Antibiotics are chemicals that inhibit the growth of bacteria deleterious to animal health. They are classified as drugs, not nutrients. In general, animals respond most to antibiotic feeding when stressors such as disease, crowding, inclement weather, muddy lots, or shipping exist.
Producers must evaluate, on a pen-by-pen basis, whether antibiotics such as chlortetracycline or oxytetracycline will benefit the transition of newly received feeder cattle to the intended feeding program and improve performance. Antibiotic usage for control of liver abscesses caused by prolonged, high concentrate feeding is common in most finishing diets and includes oxytetracycline or tylosin, approved for use in combination with ionophores.
