That may be part of it. We use antibiotics because animals get sick. In the extensive agricultural circumstances of cows out in the pasture, they get sick as well, and they need antibiotics, but the volume used is not nearly as much because you're dealing with a single individual animal. You get more intensive circumstances if you have larger volumes of animals. Consequently there is a tendency to treat the whole group of animals, so the use goes up. I don't think it's fair to blame it entirely on modern agricultural practices.
On November 9th, 2017. See this statement in context.