National Academies Press: OpenBook

A Review of Methods for Detecting Soreness in Horses (2021)

Chapter: 2 Methods Used to Identify Soreness in Walking Horses

« Previous: 1 Introduction
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

2

Methods Used to Identify Soreness in Walking Horses

This chapter focuses on the currently available methods to detect soreness in horses, some of which are currently employed by the U.S. Department of Agriculture’s Animal and Plant Health Service (APHIS) to determine compliance with the Horse Protection Act (HPA). These methods, how well they detect soreness, and their reliability are discussed. To provide background to the reader, this chapter begins with a description of the inspection process currently in place to detect if Tennessee walking horses (TWHs) entered in shows experience soreness on their forelimbs (a violation of the HPA), and it continues with a discussion of the qualifications and training of those who inspect the horses. The description of the inspection process is not meant as an analysis of or a commentary on how APHIS enforces the HPA—a task that is outside the committee’s purview (see committee’s statement of task in Box 1-3, Chapter 1).

The current inspection process of TWHs in competition relies on the observation of horse movement and palpation of limbs, which are performed primarily by inspectors trained and licensed by horse industry organizations (HIOs). These methods, while deemed subjective, are widely and routinely used in veterinary medicine to detect if horses, regardless of breed, are experiencing pain. Objective procedures that may aid the determination of pain or other violations of the Horse Protection Regulations include thermography, radiography, testing of swabs of the distal limbs of TWHs for prohibited substances, and testing of blood samples for the presence of medications that are given to TWHs to alter their response to palpation.

THE INSPECTION PROCESS

APHIS enforces the HPA under Animal Care, the same program through which the Animal Welfare Act (AWA) is administered.1 At shows and events covered by the HPA, horse inspections are performed by veterinary medical officers (VMOs), who are APHIS employees, or by designated qualified persons (DQPs), who are third-party individuals trained by HIOs, or by both VMOs and DQPs. The inspection process varies depending on who is present and performing inspections at the show or event, but the methods by which DQPs and VMOs detect horses that are sore per the HPA and Horse Protection Regulations (see Appendix C of this report) are basically the same (i.e., visual observation of the horse’s gait and palpation).

Horse shows are broken down into categories or classes, with each class showing at a designated time. Horses entered in a particular class are inspected shortly before that class shows. Inspections are performed in a facility with limited access, with the facility divided into two areas. One area is for conducting the actual horse inspection, with access restricted to the DQP, APHIS representatives, and the person handling the horse—referred to as the custodian in this report—which could be the trainer, rider, owner, or other responsible party; the second area is the warm-up area where the horse is held after being inspected and prior to showing, with access restricted to a maximum of three persons per horse—typically, the trainer, rider, and owner. The inspection and warm-up area is generally cordoned off to keep unauthorized persons from entering. There are shows in which well-lighted covered barns are used as inspection areas, but in shows held in smaller venues, inspections are conducted in graveled parking lots, with no cover and often with bad lighting.

___________________

1 See https://www.aphis.usda.gov/aphis/ourfocus/animalwelfare/usda-animal-care-overview (accessed April 2, 2020).

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

An inspection consisting of gait observation and palpation takes approximately 2-3 minutes per horse. If reinspection or additional procedures are done, the process takes longer. A horse that is found to be sore in either front leg2 (unilateral soreness) or on both front legs (bilateral soreness) or is noncompliant with scar rule criteria or is in violation of other Horse Protection Regulations (e.g., the 50 percent rule, heel toe, high band, etc.) is disqualified from the entire show.3 If the DQP inspects the horse and finds a violation, he or she issues a ticket to the custodian of the horse. Cited in the ticket are the custodian and all other persons named on the horse entry form. If a VMO inspects the horse (regardless of whether the DQP previously inspected it or not) and finds a violation, the VMO will create a case packet (i.e., collect information that may eventually be used in a federal case). In recent years, VMOs typically do not create a case packet after the DQP has issued a ticket to the custodian.

After a class shows, the winner of that class would go back to the warm-up area for a post-show inspection by the DQPs. The rest of the horses from that class would be returned to their individual stalls or trailers outside of the controlled area, unless the DQPs or APHIS request that they proceed to the warmup area. A post-show inspection is done to check if the horse that won was shown while sore; if a VMO is present at that show, the VMO can check the horse after the DQP, but this is not mandatory. As with preshow inspections, if the DQP finds the horse sore post-show, a ticket is issued; if a VMO finds the horse sore, a case packet is created. The action devices worn by the horse in the class are also examined to ensure they did not strike the coronary band, did not have rough or sharp edges, and weighed less than 6 ounces. Guidelines for the conduct of horse inspections and information on penalties for violations are contained in the Horse Protection Regulations. HIOs may also impose penalties for violations under their own rules (these rules are contained in a rule book that HIOs submit to APHIS every year).

The inspection process is discussed in more detail in the following section. Note that the inspection process will proceed somewhat differently when only a DQP is present (no VMO) versus when there is one VMO or two VMOs (with or without a DQP) present during inspection. The inspection process is not always consistent from year to year and has undergone changes, often due to new policies instituted by the APHIS Animal Care Horse Protection Program leadership.

Inspection Process When Only a DQP Is Present

As mentioned in Chapter 1, a 1976 amendment to the HPA allowed third-party individuals (DQPs) to help with the inspection of horses in order to expand the capacity of APHIS, which, because of budgetary constraints, does not have enough VMOs to inspect all shows or events covered by the HPA. While it is very common to have only DQPs at shows (no VMOs), there are shows that do not have DQPs at all because inspection by a DQP at horse shows is not mandatory. As mentioned in Chapter 1 of this report, show managers use DQPs’ services (through an HIO that facilitated the licensing of the DQP; see discussion in Chapter 1) to inspect horses at their events to reduce their liability under the HPA in case a horse that is deemed sore is shown (allowed in the show ring). Conversely, show managers and other responsible personnel that do not affiliate with certified HIOs and have no DQPs at their shows are held accountable for any HPA violations observed during unannounced inspections by APHIS VMOs at their events (APHIS, 2020). The DQP inspection process is illustrated in Figure 2-1a. When a horse is found to be sore on palpation or to be noncompliant with the scar rule criteria or in violation of other Horse Protection Regulations, the DQP has authority to write a ticket (citing the horse custodian or rider, trainer, and owner for

___________________

2 Under the HPA, soring includes all limbs or legs of the horse but since soreness is generally observed on the front legs, inspectors typically examine them and not the hind legs.

