The update allows for a lower targeted
dose of 60 milligrams of the drug’s active ingredient, zilpaterol
hydrochloride, per head per day through “one of multiple daily feedings,” such
as in a morning or evening feeding, Merck said.
Merck withdrew Zilmax from the market
last year after several leading meat packers refused to buy cattle raised with
the help of the product.
They were concerned about lameness and
some cattle deaths.
The upshot of further research was a
reduction in the maximum amount of Zilmax an animal was allowed to consume. As
feedlots kept cattle longer to bring them to heavier weights, the amount they
consumed had gone up.
There has also been advice about
limiting the length of time cattle are on Zilmax.
