In most countries, organic mostly just means that the feed they use is organic with maybe a few minor other additions, but regardless I wouldn't trust any claims of anything actually being antibiotic-free.

• Some beef ‘raised without antibiotics’ tests positive for antibiotics in study

• Antibiotic-Free Meat Not Free of Drug-Resistant Bacteria

• Antibiotic Residue Found in Antibiotic-Free Meat at Whole Foods