Pennox 343 Oxytetracycline Hydrochloride Soluble Powder is an antibiotic used in the drinking water to treat certain diseases in poultry, cattle, swine, and sheep. One 23.9 oz. packet will treat approximately 640 gallons of water, and will treat 51,200 lbs. of swine, cattle, or sheep, or 20,480 lbs. of poultry for one day. Pennox 343 contains 343 grams of oxytetracycline per pound.