3 For equipment or prohibited substance violations, the horse will only be disqualified if the DQP found the violations, not the VMO. If the VMO found these violations, the horse will be allowed to show but the VMO will create a case packet.

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

violation) and, on behalf of the show manager, to disqualify the horse from showing. Documentation of the DQP inspection process (which may or may not include video recording) is performed by the HIO employed by the show manager. DQPs sometimes have other DQPs inspect the horse and agree on the finding before writing the horse custodian a ticket (A. Rhyner, APHIS, personal communication, May 1, 2020). However, the Horse Protection Regulations do not require multiple DQPs or multiple inspections to disqualify a horse for being sore.

Inspection Process When a DQP and a VMO Are Present

At shows where both a DQP and a VMO are present, the VMO provides oversight of the DQP’s inspections to ensure that the DQP is following prescribed procedures. This inspection process is illustrated in Figure 2-1b. If the DQP finds the horse to be in violation of Horse Protection Regulations, the VMO may reinspect the horse with or without a request for a reinspection from the horse custodian. The VMO may also reinspect a horse that the DQP found to be compliant with regulations. During reinspection (i.e., when a VMO reinspects a horse previously seen by a DQP), if the VMO finds a horse to be unilaterally or bilaterally sore or to be noncompliant with the scar rule criteria and returns the horse to the DQP but the DQP does not agree with the VMO’s findings, the VMO will alert show management to disqualify the horse (Walking Horse Report, 2020). If a horse is found to be in violation of Horse Protection Regulations by the DQP, the horse custodian and all other persons listed on the horse entry form will get a ticket and the horse is disqualified. However, if the violation is found by the VMO, he or she is authorized to collect information from the individuals responsible for the horse along with any videos, pictures, or radiographs to serve as evidence of an HPA violation and to create a case packet that may be used in a federal case.

Image
FIGURE 2-1a Horse inspection process when a designated qualified person (DQP) is present at a horse show (no veterinary medical officer). NOTES: *Some of the HPA violations for which a DQP can disqualify a horse from showing are unilateral or bilateral soreness, noncompliance with scar rule criteria, equipment violations (such as high band, off on 50 percent rule, or heel/toe ratio), and detection of prohibited substances on the leg area (e.g., shoe polish to cover up lesions).
**A DQP can decline a horse custodian’s request to reinspect because there is no provision in the Horse Protection Regulations that DQPs should reinspect a horse. However, HIOs have been known to ask two DQPs to inspect the same horse and agree on the violations they found before a ruling is made.
***Ticket issued to custodian cites all persons on the horse entry form (this may include the horse custodian, rider, trainer, and owner).
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Image
FIGURE 2-1b Horse inspection process when a designated qualified person (DQP) and a veterinary medical officer (VMO) are present at a horse show. NOTES: *Some of the HPA violations for which a DQP can disqualify a horse from showing are unilateral or bilateral soreness, noncompliance with scar rule criteria, equipment violations (such as high band, off on 50 percent rule, or heel/toe ratio), and detection of prohibited substances on the leg area (e.g., shoe polish to cover up lesions)—if found initially by the DQP or if found by the VMO and the DQP concurs that the substance is present.
**Ticket issued to custodian cites all persons on the horse entry form (this may include the horse custodian, rider, trainer, and owner).

Inspection Process When There Is One VMO Present (No DQP)

As mentioned earlier, it is not mandatory for a show manager to hire an HIO that provides the services of a DQP, so there are cases where only a VMO would conduct horse inspections (this is referred to as an unaffiliated show). In this situation the process (illustrated in Figure 2-2) is procedurally similar to the DQP inspection in Figure 2-1a, but in this case the VMO inspects the horse and if he or she finds the horse in violation of HPA regulations, the horse custodian will not get a ticket; instead, the VMO will collect information that may be used in a federal case against the custodian (and all other persons named on the horse entry form). The VMO will reinspect the horse if requested by the horse custodian. (In previous years, the VMO could decline to reinspect if he or she found no sufficient grounds for doing so; this is no longer the practice.)

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

Inspection Process When There Are Two VMOs Present

The process when there are two VMOs present, which may also involve a DQP, if present (Figure 2-3), is similar to the process when there is a DQP and one VMO present (Figure 2-1b), although it has changed over the years. In previous years, if a VMO found the horse to be sore and there was an objection to the VMO’s finding, a reinspection would take place as long as there was sufficient cause (see Horse Protection Regulation 9 C.F.R. §11. 4 (h)(2)). Beginning in 2020, however, if a VMO finds a horse to be bilaterally sore, the second VMO automatically reinspects the horse, whether or not there is a request for it. The findings of the two VMOs must agree in order for the horse to be disqualified. If the two VMOs do not both find the horse to be unilaterally or bilaterally sore, the horse is allowed to show (A. Rhyner, APHIS Horse Protection Program, personal communication, April 20, 2020). If the first VMO finds the horse to be noncompliant with scar rule criteria (which qualifies the horse as sore), a reinspection by the second VMO will take place only if the custodian requests it. The horse will be disqualified if the second VMO concurs with the first VMO’s finding. If the custodian does not request a reinspection, the horse is referred to a DQP. If the DQP concurs with the scar rule violation finding, the custodian gets a ticket and the horse is disqualified. If the DQP does not concur with the first VMO’s finding, the horse is disqualified and a case packet is created (A. Rhyner, APHIS Horse Protection Program, personal communication, November 14, 2020).

