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Introduction
THE TENNESSEE WALKING HORSE
The Tennessee walking horse (TWH), also referred to as Tennessee walker, is a breed of horse that originated in Tennessee more than 100 years ago through a selective breeding process that initially combined the traits of the Narragansett Pacer and Canadian Pacer to produce a horse that could navigate rough terrains with ease (Menard et al., 2010). Later, the Morgan, Standardbred, Thoroughbred, and American Saddlebred were added to the breeding line to improve stamina (Mizell and Robboy, 1980; Menard et al., 2010). The breeding process ultimately produced a horse with smooth and easy gaits and a mild and obedient temperament (Mizell and Robboy, 1980; Kenerson and Moore, 2004; Menard et al., 2010).
Popularity in Horse Show Competitions
TWHs are popular in horse show competitions due to their unique four-beat running walk and flashy movement. A 2004 survey found that there were about 62,000 TWHs in the state of Tennessee, of which 15,500 were used for competition/horse shows, 24,900 were used for pleasure/sport, 14,900 were used for breeding, and 6,700 were used for other purposes such as agricultural work, teaching, and rider training (Kenerson and Moore, 2004). The calculated total annual economic impact from horse shows and events in Tennessee is approximately $45 million (Menard et al., 2010). Horse shows and events not only generate revenue for the state and local economies, they also provide substantial payouts to TWH owners and trainers when their horse wins or performs well in a particular class or division (Mizell and Robboy, 1980). In 2016 the total purse money at the National Tennessee Walking Horse Celebration was over $100,000, with prize money for each class ranging from $750 to $15,000. In 2017 over $15,000 was awarded to the jackpot winner at the International Grand Champion Walking Horse Show, another major TWH competition which is held in Murfreesboro, Tennessee (Medford, 2019).
Achieving the Accentuated Gait (the “Big Lick”)
The two basic categories of TWH competitions are flat-shod and performance. Flat-shod horses wear traditional horseshoes and are judged on brilliance and show presence while still being well mannered, balanced, and manageable.1 Performance horses are fitted with tall, heavy stacks of pads to accentuate their gait (Tennessee Historical Society, n.d.). Performance horses are known for their accentuated gait, referred to as the big lick, which draws people to horse shows and is rewarded by horse show judges (DeHaven, 1999).
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1 See https://en.wikipedia.org/wiki/Tennessee_Walking_Horse (accessed November 15, 2019).
There are trainers of TWHs who believe that the big lick can be achieved with hard work, training, and patience (DeHaven, 1999),2 but in the early 1950s some TWH owners and trainers began to employ methods, referred to as “soring,”3 to produce the accentuated gait in less time (Mizell and Robboy, 1980; APHIS, 2012a). Soring involves the application of chemical irritants and friction to make a horse’s forelegs sore, so that when the horse makes contact with the ground it flexes its forelimbs exaggeratedly and snaps them forward—producing the big lick. Because soring gave horses a competitive advantage, the practice became widespread in the 1960s (APHIS, 2012a).
Chemicals that are used to make the horse’s forelegs sore include mustard oil, croton oil, diesel fuel, gasoline, turpentine, cinnamon oil, kerosene, or corrosive hand cleansers. In training the horse to accentuate its gait, once such a chemical is applied, friction is created on the chemically treated areas by fastening chains to the forelegs. Alternatively, the forelegs can be made sore without the use of irritants through an extensive use of mechanical devices or action devices (DeHaven, 1999). Mechanical devices include performance packages (or stacks, which are multiple pads between hoof and horseshoe) and action devices (bracelet-like chains or rollers placed around the pastern).4 Trimming the hoof to expose sensitive tissues and tightly nailing on a shoe, inserting a hard object between the pad and the sole to exert pressure on the sensitive tissue (pressure shoeing), and over-tightening metal hoof bands to cause pressure on the hoof capsule have also been done to make a horse accentuate its gait (HSUS, n.d.; APHIS, 2012a).
Methods for Passing Inspections
Trainers and owners who practice soring do so to gain a competitive advantage in the show ring. However, for horses to be allowed to compete, they must first pass inspections designed to detect if horses are sore. Thus trainers and owners of sore horses have devised various methods to pass these inspections, including, for example, applying topical anesthetics to the forelegs to numb them transiently for the inspection. Other methods include training horses to not react to palpation by inflicting pain on other body parts (such as the tongue) and diverting the horse’s attention elsewhere to distract it from reacting to palpation. Some trainers apply salicylic acid topically to make a previously inflicted injury or lesions less visible, which causes additional pain, inflammation, and redness. Colored powders, inks, or dyes are then applied to mask the inflammation and redness or impart color to the areas of the skin that have lost hair or pigmentation (DeHaven, 1999).
