Del Mar has made changes to its Polytrack and turf course after nine horse deaths in the first nine days of its summer meeting.
Wax was added to its Polytrack, which has been very fast, resulting in track records even from a claiming horse.
The new turf course, considered very firm, has received more water, been aerated and the rail will be put out to 18 feet, making it a softer surface for horses, officials said.
"Everything they've done makes sense to me and hopefully it will take care of whatever issues there were," said Dr. Rick Arthur, equine medical director for the California Horse Racing Board.
Arthur said safety stewards arrived from Sacramento earlier this week to meet with track personnel. Investigations continue on the horse fatalities. There were four in a 48-hour period, including three after injuries racing on the turf, resulting in euthanasia.
Racing on the turf course was suspended for Sunday's races and is set to resume Wednesday.
"There's seldom a single explanation," Arthur said of the horse deaths. "We take these things seriously and look into all aspects of it. Racing should be safe."