Several pharmaceutical companies have recently received permission to change the directions for use on their penicillin procaine G labels. These are the bottles that may be purchased over the counter at the local feed mill. It was always important to read the label of any livestock medicine before using it but now it is doubly important to read the new penicillin labels. I saw three different penicillin brands in a mill's fridge the other day and the label directions were quite varied.
Not to be used in lactating cattle. Administer subcutaneously. Withhold cattle from slaughter for 14 days, swine 10 days, after last treatment.
Withhold milk from lactating cattle for 72 hours, do not send animals for slaughter for 5days after latest treatment. DO NOT administer subcutaneously, give intramuscularly.
Withhold milk from lactating cattle for 96 hours, do not send cattle and sheep for slaughter for 10 days after latest treatment and for swine do not ship for 8 days after latest treatment.
Any use of a livestock medicine beyond the label directions is considered extra-label use. Only your veterinarian can advise you on extra-label use of a product and how that will affect the withdrawal time. Always make sure you pick up the paper insert that comes with some bottles in order to have all the manufacturer's directions. Don't buy brand A bottle and take brand X's insert or you might inadvertently use the product extra-label.
These new labels are one "Best seller" you don't want to miss reading!