA-approved treatments for trich. Once a bull has been confirmed positive for the disease, the animal will always be classified as a positive animal and in Montana must be consigned to slaughter channels.
A commercially available vaccine can help cows clear an infection, but does not prevent infection. The vaccine is only recommended for use in affected herds or in herds with a high risk of exposure.
Management is the best tool that producers have to prevent trich in their herd. Best management practices for the prevention of trich include:
  • Use of only virgin bulls or bulls less than 4 years old with an annual test.
  • Define your breeding season; limit to 60-90 days if possible.
  • Culling of open females.
  • Allow only virgin heifers or pairs onto common grazing pastures, or cows that have been away from the bull more than 120 days.
  • Know the disease status and herd health programs of all herds mixing with yours.
  • Use your veterinarian to determine reproductive health of your herd, especially by pregnancy checking females and testing all bulls for trich and other reproductive diseases. Work with your veterinarian to develop a reproductive herd health plan.
  • Avoid purchasing open or short bred cows (less than 120 days) to mix with your herd.


Additional Information


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Bovine trichomoniasis is a reportable disease within one business day to the State Veterinarian's office at 406/444-2976.  

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