THE HORSE PROTECTION ACT OF 1970
Increased public awareness of soring and the resulting backlash prompted the state of Tennessee to enact anti-soring legislation in 1950; however, the legislation was mostly disregarded by industry and was ultimately not enforced (DeHaven, 1999). In 1970 the U.S. Congress declared the practice of soring cruel and inhumane and passed the Horse Protection Act (HPA, 15 U.S.C. §§ 1821-1831). The HPA makes it
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2 There are claims that the big lick can only be achieved if the horses are sored. See interview with former TWH trainer at https://www.humanesociety.org/news/hsus-releases-exclusive-video-interview-convicted-horse-abuser (accessed February 12, 2020).
3 According to Mizell and Robboy (1980), the practice of soring dates to the 1930s, though the popularity of its use began to increase in the early 1950s.
4 See https://en.wikipedia.org/wiki/Soring for information on hoof trimming and pressure shoeing techniques.
illegal to exhibit, transport, sell, or auction horses that are known to be sore5 and authorizes the inspection of horses by the U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS) personnel. However, with its funding from Congress limited to about $500,000/year, the ability of APHIS to enforce the HPA nationally was limited (DeHaven, 1999). In 1976 an amendment by Congress to the HPA (P.L. 94-360) allowed the Secretary of Agriculture to expand the inspection program (APHIS, 2016a). Following this amendment, the Secretary created a program that would permit trained third-party individuals (referred to as designated qualified persons or DQPs) to conduct horse inspections. The DQP program was established by regulations published in the Federal Register in 1979 (APHIS, 2016a). Box 1-1 lists other amendments to the HPA along with various other efforts to improve the protection of horses.
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5 “The Act states that the term ‘sore’ when used to describe a horse means that the horse suffers—or can reasonably be expected to suffer—physical pain or distress, inflammation, or lameness when walking, trotting, or otherwise moving as a result of: an irritating or blistering agent applied, internally or externally, by a person to any limb of a horse; any burn, cut, or laceration inflicted by a person on any limb of a horse; any tack, nail, screw, or chemical agent injected by a person into or used by a person on any limb of a horse; or any other substance or device used by a person on any limb of a horse or a person has engaged in a practice involving a horse” (APHIS, 2012b).
The HPA was enacted specifically to protect the welfare of gaited horses, such as the TWH, by prohibiting the showing, exhibition, or sale of horses that experience soreness or that have been subjected to methods to make them sore. Other horse breeds (i.e., thoroughbreds, Arabians, quarter horses, sport horses, etc.) that compete in sanctioned shows (i.e., shows that are officially recognized by horse show sanctioning organizations, such as the International Federation for Equestrian Sports [FEI] and the U.S. Equestrian Federation [USEF]), are tested for drugs and prohibited substances in and out of competition and may be inspected for soundness (fitness to compete) by veterinarians who are hired by the sanctioning organization. Shows that feature TWHs are not sanctioned shows under one umbrella organization; hence the horses are not subject to any exam or testing that is administered by a sanctioning organization.
Enforcement of the Horse Protection Act
The Role of DQPs, HIOs, and VMOs
APHIS relies on DQPs, horse industry organizations (HIOs), and veterinary medical officers (VMOs; APHIS veterinarians) to inspect horses before they are shown, sold, or exhibited in public. A DQP is an individual (usually a farrier, trainer, or an individual with a basic knowledge of horses and the equine
industry; see Chapter 2 for DQP qualifications) who has authority from an HIO6 to determine if horses are sore or to inspect horses or check records for the enforcement of the HPA. DQPs are licensed through DQP programs administered by HIOs after these organizations have obtained USDA certification (see Chapter 2 for more information on USDA certification requirements). A DQP program that does not comply with Horse Protection Regulations will not be certified or will be de-certified by the USDA. Affiliating with a certified HIO and having DQPs at horse shows or sales is not mandatory, but show and sale managers opt to have DQPs at their events to reduce their liability under the HPA in case a horse that is sore is shown or sold. Show managers and other responsible personnel who do not affiliate with certified HIOs and have no DQPs at their show or sale are held accountable for any HPA violations observed at their events (APHIS, 2020).
