Note: For a complete copy of the National Academies report click here

The National Academies of Sciences, Engineering and Medicine (NAS) released their report, “A Review of Methods for Detecting Soreness in Horses,” earlier today. The committee has been working on the report for over a year with their first meeting happening in October 2019. The effort by NAS was a joint effort and request by the United States Department of Agriculture, the Tennessee Walking Horse industry and the Tennessee Department of Agriculture. The NAS study marks the first time the industry and USDA have jointly worked together to make improvements in the inspection of horses for compliance with the HPA.

The committee met five times and had numerous other communications in coming up with the report. Many of the meetings had to be virtual given the pandemic and before releasing the report the committee had their preliminary report reviewed by an 11-member panel selected by NAS. The purpose of the study, as jointly requested by the USDA and industry, was for NAS to “oversee an independent study to help ensure the HPA inspection protocols, including protocols for compliance with the scar rule, are based on sound scientific principles that can be applied with consistency and objectivity.”

As part of the committee’s approach they reviewed methods currently used by VMOs and DQPs, investigated other methods and technologies that could potentially aid in examining the horse’s limbs for soreness and reviewed the scar rule to determine if the language of the rule is consistent with current findings relative to horses seen today versus when the rule was written over 40 years ago. The committee’s recommendations are for the consideration of APHIS and the industry parties responsible for protecting horse welfare through the HPA. The recommendations are just that and APHIS is not bound to implement any of the recommendations but could through the current inspection process or through rulemaking to amend the process implementing some or all of the recommendations.

In total the committee’s report contains a total of 27 findings, 24 conclusions and makes 15 recommendations. Some of those recommendations are in line with what industry stakeholders have long requested, including the use of more technology, and others fall in line with long-held beliefs of the veterinarian community when they have visited with walking horse stakeholders.

The committee recommended the abolishment of the Designated Qualified Persons program and recommended only accredited, experienced equine veterinarians conduct the inspections to determine compliance with the HPA. The data used to make the recommendation on the DQP program was outdated and didn’t take into account the time period that has seen a greater level of cooperation between HIOs and APHIS VMOs, however repeatedly the committee stated that the way to achieve a greater level of accuracy and consistency is to employ experienced equine veterinarians.

The committee did conclude that, “palpation of the limbs is the gold standard for detecting pain and inflammation.” They also concluded, “physical examination methods are critical in detecting pain when performed by an examiner with sufficient knowledge of normal versus abnormal horse movement and posture and the ways that horses react to palpation if they are in pain. To better detect soreness, it is important that these examinations be done thoroughly using proper techniques and used in conjunction with other diagnostic technologies, tools and techniques.” 

The committee’s conclusions fall in line with industry requests that inspectors use multiple methods to determine compliance and to use technology in conjunction with these methods to verify and come to better conclusions. The industry has repeatedly asked for and been granted recently the opportunity to request a second opinion. In somewhat of a surprise the committee rejected this and recommended, “APHIS should adhere to 9 C.F.R. 11.4 (h)(2), which states that reexamination of the horse shall only be granted if the show veterinarian finds sufficient cause.”

Throughout the report the committee continued to stress the importance of observation and palpations as the basis for any examination for pain and lameness as well as stressing that both are necessary and an “integral part of determining whether pain is altering the gait in a Tennessee Walking Horse.”

The committee did recommend that the extent of digital pressure need not be prescribed, provided that experienced equine veterinarians are performing inspections. In addition, the committee only recommended that horses with limb sensitivity be withdrawn for competition for the welfare of the horse and safety of the rider. The committee did not as part of its statement of task recommend or consider which types of violations should carry a disqualification from competition versus a violation of the HPA and thus subject the responsible parties to potential federal penalties.

In terms of more scientific methods, the committee recommended the use of swabs, blood testing and thermography. The committee recommended swabs to detect prohibited substances to be done at random or for horses that the veterinarian suspects from observations made on the grounds of the horse show.

With regards to the use of thermography the committee recommended, “thermographic cameras are an objective tool for recognizing alterations in blood flow to the limbs of horses, which is indicative of inflammation. Thermography can be a screening tool in the inspection process and can provide supporting evidence of soreness, which may increase the efficiency and reliability of the inspection process.”

The committee concluded that medications given to Tennessee Walking Horses are the same medications administered to other competition horses. The committee acknowledged that, “the United States Equestrian Federation (USEF) has set the standards for medication testing for the entire nonracing equine competition industry in the United States and other performance horse organizations.” Thus the committee recommended that serious consideration be given to implementing blood testing using USEF’s rules and guidelines as a model.

