Working with livestock is always a matter of biology and nothing ever occurs exactly by the book.
Should unexpected health problems occur, it is also a sign of good stockmanship and animal welfare to help the animals if a solution is available. No Antibiotic use is challenging, but not impossible. It can be a guideline, a goal to achieve, by laying out the best production standards possible, by providing the best type of feeding optimized for performance and gut health, and by trying conscientiously to keep all pathogens out as much as possible.
The world health organization aims to increase awareness of global antibiotic resistance and wants to encourage best practices among the general public, health workers and policy makers to avoid the further emergence and spread of antibiotic resistance.
Check out their website for more information!