Trichomoniasis Challenge is Growing
“Trichomoniasis can be economically devastating enough that some producers who have gone through it are no longer producers,” said Craig Payne, DVM, director of medical extension and continuing education at the University of Missouri (MU).
That’s because of the open cows and the extended calving seasons resulting from trichomoniasis (trich) infection.
Speaking at the Applied Reproductive Strategies in Beef Cattle (ARSBC) symposium in Joplin, Mo., Payne explained that the average number of open cows runs an average of 40%-50% in naïve herds exposed to trichomoniasis.
Incidentally, he explained, subsequent infections in a herd affect fewer cows because some will build immunity to the disease that can last up to 15 months.
There’s nothing new about trich, but it continues to grow beyond the western boundaries typically associated with it. For instance, Payne said, “Up until the last few years, the disease was almost non-existent in Missouri, but now it’s being diagnosed with greater frequency throughout the state.”
More states — Missouri most recently — are developing or revising trich regulations, including requirements for bulls to be tested prior to selling.
Trichomoniasis is a venereal disease caused by a protozoan parasite spread primarily by infected bulls to cows. There are no physical signs of the infection in bulls; their libido and fertility remain the same, Payne said.
He noted that bulls can be infected chronically or transiently. Though there are exceptions, bulls 3 years old and older are usually chronically infected, while younger bulls are more likely to have a transient infection.
Likewise, Payne said, there are few tell-tale signs in cows and heifers. Sometimes infected females may exhibit a mild vaginal discharge. Though the infection leads to inflammation, it doesn’t interfere with conception. Instead, embryonic death occurs, usually within 50 to 70 days of gestation.
Less than 15% of the time, Payne noted, there can be late-gestation abortions. Though more rare, some infected cows can also develop pyometra (a heavy, pus-filled uterus).
“Cows and heifers typically return to estrus one to three months after breeding, but a period of infertility may last for two to six months as a result of the infection,” Payne said. "Occasionally, cows may become permanently infected, yet be able to deliver a normal calf. This condition is rare, but of concern because these animals can serve as a source of infection to bulls in the following breeding season.”
Producers often discover trichomoniasis only after a calving season is squandered. Salt in the wound comes with the fact that there is no treatment for infection in bulls or cows.
If trichomoniasis is diagnosed in the herd, Payne explained, infected bulls will need to be removed, open cows should be culled, and only tested trich-free bulls or virgin bulls should be used as replacements.
“If trich is suspected, your veterinarian is the most qualified person to collect samples and make the diagnosis,” he advised.
Payne spoke during an evening session of the ARSBC symposium hosted Wednesday evening, Aug. 31, at the Joplin Regional Stockyards. Summaries of other presentations at the ARSBC wil be available online at www.appliedreprostrategies.com. Compiled by Angus Productions Inc. (API; publisher of the Angus Journal and the Angus Beef Bulletin), the site is made possible through sponsorship by the Beef Reproductive Task Force, SEK Genetics, and liveauctions.tv. Coverage will include summaries of the speaker presentations, PowerPoints, proceedings and audio.
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