Bovine trichomoniasis

Overview

According to the Department of Agriculture and Food Western Australia, Animal Health Laboratories, “Bovine trichomoniasis is a disease of the reproductive tract caused by Tritrichomonas foetus, a flagellate protozoan parasite. In cows, infection leads to embryonic and early foetal death, abortion, foetal maceration, pyometra and transient or permanent infertility. Asymptomatic infection occurs in bulls, which become persistent carriers and the main reservoir of infection. Young bulls are less susceptible to infection. Heifers have a higher incidence of the disease compared to cows, as the latter may remain immune for up to three years post-infection.”

In Alberta, bovine trichomoniasis (also known as trich) is a provincially notifiable disease under the Animal Health Act. There have been sporadic confirmed cases of the disease in cattle.

Clinical signs

Often the first indication of bovine trichomoniasis is when cows thought to be pregnant resume cycling towards the end of the breeding period.

The primary signs of infection in cows include:

• transient or permanent infertility
• embryonic and early foetal death (between 18 to 70 days of pregnancy)
• abortion
• foetal maceration
• pyometra (infection or the uterus)

Although bulls are the primary carrier of the disease, they show no clinical signs.

How to report

Bovine trichomoniasis is a provincially notifiable disease under Alberta's Animal Health Act and must be monitored. It is also an annually notifiable disease under the federal Health of Animals Act; laboratories must report all cases annually to the Canadian Food Inspection Agency.

All suspected or confirmed cases must be reported to the Office of the Chief Provincial Veterinarian (OCPV) within 24 hours:

Hours: 8:15 am to 4:30 pm (open Monday to Friday, closed statutory holidays)
Phone: 780-427-3448
Toll free: 310-0000 before the phone number (in Alberta)
Fax: 780-415-0810

Where it’s found

“The disease has a world-wide distribution and, at one time, was of major economic importance as a cause of abortion and infertility, especially in dairy cattle. The widespread use of artificial insemination in many areas of the world has contributed to reduced prevalence. Nevertheless, trichomoniasis  is still of importance in countries with extensive farming practices where artificial insemination is not used.” From Chapter 3.4.15: Trichomoniasis (World Organisation for Animal Health).

How it spreads

Bovine trichomoniasis is a venereal disease of cattle. The parasite Tritrichomonas foetus is transmitted when an infected bull breeds with a susceptible heifer or cow. Infected cows can transmit the disease to uninfected bulls during breeding. Although young bulls (under 3 years of age) may clear the infection, most infected bulls become long-term carriers.

Infected bulls are the main source of introducing the infection into uninfected cow herds. Other means of transmission include artificial insemination with contaminated semen and mechanical transmission by insemination instruments or by gynaecological examination using contaminated instruments.

Bulls from multiple sources commingling on community pastures, sharing of bulls by multiple herds, and purchasing and using untested older bulls pose the greatest threat of spreading the disease.

Prevention

There is no licensed vaccine in Canada for trichomoniasis.

An effective biosecurity plan is essential to prevent the introduction of infectious diseases like bovine trich into a herd. Continuous evaluation of biosecurity procedures is important. Commitment, dedication and persistence by all farm staff including owners and visitors is required for successful implementation of biosecurity.

The key elements of a bovine trichomoniasis biosecurity strategy include:

Cow management

• use as many home-raised heifers as possible
• only buy confirmed pregnant heifers if outside replacements are needed
• do not buy open cows with unknown clinical history
• cull open cows at pregnancy check and test cows that have recently aborted

Bull management

• only use virgin bulls as replacements
• keep the average bull age as young as possible
• test all mature bulls for trichomoniasis at least 3 times at weekly intervals before introducing them into your herd
• avoid using or sharing bulls from unknown herd history

Breeding

• maintain a limited tight breeding season
• monitor the breeding period to detect signs of excessive repeat breeding
• control other reproductive diseases like campylobacteriosis with appropriate vaccinations
• consider implementing an artificial insemination program

Pasture

• maintain proper fencing of pastures to avoid mixing of animals from herds with unknown status
• for community pastures:
  • perform breeding soundness exams of all bulls before turnout
  • test all bulls for trichomoniasis at least 3 times before the breeding season starts
  • only allow virgin heifers or cows with their calves at foot

Diagnosis

Testing bulls rather than cows for trichomoniasis is more rewarding and economical; infected bulls are the main source of introducing the infection and there are fewer of them to test.

Collection, culture and laboratory examination of the smegma from bulls is the diagnostic technique for field use. Polymerase chain reaction (PCR) testing of smegma is used by many diagnostic laboratories.

The chance of detecting the parasite is increased if the bull is separated from cows for at least 2 weeks before testing.

Treatment

Currently there are no approved treatments for trichomoniasis for either bulls or cows.

Resources

• BeefAIChoice decision-making tool
• A more efficient screening test for trichomoniasis (Beef Cattle Research Council)
• Keeping trichomoniasis out of cattle herds (Canadian Cattlemen)
• What is Bovine Trichomoniasis? (Oklahoma State University)