F842
Trichomoniasis

Introduction: Trichomoniasis is a common reproductive disease found throughout the United States. The disease is found  in breeding cows, and bulls. Bulls older than 4 years of age are at a greater risk of harboring the disease and can remain infected for life. Cows and heifers usually clear the infection after 60-90 days of sexual rest; however, some female cattle can remain infected for up to 12 months.

Causative Agent: Trichomoniasis is caused by a protozoal parasite called Trichomonas foetus. These protozoans are tiny microscopic organisms that infect the vagina, uterus, and oviduct in cows; and the outer lining (epithelium and crypts) of the penis and prepuce in bulls.

Clinical Signs: The most common clinical sign of disease is finding lower pregnancy rates on a herd wide basis. This drop in pregnant cows results from early gestation abortions. Infected cows can still conceive, but will often abort by 90 days of gestation. Some female animals may experience an infected uterus (pyometra) with some discharge.

Disease Transmission: The Trichomonas organism is spread by sexual contact. Infected bulls can spread the disease to a cow, and infected cows can spread the disease to a bull.

Diagnosis: The most accurate method of detecting this disease is by taking a sample from the prepuce of a bull. This sample is collected while flushing and scraping the prepuce lining with a sterile pipette. The sample is then placed on special culture medium and viewed with a microscope over a period of days. In infected bulls, the Trichomonas organism is directly identified during this microscopic examination of the sample. It is important that samples removed from the bull are NOT refrigerated, are kept out of direct sunlight, and transported quickly to the appropriate laboratory. Samples of the vaginal and cervical mucus from cows can also be tested. If an aborted fetus is found, it too can be used for diagnostics.

Treatment: Because bulls usually remain infected for life, it is recommended that they be culled. Heifers and cows should be given at least 60-90 days of sexual rest. This allows the cow to mount her own immune response and clear the disease. Some cows, however, have been known to carry the disease for up to a year.

Prevention: The most essential aspect of any prevention program involves proper management of breeding animals. There are many different management ideas:

  1. Each year, all current bulls should be tested and confirmed Trichomonas free.
  2. Maintain a completely closed herd. This is particularly challenging in a free range situation.
  3. Ideally, if purchased from an outside source, all replacement bulls and female animals should be virgin and young (have not reached sexual maturity).
  1. Purchasing non-virgin bulls, particularly those older than 4 years of age is extremely risky.
  1. If older replacements are used, both bulls and cows should test negative for trichomoniasis and come from disease free herds. This means that any non-virgin bull should be tested once a week for 3 weeks in a row. It is also recommended that replacement cows be kept separate from the rest of the herd for one entire breeding season.
  2. Commercial vaccines for the prevention of trichomoniasis are now available. These vaccines often require boosters and response to these vaccines is variable. Vaccines should not be used as the only preventative measure.
  3. Maintain a short (less than 60 days) breeding season and cull any animals that are not pregnant.
  4. Implement an artificial breeding program. This will not guarantee that the disease will not be spread, but it will greatly reduce the chances.

Control in Infected Herds: Any herd that is known to have trichomoniasis should implement a strict monitoring program for a series of years. In addition to the suggestions above, this includes the following:

  1. Testing non-virgin bulls once a week, for 3 weeks in a row. These bulls should be tested again just before the breeding season.
  2. Culling any open and late bred cows or heifers that do not have a calf by the start of the breeding season.