Montana pushes back EVA testing rule

Cattle Market & Farm Reports, Editorials
Sep 3, 2007
by WLJ

The grace period for Montana’s new horse testing rule has been extended to Sept. 7.
The Montana Board of Livestock recently approved a new rule to require all horses coming into Montana be tested for Equine Viral Arteritis (EVA), a respiratory virus that also causes abortion in mares. The new testing requirement was supposed to go into effect on Aug. 20.

“That’s just too soon,” says acting State Veterinarian Dr. Jeanne Rankin. “Some of the tests are complicated and take a long time to run.” Also, a stallion could test positive because he contracted the virus naturally or has been vaccinated previously. If a horse tests positive for EVA, further complex tests that identify the specific virus must be run before the horse is allowed into Montana.

The complexity of the tests require specialized equipment, so veterinarians must send samples to either the National Veterinary Services Lab in Ames, IA, or the Colorado State University Veterinary Diagnostic Lab in Fort Collins, CO.

EVA spreads through the air, infected semen, and through the placenta to unborn foals. Often, stallions will not show symptoms of EVA, but still transmit it to vulnerable mares.
Montana’s new order requires imported stallions to test negative for EVA within 30 days before coming into the state. Or stallions can be vaccinated for at least 28 days before coming to Montana if they test negative for EVA within 10 days prior to the vaccination.
The new rule holds one exemption: Stallions that are brought to Montana for exhibition only and then return to their home state are not required to be tested for EVA.

EVA tests are not the only requirement for traveling horses. All horses that are transported into or out of Montana also must have a brand inspection, a certificate of veterinary inspection (a health certificate) and a negative Equine Infectious Anemia test (a Coggins test) within 12 months.

Many breeders artificially inseminate mares and EVA can infect a mare through semen so the donor stallion must be tested before a breeder ships semen, too. The Department of Livestock also requires horse breeders to ship imported semen with a general health certificate and a negative Coggins test on the stallion, as well as the negative EVA test.