Feeding of by-product ingredients should be supported by sound science. Withdrawal times must be strictly adhered to. Extra-label use of feed additives is illegal and strictly prohibited. When formulating and feeding medicated feed rations, complete records must be kept. These must be checked to verify that the proper withdrawal time has been met for each animal or group of animals before being sold.
All products are to be used per label directions.
All cattle shipped to slaughter must be checked to assure that animals that have been treated meet or exceed label or prescription withdrawal times for all animal health products administered. Prospective buyers must be informed of any cattle that have not met withdrawal times. Whenever possible, make culling decisions prior to giving drug treatments because of withdrawal times. For example, the meat withdrawal time is 4 days for a lactating cow cephapirin mastitis treatment but 42 days if the dry cow treatment with cephapirin is used. A penicillin product has a withdrawal of 60 days.