The problem here is not the treatment of sick animals. It is giving antibiotics at “sub-therapuetic” levels to all the animals, sick or not.
It really is a bad idea. Any widely used antibiotic will eventually cause bacteria to develop resistance, but using them when not really necessary to treat disease accelerates the process considerably.
People have forgotten how devastating bacterial infections used to be. Personally I’ve had at least three that 100 years ago would have either killed me or led to a limb amputation. We are in essentially a race between our ability to develop new antibiotics and the ability of bacteria to evolve resistance.
In the long run, put your money on the germs. But that’s no reason to handicap ourselves by using these drugs when they aren’t needed.
I agree that using subtheraputic antibiotics on all animals, sick or not, is a very bad idea. However, so is a ban enforced by the FDA. The administration of the antibiotics is a mitigation for an abusive, unsanitary, and unsafe farming environment. This measure bans the mitigation, not the process that is using it. In doing so, it will make it more difficult and expensive for me as a farmer who does not administer antibiotics as part of a routine to otherwise healthy animals.
I recently finished Superbug: The Fatal Menace of MSRA, by Maryn McKenna, a medical writer at the Center for Infectious Disease Research at the University of Minnesota. Certainly, the title of the book is overblown, but McKenna's an award-winning writing on epidimeology and she describes in detail the battles hospitals, clinics, NBA and NFL locker rooms (and the USC Trojans), prisons, and communities wage with methicillin-resistant staphyloccocus aureus.
One of the major breeding places for MSRA? CAFOs (Concentrated Animal Feeding Operations), because of the antibiotics given to animals to keep them healthy long enough to put on weight. A minor breeding place? All other breeding operations that use antibiotics for that purpose - and the manure that comes from those breeding operations.
Each time we use antibiotics, even for therapeutic purposes, bacteria develop resistance. We're wasting our limited number of therapeutic uses by giving these sub-therapeutic doses to livestock - or at least we need to realize that we've making a trade off, and we need to consciously make that trade off. Less expensive beef and pork, or more effective antibiotics for humans.