Image
FIGURE 2-2 Horse inspection process when there is one veterinary medical officer (VMO) at a horse show. NOTES: *HPA violations for which a VMO can disqualify a horse from showing are unilateral or bilateral soreness and noncompliance with scar rule criteria. If the VMO finds equipment violations (such as high band, off on 50 percent rule, or heel/toe ratio) or detects foreign substances on leg area (e.g., shoe polish to cover up lesions), the horse cannot be disqualified unless a DQP concurs with the finding.
**The VMO cannot decline a request to reinspect a horse. If a reinspection is requested, the process restarts from the very beginning (see top of diagram).
***A case packet is created when a VMO collects information that may be used in a federal case against all persons named on the horse entry form (this may include the horse custodian, trainer, rider, and owner).
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Image
FIGURE 2-3 Horse inspection process when there are two veterinary medical officers (VMOs) at a horse show. NOTES: *HPA violations for which a VMO can disqualify a horse from showing are unilateral or bilateral soreness and noncompliance with scar rule criteria. If a VMO finds equipment violations or detects foreign substances on the leg area (e.g., shoe polish to cover up lesions), the horse cannot be disqualified unless a DQP concurs with the finding. The horse custodian may request that VMO #1 reinspect if he or she finds violations of Horse Protection Regulations other than bilateral soreness. As of 2020, if VMO #1 finds the horse to be bilaterally sore, VMO #2 will reinspect the horse automatically. Automatic reinspection by VMO #2 only occurs when VMO #1 finds the horse to be bilaterally sore; no other violation would trigger automatic reinspection.

HORSE INSPECTORS’ QUALIFICATIONS AND TRAINING

Veterinary Medical Officers

All VMOs with the Animal Care program are graduates of American Veterinary Medical Association (AVMA)–accredited veterinary medical schools, with many of them having been private-practice veterinarians before joining the program.4 Until 2010, Animal Care VMOs (full-time employees) were responsible for the humane treatment of animals covered by the AWA and for inspecting horses for compliance with the HPA. After 2010, with pressure from the TWH industry to have equine veterinarians enforce HPA regulations, APHIS began recruiting equine veterinarians (preferably members of the American Association of Equine Practitioners [AAEP]) whose main responsibility was to inspect horses at shows and events and work alongside DQPs whenever possible. These VMOs were considered intermittent VMOs (part-time employees) because they only worked for APHIS during horse shows and events and did not otherwise

___________________

4 See https://www.aphis.usda.gov/aphis/ourfocus/animalwelfare/sa_awa (accessed April 7, 2020).

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

perform duties related to AWA. However, in recent years horse inspections for HPA enforcement have reverted to being conducted mostly by Animal Care VMOs who are not necessarily equine veterinarians (the primary duty of these VMOs is to inspect for AWA violations; they inspect horses for compliance with Horse Protection Regulations if their schedule permits). At the time of hiring and yearly thereafter, intermittent VMOs and Animal Care VMOs who inspect horses are required to undergo training in Horse Protection Regulations, performance of horse inspections, and how to recognize violations of the HPA.

Designated Qualified Persons

DQPs obtain their licenses after completion of training provided by HIOs. To train DQPs, HIOs must first obtain certification from USDA for their DQP programs.

According to 9 C.F.R. § 11.7 of the Horse Protection Regulations, individuals may qualify as DQPs if (1) they are doctors of veterinary medicine who are accredited in any state by the USDA and who are members of the AAEP, or are large-animal practitioners with substantial equine experience, or are knowledgeable in the area of equine lameness as related to soring; or (2) they are farriers, horse trainers, or other knowledgeable horsemen with experience that would qualify them for positions as HIO stewards or judges and who have been formally trained and licensed as a DQP by HIOs with USDA-certified DQP programs.

To obtain certification for their DQP program, HIOs must provide the following to the USDA:

  1. The criteria to be used in selecting DQP candidates and a list of the minimum qualifications and knowledge each candidate must have in order to be admitted to the DQP program;
  2. A copy of the formal training program (classes and practical training) that each DQP candidate is required to attend before a license can be granted by the HIO. The minimum training requirements are given in 9 C.F.R. § 11.7 of the Horse Protection Regulations (Appendix C of this report); they include:
    • Classroom instruction on the anatomy and physiology of the horse’s limb (2 hours);
    • Horse Protection Regulations (2 hours);
    • Soring history and methods for detecting soreness (4 hours);
    • Practical instruction in clinics and seminars wherein knowledge gained from the previous classes can be applied (4 hours), including procedures for conducting a thorough and uniform examination of a horse. Except for the Horse Protection Regulations class, which should be taught by an instructor provided by the USDA (a VMO), all other classes are to be provided by an instructor that the HIO has specified and whose resume has been submitted to the APHIS Animal Care program. The DQP training program should also include instruction on DQP standards of conduct and record keeping and reporting requirements and procedures.
  3. A sample of a written examination that the DQP candidates must pass for completion of the program and the sample answers and scoring thereof, as well as proposed passing and failing standards.
  4. Criteria used to indicate successful completion of the training program, in addition to the written exam.
  5. Criteria and schedule for DQP continuing education, which should be no less than 4 hours per year.

Every year, APHIS conducts a refresher training course for DQPs, but attendance to this course is optional. If a DQP does not attend the APHIS refresher training course, the HIO should provide a refresher course to the DQP to fulfill the requirement for 4 hours of continuing education per year. Throughout the

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

year DQP performance is evaluated by VMOs at selected shows and events.5 If the DQP’s performance at a show is found to be unsatisfactory, APHIS sends a warning letter to the HIO that granted license to the DQP. According to Horse Protection Regulations §11.7 (f) “Each horse industry organization or association having a DQP program certified by the Department shall issue a written warning to any DQP whom it has licensed who violates the rules, regulations, by-laws, or standards of conduct promulgated by such horse industry organization or association pursuant to this section, who fails to follow the procedures set forth in §11.21 of this part, or who otherwise carries out his duties and responsibilities in a less than satisfactory manner, and shall cancel the license of any DQP after a second violation.” Any DQP whose license has been cancelled is permanently barred from being a DQP (A. Rhyner, APHIS, personal communication, April 9, 2020). For more information on the certification and licensing of DQPs, see the Horse Protection Regulations in Appendix C of this report.

