By P.J. Huffstutter
CHICAGO (Reuters) - U.S. drugmaker Merck & Co plans to resume sales of the controversial Zilmax animal feed additive in the United States and Canada after it completes an audit of how the product is used, a spokeswoman said on Tuesday.
Merck halted sales of the muscle-building drug in August after Tyson Foods Inc. said it would stop accepting Zilmax-fed beef given some cattle were observed arriving for slaughter with signs they were having difficulty walking or moving. Merck has said it stands behind the safety of its product, but the pause added to global concerns over its use.
On Tuesday, a spokeswoman for Merck's Animal Health unit said that while "it is too early to speculate on when we will resume sales for Zilmax in the U.S. and Canada," Merck was pushing forward with its quality control program to ensure the drug was being properly used.
It is the first time that the company has said it intends to bring the highly successful product back to the market. It is unclear how big beef buyers may respond, given worries that lame or distressed animals could stir further criticism of their methods from animal welfare groups.
The email from company spokeswoman Pamela Eisele said Merck was "committed to completing this as quickly as possible, while also ensuring it is conducted appropriately and with rigorous scientific measures."
In a separate statement, Merck said it has formed an advisory board that includes representatives from meat processors, cattle feeder operations, producers, veterinarians, academics and industry consultants. The company declined to say who had been appointed to the board, which convened for the first time in October.
In August, Tyson Foods, the largest U.S. meat processor, said its decision to stop using Zilmax was not made over food-safety concerns. It said it did not know exactly what was causing the animals' behavior, but Tyson officials said animal health experts suggested that the use of Zilmax may be one possible cause.
Cattle carcass weights have dipped in recent weeks as feedlots rush animals to market to cash in on record-high prices but are no longer feeding them the growth promotant, analysts and economists said.
Feed lot operators have been peppering Merck with questions over if or when Zilmax sales will resume, according to nutritionists and feed lot owners who have spoken to Merck.
Lighter cattle weights have meant less beef at a time when there are fewer cattle going to slaughter. The combination of less beef and fewer cattle should mean record cattle and beef prices at least through the coming year, analysts have said.
(Additional reporting by Theopolis Waters; Editing by David Gregorio and Alden Bentley)