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Veterinarians are working to harmonize trichomoniasis regulations between states, but rules can only do so much.
"Just because you go fishing in the river and don’t catch anything, it doesn’t mean there are no fish in the river,” says Carl Heckendorf, Livestock Disease Veterinarian for the Colorado Department of Agriculture. He was talking about the vagaries of trichomoniasis (trich) testing and all of those best laid plans that can be so easily undermined by contaminated samples, poor shipping protocol and the like.
“Producers get extremely frustrated that we don’t have a definitive test,” says Jeremy VanBoening, DVM, of Republican Valley Animal Center (RVAC) at Alma, NE.
Both of these comments illustrate some current challenges surrounding trich control.
On one hand, the risk of infection appears to be growing, especially in states where it hasn’t been found, typically.
In Kansas, for example, Bill Brown, DVM, Animal Health Commissioner with the Kansas Department of Agriculture, says 26 infected herds were discovered last year, the most ever. The number of infected herds has increased in Kansas for the past three years. According to Dr. Brown, at least part of the increase is due to more testing spawned by an 18-month-long producer and veterinarian outreach program that led to revised trich regulations in the state (more later).
“I believe trich is getting more attention today because we have seen an increased incidence of the disease in the past five years in states that have a large number of beef cows, such as South Dakota, Nebraska, Kansas, Missouri and Texas,” Dr. VanBoening says. “Outbreaks that started in South Dakota have moved south to Nebraska and now to Kansas.”
Trich is becoming more common further east, too.
“In addition, we’ve seen large numbers of cows and bulls moving from the extended droughts in the Southern Plains and Great Plains,” Dr. VanBoening says. “States have been shoring up their borders with regulations to keep the disease out, and that has certainly brought an increased awareness of the disease.”
“Many states have adopted regulations for trich testing for the interstate movement of cattle and that has brought it to the attention of more producers,” agrees Kathy Simmons, DVM, chief veterinarian for the National Cattlemen’s Beef Association (NCBA).
State regulations are the challenge on that other hand. The diversity of new and revised trich regulations can get confusing in a hurry for producers and veterinarians moving bulls—and breeding age females in some cases—between states.
For instance, Dr. Heckendorf, points out that over time, the minimum age states required for testing virgin bulls for interstate movement has varied as widely as 9 to 24 months.
“States range from having no trich requirements whatsoever to having programs that require testing of any bull greater than 12 months of age regardless of virgin status,” Dr. VanBoening explains. “Moreover, many states have recently added requirements for cows moving interstate. This can be a real challenge for veterinarians close to state borders with clients moving cattle between states for grazing, as well as auction market veterinarians that must comply with regulations of neighboring states.”
Some states allow PCR testing and some don’t. Some states with PCR testing allow pooling samples and some don’t. Some states require three negative culture tests conducted a week apart. One state even requires both PCR and culture testing. Depending on the state, a negative test result is valid for 30 days or 60 days.
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That’s before considering the inherent variation associated with collecting, preparing and shipping samples.
“When you’re underneath a five-year-old bull, and it’s snowing and blowing, you can try to do the best job in the world, but there will be variation,” Dr. Heckendorf notes.
“There are many challenges regarding trich testing including variation in sampling (preputial scraping), variation in incubation times, contaminated samples, shipping challenges to diagnostic labs, and variation amongst labs in their testing protocols/workflows,” Dr. VanBoening explains. “In addition some diagnostic labs are only running PCR testing on certain days of the week, which can present a challenge when results are needed to complete CVIs (certificate of veterinary inspection)for cattle movement.”
Last fall, Dr. VanBoening asked one of RVAC’s technicians to call and ask ten different diagnostic labs these same four questions:
- Can your lab do PCR testing and how many can be pooled?
- Do the samples need to be incubated and for how long?
- How should the samples be sent to your lab?
- What is the labs preferred collection medium?
Not even two labs’ answers were in complete agreement.