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High-Tech Record Keeping

Using Electronic ID Boluses

By Rosemary Colombraro

Photos: Virginia State University Small Ruminant Program

With rising concerns about homeland security, and also the occasional need to trace back livestock to their origination point, tamper-proof sheep identification becomes more important than ever before. One method of identification, the electronic bolus, has made marks in Europe and may be a viable option in the United States.

Electronic Bolus Details

A Spanish company, Rumitag S.L. (the new name of Gesimpex Comercial,S.L.), offers a bolus that can be used in sheep. The bolus is made of ceramic material that has been baked at 1,300 degrees Centigrade. Inside, a radio frequency transponder (from the words transmitter and responder) consists of a microchip with electronic circuitry, coil and capacitor-all of which are waterproofed and sealed with silicone. The bolus is activated by a radio signal sent out by a “reader” and then gives the operator a preprogrammed identification code.

Boluses and equipment:  Left to right: Probe and electronic reader; different size boluses and applicators.
Boluses and equipment: Left to right: Probe and electronic reader; different size boluses and applicators.

Rumitag offers different size boluses. The standard size weighs 76 grams and measures approximately 2.75″ long by 13/16″ diameter. A smaller size is 2-3/8″ long x about 3/8″ diameter and weighs approximately 20 grams. Handlers install the boluses using a balling gun or applicator available through Rumitag: The bolus is applied at the back of the sheep’s throat causing it to swallow.

Using Electronic ID

Douglas Davidson, Rumitag sales agent and owner of Windy Meadow Farm in Arcade, New York, is currently using Rumitags on his older breeding ewes and plans to install the boluses on his replacement ewes. His current flock size is 250 ewes. “We started with the old style Dorset. For the last five years we have been cross breeding using purebred East Friesian (EF) rams, and crossbred rams EF x Dorset and Lacaune/EF x Dorset. We did this in order to have at least 200 ewes of dairy breeding when we were ready to start milking.”

Even the large size bolus is quickly installed into sheep.
Even the large size bolus is quickly installed into sheep.

Davidson got interested in this product when he saw a demonstration of what they were doing with them in Spain. Prior to that, he had been losing between 10% to 20% of ear tags per year.

The application is simple, says Davidson, and using the handheld reader saves him time and aggravation. “It sure does make a nice savings come lambing time. By just running the reader down her left side I get her number: I don’t have to catch her; I don’t have to put my glasses on to read the tag number.”

With an antenna attached to the handheld reader, Davidson says the boluses can be read by running the scanner along the animal’s belly, and in some cases, a reader with an antenna might be able to pick up information at 10 to 12 inches. The company also offers a reader and antenna that can be attached to a single chute, reading each animal passing through the chute.

Davidson says that in Spain, 1,200 sheep installed with electronic boluses were run through a chute in 25 minutes. The chute reader successfully recorded all 1,200 sheep.

Davidson also anticipates ease of use at milking time. “You can run the antenna [attached to the handheld reader] underneath her belly and pick up her number. You enter the amount of milk that she produced and go onto the next animal,” he says. “If you happen to read her number again and try to enter another amount of milk, the reader tells you that you have made a mistake. It doesn’t let you enter that second amount of milk. There is virtually no way in your milk recording that you can make a mistake and get away with it.”

Implant Processing Time Chart

Problems & Solutions

Yves Berger, superintendent of sheep at Spooner Ag Research Station, University of Wisconsin-Madison, also finds the Rumitag bolus to be satisfactory, noting a 98% reading success rate with the station’s flock of 300 milking ewes. The handheld reader adds to ease of use. The only drawback he has found is a poor battery charge on the reader; however he says he remedies that by having another reader available.

The reader’s keyboard is alphanumeric and has 14 informational fields. Four of the fields are fixed-for the bolus number, the animal’s number, date and time. “When you insert the bolus into the animal, you read the bolus and punch her number into the reader, and that records her number with that bolus,” explains Davidson. “So every time you read that animal’s number that electronic number comes up, and her number comes up.”

The Rumitag reader is portable, and its data can be transferred to computer for storage and processing.
The Rumitag reader is portable, and its data can be transferred to computer for storage and processing.

The 10 remaining data fields can be used for individual needs, such as vaccinations, worming, milk production, lambing information, etc. Information can be added directly into the reader by using the keypad. “You just go to your computer, plug the reader into the computer, bring up the Gesimpex or Rumitag software which comes with the reader, and then you download all the information that is in the reader into the computer.”

