Colorado - Prepared from the blood of horses that have been hyper-immunized against tetanus. For use in treatment and temporary prevention of tetanus in domestic animals. Dosage: Prevention: 1500 units SQ or IM. Treatment: 10,000-50,000 units to horses and cattle and 3,000 - 15,000 units to sheep and swine. Repeat in 7 days. 21 day withdrawal.