Ask the Vet

A Clean Trich Test

(Robert Lagerstrom)

READER: We have a buyer for a 5-year-old bull we can no longer use. He wants a health certificate and a trich test before he will buy this bull. This is new to us; can you explain?

DR. McMILLAN: Absolutely. First, let's talk about "trich," or trichomonas foetus. This is a venereal disease caused by a single-celled protozoa. Bulls are carriers, and they become infected after breeding an infected cow.

Cows infected with trich often have early pregnancy loss and sometimes abortions later. The organism that causes this lives in the crypts or small folds on a bull's penis and prepuce. Those crypts increase in number and depth as bulls age, so older bulls are more likely to have become infected.

Transmission of trich occurs during natural breeding. A bull can infect a cow, and a cow can infect a bull. Most infected cows, however, eventually clear this infection. Bulls remain infected for life. That's why most trich control programs focus primarily on detection and elimination of infected bulls.

Every state has its own rules and import requirements with regard to cattle, and this can impact a trich-positive bull that is bought in one state and brought into another. A certificate of veterinary inspection, issued by a licensed and accredited veterinarian, is required.

In Texas, for example, as of this writing a breeding bull coming into the state must have a negative trich test (official) within the 60 days prior to entry. This is for breeding bulls more than 12 months of age. An official test means three consecutive culture tests conducted no more than seven days apart, one real-time polymerase chain reaction test (RT-PCR) or one direct-sample quantitative polymerase chain reaction (qPCR) test.

A good place to check state requirements for entry of cattle is

This is an easy-to-use resource that I've consulted in the past. Another resource is the destination state's veterinarian's office. It can provide the most current information and help with any questions you may have.

READER: We always use ear tags to identify our cattle, but I've been told these are not considered an official form of identification. What is official identification now, and should I be worried about it?

DR. McMILLAN: Every state has its own rules and import requirements for cattle, and Trich testing is almost always required for interstate transport. Your best resource for specific information is often the destination State Veterinarian's Office.

Some form of on-farm animal identification (ID) has always been a key to good herd management. This could include ear tags, brands, tattoos or a combination. Many on-farm systems, however, are not unique, so when an animal leaves the farm we need official ID. In the event of a disease outbreak, a workable system must be in place to trace movement of livestock, so we can quickly gain control of the situation. An official ID is almost always required now for interstate movement of show, breeding or sale cattle, and other types of livestock.

There is no national ID standard. Each state sets its own rules. As far as I can determine, all states recognize an official 840 radio frequency identification device (RFID), and an official 840 bangle tag. Many, if not all, still accept official USDA alphanumeric metal ear tags (silver bangs tag or orange calfhood vaccination tag)-- though, these are scheduled to be phased out in the next couple of years. Some states recognize official breed registry tattoos and brands.

Official ID tags have certain requirements. Each must be tamper-proof with a unique, preprinted, 15-digit number beginning with 840, the USDA shield and manufacturer's logo or trademark, and contain the statement "Unlawful to Remove." A herd ID number can also be printed on the tag. Only certain manufacturers produce these tags, which are issued to a specific producer, farm or ranch, and linked to the location identification system used by that state (usually the Premises ID Number).

COVID has shown us, diseases know no boundaries and spread quickly. The USDA has done a remarkable job keeping foreign diseases out of this country and controlling outbreaks that have occurred. Animal traceability will only become more important in the coming years.


READER: Your recent article about farm ponds and the potential dangers was very timely. I live in north Mississippi and train retrievers for field competition. We have a 5-acre training lake on our property. Memorial Day weekend, I was preparing to train and saw a strange, light blue film on the surface in two training bays I had set up. It looked like someone threw sky-blue, oil-based paint in the lake. Fortunately, I was aware of the dangers of blue-green algae and kept my dogs out of the lake. It cleared in about three days, but to be safe, I kept them out for a month.


-- Please contact your veterinarian with questions pertaining to the health of your herd. Every operation is unique, and the information in this column does not pertain to all situations. This is not intended as medical advice but is purely for informational purposes.

-- Write Dr. Ken McMillan at Ask The Vet, 2204 Lakeshore Dr., Suite 415, Birmingham, AL 35209, or email


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