Different solutions to the same problem
June 19, 2013
Trichomoniasis (Trich) can sneak into a cattle herd without obvious signs, until cows are observed returning to heat when they should be pregnant. This sexually transmitted disease is caused by protozoa living in the reproductive tract of cows and the sheath of bulls. It occurs most often when ranchers use untested bulls, purchase open cows with an unknown background, or when cattle herds co-mingle in community range pastures. Trich has been a problem for many years in western states, and most of those states have taken steps to try to control it, with import regulations and testing.
Dr. Dustin Oedekovan, the South Dakota State Veterinarian, says this is a simple disease to clean up in one season, as compared to something like Johnes disease. "But the patchwork of state regulations makes it hard for producers and veterinarians to navigate those rules from state to state. Several states are working on trying to harmonize those import regulations, but producers in different parts of the country have different attitudes about how strictly they want to regulate it," he said.
"In South Dakota we had no regulations before 2005. We treated it as a production disease that was handled by producers and veterinarians. That year we had 45 infected herds, most of them west of the Missouri River. Our livestock industry wanted some regulations to help prevent the spread of this disease," he explained.
The Animal Industry Board adopted some rules in 2006. Since that time, the incidence of Trich has dropped. "Last year we had no cases reported, but now in 2013 we recently had three cases, in two different areas of the state," Oedekovan said. The most recent case was discovered in a Tripp County beef herd.
South Dakota has an import requirement for bulls. "Any non-virgin bull that comes in for breeding purposes has to be tested. We recognize pooled samples, one PCR test or three cultured tests. We also have the same requirement for any bulls sold within our state. Something we also do here in South Dakota, that is not as common the farther west you go, is that we also consider the cows, reminding people that this is a sexually transmitted disease and there are two sides to this equation," he said.
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"One way this disease gets spread is via cows that have been infected and lost a pregnancy and maybe re-bred (and infected the bull that re-bred them). So we have a restriction on both the import and sale within the state of non-virgin, non-pregnant cows (open cows). There is a chance that those cows lost a pregnancy due to Trich." Anyone who buys open cows and plans to breed them is taking a huge risk, not only for Trich but for several other diseases.
Dr. Susan Keller, of the North Dakota Board of Animal Health, says that in North Dakota Trich was first dealt with as an education and outreach effort. "If producers managed their herds properly, the feeling was that we didn't need a lot of regulations. The problem is that even if a person is managing their herd and the neighbor is not doing things properly, there is still risk because fences don't always keep animals where they belong. We are happy that most states now have some regulations in place, but they are all a little different. I'm not sure we are ever going to get consistency, but at our regional meetings we talk about this, trying to come up with consensus, to make it easier for producers to remember the requirements," she said.
"South Dakota and some of the other states have had some major Trich issues, so now we address open cows. Any open cows coming into North Dakota have to go to a dry lot or feedlot situation for feeding and slaughter purposes only. Simply addressing the bulls and saying they need to have a negative Trich test is looking at only half the problem," Keller said.
"Our state has not had Trich for a long time. But if you think you don't have a problem there is not a lot of testing going on and the disease could sneak in. Our Extension and Board of Animal Health messages and private veterinarians deserve a lot of credit because they are telling producers to never keep open cows and to only buy and use virgin bulls or bulls that have been tested, from a known source," Keller explained.
"Some people don't think they have Trich because their cows are pregnant, but they have cows that re-cycled and calved late. They might not realize that having late cows (different ones each year) can be an indication of Trich in the herd. Cooperative grazing associations can get stung hard by this disease, so it is important that they have their own requirements for animals coming into those pastures, especially testing requirements on bulls," she said.
Dr. Jim Logan, Wyoming State Veterinarian, says that when he came on board in 1998, Wyoming didn't have any rules for Trichomoniasis. "There were a few times, such as in the 1980s, when the Livestock Board implemented test requirements on six counties in western Wyoming, where all bulls had to be tested. After that was dropped, we didn't have any requirements for testing. In early 1998, cattle producers had major concerns about Trich and requested that the Livestock Board develop some rules."