Is It Safe For Sheep & Man?

A test of electronic identification devices was conducted by the Centre Internationale de Haute Etudes Agronomiques Mediterraneenes (CIHEAM). Results showed that electronic boluses can be used successfully in sheep. After a year of testing (which included Rumitag products and readers), no losses, breakage or failures were noted in grazing and semi-stabled sheep. In cases of diarrhea, and two cases of bloat, the boluses remained in place either in the rumen or the reticulum.

The organization concluded that electronic bolus identification proved to be a reliable option, as well as a useful tool in management and milk recording.

They went on to suggest that individual situations (race-way reading, feeding, veterinary and market control among others) had to be considered in the decision to use the devices, and that a second manual and visual tagging would make the system completely reliable.

The electronic boluses can be retrieved from slaughtered sheep, and even re-used.
The electronic boluses can be retrieved from slaughtered sheep, and even re-used.

Rumitag was also included in the European IDEA Project (Identification Electronique des Animaux), launched in 1998, which examined an introduction of an electronic identification system based on progress already made by the International Standards Organization (ISO). Its main objective was to validate application techniques, recovery of transponders after slaughter, organizational structure of data management and flow of information, plus structure for identification and registration.

One million animals (cattle, sheep and goats) were used in the study and three types of electronic identification were tested (ear tags, injectable transponders, and boluses), which included Rumitag products. Injectable transponders were eventually omitted for sheep and goats due to recovery losses. Rumitag received a Certificate of Laboratory Acceptance for the IDEA Project (CERTIFICATE No. JRC/037/IDEA/97).

In slaughter situations, the bolus can be easily retrieved in the reticulum. Davidson uses a small slaughter operation and simply asks them to retrieve his boluses from the offal. The boluses can then be reused, by deleting the animal number, installing the bolus into a new animal and entering the new animal number. A possible money-saving option for a meat lamb operation would be the installation of boluses in breeding ewes, and ear tags on lambs.

What Does It Cost?

Cost for the handheld reader-rechargeable battery included-is approximately $700, and the cost for boluses can vary depending on order quantity and cost of freight. Davidson says a ballpark figure for boluses is approximately $4.50 each, including freight. Co-ops or groups of small flock operaters could share the cost of one or two readers as well as buy a larger quantity of boluses to be divided on site. Members would be able to read their animals and download the information into their own computers, then pass on the reader to the next member. Battery replacements run around $15-$20.

Small boluses, only 3/8 inch diameter by 1-1/2 inch long, are available for smaller animals.
Small boluses, only 3/8 inch diameter by 1-1/2 inch long, are available for smaller animals.

Davidson believes a national database could be created to register bolus numbers, perhaps in accordance with the Scrapie Program. If a sheep were stolen and she retained a bolus, says Davidson, the owners could be located through such a database. “In my case, the electronic number and the animal number will go into the database together. So if some of my sheep end up somewhere that I don’t know about, they have an electronic implant. Then they are going to catch who stole them. It would come back on the Scrapie Program. If somebody stole an animal with a bolus in it, he would have to get a very experienced vet, and spend an extreme amount of money to get that bolus out so he could change it. All you would have to do is go with your reader; scan the animal: Her number would come up. They can’t tamper with it.”

The Food and Drug Administration (FDA) has not approved these devices yet, out of concerns for damages at rendering plants. Therefore, users must sign an agreement that they will have the boluses removed upon slaughter, before the offal goes to rendering.

For more information on Rumitags contact Douglas Davidson, Windy Meadow Farm, Arcade, NY 14009; dwindymeadowfarm@aol.com; 585-492-1090

Additional Data On Bolus Use At Virginia State U.

We have been using the ceramic boluses as a means of identifying our sheep and goats, and for data collection (i.e., weights via the reader/data logger) since early 2002.

We initially implanted about 320 of the large boluses, 60 of the small boluses, and subsequently some of the medium boluses. It is my understanding that type and dimensions of some of these boluses have since changed.

We had the best luck with the large boluses and these boluses have since been used to identify replacement animals entering our breeding flock, as well.

Recently (over the past several months) we have observed a signal loss in some of our animals, while actually recovering two boluses on pasture. We did not observe how these boluses were passed, but assume that they were regurgitated. Without additional data and observations, any explanation of these recent losses would be very speculative.

Stephan Wildeus, Ph.D.
Associate Research Professor
Small Ruminants Ag.
Research Station
Virginia State University

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