To ensure that horses are disqualified when soreness is detected or when other HPA violations are found and that proper penalties were imposed by the HIO for noncompliance with rules set forth in the HIO rule book,7 APHIS reviews show management, HIO, and DQP reports and conducts audits of records that are maintained by certified DQP programs. In addition, VMOs attend selected horse shows and sales to assess the inspection procedures of the HIOs as well as DQP performance (APHIS, 2018). Owing to budget constraints, VMOs typically only conduct additional unannounced inspections at very few shows (less than 10 percent) annually (AAEP and AVMA, 2015). In fiscal year 2007, with a budget of $497,000 for HPA enforcement, APHIS was able to send VMOs to only 30 (6 percent) of the 463 sanctioned shows throughout the country (USDA OIG, 2010).
While the DQP program has expanded the coverage of HPA enforcement beyond what APHIS alone can cover, a 2010 audit conducted by the USDA Office of Inspector General (OIG) found that the DQP program “was not functioning as intended.” The resulting report explains the DQPs’ conflict of interest in this way:
DQPs realize that by ticketing horse exhibitors, or by excluding horses from a show, they are not likely to please their employers—who are interested in putting on a profitable show. DQPs are also likely to be exhibitors themselves, and so while they may be inspecting horses at one show, they could be exhibiting horses at another. If they inspected other exhibitors’ horses rigorously, they might find their own horses subjected to much more strenuous inspections at other shows (USDA OIG, 2010).
PURPOSE OF THE STUDY AND THE COMMITTEE’S CHARGE
Horse inspections are performed by VMOs and DQPs using similar methods—that is, visual inspection of the horse’s gait, palpation of the horse’s front legs to determine soreness, and examination of the skin on the forelimbs for evidence of previously inflicted lesions or prohibited substances that cause or mask soreness. However, even though the two types of inspectors employ the same methods, there have been significant disparities between VMO and DQP inspection outcomes. According to the 2010 OIG audit, DQPs issue fewer tickets when not being observed by APHIS representatives. From 2005 to 2008, DQPs were found to have issued almost half of all their violations at the shows that APHIS attended (USDA OIG, 2010), which represented only 6 percent of all shows monitored by DQPs. Additionally, there is concern within the walking horse industry that the determination of soreness in a horse is inconsistent between inspectors because the methods themselves may not be reliable. Another focus of debate is the technical merits of the “scar rule” (see Box 1-2), which specifies that a horse will be considered to be sore if certain types of lesions are found on the horse’s pastern or fore pastern.
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6 An HIO is an organization that is engaged in the showing, exhibition, sale, auction, or registration of horses.
7 HIOs are required to submit a rule book to APHIS every year.
In July 2017, APHIS and the Tennessee walking horse industry jointly requested the National Academies of Sciences, Engineering, and Medicine to oversee an independent study that would help ensure that 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. The committee’s statement of task is presented in Box 1-3.
COMMITTEE’S APPROACH TO ITS CHARGE
Committee Formation
Individuals appointed to the committee were chosen for their individual expertise and the relevance of their experience and knowledge to the statement of task, not their affiliation with any institution. All committee members volunteer their time to serve on a study. Areas of expertise represented on the committee included equine veterinary medicine, animal behavior, dermatopathology, pain detection technologies, horse show, horse racing, and horse walking experience, farriery, and the HPA. Biographies of the committee members are in Appendix A of this report.
Scope of Review and Guiding Principle
In accordance with the committee’s charge, the committee reviewed the methods that are currently used by VMOs and DQPs and methods typically used by equine veterinarians to determine if a horse is experiencing pain and soreness. In addition, the committee investigated other pain assessment methods and technologies that could potentially aid in the examination of a horse’s limbs for soreness.
The committee also reviewed the scar rule of the Horse Protection Regulations to determine if the language of the rule is consistent with current findings relative to dermatopathological changes seen in walking horses examined recently versus when the rule was written over 40 years ago.
The committee conducted this study with the protection of the horse’s welfare as the guiding principle in all of its discussions and ultimately in the recommendations put forth in the committee’s final report. These recommendations are for the consideration of APHIS and other parties responsible for protecting horse welfare through the HPA.