METHODS CURRENTLY USED TO INSPECT HORSES FOR SORENESS

In accordance with Horse Protection Regulations, a horse is inspected by a DQP or a VMO before a show and, if the horse wins in its class, after the show as well. Section 11.1 of those regulations specifies what methods constitute an inspection:

Inspection means the examination of any horse and any records pertaining to any horse by use of whatever means are deemed appropriate and necessary for the purpose of determining compliance with the Act and regulations. Such inspection may include, but is not limited to, visual examination of a horse and records, actual physical examination of a horse including touching, rubbing, palpating and observation of vital signs, and the use of any diagnostic device or instrument, and may require the removal of any shoe, pad, action device, or any other equipment, substance or paraphernalia from the horse when deemed necessary by the person conducting such inspection.

Observation of Horse Movement and Appearance

The VMO/DQP inspection process mainly relies on two methods to determine soreness, which are also the methods employed to diagnose lameness in horses. The first method is to observe the horse’s movement and appearance. The way that a horse moves and its resting posture may indicate if the horse is experiencing lameness, a condition that often involves the limb and is associated with inflammation caused by trauma (such as by way of soring) or infection (Parks, 2010). Compensatory movements—changes in leg movement or how a foot lands on the ground, head bobbing, and weight redistribution (Kellon, 2017; Smith Thomas, 2019) —may be subtle, but these movements are observable if the whole horse is carefully watched. Observing the horse’s posture also helps in determining which limb is sore and the nature of the problem. For example, the rocking back stance is indicative of bilateral forelimb laminitis (Parks, 2010). Observing a horse’s gait and posture is a standard of practice among veterinarians and is the first step in deciding if a horse is experiencing soreness or pain (Davis, 2018). To reliably detect lameness by observation, an observer must have knowledge of the anatomy and function (physiology) of the structures of the horse’s legs, of the horse’s optimal conformation, and of normal gaits (Adams, 2015).

Experienced equine veterinarians have a high degree of agreement when independently examining the same horse for the presence of an abnormal (painful or lame) gait (Keegan et al., 2010). Any horse that has been observed to have gait or posture abnormalities should be further examined for signs of pain and inflammation.

___________________

5 See https://www.aphis.usda.gov/aphis/ourfocus/animalwelfare/hpa/ct_hpa_inspections_examinations (accessed April 9, 2020).

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

In 9 C.F.R. § 11.21 of the Horse Protection Regulations, the following instructions are provided for the DQPs:

(a)(1) During the preshow inspection, the DQP shall direct the custodian of the horse to walk and turn the horse in a manner that allows the DQP to determine whether the horse exhibits signs of soreness. The DQP shall determine whether the horse moves in a free and easy manner and is free of any signs of soreness.

Palpation

Palpation is the process of using one’s hands to examine the body (or a part of the body) to detect pain or diagnose a disease. In musculoskeletal evaluation of the horse, palpation is recognized as the gold standard for detecting local pain, local inflammation, and changes in tissue architecture and range of motion in joints and soft tissues (Adams, 2015). Palpation has also been defined as the application of a non-noxious stimulus (such as digital pressure) to an area of the body while observing the horse for responses, such as an effort to withdraw, a change in facial expression, or a movement of whole body (Ross, 2011; Adams, 2015; Davis, 2018). Typically, palpation is repeated several times to make sure the withdrawal response is repeatable and consistent, although prolonged stimulation or pressure on a painful area can elicit some level of analgesia through secretion of local endorphins, gate control (inhibition of presynaptic nociceptive spinal neurons), or hyperstimulation analgesia (activation of descending inhibitory systems) (Melzack, 1975), adding to the complexity of the pain identification. However, Bussieres et al. (2008) found that the pain response to palpation had good to excellent reproducibility across raters. Scores given for the “response to palpation” had high sensitivity and specificity, meaning that they accurately discriminated between horses with and without pain. Adams (2015) discusses in detail how palpation should be done and the factors that help improve lameness diagnosis via palpation, which include the examiner having knowledge of equine anatomy and normal conformation and gaits and being able to recognize lameness.

Palpation has been used as a regulatory measure for detecting hypersensitivity in distal limbs in show jumping horses by International Federation for Equestrian Sports (FEI)–accredited veterinarians since 2010 (this process is discussed in Box 2-1). Limb sensitivity testing is an integral part of FEI’s efforts to protect equestrian horse welfare. This examination ensures that only horses fit to compete are allowed to do so.

The Horse Protection Regulations provide instructions for the DQP on how palpation should be done. Section 11.21(a) of the regulations states:

(2) The DQP shall digitally palpate the front limbs of the horse from knee to hoof, with particular emphasis on the pasterns and fetlocks. The DQP shall examine the posterior surface of the pastern by picking up the foot and examining the posterior (flexor) surface. The DQP shall apply digital pressure to the pocket (sulcus), including the bulbs of the heel, and continue the palpation to the medial and lateral surfaces of the pastern, being careful to observe for responses to pain in the horse. While continuing to hold onto the pastern, the DQP shall extend the foot and leg of the horse to examine the front (extensor) surfaces, including the coronary band. The DQP may examine the rear limbs of all horses inspected after showing and may examine the rear limbs of any horse examined preshow or on the show grounds when he deems it necessary, except that the DQP shall examine the rear limbs of all horses exhibiting lesions on, or unusual movement of, the rear legs. While carrying out the procedures set forth in this paragraph, the DQP shall also inspect the horse to determine whether the provisions of §11.3 of this part are being complied with and particularly whether there is any evidence of inflammation, edema, or proliferating granuloma tissue.

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

To understand how the physical examinations are performed by DQPs, the committee requested videos from APHIS and SHOW, Inc. an HIO. The committee viewed 61 videos of horse inspections done during TWH shows, and its observations are in Box 2-2.

