Based on the results of an investigation by Purina Animal Nutrition, the California Horse Racing Board (CHRB) has announced its licensed feed vendors can once again deliver some of the manufacturer’s sweet feed products previously found to contain the drug zilpaterol.

On March 22, the CHRB reported that a number of sweet feed products containing a molasses base produced by Purina at its Turlock, Calif., mill contained zilpaterol (a beta-2 agonist used to promote weight gain in livestock), which is prohibited in racing and many other equestrian sports. The CHRB subsequently dismissed 48 zilpaterol-positive drug tests from March 1 to March 26, citing feed contamination.

In an April 3 statement, the CHRB said, "The California Horse Racing Board has received assurances from Purina that feed produced at their Turlock plant no longer contains zilpaterol. Independent testing of the new Purina feed by the CAHFS (California Animal Health and Food Safety) toxicology laboratory at the University of California, Davis, was negative for zilpaterol in all samples submitted. Accordingly, the CHRB will allow CHRB-licensed feed vendors to deliver any Purina products that were milled at Purina’s Turlock plant on and since March 27, 2013."

According to an April 3 statement from the feed manufacturer, "Purina does not use zilpaterol in any plant. Our investigation has revealed that small amounts of zilpaterol were included in a single ingredient supplied by a vendor to the Turlock plant in February. Purina and Country Acres products produced at any other Purina plant were not impacted and can be used without restriction.

"We have not had any reports of health issues caused by zilpaterol and don’t anticipate any given the low levels detected in the feed," the statement continued.

The feed manufacturer recommended owners of horses taking place in competitions either stop or avoid using "Purina or Country Acres feed produced between Feb. 14 and March 26 at the Turlock plant. Competitive horse owners should contact their feed dealer for replacement product."

Purina noted that owners can check the bottom seam tape on feed bags to determine when and where the product was produced. Products manufactured at Turlock will have the letters ‘TRL’ in the date code, the company explained. Date codes are formatted as follows: Example 3MAR15TRL1— 3=Year (2013) / MAR= Month / 15=Day of Month / TRL = Plant Code (Turlock) / 1 = Shift Code

Purina said it stands behind its satisfaction guarantee, and horse owners with questions can contact their customer service department at 800/227-8941.