This study examined the efficacy of electronic transponders of different size and location for losses, readability, and recovery. Transponders may be used in a variety of situations to facilitate animal management or maintain identification throughout the animal’s life. In cattle these transponders may be a means of eliminating or reducing branding. Larger transponders (32 mm) were more efficient than small ones (23 mm), although they broke more, they were more readily read and removed. Placing the transponders in the armpit reduced losses, achieved high levels of readability, but took longer to remove at slaughter. These were often removed with the hide, making carcass identification less feasible. Recovery was easiest in the lip, then the ear, and took longest in the armpit. Breakages were less than 1%; losses varied from less than 2% (armpit) to 14% (lip), readability was 95% in the armpit but fell to 60% in the lip. Recovery exceeded 96% in all cases. The armpit location was best with the exception that they were more difficult to recover.