By Claire Swedberg
Jan. 6, 2006—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.
In the most recent of two Colorado cervid pilots—using passive UHF RFID tags and interrogators (readers) made by
Advanced ID Corp.—the state’s agriculture department was able to
read 100 percent of the tags on one of the three herds tested, but considerably less on the other two, says Scott Leach, the department’s CWD field investigator. The first pilot, which took place in late 2004 and early 2005, involved low-
frequency tags (134.2 kHz) and readers, with hardware supplied by
Digital Angel,
Allflex,
Y-tex and
Avid Identification Systems. The second, a nine-month trial held from March to December 2005, used Advanced ID’s UHF (915 MHz) tags and interrogators.
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Scott Leach, Colorado Dept. of Agriculture
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Under the
National Animal Identification System (NAIS) mandate, currently being developed by the
United States Department of Agriculture (USDA), all cervid ranchers in the United States will be required to inventory their animals using RFID or some other method. No specific date for compliance has yet been determined. They can also use RFID tracking to keep a record of their herd’s general health, nutrition and other activities. Ranchers in Colorado also need to be able to recognize when an animal is missing and, if the animal has died, locate its body before it decomposes—for CWD testing.
Leach says he has not yet tried to use a passive RFID system to track an animal, live or dead. He adds, however, that active RFID equipment manufacturers have indicated tracking of animals may be possible. In the meantime, passive RFID systems allow the ranchers to recognize the loss of an animal and search for it.
Reading tags on elk is uniquely challenging because the animals resist being run through chutes, where they could pass an RFID
reader at close range. Elk are often skittish around humans, even ranchers with whom they are familiar. Places in Colorado where captive cervids live include 1,000- to 2,000-acre fenced-in hunting ranches, Leach says, where it is very difficult to get within
read range of the handheld UHF interrogators used in the trial. Such readers have a range of about 3 meters, or slightly less than 10 feet. “When you have large bulls with full antler racks in rutting season, you don’t want to be too near [them],” Leach says.