What is Trich?
Trichomoniasis (Trich) is a sexually-transmitted disease of cattle caused by the protozoal parasite Tritrichomonas foetus. This parasite lives in the small folds of tissue within the sheath and on the penis of infected bulls and can be spread to cows through breeding where it survives for a short time within the female reproductive tract.
What are the symptoms of Trich?
Infected bulls show no clinical signs but are the primary carriers of the parasite. Females are infected at breeding and the parasite causes the developing pregnancy to die. This is usually early enough in the pregnancy that the embryo is reabsorbed by the cow and an abortion does not occur. The only symptom that a producer will notice is that the cow comes back into heat again and doesn’t remain pregnant. Typically the female will clear the infection by the time she comes back into heat again. The male remains infected and carries the disease for life. This disease should be suspected in herds that have a poor conception rate and prolonged calving periods.
How is Trich spread?
Trich is spread through natural mating from an infected bull to a cow. If another bull breeds that cow while she is infected, the parasite can be then be passed to the second bull. Breeding through artificial insemination does not spread Trich.
How is Trich treated?
Unfortunately, there is no treatment for Trich. Cows typically clear the infection by the time they come back into heat again. Bulls remain infected for life. We can only control this disease by identifying and eliminating infected bulls.
Testing for Trich
Because of the economic impact of this disease, most states have a requirement that bulls over a certain age must be tested for Trich any time they go from one producer to another or if they cross state lines. In Oklahoma, all sexually active bulls regardless of age and all bulls over 18 months of age must be tested whenever they go from one producer to another. This includes change of ownership or loaning a bull to another producer. If a producer is transporting a bull to another state, that state’s Trich requirements apply.
To test for Trichomoniasis, a sample is acquired by scraping the interior of the bull’s sheath with a plastic pipette. This sample is then shipped in a special transport media to Oklahoma
Animal Disease Diagnostic Lab in Stillwater, OK where a Polymerase Chain Reaction (PCR) test is performed to detect the DNA of the parasite within the sample tissue. From the time the sample is taken until results are available usually takes an average of 7 days. This time should be taken into consideration when bulls are bought and sold.
Economic losses caused by bovine trichomoniasis can be avoided or minimized by practicing sound biosecurity principles:
1. Maintain good perimeter fences to segregate cattle of unknown status. Fences are the first line of defense in preventing the introduction of Trich in the herd.
2. Keep the bull battery as young as possible. Buy only virgin bulls and heifers, preferably from the original breeder. Test all bulls over the age of 18 months before adding them to the herd.
3. Implement a defined breeding season. Trich can go undetected in continuous-breeding herds.
4. Identify herd sires and record the breeding group of each bull if multiple bulls are used. If the herd becomes infected, this will make it easier to isolate the problem and start management protocols to eliminate the disease.
5. Consider keeping bulls in the same breeding groups for several breeding seasons. Should there be a false negative bull in the battery, this will keep uninfected cattle from being exposed.
6. Consider small sire groups (but not necessarily single-sire), versus large sire herds, to avoid infecting many bulls in a single season. Monitor pregnancy closely in one-herd grazing systems and implement an annual bull testing program to detect the introduction of Trich during the first breeding season.
7. Consider artificial insemination to avoid introducing Trich or to help break the cycle of infection in a herd. Reputable semen companies repeatedly test bulls for many diseases including Trich, to ensure the semen is not contaminated.
8. Avoid buying open or short-bred (less than 120 days) cows. Open or short-bred cows from unknown sources are particularly risky and must be quarantined and examined before they are added to the herd.
9. If you buy replacement cows, isolate them from the existing herd during the first breeding season.