Lexington, Ky. - Dr. Katie Flynn and Dr. Stephen Schumacher co-led a conversation on Biosecurity and Medications on Thursday, Jan. 23, at the 2025 US Equestrian Annual Meeting. The session, which was presented by Neogen, started with Dr. Flynn leading a conversation on the new microchip requirement that is to go into effect in December 2025. Dr. Schumacher’s presentation focused on Pharmacology, providing an overview of pharmacokinetics vs pharmacodynamics, how medications work within the horse’s body, and more.
Microchip and Readers – Dr. Katie Flynn, Senior Veterinarian Equine Health and Biosecurity
New Microchip Rule: Beginning December 1, 2025, under GR1101.1, all horses competing in USEF-licensed or –endorsed competitions must be microchipped with a 15-digit ISO-compliant 11784/11785 chip.
ISO-compliant microchips are designed with 15-digit numbers (without letters) that can be easily read by all universal readers currently available. Dr. Flynn stated, "Historically, there were different frequencies, but now we are consistently using these ISO-compliant chips that are read by the readers currently on the market.” This level of standardization ensures that these microchips are accessible to a wide range of readers, making them highly versatile and reliable for various applications. These chips are passive, meaning they do not have any capability to store or upload information. Instead, they are only activated when a reader sends a signal to them, allowing for one-way communication where the chip transmits its ID number back to the reader.
Biothermal microchips are a more specialized version of the passive chips, with a unique feature: they incorporate a temperature-sensing component in the chip. This provides valuable data in environments where temperature monitoring is critical. Dr. Flynn recommended the Biothermal Chips, stating, “It’s an easier, safer, and quicker way to take a temperature.”
Dr. Flynn explained that in certain diseases, a horse’s temperature may spike before it begins shedding the bacteria or virus, making temperature monitoring a key early indicator of potential illness. Biothermal technology allows users to track temperature trends in horses over time, enabling them to identify irregularities early. This makes it possible to quickly isolate a potentially sick horse, minimizing the risk of exposure to other animals. If a temperature spike is detected by a reader, Dr. Flynn recommends taking a rectal temperature to confirm the accuracy of the reading. The current microchips available to veterinarians include LifeChip®, Bio-Thermo®, Destron Fearing ® and Datamars. It is important for horse owners and veterinarians to note that while U.S. microchips are typically ½ inch long, some European microchips are considerably shorter.
Implantation and placement are critical to ensuring the effectiveness of the microchip and the safety of the horse. When properly implanted, a microchip should remain in place without migrating. Microchips should be implanted into the left nuchal ligament on the horse’s neck. “If they do not go directly into the skin, to the hub, they are not getting implanted deep enough in the nuchal ligament,” said Dr. Flynn. “The microchip itself has a polymer coating that will cause a reaction in the nuchal ligament and secure it there. If they go in at an angle, they can go in subcutaneously and they are going to move.” Improperly implanted microchips can migrate, sometimes moving as far as the poll or down to the chest area. This is why it is essential to scan both sides and the entire length of the horse’s neck when looking for a microchip, ensuring that the chip is correctly placed and easily identifiable.
When it comes to selecting the best microchip readers, Dr. Flynn emphasized that the choice largely depends on the specific needs of the user. “They all have different capabilities, read ranges, and abilities to scan a horse, but they are all built for the same frequency and detect ISO compliant microchips.”
In 2024, an observational study was conducted at both the Pennsylvania National Horse Show and the Kentucky National Horse Show, focusing on horses of hunter and equitation disciplines. The study aimed to assess microchip placement in the neck, ease of scanning, and the country codes of the microchips. Among the 469 horses scanned, 63.97% had their microchips placed in the correct location, 17.7% had chips placed too high, and 14.07% were placed too low. 79.32% of the microchips proved difficult to scan and 330 horses had microchips with country codes of outside the United States.
After concluding the presentation, Dr. Flynn addressed concerns raised by the audience. One common question involved potential allergic reactions to microchips. Dr. Flynn clarified that the microchip itself is not the cause of allergic reactions; rather, it is typically the needle used to insert the chip that may trigger a response. However, there have been no documented cases of allergic reactions. There is also no allergen-free microchip on the market. She also responded to concerns about weather-related challenges, specifically the impact of cold temperatures on microchip readers. Dr. Flynn reassured the audience that steps have been taken to ensure the durability of readers in cold conditions, such as providing an insulated sleeve that the reader sits in.
The USEF microchipping website and resources can be found here.
Watch the Microchip & Readers Presentation here.
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Pharmacology and Understanding Drug Rules – Dr. Stephen A. Schumacher, Chief Veterinary Officer and Chief Administrator of USEF’s Equine Drugs & Medications Program.
