Recent outbreaks of equine herpes in Ohio and Kentucky have prompted River Downs race track to impose new restrictions on horses stabled at the track.

Horses brought to River Downs when the track opens its backstretch for training on Saturday will be required to have a veterinarian-approved health certificate noting the horse's temperature within the previous 24 hours.

"While it may be an inconvenience to some horsemen, they should understand that it is a precaution we are taking to protect the entire equine community on the backstretch," said racing secretary Ed Vomacka.

River Downs' racing season begins April 12 and continues through Labor Day.

About 70 horses that had been confined for nine days because a strain of equine herpes was found in three horses at Turfway Park were allowed to resume training Thursday.

Other than training, the horses will remain in the barn until April 5, when a 21-day quarantine ends, as long as no more cases surface.

Turfway Park, in Florence, Ky., is about 15 miles from River Downs.

In Ohio, stable owners have canceled horse shows and clinics, fearing a virus that killed 14 horses at the University of Findlay could spread.

Although the virus has been eradicated at Findlay's equestrian complex, it is suspected in the recent death of a horse in Lake County. Two other horses in western Pennsylvania have died from the disease.