Uh, I think your making it quite a bit more glamorous than it is. Feedlots are like if you were placed in a bathroom and given a buffet of a single food source that is designed to be both as cheap as possible whilst fattening you as fast as possible. Than having antibiotics given to you in order to survive the bacteria filled area.
Antibiotics are not given to animals for health reasons (at least not primarily). The antibiotics somehow help the animals grow faster for reasons that are not well understood. As a not so fun fact the vast majority of all antibiotics in the US end up being given to animals.
They are given for health reasons. It’s no longer legal in the US to give cattle antibiotics to encourage faster growth. It is legal to give them antibiotics to prevent/treat the liver abscesses they frequently develop as a result of their diet in the feed lot.
The FDA rules left a number of loopholes. Overall usage has declined and in some cases quite substantially, but they're still being misused. For instance animals can still be given antibiotics as a 'preventative measure.' In 2017, there were still 2.3 million kg of antibiotics sold for usage in cattle alone. [1] To try to give that number some context there are about 95 million head of cattle in the US, so that works out 24g per cow per year even at the current reduced rate.
Actually creates quite a sick motivation system if the FDA does close the loopholes. Growers would have an incentive for their animals to develop conditions requiring antibiotics, so long as it did not significantly risk the animal's health.