Deliberations and Information-Gathering Activities
To address its charge, the committee deliberated from September 2019 to September 2020, holding five meetings (four were virtual and were held on October 16, 2019, and on January 30, May 7, and June 4 in 2020, while one was an in-person meeting held on February 18–19, 2020 in Washington, D.C.), open sessions (at three of the committee meetings), and the following webinars: Horse Facial Expressions to Assess Pain and Algometry for Assessing Pain in Tennessee Walking Horses (December 2, 2019), Limb Sensitivity Testing and Drug Testing in Tennessee Walking Horses (February 13, 2020), and Equine Pain: Physiology and Assessment and Prohibited Substance Detection and Testing on Tennessee Walking Horses (April 2, 2020). Agendas for the committee meeting open sessions and webinars are included in Appendix B. Video recordings of webinar presentations and the webinar speakers’ slides are available at the study website.
Throughout the study, the committee also received input from interested stakeholders and the public via the study website or via e-mail. All submitted comments and documents were added to the study’s public access file, which is available on request from the National Academies’ Public Access Records Office. Requests can be directed to PARO@nas.edu.
Information from the Study Sponsors
APHIS provided the committee with video recordings of inspections being performed by VMOs and DQPs at horse shows. An HIO also provided the committee with video recordings of inspections being performed by DQPs. As with other materials received from the public, copies of these videos and documents have been deposited in the study’s public access file.
Materials Used in the Review of the Scar Rule
Because there are no published studies on TWH tissue biopsies, the committee’s review of the scar rule was conducted using an unpublished paper by Stromberg (2017) in which the author evaluated 136 pastern biopsies from 68 TWHs that were disqualified for violations of the scar rule. This paper was provided to the committee by the representative of the Tennessee walking horse industry for its consideration during the review of the scar rule. The two pathologists8 involved in the evaluation of the pastern biopsies provided 24 pairs out of the 68 pairs for additional review by Dr. Pamela E. Ginn, a member of the study committee and a board-certified veterinary pathologist and a specialist in veterinary dermatopathology.
ORGANIZATION OF THE REPORT
This report contains four chapters. Chapter 1, this chapter, introduces the study, provides the general background for the study and statement of task for the committee, and explains how the committee addressed its task. Each of the next three chapters addresses a particular item in the statement of task. Chapter 2 focuses on the currently available methods to detect soreness in horses, some of which are currently employed by APHIS to determine if horses are compliant with the HPA. The chapter includes discussions of these methods, how well they detect soreness, and their reliability. In Chapter 3 the committee addresses its task of identifying potential new and emerging methods, approaches, and technologies for detecting hoof and pastern pain and its causes. The chapter includes a discussion of pain and factors that affect pain perception and the expression of pain as well as a review of pain detection methods and technologies based on horse behavior and physiological parameters and a discussion of their potential use in improving the detection of soreness in horses during inspections for compliance with the HPA. Chapter 4 reviews the scar rule, its limitations, and what changes are currently documented regarding the skin of horses that are suspected of being sore. The basics of dermatologic (skin) examination are discussed in detail, along with a basic overview of pathologic lesions of the skin as they apply to the scar rule. Suggested changes to the language of the scar rule are also included in this chapter.
REFERENCES
AAEP (American Association of Equine Practitioners). 2008. Putting the horse first: Veterinary recommendations for ending the soring of Tennessee walking horses. White Paper. https://aaep.org/sites/default/files/2016-11/AAEP%20White%20Paper%20on%20TWH%20Soring.pdf (accessed February 4, 2020).
AAEP and AVMA (American Association of Equine Practitioners and American Veterinary Medical Association). 2015. Horse soring: The PAST Act S. 1121 and H.R. 3268. https://www.avma.org/sites/default/files/resources/2015-Soring-Booklet-Final_Logo.pdf (accessed February 4, 2020).
APHIS (U.S. Department of Agriculture Animal and Plant Health Inspection Service). 2012a. Animal care factsheet. https://www.aphis.usda.gov/publications/animal_welfare/content/printable_version/faq_rev_horsep.pdf (accessed February 12, 2020).
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8 Dr. Paul Stromberg (Ohio State University College of Veterinary Medicine) and Dr. Lynne Cassone (University of Kentucky Veterinary Diagnostic Laboratory).
