Trichomoniasis is not a new disease but its prevalence has increased dramatically in recent years, mostly due to the increased movement of breeding stock from region to region. Commonly called Trich, it is a highly contagious venereal disease that causes infertility and abortions.
Trich is caused by the protozoan pathogen Tritrichomonas foetus, which can live in the cow’s reproductive tract and on the surface of the bull’s penis. This organism has a close cousin, Tritrichomonas intestinalis, which lives in the intestinal tract and causes no problems. It may however be picked up in testing, causing a false positive, if fecal material splashes onto the penis.
There are no apparent signs of sickness in animals infected with Tritrichomonas foetus, but the herd will have too many open cows, abortions, extended calving season, and in a few cases uterine infections. The bull serves as a mechanical vector to spread the disease within the herd. In some younger bulls the infection may clear itself in time if the bull is not reinfected by breeding more infected cows. In older bulls the microscopic crypts in the prepuce, or sheath, become deeper and the organism establishes itself deep within these crypts, resulting in chronic infections.
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