Trich leads to test requirements for bulls coming into Missouri

May 17, 2010
by WLJ

Trichomoniasis is a reproductive disease in cattle caused by a protozoan parasite that results in early pregnancy loss. It is passed from bull to female during breeding, and infected bulls show no symptoms.

“For years, it has been viewed as a disease in western states, and those of us in the Midwest were not too worried about it. However, in the last five to 10 years, the disease has surfaced on more Missouri farms,” said Eldon Cole, a livestock specialist with University of Missouri (MU) Extension.

Increasingly, states to the west and south of Missouri have established health requirements for bull traffic into and within the states to prevent the spread of “trich.”

On March 1, 2010, Missouri began a negative test requirement for bulls over 24 months of age that are coming into Missouri. So far, Cole says intrastate movement of bulls is not being affected.

A natural immunity can help clear the parasite from the cow’s reproductive tract. Unfortunately, this isn’t permanent and the female can become reinfected in the future.

Bulls over three years of age rarely clear the parasite and they become long-term carriers of the problem.

Public enemy Number 1, as transmission of trich is concerned, is older bulls. Virgin bulls should be free of the trich organism.

The new polymerase chain reaction trich test only requires one test in stead of the three procedures used in the past. Veterinarians often recommend in high trich incidence areas that all non-virgin bulls be tested during breeding soundness exams and before turnout time.

In the meantime, Cole says to monitor the breeding activity in your herd and take action quickly if several females thought to be bred start cycling.

He also recommends limiting your breeding season to 90 or fewer days, culling open cows, and avoid buying open cows and shortbreds.

Vaccination of females may be a consideration, but it does require a booster.

For more information, contact any of the MU Extension livestock specialists.— WLJ