The other half of that sentence is important too:<p>&gt; ... or prevent future illness<p>The future illness that they&#x27;re often protecting the animal from is the natural result of feeding the animal an unnatural diet (corn, soy, etc...stuff that&#x27;s cheaper than what the animal is historically fed). The illness that&#x27;s being prevented isn&#x27;t just possible, it&#x27;s what would be expected without the antibiotic. Any controls on using antibiotics would need to include provisions for banning them in situations where the health of the animal was knowingly compromised. Otherwise, you create a loophole that allows the industry to make the animals sick and then use antibiotics to treat the sickness they caused.