There was a time when feeding milk replacers supplemented with antibiotics was considered a “blanket” insurance policy to protect calves from disease. But that practice has changed considerably. Industry data suggests that 20 years ago, roughly 20-40% of all calf milk replacer contained antibiotics. Today, it’s less than 5%.

When calf milk replacer became commercially available decades ago, adding antibiotics like oxytetracycline, neomycin, and chlortetracycline was a common practice. Often these were delivered at “sub-therapeutic” levels, meaning they were not intended to treat disease, but rather to promote growth.