The committee also reviewed various methods and technologies in variability of pain expression and behavioral assessment of pain. One of the methods looked at was facial expressions, however more studies would be needed in this area in order to include it as part of the inspection process. However the committee did conclude, “A common set of objective criteria grounded in behavioral science, including facial expressions indicative of pain is lacking from inspector training. Thus, an inspector’s interpretation of a horse’s behavior is subjective, but it can influence a determination of soreness.”

As part of the recommendations in this area, the committee stated, “To improve consistency across inspectors, science-based information about behavioral indicators of pain in horses should be incorporated into inspectors’ training.” However they also recommended that much more additional research is needed in this area before any implementation could be done.

The committee also looked at physiological parameters (heart rate, respiratory rate, body temperature and blood pressure) used to assess pain in horses. They found however, “they are objective and can be measured easily and repeatably; however, they have a low specificity for pain, vary across individuals, and fluctuate between measurements.”

The committee agreed with a long-held belief of industry stakeholders that the scar rule as written is not enforceable. The committee looked at the language as well as reviewed the biopsies taken by Dr. Paul Stromberg at previous Celebrations. In looking at those slides (of horses that had been disqualified under the scar rule), the committee agreed with Stromberg regarding the lack of scar tissue present. However, the committee did find, “the changes of hyperkeratosis and acanthosis, which were prominent in the biopsy specimens, do not normally occur without a previously inflicted injury on the pasterns.”

The committee concluded that more studies are needed in the area of the scar rule and the effect of training methods on the changes in the skin on the pasterns as well as concluded, “the scar rule language needs to be based on what can accurately be assessed by a gross examination, which ideally would only be performed by an experienced equine practitioner.”

The committee also recommended a revision and proposed the following language:
“A trained inspector should examine skin of the front limb of the horse from the knee (carpus) to the hoof with particular attention to skin of the pastern and fetlock and the coronary band. All areas of skin from carpus to hoof of both limbs, should be free of foreign substances such as dyes, hair fillers, ointments, and other substances designed to camouflage scar rule violations during pre- and post-show inspections. Detection of previously approved substances such as lubricants during post-competition inspection does not constitute a violation. There should be no chemical smell emanating from the skin and no substance present that can be rubbed off onto the hands or a cloth. Skin should be haired with no areas of loss of hair, patchy or diffuse. There can be no swelling, redness, excoriation, erosions, ulcers, seeping of fluids, or signs of a response to chronic injury such as epidermal thickening or presence of scales. Photo documentation of lesions, identifying information about the horse, and a date should be provided for any horse determined to be or suspected of being in violation of the scar rule.”

The final report wraps up the duties of the committee and NAS will consider the study completed. It is not yet known the reaction of USDA-APHIS nor if any of the recommendations will be implemented in the coming show season. The USDA and industry HIOs had previously started a pilot program utilizing swabbing which will continue during the 2021 show season in hopes to implement protocols for HIOs to enforce.

Who are the committee members

Jerry Black, DVM (Chair), Colorado State University
Robin Foster, PhD, CAAB, Private Consultant/University of Puget Sound/University of Washington
Pamela Eve Ginn, DVM, Dipl. ACVP, University of Florida
Sarah Le Jeune, DVM, DACVS, DACVSMR, CVA, Cert. Vet. Chiro, University of California, Davis
Bart Sutherland, DVM, Private Practitioner, Oxford, MS
Tracy Turner, DVM, DACVS, DACVSMR, Turner Equine Sports Medicine and Surgery, Stillwater, MN
Susan L. White, DVM, MS, Dipl. ACVIM, University of Georgia, Athens (Emerita)

Statement of Task

The NAS will convene an ad hoc committee of equine veterinarians and experts with relevant experience and appropriate professional certifications or academic degrees to review the scientific and veterinary medical literature on hoof and pastern pain and skin/tissue changes on the pastern of horses and evaluate methods used to identify soreness in horses (as defined by the HPA and regulations) for their scientific validity and reliability.  In the course of its study, the committee will:
• Examine what is known about the quality and consistency of available methods to identify soreness in horses
• Identify potential new and emerging methods, approaches, and technologies for detecting hoof and pastern pain and its causes
• Identify research and technology needs to improve the reliability of methods to detect soreness

In a consensus report, the committee will describe its conclusions about the validity and reliability of methods and provide recommendations to improve the efficacy and consistency of approaches to identifying soreness.  The report will also review the HPA regulations, including the “scar rule” and identify changes that would be necessary to implement the findings of the study.