The Facts on Trichomoniasis
Trichomoniasis is a sexually transmitted disease in cattle that can cause significant economic losses in herds. The disease is caused by a single celled parasite, Tritrichomonas foetus. Though the true prevalence of trichomoniasis in cattle is not known, several states have recently enacted stringent rules to control the importation or transmission of the disease.
The parasite lives in the prepucial membranes of infected bulls without affecting semen quality or sexual behavior. Susceptible cows are infected when they are bred by an infected bull. In cows, T. foetus often causes early embryonic or fetal death, abortion, pyometra, fetal maceration and/or infertility. Economic losses from T. foetus are associated from reproductive wastage, culling and replacing infected bulls and open or late cows, lost calf crop and delayed conception. In rare cases, a cow may become pregnant, deliver a healthy calf and still carry the infection into the next breeding season. Though a vaccine exists to help control infection in cows, there is no effective treatment for infected bulls. The disease is spread between herds by the introduction of infected breeding stock.
Definitive diagnosis of trichomoniasis is made by detecting the organism in prepucial samples from bulls following at least a two-week sexual rest. Parasites may be detected by direct, microscopic observation of the sample, in vitro culture (enhances parasite numbers) of the sample and microscopic examination, or the use of polymerase chain reaction (PCR) for initial, confirmation or differentiation from non-pathogenic trichmonads. At least three negative tests performed one week apart are required to declare a bull negative.
Prevention is the most effective approach in controlling this disease. It is recommended that only virgin replacement cattle be added to the herd. If a used bull is to be used then he needs to have at least three negative tests prior to introducing to the cows. Adding open, dry cows to the breeding herd is a high bio-security risk and is not advised. Good fences to control introduction of infected cattle from neighboring herds is also important.
Within the last 12 months two bulls have tested positive for this parasite in the state. One was from a group of bulls sold through a south Georgia sale barn in April 2011. Other bulls from the same herd were not tested and presumably were distributed to other herds. The other positive case was from a young bull exposed to cows brought in from Texas. Due to the high number of livestock brought into the state from areas affected by drought, it is likely more cases of Trichomoniasis could be diagnosed. The Georgia beef herd increased by more than 10% in 2011, primarily from imported livestock from drought-affected areas.
Trichomoniasis Import Testing Requirement – Georgia Department of Agriculture
Newly adopted Rule 40-13-2-.07, entitled “Bovine Trichomoniasis,” requires testing of all virgin and non-virgin bulls 18 months of age and older before entering Georgia. The rule requires bulls to test negative within 30 days prior to entering the state. The rule prevents bulls from having contact with female cattle between the test and importation into Georgia. Bulls comingled with cows after testing are required to be retested.
All bulls must be identified with a USDA-approved ear tag, registry brand, or registry tattoo. The rule further provides that the collection of samples must be conducted by an accredited veterinarian and that animals must be identified on an official test chart.
The rule allows the State Veterinarian to exempt certain bulls from trichomoniasis testing. This includes: bulls going directly to slaughter; bulls being transported through Georgia in interstate commerce and not offloaded and comingled with female cattle; and virgin bulls under 18 months of age.
For additional information please contact the Georgia Department of Agriculture Office of the State Veterinarian at 404.656.3671.