Trich: testing the ‘tip of the iceberg’ as Wyoming finds more casesWritten by Christy Martinez
According to Wyoming Livestock Board (WLSB) Lead Animal Health Specialist Douglas Leinart, the 2010/2011 trichomoniasis year was a busy one.
“We had 34 bulls test positive out of 8,398 head tested, and that’s the most bulls tested in a season ever,” says Leinart. “While 34 positive cases is about average, Wyoming did set a record for the most premises across the state that had trich, as 16 total ranches had one or more bulls test positive.”
“It’s not going away, obviously,” says Wyoming State Veterinarian Jim Logan of the state’s trich problem. “The numbers are up because there are more cases to be found, and the disease is continuing despite the fact that we have rules, and so do other states, requiring testing.”
Leinart says the record numbers might be due, in part, to the new state trich rules that require contact herds to test their bulls.
“In keeping with the new rule, the WLSB sent out 125 letters to known contacts of trich-positive herds, informing them of the requirement to test their bulls,” says Leinart. “The direct result of this, undoubtedly, is the record number of trich tests being done. More bulls getting tested as a result of the new rule boils down to more trich-infected herds being discovered.”
Leinart says that will hopefully lead to a decrease in positive bulls and affected ranches over the next few years, and an overall decrease in the prevalence of the disease.
Logan calls Wyoming’s trich program “semi-active surveillance.”
“We require testing on a change of ownership and on bulls on common grazing allotments, but that leaves a huge number of bulls that are never tested,” says Logan. “As a result, trich could be sitting in herds that may not ordinarily go on common grazing, so for several years it could sit in a herd, and if the cows aren’t preg tested and the producer doesn’t wonder about a lower calf crop, this disease can sit there for a long time.”
Leinart points out another statistic of interest – the number of bulls tested using Polymerase Chain Reaction (PCR) laboratory test procedures.
“This number has only been tracked and counted since the beginning of the 2010/2011 season, so numbers are not available for previous years, but 1,984 bulls tested using PCR, or nearly 23 percent of all tests, and that represents considerably more PCR testing than has been done in the past,” he explains.
Leinart says the number for PCR and the number for culture tests adds up to more than the number of bulls tested because some bulls were double-tested, and currently there is no method to identify how many bulls were tested with both procedures or just one or the other.
Of the trich situation in Wyoming, Logan says, “We can continue with the type of testing we’re doing, and we’ll never get it cleaned up based on testing common grazing allotment bulls without doing additional surveillance and cleanup. So far the industry and the board has not been in favor of expanding the test requirements, though I have requested, as have some industry people, that the board go a little farther with test requirements.”
“We’re testing the tip of the iceberg, so we’re finding the tip of the iceberg, and we’re running into the same thing in other states,” adds Logan. “Until there’s an active, stringent test requirement it will continue to fulminate.”
Logan says other states are facing the same problem as Wyoming. He says Utah has more strict requirements, requiring all bulls over nine months old to be tested every year one time, but he says the problem is they don’t do a great job enforcing, so they, too, continue to fight trich.
WLSB has conducted several trich certification courses for veterinarians and seminars for livestock producers to discuss the disease and Wyoming’s program to control it. Logan says vets have to be certified every five years for trich sample collection procedures and sample handling and diagnostics.