Cow-Calf Corner: Challenging Times for Growth Promoting Implant Use

By Paul Beck

The U. S. Beef industry has used anabolic implants since the mid 50’s when Synovex-S was approved for use in growing cattle. The artificial equivalent to testosterone, trenbolone acetate (TBA), combined with estrogen like compounds has been in use since the late 80’s. The U. S. Food and Drug Administration (FDA) approved implants in use today as efficacious and safe for beef cattle production. There has never been a substantiated adverse event for humans since approval in 1956. All implants are approved for no withdrawal before slaughter, emphasizing their safety.

Label changes, effective July 1, 2023, make reimplanting within a production phaseoff-label use of implants unless the label specifically states it is approved for reimplanting.

What are the stages of production? 

There are currently 3:

1. “Beef calves 2 months of age and older” – defined by FDA as “Beef calves considered ruminating and nursing their dams from 2 months of age to weaning.”

The FDA states: “While there are cattle ear implants approved for use in this production phase, no implants are approved for use in a reimplantation program in this production phase of cattle.”

2. “Growing Beef Steers and Heifers on Pasture (stocker, feeder, and slaughter)” – FDA defines as “Weaned growing beef steers and heifers … intended only for slaughter (i.e., not for reproductive purposes) maintained on pasture and receiving the majority of their diet from grazing.”

The FDA also states: “While there are cattle ear implants approved for use in this production phase, no implants are currently approved for use in a reimplantation program in this production phase of cattle. Cattle in this production phase may only receive one implant during this production phase regardless of whether they are considered part of the subclasses “stocker”, “feeder”, or “slaughter”.”