A recertification process is now regulating stockmen, nutritionists and veterinarians that feed Zilmax growth promoter to cattle.

The markets were stirred last week when Zilmax, a zilpaterol product used to boost muscle gain and feed efficiency, was linked with reports of non-ambulatory cattle by Tyson Fresh Meats.

Merck, the product manufacturer, has maintained that Zilmax is a beneficial and safe supplement that is FDA approved.

Tyson expressed concern over sightings of lame cattle in a letter to cattle feeders last week, although expressed uncertainty regarding the cause of the lameness.

Animal health experts were cited as saying that Zilmax is ‘one possible cause'.

Tyson asserted that the issue was not one of food safety but of animal well-being and that the ban was an ‘interim measure’.

The recertification scheme – to be overseen by third party experts - heads a range of measures that intend to shed light on the lameness and well-being concerns noted in Tyson beef plants.

Yesterday, Merck released a five-step responsible beef plan that will ensure those using the product can mix feed appropriately and determine which cattle are ‘good candidates’ for the use of beta-agonists.

A scientific audit will also be released to beef packers and suppliers, to be issued within 30 days.

This will trace animals from the feedyard system to the packing plant to pin-point where lamness problems are occurring.

Third party experts will oversee the investigations, which will be bolstered by the creation of an advisory board, to be made up of industry stakeholders and specialists.

Merck has committed to transparency throughout and will share findings and put better understanding into management practice. Since Tyson’s announcement it has stood alone. Cargill, JBS Swift and National Beef have all stated that cattle fed zilpaterol will be procured as normal.

The National Cattlemen’s Beef Association has commended Merck for its actions.

Full clarification has been requested by the NCBA, which wants to see decisions based on science and not speculation.

The NCBA commented: “The five-step plan announced by Merck today will accelerate this process while ensuring that every feedyard worker handling Zilmax is properly trained and certified to use the product. In committing to retrain and recertify every customer using Zilmax they are going above and beyond what is required to ensure their product is used responsibly.“

It stressed that there is currently no evidence to say that banning beta-agonists will impact on the animal welfare concerns cited by Tyson.