The Trick of Trich: Understanding Bovine Trichomoniasis
Mario Villarino, County Extension Agent for Agriculture and Natural Resources- Hopkins County
Well, now that you got some rain, your pastures are growing and you were even able to get some hay. Winter pastures are rolling hay even 10 times more than last year. The next logical step would be to get some cows. But before you run and find the best looking cows for your ranch, you must be aware that together with the cows you can bring diseases that we do not want in Texas anymore. One of those is bovine trichomoniasis or “trich”. Trich is a venereal disease caused by the protozoan Tritrichomonas foetus. Because trich has no visible symptoms in bulls and few if any symptoms in cows and heifers, it is best to prevent exposure rather than try to control or eradicate the disease. The primary production and economic impact of trich is on cows because it causes infertility and abortions and often extends the breeding/calving season. The infection can be transmitted only by sexual intercourse and not by the environment. Bovine trichomoniasis is not transmitted to people. Bulls become infected by breeding infected cows. The protozoa live in microscopic folds, or crypts, on the surface of the bull’s penis and internal prepuce. Infected bulls must be moved to slaughter because there is no effective treatment for them. The remaining bulls in the herd must be held and isolated from female cattle until tested negative. Two laboratory tests can determine whether a bull is infected. Cows and heifers become infected when they are bred to infected bulls. The protozoa live in the vagina, cervix, uterus, placenta, and fetus. Most infected cows will rid themselves of the infection if they receive an extended period of sexual rest (120 to 150 days). However, the immunity is short-lived—a cow can become re-infected. A vaccine can help reduce the severity of the disease in an infected herd.
Bovine trichomoniasis enters a herd or ranch only via infected bulls, cows, or heifers. Again, an infected bull can transmit the disease to a cow or an infected cow can transmit the disease to a bull. To avoid this disease, practice sound biosecurity principles: Maintain good fences to control the movement and commingling of cattle, buy only virgin bulls and heifers, preferably from the original breeder. Keep the bull battery as young as possible. Older bulls harbor the protozoa more easily. Consider artificial insemination as a way to avoid introducing trich. Reputable semen companies repeatedly test bulls for many diseases, including trich, to ensure that the semen is not contaminated. Implement a defined breeding season. Trich may go undetected in a continuous mating system. Identify herd sires, and record the breeding group to which each bull is exposed. Consider keeping bulls in the same breeding groups for several breeding seasons. Should a false negative (infected) bull be in the battery, the infection would not be spread to uninfected groups. To avoid infecting many bulls in one season, consider maintaining small—but not necessarily single— sire groups instead of large, multiple-sire herds. Avoid buying open or short-bred (less than 120 days) cows. If you buy replacement cows, do not commingle them with the existing herd during the first breeding season. As with many things is life, a little prevention and testing go a long way rather than trying to fix a non-productive herd. Remember that all that work done to produce hay or grass will be wasted if you do not have a good calf crop at the end of the year.
Do not let trich play a trick on you. For more information on cattle diseases or any agricultural or natural resources question, please call the Hopkins County Extension Office at 903-885-3443.