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

VMOs follow the USDA Standard Operating Procedure for Digital Palpation to Detect Soreness (APHIS Animal Care, 2018). A VMO physical examination of the horse pastern and hoof is similar to an examination by a DQP, but the VMO is required to follow these steps:

When palpating the posterior pastern use an inverted U pattern and begin on the left side of the pastern at the base of the heel bulb. Palpate up the left side and across to the right and down the

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

inverted U until you reach the right heel bulb. Then smaller concentric inverted U patterns would be used. Then the center of the posterior pastern would be palpated until reaching the area between the heel bulbs. The anterior pastern would then be palpated in left to right rows starting at the coronary band until reaching the fetlock. All this should be done in 1.5-2.5 minutes in a compliant horse. (APHIS Animal Care, 2018, p. 1-3)

VMOs attend only a very small number of TWH shows compared with DQPs (estimated to be 6 percent of shows attended by DQPs). Originally the duty of the VMOs was to “inspect the inspectors” (DQPs) to ensure that the Horse Protection Regulations were enforced. Currently, VMOs may observe horses on any part of the show grounds, including horses in trailers, in stalls, or in the alleyways, and they may inspect any horse that appears to have abnormal behavior or signs of injury to the lower front or hind limbs. In its 2010 audit report, the USDA Office of the Inspector General noted that VMOs have to perform their duties under a hostile environment—VMOs are often intimidated in order to prevent them from inspecting horses—which necessitates the presence of armed security or police at shows (USDA OIG, 2010). When inspecting horses, VMOs are restricted to more stringent requirements concerning where to stand and must follow a prescribed pattern of palpation and apply a prescribed amount of pressure using the pad of the thumb. The palpation protocol specifically instructs VMOs to “use the flat part of your thumb to apply enough pressure to flatten the flesh of the thumb, thus blanching the thumbnail”—which is an amount of pressure that is well below the threshold to produce a flinch response indicating limb sensitivity in normal TWH limbs (Haussler et al., 2008). These rules were first instituted in late 2016 in response to objections raised by the TWH competitors (owners, trainers, handlers, and attorneys for the TWH industry). VMOs may inspect any horse for what is deemed cause, pre- or post-show, after a DQP has inspected the horse. Additionally, since late 2016, horses found in violation of the HPA have been reinspected by a second VMO, if present. The findings to disqualify a horse must be exactly the same as to the area of apparent pain and the type of response given by the horse as well as findings of skin changes indicative of previous injury (J. Baker, former VMO, USDA Animal Care Horse Protection Program, personal communication, July 27, 2020). Prior to the institution of the required second VMO inspection and prescribed VMO palpation method (in late 2016), the findings of DQPs and VMOs at TWH shows often varied significantly. When the mandatory second VMO inspection was instituted with the requirement that the findings of the two VMOs had to agree exactly, the number of horses found to be unilaterally or bilaterally sore dramatically declined, as indicated by activity reports that were provided to the committee by USDA. The numbers presented below are the sum of bilateral and unilateral findings from the pre-show inspection of padded and flat-shod walking horses that were entered in the 2014, 2015, 2016, 2017, 2018, and 2019 TWH National Celebration.

Inspector/Soreness Finding 2014 2015 2016 2017 2018 2019
VMO bilateral 19 29 35 0 0 0
VMO unilateral 25 35 29 1 0 0
DQP bilateral 3 4 5 6 5 7
DQP unilateral 14 10 12 21 10 20

During diagnostic lameness examinations, once an abnormal, painful, or inflamed structure is identified, further diagnostic methods that provide objective data are used to make a definitive diagnosis (Turner, 2015; Davis, 2018). Some of these diagnostic tools can be used to provide evidence of soreness during horse inspections and are discussed in another section of this chapter.

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

Finding 2-1: At shows covered by the Horse Protection Act (HPA), horse inspections are performed by a designated qualified person (DQP) employed by horse industry organizations (HIOs) or, less often, by a USDA veterinary medical officer (VMO) or, in some instances, by both. These individuals have different backgrounds, training, and experience in detecting pain and inflammation in animals. DQPs are not required to have a veterinary degree, and most are not veterinarians. DQPs receive 10 hours of instruction in examining horses from instructors who are not veterinarians. VMOs attended veterinary schools for 4 years and some have private-practice experience prior to being employed by APHIS. Additionally, DQPs are known to have close ties to the industry and may have conflicts of interest (as pointed out in the 2010 OIG audit).

Finding 2-2: The current horse inspection process for detecting soreness involves observation of the horse’s movement and posture and palpation of the limbs, which is the gold standard for detecting local pain and inflammation. These examination methods are known to be valid and reliable when performed by veterinarians who are trained and highly experienced in detecting lameness and pain. They are employed to detect lameness, injury, and pain in all breeds of horses that are used in competitions, shows, recreational riding, work, breeding, and teaching.

Finding 2-3: As seen from 61 DQP inspection videos that the committee was allowed to view, inspectors do not carry out a sufficient observation of horse movement. During the visual inspection of the horse’s gait, the distance between the two cones is too short and not all horses complete an entire figure 8. The horse takes three or, rarely, four steps around the right cone and may pivot toward the cone on the left. Furthermore, the horse may not complete a sufficient straight-line walk.

Finding 2-4: VMOs are required to perform inspections according to APHIS protocols that are highly prescriptive. Recently APHIS adopted a process wherein a reinspection by a second VMO will automatically occur if the first VMO finds the horse bilaterally sore. This process requires both VMOs to make exactly the same findings before a violation ruling is made.

Finding 2-5: VMOs are required to use the pad of the thumb with only enough pressure to blanch the thumbnail and to follow a specific pattern of applying digital pressure when palpating the horses’ limbs during inspection. This prescribed palpation method for VMOs falls short of established protocols for lameness examinations.

Conclusion 2-1: Differences in training and experience account for the discrepancies between VMO and DQP inspection results in past years. This discrepancy will continue to affect inspection outcomes if DQPs are not trained adequately and evaluated for competency by experienced equine veterinarians. Conflicts of interest may also influence decisions of DQPs in finding whether a horse is in compliance with the HPA and in issuing a ticket of violation.

Conclusion 2-2: 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.

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

Conclusion 2-3: During inspection, ideally a horse should walk around the cones in a figure-8 pattern. Expanding the figure-8 pattern to consist of two adjoining circles, each with a 10-foot radius, would allow for better observation of horse movement. The required straight-line evaluation could be done as the horse is walking to the top of the first circle and then back from the figure 8.

Conclusion 2-4: Prescriptive protocols, if not followed strictly by a VMO, may allow for a possible objection to a VMO’s finding by the horse custodian. Moreover, the required inspection by a second VMO may cast doubt on the ability of VMOs to detect pain or other abnormalities and may negatively affect the VMO’s ability to make appropriate judgments.

