With the breeding season just a few weeks away, local farmers and ranchers are working to get their herd bulls set to put out.  Last year, news of a trichomoniasis (trich) outbreak reached cattlemen that has continued to spread as the outbreak is being tracked and attempted to stop the spread.  This outbreak has become a concern for several Oneida County producers and should be taken seriously to keep additional herds from being infected.

 In April of 2023, ten herds were identified as having trich, found to all be a part of the King Creek grazing allotments in southeastern Idaho.  Untested bulls were sent out in the breeding season that began the spread of the venereal disease.  Trich will cause pregnant cows to spontaneously abort their calves in the first 120 days of gestation.  The illness spreads through a herd as multiple bulls breed a single cow or as a single bull covers multiple cows.

As ranchers have begun trich testing their bulls in 2023, an additional five herds have been identified as testing positive for trich.  Not always being able to track the whereabouts of an infected animal, it can be difficult to pinpoint exactly where the various herds are coming in contact with the disease.

The disease and the prospective damage it can occur in a herd and the rippling effects of an outbreak can be very concerning for cattlemen in close proximity to infected herds.  It is especially worrisome for producers that mix their cattle with other ranches as they run on public range allotments.  Despite the additional risk that this raises, there are management steps ranchers can take to decrease the likelihood of trich infecting their herds.

Preg testing cattle at the end of the breeding season can be a good indicator of such a disease in a herd.  If pregnancy numbers are very low or several cows are just beginning in their gestation, it could point to trich.  As cows are infected, they will lose their calves and either by open or just recently bred again.  Without testing for a herd’s pregnancy rate, it is impossible to find diseases spreading through the herd until it is far too late.

In addition to preg testing the cows, all herd bulls should be tested for trich.  Western states, including Idaho and Utah require bulls to be tested previous to each breeding season.  This mandate is largely due to the vast number of operations that mix herds with other ranches.  Trich is physically unnoticed in bulls and will only be positively identified with testing.  A certified veterinarian will collect skin cells from the bull’s sheath and penis where the protozoa resides.  Currently, the most efficient and timely testing for trich is conducted with a pcr test.  This testing can find positive results in just days and is considered to be more sensitive than culture tests. 

Having a defined breeding season is an important management tool to help stop the spread of trich.  Bulls or cows that are infected with trich can continue to reinfect and pass on the disease if they continue to run together.  Infected cows can usually clear the disease if they are removed from the exposure but do run a higher risk of being reinfected.  Because cows are not individually tested for trich an open, an infected cow allowed to continue being run with bulls will infect other bulls which will in turn, infect more cows.  Keeping open cows away from bulls by having a defined breeding season will stop the spread cycle as she clears the infection.

Positive trich test findings result in the infected bull being sent to slaughter within 14 days of detection.  Herd’s with positive herds are recommended to have second and even third rounds of trich testing carried out on all herd bulls.  Additional testing improves the finding of no trich as more tests are performed as fall negative results can occur.  Quarantining after a positive result is recommended to keep the spread from additional herds.

A final management tool grazing associations can count on is establishing bylaws that address the very issue of trich.  Local veterinarians strongly suggest that bylaws include protocols such as before a bull can be turned out that comes from an operation with a positive trich test, it must have multiple negative trich tests.  In addition, they recommend bylaws that allow for quarantine and reducing the exposure to herds that have had positive test results.

It is unreasonable to believe that a trich outbreak will clear up in a single season.  But it isn’t unreasonable to believe that has producers responsibly manage their herds, the spread of such an infection and its consequences will be minimal.  Employing these few management tools is a great to protecting herds and minimizing the time of such an outbreak.