Trichomoniasis Fact Sheet
By Rachel Endecott, MSU Extension Beef Cattle Specialist, Miles City, Mont.
What is trichomoniasis?
Trichomoniasis is a venereal disease caused by the protozoan parasite Tritrichomonas foetus. Protozoa live in the sheath of infected bulls, with no ill effects on the bull’s health. When passed to cows, trich can lead to embryonic death, irregular estrous cycles, and repeat breeding.
Is there a testing law in Montana?
A new Montana trichomoniasis testing law took effect in spring 2007 where positive trich tests are reportable to the State Veterinarian’s Office.
What bulls need to be tested?
Non–virgin bulls over 12 months of age and virgin bulls over 24 months of age that are imported into Montana, as well as bulls that are sold, loaned, or leased within the state require testing. Bulls must test negative 3 times at no less than 1 week intervals (culture test), with no breeding between testing and time of sale/loan/lease. An alternative, one–time complete bull herd PCR (polymerase chain reaction) test may be conducted where all bulls must test negative.
According to the rule, a virgin bull is defined as a sexually intact male bovine less than 12 months of age or a sexually intact male bovine 12 to 24 months of age accompanied by a signed affidavit as having had no potential breeding contact with sexually intact female cattle. Affidavits can be obtained from brand inspectors.
How are tests conducted?
For the culture test, a fluid sample is obtained from the inside of the bull’s sheath and is inoculated into culture media to identify the presence or absence of the protozoa. Three negative tests are needed because assurance that the bull is truly negative increases with each progressive test. For the PCR test, the laboratory is testing for the presence or absence of the protozoa’s DNA, and only one test is required. However, exporters of bulls should be aware that the accepted testing method may vary from state to state.
Are there exceptions to the testing rule?
Bulls shipped to a licensed livestock market or state veterinarian–approved feedlot who are destined for harvest are exempt from the testing rule, as are bulls transported from the ranch directly to a licensed slaughtering establishment. Bulls transported through Montana with no intent to unload do not require testing, nor do bulls imported for exhibition or rodeo purposes that are held in confined facilities. Non–virgin bulls from out of state that are destined for a Certified Semen Sales collection facility are also exempt. Finally, bulls imported as part of a state veterinarian approved seasonal grazing operation without changing ownership, following a risk assessment, are not required to be tested.
What happens to test–positives?
Test–positive bulls will be individually identified with a "V" brand on their right tailhead and are subject to immediate hold order until shipped to licensed livestock market, feedlot, or slaughtering establishment. After positive animals are identified, an epidemiological investigation will be conducted to identify other animals or herds potentially exposed to a test–positive animal or herd. An exposed herd notification is issued to appropriate owners and managers, and exposed herds may be subject to hold order and testing.
Still have questions?
Contact your local veterinarian, the Department of Livestock at (406) 444–2043 or go to the web at www.mt.gov/liv