Comments sought on proposed cattle "trich" program

Ranchers, cattle owners, veterinarians and other interested persons are encouraged to comment on Texas' proposed regulations to control Trichomoniasis, or "trich," a venereal disease of cattle that causes the early death of fetuses and abortions, resulting in infertility in cows and extended breeding seasons in a herd.

The comment period for the proposed regulations by the Texas Animal Health Commission will end Jan. 30, 2009.

"Trich infection often occurs when a producer unknowingly introduces into the herd a trich-infected bull, which in turn, infects cows during breeding. Likewise, infected cows can transmit the disease to 'clean' bulls, creating a cycle of disease. Cattle experts say that the extended breeding seasons, loss of a percentage of the calf crop, and strung-out calf crops resulting from trich infection can cause up to a 20 percent loss of herd income," said Dr. Bob Hillman, Texas' state veterinarian and executive director of the Texas Animal Health Commission, the state's livestock and poultry health regulatory agency.

In the absence of a national trich control or eradication program, all western states, except Kansas and Texas have taken regulatory action to prevent the introduction of infected bulls, and to control the spread of this cattle disease within their states.

After being approached by the Texas cattle industry regarding the need for Texas trich regulations, the 13-member governor appointed TAHC commission appointed a working group of cattle industry, veterinarians, university and allied representatives to provide recommendations to the TAHC on the components and implementation strategy for a proposed Texas Trichomoniasis Program.

"The working group met in September and made recommendations to the commission on the components of a proposed trich program. A proposed Texas trich program has been developed from these recommendations, focusing on breeding bulls," Hillman said.

TAHC commissioners are seeking public comments on the proposed trich rules, which will be published in the Texas Register by Nov. 28, 2008, so the input may be considered prior to their Feb. 24, 2009, commission meeting in Austin.

"The Texas Trichomoniasis Program, as proposed, would roll out in two stages," explained Hillman. "The first stage could go into effect in late March 2009 and would place new entry requirements on bulls entering Texas from other states. Breeding bulls would have to be officially identified and certified as virgin bulls, or be tested negative for trich within 30 days prior to entering Texas from any state."

Bulls could be certified as virgins until they were about 18 months old, as evidenced by the eruption of permanent incisors, and accompanied by a breeder's statement that the animal had not been co-mingled with heifers or cows. Bulls entering Texas without certification as virgin or proof of negative trich tests would be restricted to sale or movement for slaughter only."

"Culturing the trich organism is the 'gold standard' for testing bulls. In nearly all states with regulations, accredited private veterinary practitioners must be certified to collect a sample from the bull, and the laboratories must be approved to conduct trich tests," Hillman explained.

The system specified for Texas is the InPouch, which allows for the sample to be collected and incubated in the pouch. The cultured sample is then microscopically examined. Another test, the Real Time Polymerase Chain Reaction test (RT-PCR) can also be run on the incubated sample.

According to the proposed regulations, all the non-virgin bulls in a herd could be tested at the same time, and if results are negative, this single test would be sufficient for Texas import purposes for any of the bulls in the tested herd. For individual bulls not part of a whole herd negative test, three consecutive negative culture tests would be required, at least seven days apart; or two negative RT-PCR tests performed at least seven days apart.

"One positive test indicates that the bull is infected. In most states, a positive-test bull may undergo a confirmatory test before being classified as infected and restricted to slaughter only.

"Repeated tests are needed on individual bulls, due to the diffi- culty in collecting the tiny trich protozoa from the surface folds of the infected bull's reproductive organs. Oftentimes, a second or third attempt is needed to either assure the absence of trich, or to capture the organism in the collection pipette, so it can be cultured," explained Hillman. "If an entire bull herd is tested, statistically the disease, if it is present, should be detected on a single test of all bulls in the herd."

There is no effective treatment for infected bulls. To halt the spread of disease, these animals should be culled. As infected bulls age, they become persistently infected, as the surface tissues of the reproductive organs become more hospitable to the growth of the trich protozoa.

On the other hand, most infected cows can recover from the disease. The trich protozoa, which can colonize in the vagina, cervix, uterus and oviducts, will clear, if the animals are given three to four heat cycles of sexual rest. A small percentage of cows will not clear, and these cows should be culled. A cow's disease status can be identified through a veterinary examination of the reproductive tract.

Under the proposed regulations, trich would become a reportable livestock disease in Texas, requiring both negative and positive test results to be reported within 48 hours.