Campylobacteriosis

Campylobacteriosis is a venereal zoonotic disease caused by the bacterium Campylobacter fetus that affects the reproduction of dairy cattle.

Etiology

Campylobacteriosis in cattle is caused by the bacterium Campylobacter fetus subsp. venerealis, as well as its variants Campylobacter fetus subsp. venerealis biovars intermedius and C. fetus subsp. fetus.

Transmission

Most cases occur after the introduction of an infected bull or cow into a susceptible breeding herd. Possible sources of transmission include1:

  • Venereal transmission
  • Contact with feces, vaginal discharges, aborted fetuses and fetal membranes
  • Contact with contaminated instruments and bedding
  • Artificial insemination using contaminated semen

Susceptibility to infection varies between individual bulls; some become permanent carriers, while others appear to be resistant to infection.

cows laying down

Meanwhile, some cows can clear the infection rapidly, while others can carry the bacteria for more than two years.

Clinical Presentation

  • Infertility in the female
  • Early embryonic death
  • Abortions late in gestation (uncommon)
  • Increased number of services per conception
  • Mild endometritis

After infection, a cow becomes immune to the disease, but the bacteria can be found in vaginal mucus for more than one year after the development of immunity. As a result, the cow becomes an important source of infection for uninfected bulls.

Impact on Reproduction

The disease represents a large economic loss, because it has a significant impact on cattle reproduction, including:

  • Decreased conception rates
  • Infertility
  • When embryo loss occurs, the animal usually returns to estrus, but often with prolonged and irregular cycles
  • Bulls are asymptomatic and produce normal semen.

Diagnosis

A tentative diagnosis can be made by herd data (high return rates or poor pregnancy rates in herds using natural service) and can often be confirmed by laboratory means.

  • Bacteria isolation from aborted fetuses and fetal membranes
  • Identifying infected bulls: culture of sheath washings
  • Identifying infected cows: culture of vaginal mucus not a very sensitive test

In cows, treatment is not very effective, and particularly because diagnosis is often made in the late stage of the disease, it is usually best to wait for natural immunity to eliminate the disease. Routine treatment of bulls brought onto a farm can reduce (but NOT eliminate) the risk of them spreading disease2.

Treatment and Prevention

Success in treating infected cows depends on the stage of the infection. When the disease is in an early stage, response to treatment is fairly good. Routine treatment of bulls can reduce the risk of the disease spreading.

  • Maximizing biosecurity: close herds when disease is not present and treat suspected bulls with antibiotics before mating cows.
  • Vaccination is effective: although cows may remain carriers, fertility is greatly improved. Bulls are also vaccinated for treatment and for prevention, and it is the best way to maintain healthy herds.

Antibiotic treatment of infected animals has been attempted. Success in treating infected females depends on the length of time the infection has been established. When initiated in the early stage of infection, response to treatment is fairly good. If attempted at later stages, the results are questionable. Treating infected bulls with antibiotics has been successful in more recent years. Since the treatment is an extra-label use of the products involved, it is suggested that you consult with your veterinarian for prescriptions and instructions. Vaccination is reported to be an effective treatment for infected bulls; however, vaccination as a treatment has not been reliable in females.