The California Horse Racing Board has determined that 48 positive tests for zilpaterol have resulted from feed contamination, The positives involve horses at all California racetracks. The contamination of the feed appears to have occurred in mid-February and the first positive was detected from a race run March 1.

After reviewing the situation, the executive director with the concurrence of the equine medical director, as required by law, has recommended to the Board that the current cases related to the contaminated feed be dismissed. The Board has agreed and the cases from March 1 to this date have or will be dismissed.

The contaminated feed has been identified, as described in the March 22 advisory, and horsemen are or should be aware of the contaminated feed, so the problem should pass quickly. If trainers have removed the feed, residues of zilpaterol in horses should be eliminated by week’s end.

The California Horse Racing Board issued a directive to all licensed CHRB food vendors. Click here to view the directive.

Trot Insider reported earlier this week Purina Mills Inc. is not affiliated with Agribrands Purina Canada Inc., which is the manufacturer of Purina brands in Canada.