APHIS. 2012b. Horse Protection Act; requiring horse industry organizations to assess and enforce minimum penalties for violations. Fed. Reg. 77: 33607-33619. https://www.federalregister.gov/documents/2012/06/07/2012-13759/horse-protection-act-requiring-horse-industry-organizations-to-assess-and-enforce-minimum-penalties (accessed October 16, 2019).
APHIS. 2016a. Horse Protection Act and its administration. https://www.aphis.usda.gov/aphis/ourfocus/animalwelfare/hpa/ct_hpa_history_and_administration (accessed Feb 13, 2020).
APHIS. 2016b. Final Rule: Horse protection; licensing of designated qualified persons and other amendments. https://www.aphis.usda.gov/newsroom/federal_register/hpa-rule.pdf.
APHIS. 2016c. Proposed Rule: Horse protection; licensing of designated qualified persons and other amendments. Federal Register 81:49111–49137. https://www.federalregister.gov/documents/2016/07/26/2016-17648/horse-protection-licensing-of-designated-qualified-persons-and-other-amendments (accessed January 2, 2020).
APHIS. 2018. Horse Protection Act inspections and examination technology. https://www.aphis.usda.gov/aphis/ourfocus/animalwelfare/hpa/ct_hpa_inspections_examinations (accessed January 2, 2020).
APHIS. 2020. Horse industry organizations and designated qualified persons. https://www.aphis.usda.gov/aphis/ourfocus/animalwelfare/hpa/ct_hpa_hio_and_dqps (accessed March 26, 2020).
AVMA (American Veterinary Medical Association). 2013. H.R. 1518/S. 1406 Prevent All Soring Tactics (PAST) Act: AVMA Position. https://www.avma.org/sites/default/files/resources/IB__PAST_Act_30Aug2013.pdf.
DeHaven, W. R. 1999. The Horse Protection Act—A case study in industry self-regulation. Journal of the American Veterinary Medical Association 216(8):1250–1253.
HSUS (Humane Society of the United States). n.d. What is soring? Important facts about this cruel abuse. https://www.humanesociety.org/resources/what-soring (accessed February 13, 2020).
Kenerson, D., and J. Moore. 2004. A Tennessee tradition, equine 2004. Nashville, TN: U.S. Department of Agriculture, August. https://www.nass.usda.gov/Statistics_by_State/Tennessee/Publications/Special_Surveys/2004equine.pdf (accessed January 15, 2020).
Medford, H. 2019. Perceptions of soring in Tennessee walking horses. Masters thesis, Eastern Tennessee State University. https://dc.etsu.edu/etd/3547 (accessed March 26, 2020).
Menard, R. J., K. W. Hanks, B. C. English, and K. L. Jensen. 2010. Tennessee’s equine industry: Overview and estimated economic impacts. Lexington, KY: University of Kentucky, Institute of Agriculture, Department of Agricultural Economics. https://ag.tennessee.edu/arec/Documents/AIMAGPubs/EconomicContributionandImpactStudies/Livestock/EquineIndustryTN.pdf (accessed March 26, 2020).
Mizell, T. A., and H. Robboy. 1980. Tender feet and high stepping: Soring in the Tennessee walking horse industry. Deviant Behavior 1(2):217–229.
Stromberg, P. 2017. Summary report about soring in Tennessee walking horses. Unpublished manuscript, available from the Public Access Records Office of the National Academies of Science, Engineering, and Medicine.
Tennessee Historical Society. n.d. Tennessee walking horse. https://www.tennesseehistory.org/tennessee-walking-horse (accessed November 15, 2019).
U.S. Congress, House. 2012. To amend the Horse Protection Act to designate additional unlawful acts under the Act, strengthen penalties for violations of the Act, improve Department of Agriculture enforcement of the Act, and for other purposes. H.R. 6388, 112th Cong. https://www.govtrack.us/congress/bills/112/hr6388/text (accessed February 14, 2020).
U.S. Congress, House. 2019. U.S. Senator Joseph D. Tydings Memorial Prevent All Soring Tactics Act of 2019. H.R. 693. 116th Cong. https://www.congress.gov/bill/116th-congress/house-bill/693.
USDA OIG (Office of the Inspector General). 2010. Animal and Plant Health Inspection Service administration of the Horse Protection Program and the Slaughter Horse Transport Program. https://www.usda.gov/sites/default/files/33601-02-KC.pdf (accessed February 14, 2020).
