One of our readers had requested an article in regards to trichomoniasis. This happens to be a very timely topic as Missouri has seen a recent increase in the diagnosis of this disease and has implemented more rigorous testing requirements for bulls entering the state in an effort to limit its spread.
Trichomoniasis is a sexually transmitted disease of cattle that is caused by a protozoal organism called Tritrichomonas foetus. This organism lives in the reproductive tract of cattle; primarily bulls and is transmitted during natural breeding.
‘Trich’ as it is often called, is not commonplace in every herd. Instead, the disease is often introduced by an infected animal that is added to the herd or by a bull that conveniently jumps the fence. Producers may not become aware of the existing problem initially as trich does not cause overt clinical signs in most cases. Instead, cows frequently become pregnant only to abort the pregnancy early in the first trimester. This will result in repeat breedings and producers may notice cows returning to estrus time after time.
Other cows may not cycle back in a timely fashion, and in turn, are found open on pregnancy evaluation after the breeding season. However, the hallmark of the disease is early embryonic death and poor reproductive performance potentially leaving as much as 50 percent of the cows not pregnant at the end of a standard 60 to 90 day breeding season. This scenario represents the economic importance of pregnancy evaluation after a controlled breeding season.
Should a producer suspect a problem or should an apparent problem be identified at preg-check, diagnostic procedures become warranted. Cows generally clear the infection on their own in a few months time, but in contrast, bulls and especially older bulls often become chronic carriers.
Chronically infected bulls are the primary source of infection. Unfortunately, there is no good treatment option for an infected bull. Therefore, if a herd is found to be infected, the typical course of action involves culling infected bulls and non-pregnant cows. Allowing several months of sexual rest for cows to clear the infection on their own may also be a viable option to avoid culling an excessive number of cows.
Prevention is key in managing trich. When purchasing or leasing bulls, producers should select virgin bulls or bulls that have been tested negative. Older bulls that have ‘been around the block’ are a significant risk for introducing trich to your herd and should be tested prior to turnout with the cows. Maintaining a closed herd can eliminate the risk of disease. This also includes maintaining good perimeter fencing to prevent neighboring bulls from visiting your cows.
Southwest Missouri appears to be a higher risk area of the state as determined by positive herds identified in recent months. Producers should raise their awareness of trichomoniasis and strengthen prevention measures on the farm.
Darren Loula, DVM, is a large animal veterinarian at Fair Grove Vet Service in Fair Grove, Mo.