Conclusion 2-5: The basis of all examinations for pain and lameness is observation and palpation, which are an integral part of determining whether pain is altering gait in a TWH. The strict requirements of following a specified pattern and using only the pad of the thumb with no more pressure than it takes to blanch the thumbnail limit the ability of palpation to detect the presence of limb sensitivity. The requirement that two VMOs must make exactly the same findings (i.e., sensitive on the lateral pastern but not bulbs of heels or medial pastern) does not consider changes that may occur over time between examinations, how the horse may respond to repeated palpation, or how the presence of foreign substances either parenterally or topically may influence findings over time.

Gas Chromatography–Mass Spectrometry to Detect Prohibited Substances that Mask Soreness

At events covered by the HPA, horses presented at the inspection area must not have any prohibited substances on their limbs. Lubricants (glycerol, petrolatum, and mineral oil) may be applied only after a horse has been inspected by a DQP or VMO and only if these lubricants are supplied and controlled by the event management (9 C.F.R. § 11.2). However, as mentioned in the previous chapter, some horse trainers apply other substances (e.g., copper naphthenate6 or diesel fuel) to the horse’s lower legs to make them sore. Trainers may also apply numbing agents (lidocaine, benzocaine, etc.) to mask soreness, or substances (e.g., shoe polish) to hide lesions that are evidence of a previous injury so that the horse can pass inspection. Some of these substances may rub off on inspectors’ hands, while others are not visible. In 2004, APHIS began using gas chromatography–mass spectrometry (GC–MS) as an additional tool in a pilot program to gather information on prohibited substances that have been applied topically on horses’ limbs (Melissa Radel, APHIS, personal communication, April 3, 2020).

GC–MS is an analytical method that involves the use of a gas chromatograph coupled to a mass spectrometer, by which complex drugs or chemicals may be separated, identified, and quantified.7 GC–MS has been in use for many years and is considered the “gold standard” for the detection of drugs, medications, or environmental contaminants and for use in forensic investigations (Hites, 2016; Lynch, 2017). The introduction of GC–MS in the late 1960s was one of the most significant advances in the testing for drugs used in horse racing (Kim and Yoon, 1996). At present, GC–MS confirmation of drug identification is required by many regulatory bodies in horse racing (Wu, 1995) and other equestrian sports, such as the U.S. Equestrian Federation (USEF) and the FEI. With GC–MS confirmation, drug identification is able to stand up to scrutiny in court (Stanley and Kollias-Baker, 1997).

GC–MS identifies and quantifies whatever substances are found. For many drugs, particularly those that mask pain, horse organizations have a zero-tolerance policy (no amount of drug allowed), which has been put under question because of the possibility of contamination and the ability of GC–MS to detect

___________________

6 Commonly used treatment for thrush in horses and ponies.

7 See https://www.bristol.ac.uk/chemistry/facilities/nerc-lsmsf/techniques/gcms (accessed May 23, 2020).

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

down to the picogram level (1 picogram is 0.000000000001 gram) (Hersh, 2010). For medications that are frequently used to legitimately treat disease in horses, acceptable limits may be established.

USDA APHIS Protocol for Detecting Prohibited Substances that Mask Soreness

According to the Horse Protection Regulations (9 C.F.R. § 11.2(c) Substances), “all substances are prohibited on the extremities above the hoof of any Tennessee Walking Horse or racking horse while being shown, exhibited, or offered for sale at any horse show, horse exhibition, or horse sale or auction, except lubricants such as glycerine, petrolatum, and mineral oil, or mixtures thereof.” To determine the presence of prohibited substances (such as topical anesthetics and any other substance that is not glycerine, petrolatum, or mineral oil), a USDA Animal Care inspector or technician obtains swabs at the request of a VMO (DQPs do not take swabs) from the surface of the pastern of the horse prior to inspection/palpation. TWH industry personnel have raised the objection that prohibited substances found on a horse’s leg(s) were from environmental contamination. Thus, to rule out any environmental contamination swabs are also taken from the surrounding air. Additionally, the majority of the substances found in the past 2 years were topical anesthetics, substances not found in the environment. All swabs (three samples: a blank/control and swabs from both the left and right forelegs of the horse) are placed immediately into sealed evidence bags and sent directly to an APHIS-accredited laboratory for testing using GC–MS. One person conducts all tasks involved in the sampling for prohibited substances, from the preparation of collection tubes to the actual swabbing and packaging for shipment to the laboratory. However, because of budgetary constraints, swabbing/testing cannot be done on all of the horses and shows that VMOs inspect. APHIS follows a risk-based approach in which VMOs only take swabs at shows where prohibited substances are more likely to be detected (shows with padded horses). In 2018, 144 out of 194 (74.23 percent) padded horses tested positive for prohibited substances, while 28 out of 66 (42.42 percent) flat-shod horses tested positive. In 2019, 84 out of 111 (75.68 percent) padded horses tested positive, while only 3 out of 23 (13.04 percent) of flat-shod horses tested positive (Radel, 2020).

Because results from swab tests are not obtained on the same day (they are received by USDA days after the show has taken place), they do not factor into the decision to allow the horse to show or to disqualify the horse. Results from prohibited substances testing provide information on what types of prohibited substances are being detected on horses, the compliance rate for padded horses compared with flat-shod horses, and the compliance rates according to the type of shows and geographic location. Depending on the type of substances detected (i.e., numbing agents), the results may be used to build a federal case against the horse custodian (Melissa Radel, APHIS, personal communication, April 3, 2020). APHIS posts data from prohibited substance tests on its Horse Protection Program website. Prior to 2017, lab results only indicated which prohibited substances were detected, but concentrations were not determined. In fiscal years 2018 and 2019 the prohibited substance testing results included the concentrations of the detected substances if they were on the APHIS target substances list. If the detected substances were not on the target list, only their presence was indicated, not the concentration (Radel, 2020).

Finding 2-6: Budgetary constraints limit swabbing and testing by APHIS for prohibited substances that cause soreness or that can mask soreness.

Conclusion 2-6: Testing of swabs is an effective method to determine if prohibited substances have been applied to the limb of horses to cause soreness or to mask soreness.

