Two weeks ago, the Agriculture & Livestock page featured a story about the new trichomoniasis rule in Colorado. Information for the article was provided by assistant state veterinarian Nick Striegel.
This week, Striegel answers questions about “trich.”
First, a reminder that trichomoniasis in cattle is caused by a small protozoan parasite, Trichomonas foetus (T. foetus). The organism causes a venereal infection that can affect dairy and beef cattle, resulting in fertility problems such as early embryonic death or abortion of the calf, and delayed calving seasons.
Trich is spread by bulls during calving season. Some people believe that cows may carry the organism and spread it to other bulls.
The Q and A follows:
Q: Under what circumstances is a cattle herd quarantined because of trich? What are the conditions of the quarantine and when is the quarantine lifted?
A: Once a bull has a positive test for trich, that herd, including cows, is quarantined.
The infected bull goes to slaughter (since the bull cannot clear the infection). After a week, the other bulls that tested negative are tested again. If a PCR test was used both times and the bulls test negative again, the quarantine is lifted.
If a culture test was used, a total of three tests, including the first one, must be negative. (See the second question for test information.) All cows exposed to the positive bull must be quarantined until: (1) preg tested and found to be 120 days pregnant or (2) have a calf at side and have had no exposure to bulls or (3) have a documented 120 days of sexual isolation.
Q: What are the two trich tests? Is one of them better than the other?
A: The two tests are “culture” and “PCR.” They are both good tests. For both tests, a sample is taken from the sheath around the penis. The sample is placed in a pouch or transport system and sent to a lab. The sample much be reached by the lab within 48 hours. For the culture test, the sample is grown in media. The PCR test involves DNA testing. Some feel that the PCR test is a little more sensitive.
Q: Is there a test for cows?
A: There is no test for cows.
Q: Are all veterinarians accredited for collecting samples of T. foetus?
A: Veterinarians who are licensed in the state and are accredited to do regulatory testing and to write health certificates can do trich tests. Veterinarians do receive special training on taking trich samples.
Q: How long does it take to get the results from trich testing?
A: The sample has to be received by the lab within 48 hours after it is collected. It usually takes about five days from the time of testing to get the results. However, that may not include mailing time.
Q: What is the approximate cost for trich testing?
A: It’s dependent on the distance the veterinarian has to go to get to the ranch versus taking the sample at the clinic. A fact sheet with some scenarios can be found at www.colorado.gov/ag/. Sometimes a “pooled” PCR test is done. The lab takes five samples and puts them in a pool. If the sample comes back negative, that’s all that needs to be done. However, if it’s positive, the individual samples have to be checked for the identity of the positive bull. The pooled PCR test can save money.
Q: Is there treatment for cows with trich?
A: There is no treatment for bulls or cows. Bulls that are positive for trich have to be slaughtered. A great majority of cows clear the infection on their own. However, some believe that cows can carry trich into the next year.
Q: Is trich found only in the U.S.? What is the status of trich in Colorado?
A: Trich has been diagnosed worldwide. As of May 30, there were five positive locations for trich in Colorado, involving five counties.
Q: What should ranchers know if they’re selling bulls out of state?
A: If ranchers are selling bulls out of state, they need to check on that state’s regulations about trich. The regulations differ from state to state. For example, they need to know what type of trich test that state will accept. Some states do not accept the pool type of testing.
Information about trich can be found on the website at www.colorado. gov/ag. Also, if you have questions or comments about trich, you are invited to call the state veterinarian’s office at (303) 239-4161.
Thanks go to Dr. Nick Striegel for his time in answering the questions.