ACC&D Projects

Marking & Identification of Free-Roaming Populations of Dogs & Cats

The Need

ACC&D has been tackling the challenge of how to mark and identify animals who have been non-surgically contracepted (temporary infertility) or sterilized (permanent infertility), as well as those who have been vaccinated against diseases such as rabies.

The need is particularly acute for animals who roam freely. For these individuals, sterilization and vaccination can quite literally be lifesaving. Across the globe, some communities with large free-roaming dog populations agree to not impound or cull those animals who have been spayed or neutered and vaccinated. The same is true for free-roaming and feral cat populations. Increasing numbers of communities have committed to leave healthy sterilized cats in their outdoor homes. A marker could be an asset not only to traditional Trap-Neuter-Return (TNR) programs, but also to initiatives using multi-year contraceptives for free-roaming cats.

The ear tipping or notching that is currently used to identify surgically sterilized animals would not be humane for animals sterilized without anesthesia. And while traditional collars have many strengths, they are easily removed, and they cannot be used safely on a growing puppy.

Current focus: microneedle patches

We are currently exploring use of microneedle patches to deliver tattoo ink to the inside of a dog or a cat ear.

What are microneedle patches?

Microneedle patches are small patches with even smaller needles – as many as 100 needles in a 1cm square patch. When the patch is pressed onto the skin, an adhesive makes the patch stick to the skin temporarily, during which time the microneedles dissolve. To date, microneedles have successfully delivered vaccine (including rabies vaccine to dogs); we are adapting the technology to deliver tattoo ink.

Pictured: A tattoo applied via microneedle patch.

In 2018, ACC&D established a partnership with Dr. Mark Prausnitz, Director of the Center for Drug Design, Development and Delivery at the Georgia Institute of Technology. Among other pursuits, the laboratory designs microneedle patches to deliver the flu vaccine to humans, which has proven successful and well tolerated. We have been exploring how we can apply this promising technology to help animals.

The patch has shown promise in administering rabies vaccine to dogs; in one study, beagles tolerated a patch better than a typical needle injection. Now, ACC&D and Dr. Prausnitz are exploring the use of microneedle patches to deliver ink to the inside of a dog or cat’s ear. We hope that this could be a painless and humane method to identify a non-surgically sterilized animal, and have the additional benefit of use to distinguish animals who have been vaccinated against rabies.

After demonstrating that it is possible to load microneedle patches with tattoo ink, we tested administration and visibility of ink in the ear of a pig cadaver. Given positive results, we then fashioned the patches into the shape of numbers and loaded them with UV-excitable ink. Patches were applied to cadaver cat and dog ears, and the results inspired us to conduct a pilot study.

We have worked with dedicated volunteers to apply patches to a small number of pet dogs and cats. The results are good! Overall, the patches have been well-tolerated and have not caused concerning site reactions, and the tattoos are demonstrating good longevity.

We are currently working to optimize this technology, with a particular focus on reducing application time, making the application process more user-friendly, and improving visibility. Once we achieve these objectives in a small number of pet animals, we will shift to a field study to evaluate “real world” feasibility.

Thank you to the Regina Bauer Frankenberg Foundation and the john t. and jane A. Wiederhold foundation for supporting this work.

Past Work

In the past, we have worked with partners to create a “21stCentury” ear tag and have trialed the tag in both dogs and cats with mixed results.

"21st Century" Ear Tag

This work was inspired by a Think Tank in 2013. Consensus among Think Tank participants was that existing use of ear tags has not been optimized in terms of either material or methodology. As such, ACC&D worked with partners to create a “21stCentury” ear tag and has trialed the tag in both dogs and cats.

With generous support from Cornell University’s Atkinson Center for a Sustainable Future, ACC&D worked with faculty, undergraduate, and graduate students from Cornell’s College of Veterinary Medicine, College of Human Ecology Fiber Science & Apparel Design, and College of Engineering in a novel and interdisciplinary initiative to improve on traditional animal ear tags. We also benefited greatly from volunteers from Oregon to Ohio to North Carolina.

In this project, we began by evaluating potential tag materials for their weight, flexibility, breathability, resistance to tearing, cost, and durability, particularly in different weather conditions. We determined that solution-dyed acrylic fabric—the same type that's used in outdoor patio cushions, for example—best fit these requirements and could accommodate an RFID tag to communicate even more information about an animal. We further concluded that a price-tagging "gun" showed greatest promise for creating a tiny hole through which a fastener can be threaded and hold the tag in place; in fact, this application method has been successfully used to mark and identify guinea pigs.

The prototype tag has been evaluated in three separate studies, with mixed results. A small study started in 2016 in indoor-outdoor pet cats, which applied tags when cats were anesthetized for dental work, yielded mixed results in terms of cats’ responses to wearing the tag, retention, and lack of irritation or infection. In a “real-word” study in dogs in conjunction with an international rabies vaccination campaign, we found that dogs exhibited discomfort with application even with a topical anesthetic, and tags were lost relatively quickly (a process that caused no damage to the ear).

Given study outcomes, ACC&D believes that this tag does not have enough viability to justify further trials in dogs or cats.