In 2000, the Livestock Board established the first rules for Trich in Wyoming. Since then, those rules have undergone several revisions. "We have a state-wide rule and also a rule for a special focus area in the southwest part of the state where we have problems. State-wide we require testing for bulls imported into the state, with exemptions for virgin bulls. We require Trich testing for all non-virgin bulls that are turned out on common grazing pastures. We have change of ownership testing for non-virgin bulls, and an ID requirement for any bulls that are tested. We coordinate with Idaho, Montana, Colorado, Utah and Nebraska on the color of tag for a given year. Cattle from all five states end up in some grazing areas, so they need to match," he explained.
"If we find Trich in a herd, we quarantine all sexually intact cattle in that herd, including females. We require bulls to be tested if the producer plans to keep them, or allow them to be sent to slaughter. But they have to go with a V brand on their left hip and must go to slaughter on a VS1-27 form, which is a quarantine movement form. In Wyoming they also have to go with a brand inspection," Logan said.
"If a producer opts to keep bulls in an infected herd, they have to be tested and Trichomoniasis certified negative. This means they either have to be tested three times with a culture test or two times by the PCR test, or one culture and one PCR test," he said.
"We continue to see some cases, partly because the industry has not wanted to support testing all bulls in the state, even if it was just one time, to find the pockets of infection. I am sure we'll continue to have cases until we can do more testing."
This last year, several related cases were found in Washakie County. "We got it under control but will continue to watch that situation to see if it keeps cropping up. In Uinta, Lincoln and Sweetwater counties, in the southwest, for a number of years we've had continued cases, some in the same herds and some in related herds, for six years or longer," he said.
"As a result, producers asked the Livestock Board to create more stringent requirements for testing in those three counties. A year ago the Board adopted an order that required testing of bulls at 9 months of age and older, and required all bulls that were going to be turned out to have official Trichomoniasis identification even if they were virgin bulls," says Logan.
"Our current board order in that area requires bulls of any age (unless they are still nursing their mothers) to be tested. We are also requiring anyone who doesn't have a six month or less calving season to gather and test their bulls," he said.
"Our statewide requirement when we quarantine a herd is that not only are the bulls quarantined, but the cows as well. In order to be released from the quarantine, the producer has to develop with us a quarantine release plan, which includes that the cows be pregnancy tested and pregnant at least 120 days. Or if they are not pregnancy tested, the producer must be able to verify that the cows have been away from sexual contact for a minimum of 120 days. Hopefully this will reduce the instance of Trich," said Logan.
Dr. Tahnee Szymanski, Assistant State Veterinarian, Montana Department of Livestock, says Montana has requirements for imported animals. "Non-virgin bulls coming into this state must have a negative test. Animals in Montana grazing in common require an annual test. We have four counties that are designated as higher risk areas. These are Glacier, Pondera, Yellowstone and Bighorn counties. Any change of ownership within those counties or all movements out of those counties require a negative test on bulls," she said.
Montana recognizes three negative culture tests, a single individual PCR, or a pooled PCR. "The only time we don't recognize pooled tests is for active disease investigation. If it's a positive herd that has test requirements we need more specific individual tests."
"We had a significant outbreak in central Montana in 2011-2012. Based on how that investigation progresses and what we learned about our regulations, and feedback from producer organizations within the state, we will likely propose some rule changes in the coming months. This would change regulations for the positive herds, but not the general program of testing," she explained.
Montana currently has had two new positives this spring, in Yellowstone County, and they were related.
For more information about Trich and current numbers visit: http://msuextension.org/publications/AgandNaturalResources/MT201210AG.pdf
The Montana Department of Livestock (MDOL) website has information about Trich in Montana, it can be accessed here: http://www.liv.mt.gov/ah/diseases/Trichomoniasis/default.mcpx