[Fomite]

There's three reasons for using antibiotics in livestock:

1. Growth promotion 2. Prophylactic treatment (what you're suggesting) 3. The treatment of actual disease

Those go from the most to the least problematic - but I was mostly addressing the idea that a decrease in antibiotics would result in more animal products with bacterial contamination. For #1, that's not true, and for #2 it's not linear (infections in animals don't necessarily mean contaminated food products).

When we talk about reducing antibiotic use in livestock, it's usually focused on #1 and putting #2 in the hands of vets (prophylactic treatments when there's actual risk of disease). Rarely do we actually suggest banning #3.