Trichomoniasis is a venereal disease of cattle caused by an organism called Tritrichomonas foetus. It has caused significant economic losses in American cattle herds for many years due to the nature of the disease. Economic losses in affected herds occur due to smaller and less uniform calf crops, costs of culling and subsequent replacements and increased veterinary expense.
Bulls carry the protozoa only on the penis and preputial membranes where they localize in the lining of the rear portion of the prepuce. Bulls show no outward signs of the disease, and it does not affect their semen quality or sexual behavior.
Cows that become infected by a carrier bull usually miscarry or abort in early pregnancy. Symptoms are not usually seen in individual animals, but uterine infections and abortions may be noticed in the herd. Infection results in cows breeding over an extended period of time. In a herd with a short breeding period, as high as 50 percent of the cows may be open at pregnancy testing time. In herds where the bull runs with the cows throughout the year, cows will settle and carry a calf. However, they calve on the average of once every 18-20 months instead of once every 12 months as they should.
Diagnosis is normally achieved by collecting some material from the back of the bull’s sheath, inoculating the collection into transport media, transporting to an approved laboratory where it is incubated (cultured), and examining the specimen for the organism. Testing by PCR is a more recent and more sensitive method of diagnosis which is performed from the same specimen as the culture test.
Management of an infected herd involves selling all infected bulls, allowing cows to cycle 2-4 times to clear the disease, and possibly vaccinating the cows. The vaccine is available by itself or in combination with Vibrio and Lepto.
If you export cattle, you should have your veterinarian call the state of destination as soon as possible because some testing protocols may take several weeks.
Oklahoma passed regulations in 2008 that require a negative Trichomoniasis test for bulls within 30 days prior to entry into the state. Bulls from an infected herd must have 3 negative tests within 30 days prior to entry, while virgin bulls may enter without a test, but must have a statement to that effect on the CVI.
Oklahoma’s legislature passed regulations this spring that will go into effect January 1, 2011 making it mandatory for bulls changing ownership to have a negative test for Trichomoniasis. This includes bulls sold by private treaty or public auction, leased bulls, and bulls being traded or loaned. Exceptions to the testing requirements will be bulls less than 24 months of age that can be certified as virgin bulls, bulls that are going directly to slaughter, and cutter bulls. Bulls consigned to a Livestock Market that are not tested but are purchased by a person who will use them for breeding will be sampled at the market by the market veterinarian and allowed to go to the buyer’s premise under quarantine until negative test results are received. If the bull tests positive for Trichomoniasis he must be sold for slaughter only and monetary losses will be the responsibility of the purchaser.
Rod Hall is a Staff Veterinarian, Oklahoma Department of Agriculture, Food, and Forestry.