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

METHODS FOR DETECTING SORENESS NOT CURRENTLY USED IN HORSE INSPECTIONS FOR HPA ENFORCEMENT

Thermography (Thermal Imaging)

Thermography is a noncontacting, noninvasive method of detecting heat emitted from the body or from a part of the body and representing the heat as a pictorial display, called a thermogram. This method involves the use of an infrared camera. Thermography measures infrared radiation emitted from a body (or a particular body part) which then can be directly converted to temperature measurements (see Figures 2-4 and 2-5). The heat detected is directly related to the presence of blood vessels near the skin; warmer temperatures are indicative of increased circulation or a change in blood flow—conditions that are correlated with injury or inflammation (soreness) or lameness (Robson, n.d.; Veterinärmedizinische Universität Wien, 2013; Turner, 2015).

Image
FIGURE 2-4 Thermographic images of horse palmar pastern. Warmer temperatures are indicated by white and red. As the temperature decreases, the colors transition to blue and purple, as indicated on the temperature chart. Higher skin temperatures are correlated with inflammation. The image on the left shows a normal palmar thermogram; the warmest area is in the “pocket” and down through the cleft to central sulcus. The image on the right is not a normal thermogram; it shows a significant increase in thermal emissions over the palmar pastern and vertical striations. This pattern has only been seen in association with a horse that is sore with dermal changes. SOURCE: T. A. Turner, D.V.M.
Image
FIGURE 2-5 Thermographic images of the fore pasterns of two different horses. These thermal images are not normal and are suspicious because of the asymmetry of the pattern. SOURCE: T. A. Turner, D.V.M.
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

Thermography can help locate an area that is inflamed, but it does not characterize the etiology of inflammation. It is commonly used in equine medicine (in conjunction with other diagnostic methods) to help with the proper diagnosis and treatment of back injuries and lameness (Turner, 1999, 2015). In clinical cases thermography has been found to successfully detect a number of equine inflammatory conditions including laminitis, arthritis of the femoropatellar joint, and tendonitis (Purohit and McCoy, 1980). At FEI-sanctioned show jumping events, limb sensitivity examinations employ thermography to determine abnormalities in the heat patterns on a horse’s skin (FEI, n.d.).

Thermographic measurements are highly accurate and repeatable (Turner, 2011) when taken under optimal conditions (listed in the American Academy of Thermology Veterinary Guidelines for Infrared Thermography; AAT, 2019). While no more complicated than other imaging techniques (Lesté-Lasserre, 2013), thermography is sensitive to environmental factors such as sunshine, ambient temperature, and drafts and to the presence of haircoat, topical moisture, and topical liniments (AAT, 2019). One study found that airflow can cause the temperature of horses’ forelimbs to decrease, which necessitates taking measurements in a draft-free environment in order to avoid false-negative or false-positive diagnoses (Westermann et al., 2013b). However, measurements are not affected by the position of the infrared camera, as shown by a study by Westermann et al. (2013a) in which they found that changes in the camera angle (up to 20°) or a 0.5-m increase in camera distance from the forelimb did not affect thermographic measurements. In fact, when used by trained individuals who understand and know how to compensate for such “artifacts,” thermography is a highly useful tool under competition conditions (Turner et al., 2001).

Past Use of Thermography for HPA Enforcement

Thermography was originally used by USDA in 1978 as additional basis for enforcement of the HPA, which at that time mainly relied on palpation as the method for detecting soreness. The decision to use thermography was based on research performed by Nelson and Osheim (1975), which showed thermography to be an accurate and objective diagnostic tool.8 After the use of thermography became standard protocol9 for Federal Veterinary Service employees (the equivalent of VMOs today), two issues were identified that resulted in a change in the Horse Protection Regulations. Specifically, it was noted that certain preparations used by the industry for the lubrication of action devices could block infrared emissions; as a result, the rule was established that only glycerin, petroleum, or mineral oil could be used and only after the inspection process (APHIS, 1978). In addition, while examining young horses (2-year-olds) thermographically, a high incidence of tendonitis was observed. This was attributed to the weight of the shoe and pads and to the length of time these horses worked. Subsequently, regulations were added to the HPA that limited the workouts and performances of 2-year-old horses.

During the 1990s the use of thermography to help with HPA enforcement ceased. This was due to the cost and complexity of the equipment, as the machines were cumbersome, required special training, and were not easy to use or get to the horse shows. Another reason was that industry was not in favor of thermography because it added to the time of the inspection, and custodians wanted to get their horses warmed up and in the ring (R. DeHaven, former APHIS administrator, personal communication, August 3, 2020).

In 2008, thermography was reintroduced into the show inspection process and became part of the USDA protocol when inspecting horses for compliance with the HPA. Technology had improved markedly,

___________________

8 Kimberly Copher Back, HPA Docket No. 08-0007 (U.S.D.A. May 12, 2009) (Decision and Order), https://oalj.oha.usda.gov/sites/default/files/090512_HPA-08-0007_DO.pdf (accessed June 19, 2020).

9 Thermography was typically used on horses that exhibited pain reaction during digital palpation (R. DeHaven, former APHIS administrator, personal communication, August 3, 2020).

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

with the equipment being less expensive, more durable, and easier to use. The standard operating procedure for thermography10 was as follows: Thermography screening inspections were to be used to screen horses prior to palpations by DQPs or VMOs. The screening would consist of three images of the limb from the carpus (knee) distally; front (dorsal), left side (lateral LF and medial RF), and right side (medial LF and lateral RF); and then two close-up images, one of each palmar surface of the front pasterns. These inspections also were to be used to gather data to analyze thermography image results in comparison with soring. The USDA Horse Protection regional or national coordinator requested VMOs who attended competitions, exhibits, or sales to perform thermography screening inspections. The custodians of horses that displayed abnormal images had the option to take the horse back to the barn or to proceed forward through inspections. Foreign substance sampling might be conducted after the thermography screening inspection if image patterns indicate that a foreign substance might have been applied to the horse’s legs. Thermography was last used at the 2016 TWH National Celebration.

