Comparison of electronic and visual identification systems in pigs

Internal and external electronic identification devices (EID) were compared with visual ear tags in a series of trials in pigs. In sows (244 animals), external EID tags and visual tags performed comparatively well with loss rates of 1.6% and 3.7%, respectively, over - on average - 338 days (SD = 168 days). External EID failure rate was 0.4%. In two other trials, 180 piglets were tagged at weaning with external EID, visual tags and implantable EID (type A: 23 mm; type B: 11.5 mm). A location at the right ear base was used for implantation. Only minor migration of <1 cm occurred. A total of 3.3% of pigs showed signs of infection at the implantation site (all with type A). The loss rate of type A and type B transponders within 4 weeks after implantation was 18.1% and 0%, respectively. Loss rates before slaughter for the different identification systems were: EID ear tags 0%, visual ear tags 1.7%, implant A 19.4%, implant B 0%. At slaughter, 23.4% of the EID ear tags were either lost or damaged. Remaining technical problems related to practical use of EID systems will have to be removed before their value can be fully realised within the pig industry. © 1998 Elsevier Science B.V.