Perhaps. Field research in Kansas has shown that re-implanting midway through the suckling period will increase weaning weight by 10 to 15 pounds. The additional time and labor required to re-implant calves must be considered in evaluating this practice. One practice that many cattlemen have found useful is to re-implant spring-born calves in mid-August and give the calves their preweaning vaccinations at the same time. Heifers intended for breeding should not be implanted before weaning as this usually is determental to future reproductive performance.