IMO….Lack of enforcement. As I understand it at the state level there is one official to cover all animal feed sold in the state. Depending on the state, and I’d guess funding, there are likely lots of holes in the system. Additionally, I think smaller companies are more likely to fly under the radar. Months ago I reported an illegal label to my state official. The official agreed and said the food was being sold in the state illegally….. but it is still being sold here. Shrug
Products sold for tear staining that contain tylosin have been sold for years but from this it looks like it is just recently that the FDA is acting on it http://www.fda.gov/ICECI/EnforcementActions/WarningLetters/2014/ucm411975.htm
