PenOne Pro™ Penicillin is a potent antibacterial agent that is effective against a variety of pathogenic organisms, chiefly in the Gram-positive category. It is recommended for treatment of bacterial pneumonia (shipping fever) caused by Pasteurella multocida in cattle and sheep, erysipelas caused by Erysipelothrix insidiosa in swine, and strangles caused by Streptococcus equi in horses. Not for use in calves to be processed for veal or in horses intended for food. Milk withhold: 48 hours. Meat withdrawal: Cattle 14 days, Sheep 9 days, Swine 7 days. Administer IM.