In the last 10 to 12 years we have had a new disease come into our area of northwest Arkansas. It has been traveling east for quite some time. The name of this disease is TRICHOMONIASIS, caused by Trichomonas fetus. This disease causes early embryonic death of the fetus, usually in the first 90 days, but may also cause late-term abortion. This is a true sexually transmitted disease (STD) of cattle. Bulls that are infected with Trich (pronounced 'trick,' short for Trichomoniasis) act and appear normal but they continue to spread the disease. Trichomonas fetus lives in the prepuce of the bull’s penis and is transmitted to the cow during intercourse or breeding. This organism is a protozoon and will live in the prepuce of the bull for the rest of his life and for up to four to six months in the cranial vault of the vagina of the cow.
The only way to know if you have this disease in your herd is to test. You might be suspicious if you notice a lot of cows either open at preg check time or see a lot of cows breeding back within the first trimester of pregnancy. Cows are hard to test for this disease since they will clear the disease within four to six months. The only accurate way to check a cow is to catch her in heat and do a cervical scraping. The bull on the other hand is very easy. At any point in time you can do a preputial scraping. This is done with a hard plastic pipette with the bull in a secure squeeze chute. The pipette is put into the bull’s sheath and ran back and forth until you have some pink liquid and tissue in the pipette. This sample is then sent to the lab for either culture or PCR (Polymerase Chain Reaction Test), read under the microscope after a few days of incubation and results are sent back within the week. The PCR has greater specificity and greater sensitivity. Plus, the results are not taking 10 to 14 days to get back. It has also been shown scientifically that only two PCR tests done at two to three week intervals will validate a bull negative. If using the culture method we will need three tests done at two to three week intervals to validate a bull negative.
The reason we test more than once when dealing with this disease is the variability with sampling and testing procedures. One positive test will knock the bull out. No approved treatment or vaccine exists for bulls. So, this will mean the bull goes to the packer and is sold. And because this disease can knock out 50 percent of your calf crop in just one year, I would like to be sure we have eliminated the disease from your herd. With the cows there is a vaccine that will help some. However, I do not know the efficiency of this vaccine and the cost is quite high. The first year it takes two doses two to four weeks apart and then yearly boosters at a cost of around $5 per dose.
In the last 10 years I have diagnosed Trich three times. I just diagnosed Trich in a herd of cattle in Washington County, Arkansas last month. Now to get rid of Trich we have to test all bulls at least twice with the PCR test. Then I recommend preg checking all cows. Any bull testing positive at any time will be culled and sold for slaughter only. Any cow that is not second stage pregnant or that does not have a calf under two months of age will be culled and sold for slaughter. With the cows you do have another option and that is to keep all cows and give them six months sexual rest. Then you can turn in Trich validated negative bulls to start breeding again.
The six month hole in breeding will mean no calf crop for almost 18 months and no calves to sell for at least one to two years. This puts a serious drain on your cash flow and pocketbook.
Our state veterinarian has already put an emergency law in force requiring all non-virgin bulls coming into our state to be tested negative for Trich. This regulation is Act 87 of 1963 (Code 2-33-101) and Act 150 of 1985 (Code 19-6-448). This regulation states that any bull brought into this state without being accompanied by a negative test for Trichomoniasis shall not be comingled with any cow unless the bull is tested and found to be negative for Trichomoniasis prior to comingling. This was enacted under the emergency provisions of the state veterinarian May 15, 2009, and is going from emergency to standard law right now. I encourage anyone buying bulls out of state to have them tested negative for Trich prior to bringing them into our state and your herd.
Dr. Tim O'Neill owns Country Veterinary Clinic in Farmington, Ark.
