The experiment was conducted in three oxen about 350 kg BW in Latin square design. The basic diet consisted of barley grain, meadow hay and mineral mixture. The diets were supplemented with avoparcin and Zn-bacitracin of 20 and 35 mg per kg of the ration (DM basis), respectively. The preliminary period lasted 30 days for each cycle of in situ measurements. The Ca, Mg, K, Na, Cu, Zn content was estimated in the feed samples (rye grain, wheat grain, barley grain, peas seed, horse bean and soyabean meal) and in bag-residues. The ranking of mineral release in animals fed without any antibiotics was as follows: K (98,4%) > Mg (92,2) > Na (89,6) > Cu (86,6) > Zn (72,7) > Ca (20,1) and in animals fed with antibiotics the ranking, except of Na was similar: K (99,4) > Na (97,6) > Mg (94,0) > Cu (91,9) > Zn (75,0) > Ca (3,4) and: K (99,5) > Na (98,4) > Mg (93,4) > Cu (90,9) > Zn (65,3) > Ca (11,87) for avoparcin and Zn-bacitracin, respectively.