Avoid freezing | Warm ear tags also require less force to be inserted
Correction: January 30, 2014 – The original version of this story incorrectly stated that RFID ear tags subjected to freezing are permanently weakened. The PAMI study found tag retention is lower if the tags are frozen at time of insertion, and that inserting tags when frozen reduces their strength. The study confirmed the importance of keeping tags warm when inserting them.
Calving season has begun for some prairie ranchers, and the advice when it comes to ear tags is this: keep them warm.
A study by the Prairie Agricultural Machinery Institute shows that radio frequency identification (RFID) tag retention rates drop if they are applied when cold.
“Keep the tags in your pocket until right before you apply them,” said PAMI project lead Joy Agnew.
RFID tag use is a requirement for national traceability policies, and the Canadian Cattle Identification Agency tests and approves various brands for readability and retention. PAMI conducted enhanced tests to obtain more information for better retention.
The temperature findings are not necessarily a surprise to ranchers, although confirmation is useful.
“Everybody knows if you’re tagging in cold weather, you throw them on the dash of the truck and turn the heater up and keep them warm,” said Saskatchewan Cattlemen’s Association chair Mark Elford.
He heads an ongoing CCIA study on tag retention prompted by numerous producer complaints about lost tags and the problems it creates with the Canadian Food Inspection Agency.
Among CCIA requirements is that tags must require no more than 100 pounds of force to correctly insert in cattle ears.
“When inserted in the warm, all of the tags met that requirement, but when inserting in the cold, it was harder to insert every single one of them, and the average insertion force in the cold was over 120 lb.,” Agnew said.
PAMI also tested the force required to break a tag and pull it apart and is examining the effect of pneumatic tag applicators on retention rates.
Six types of RFID tags were tested using either cattle ears obtained from slaughter plants or equivalent material. Sufficient ears were not available for the thousands of tests required.
CCIA tests the tensile strength of tags, meaning the force required to pull the front button from the back portion. PAMI tested that as well as sheer and impact force.
“The tags are weaker in sheer than they are in tension, but the forces required to break the tags are still well above the thresholds set by the CCIA for both cold and warm inserted tags,” said Agnew.
Research also showed that force beyond 70 lb. per sq. inch has an effect.
“Any force on the tag that could potentially make the hole (in the ear) bigger, or anything that can generate an impact force of more than 70 lb. can cause trouble,” she said.
“That’s where we’re finding where most of the ears are ripping, is around the 70 or 75 lb. impact force.”
Repeated tugging, which might occur if cattle are grazing in bushy areas or banging their ear tags against feed bunks, could result in larger ear holes, which increases the chance for loss.
Some brands of RFID tags are more susceptible than others to ripping through ears because they stretch to form a thin wire that slices through cartilage.
PAMI advises producers not to mix and match tag brands. The front and back of the tag should be the same brand, and the applicator should be suited to that brand.
Agnew said PAMI may have recommendations for tag manufacturers once studies are complete, but the main goal is to provide producers with useful information.
“We still maintain that if the best management practices are followed, then tag retention should be in that 90 to 95 percent retention range,” Agnew said.
Jim Lynch Staunton, a cow-calf producer from Lundbreck, Alta., said he has few problems with tag retention.
“If you put them in the place where they’re supposed to be put in the calf’s ear, they stay in, so if people are having problems, they’re not applying them properly,” he said.
“The issue I’ve had a lot more than retention is whether or not they read.”
RFID tags can be read with a wand, but Lynch Staunton said older ones can present problems because of wear.