Dr. Stephen Schumacher began his presentation by explaining the difference between Pharmacology and Toxicology, noting that “drugs can be both beneficial and toxic.” Pharmacology itself is further divided into two main areas: Pharmacodynamics and Pharmacokinetics. Pharmacodynamics (PD) refers to what the drug does to the body- whether it modifies pain, reduces fever, or has other therapeutic effects. In contrast, Pharmacokinetics (PK) is what the body does directly to the drug, such as its metabolism, distribution, and how it is eliminated from the body.
Schumacher then highlighted the importance of considering individual variability in animals, particularly when administering drug therapy. Factors such as body size, age, species, breed, disease, and the presence of other medications must all be taken into account.
A key aspect of drug therapy in horses, Dr. Schumacher explained, is the use of Non-Steroidal Anti-inflammatory Drugs (NSAIDs). NSAIDs block Cyclooxygenase, the enzyme responsible for converting arachidonic acid into prostaglandins. There are two main types: COX-1 and COX-2; which promote inflammation, pain, and fever (COX-2) but can also be protective (COX-1). If overused, they can negatively impact a horse’s kidneys, gastrointestinal tract, and liver. “Oral ulceration and colic are real concerns with prolonged non-steroidal use,” said Dr. Schumacher, emphasizing the need for caution and proper dosing when using NSAIDs in equine medicine.
Dr. Schumacher also discussed the significance of absorption when administering any drug therapy. Different routes of administration-whether oral, transdermal, sublingual, or intravenous- affect how the drug is absorbed and its overall effectiveness. “Oral medications make it [absorption] tough,” said Dr. Schumacher. “It takes time for it [medication] to cross the barrier in the stomach or GI tract.” On the other hand, intravenous administration allows the horse to receive 100% of the drug, which is a significant advantage over oral medications that have low bioavailability.
To further illustrate the importance of dosage and species difference, Dr. Schumacher used Firocoxib as an example. Firocoxib is used to treat pain and inflammation in both dogs (Previcox®) and horses (Equioxx®). However, the dosage for these two species is extremely different. For a 100lb dog, a typical dose is a 227mg tablet of Previcox® (5mg/kg), whereas for a 1000lb horse, the dose is only 45.4mg of Equioxx® paste (0.1mg/kg)- a dosage that is 1/50th the amount given to the dog.
“We compete horses differently, and we recognize that,” said Dr. Shumacher. “Our horses compete older; they compete much more frequently.” He stressed the importance of understanding the regulations surrounding drug use in competitive equine sports, noting that the safety and wellbeing of the horse must always be the primary concern. In defending US Equestrian’s non-steroidal drug rules, Dr. Schumacher concluded, “the horse doesn’t have a say in what they are going to be administered,” reinforcing the responsibility that trainers and veterinarians must protect the horses in their care.
Watch the full Pharmacology and Drug Rules presentation here.
About Dr. Stephan Shumacher
Dr. Stephen Schumacher, DVM, PhD is the Chief Veterinary Officer and Chief Administrator for the US Equestrian (USEF) Drugs and Medications Program. Dr. Schumacher has been working for the Equine Drugs and Medications program for more than two decades, working first as a Testing Technician and then as a Testing Veterinarian, prior to assuming the Chief Administrator position. Dr. Schumacher has also served as a member of the FEI Veterinary Committee and is currently a member of the FEI List Group. He oversaw equine drug testing at the 2010 Alltech FEI World Equestrian Games in Lexington, Ky. Dr. Schumacher graduated from The Citadel, The Military College of South Carolina before earning his veterinary degree and PhD from Ohio State University’s College of Veterinary Medicine.
About Dr. Katie Flynn
Dr. Katie Flynn was raised on a Standardbred racehorse farm in South Grafton, Mass. She received her undergraduate degree in Animal Science from the University of Massachusetts. In 2001, she received her veterinary degree from the University of Glasgow, Scotland. In 2002, Dr. Flynn began a regulatory career with the California Department of Food and Agriculture (CDFA) Animal Health Branch (AHB), where she held several positions, including field veterinarian, livestock health program veterinarian, and equine staff veterinarian. While at CDFA, Dr. Flynn participated in numerous equine disease responses including equine herpesvirus-1, equine infectious anemia, equine influenza, equine piroplasmosis, and contagious equine metritis.
Dr. Flynn left California in 2020 to continue her regulatory career as the Kentucky State Veterinarian. In March 2023, Dr. Flynn followed her equine infectious disease interest and accepted the position of senior staff veterinarian for equine health and biosecurity with the United States Equestrian Federation. Dr. Flynn now focuses her efforts on protecting and promoting the health of equine athletes in the United States and abroad. Dr. Flynn is an international subject matter expert on equine biosecurity, authoring the Biosecurity Toolkit, which has been distributed to all 50 states and 12 countries.