After a trial of passive RFID tags, the state’s agriculture department plans to test battery-powered tags to attain the 100 percent read rates it seeks for tracking elk and deer on ranches.

After completing a trial of passive low-frequency and UHF RFID tags for cervid tracking, the Colorado Department of Agriculture has determined that active RFID tags may be the only way to gain the 100 percent read rate it seeks for cervid herds in the state. Cervid tracking is more rigorous in Colorado than in some other states because of a state mandate requiring ranchers to test dead elk and fallow deer for CWD, or chronic wasting disease. CWD is part of a group of ailments known as transmissible spongiform encephalopathies, which includes mad cow disease. If an animal decomposes before being tested, neither ranchers nor the state can determine if it died of the lethal and contagious disease.