During the time thermography was used—between 2009 and 2016—thermal patterns were detected that were consistent with and subsequently shown to be indicative of foreign substances applied to the legs. Patterns were also found that were determined to be consistent with chronic inflammatory conditions of the pastern as well as patterns to be expected after the application of desensitizing agents.

Finding 2-7: Thermography, an imaging technique that veterinarians use to detect inflammation and that was used in HPA enforcement in the past, is currently not being used in detecting soreness during horse inspections.

Conclusion 2-7: 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.

Radiology/Radiography

Radiology is the use of x-rays and other high-energy radiation for the diagnosis and treatment of disease (radiography is the type of technology used to produce images). Radiologic techniques are used to produce images (called radiographs) to help evaluate an anatomic structure during pre-purchase or lameness examinations. Radiographs are useful in determining damage or changes to bony tissues but provide limited information on soft tissues, such as tendons or ligaments. They require interpretation by an experienced and knowledgeable veterinarian (AAEP, 2020) and are often used in conjunction with clinical examination. Because radiographs are two-dimensional, taking multiple views of the area of interest is required to allow for sufficient examination of changes in the structure of the bone or soft tissues (Turner, 2015; Oke, 2019). Plain film radiography, the standard system for many years, has now been replaced by computed radiography and digital radiography systems (Turner, 2015). Currently available portable radiologic machines allow radiographs to be easily viewed on laptops, and they are reasonably priced.

Digital radiography was introduced into the horse inspection process during the 2009 show season. It was used to examine the hoof packages for the use of illegal weights, nails, packing, or other devices prohibited by the HPA (see Figures 2-5 to 2-9). The digital radiography standard operating procedure is as follows: Radiography may be used to further evaluate a horse for soring after palpations by DQPs or VMOs. These inspections will also be used to gather data to analyze digital radiography image results

___________________

10 USDA APHIS Thermography Standard Operating Procedure. Unpublished. March 25, 2011.

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

comparing compliant and noncompliant horses. The USDA Horse Protection regional or national coordinator requests VMOs who may attend competitions and exhibits to work with veterinary consultants to include digital radiography in the inspection process when needed. The procedure requires digital radiography equipment (plate and x-ray generator), safety lead gowns and gloves, and a computer with imaging analysis software and the ability to calibrate images. Four radiographic images are made, two of each front foot. The images should include a horizontal dorsal palmar and a lateral-to-medial projection of each front foot with the x-ray beam centered on the shoe (APHIS Animal Care, 2018).

Data collected from various radiographs show that some horses have had evidence of excessive trimming of the sole and excessive dressing of the dorsal hoof capsule as well as the presence of laminitis or other hoof abnormalities that would cause pain to the horse. As a result of this information, regulations were instituted specifying that a horse having greater than 5 degrees of rotation is to be considered evidence of soring (Stick et al., 1982).

Testing of Blood Samples for the Presence of Prohibited Medications

Blood testing is most commonly done in the horse racing and nonracing performance horse industries to test for the presence of medications that are given to horses to enhance the horses’ performance (e.g., analgesics, steroids, or bronchodilators), to calm or improve the performance of excitable horses (e.g., sedatives, tranquilizers), or to make it difficult to detect the presence of illegal drugs (e.g., diuretics) (Slifer, 2018). Annually, the racing industry spends about $11 million on sample collection and about $26.5 million on testing (Jockey Club, 2014). Blood testing is performed according to medication rules and guidelines set by the regulatory body (i.e., state or sanctioning organization) that contracts with the testing laboratory (S. Stanley, University of Kentucky, personal communication, February 18, 2020). The USEF has established a protocol for testing and a policy on prohibited drugs and permitted medications, including concentrations allowed for permitted medications. For verification of horse identity, record keeping, and exchange of information, racehorses and other horses that compete in FEI or USEF/U.S. Hunter Jumper Association (USHJA)–sanctioned events are required to be identified by microchip.11 APHIS does not perform blood testing as part of HPA enforcement.

Image
FIGURE 2-6 Radiographs showing hoof wall width and sole depth. Although the Horse Protection Regulations do not currently specify acceptable ranges for these measurements, many feet that were radiographed showed measurements that were significantly outside of normal measurements. The image on the right shows an excessively thin hoof wall.

___________________

11 See https://inside.fei.org/fei/your-role/veterinarians/passports/microchips; https://www.usef.org/learning-center/videos/horse-microchipping (accessed November 12, 2020).

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Image
FIGURE 2-7 Radiographs of illegal substances inside hoof packages: of a Chadwick spring (left, encircled), which constitutes an illegal substance between sole and pad; (right) an illegal weight inside the package.
Image
FIGURE 2-8 Radiograph showing a rotation of >5 degrees.

In 2014 the Tennessee Walking Horse National Celebration sought the creation of a veterinary advisory committee (VAC) that would provide oversight for the collection and testing of blood samples taken from TWHs entered during the 2014, 2015, and 2016 National Celebration. Blood testing was done by accredited laboratories (LGC Sciences, Inc. in 2014; University of California, Davis, in 2015 and 2016) to determine compliance with the medication withdrawal guidelines set by the VAC (S. Stanley, University of Kentucky, personal communication, February 18, 2020). The laboratories were asked to test blood samples for the presence of prohibited substances and drugs that were identified by the VAC. These substances fell under the following general categories: nonsteroidal anti-inflammatory drugs (NSAIDs), sedatives, corticosteroids, non-androgenic reproductive hormones, immunostimulants, electrolytes, vitamins and minerals, and intra-articular injections.

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Image
FIGURE 2-9 Radiographs of (left) a lateral view of an illegal metal pad and a legal weight on the sole of the package and (right) a dorsal palmar view of an illegal metal pad and a legal weight on the sole of the package.

The method for detecting the presence of prohibited substances employed standard equipment and technologies that are used to test blood samples from racehorses (i.e., liquid chromatography–mass spectrometry). In all of the 3 years that blood testing was done, the samples tested all came from winners from each of the classes of the National Celebration (Stromberg, 2017). Test results were sent by the laboratories to the VAC. According to one of the documents provided by the TWH industry representative,12 the number of samples taken in 2014, 2015, and 2016 were 407, 88, and 84, respectively. Of these samples 230, 88, and 26 were selected for testing. The numbers of samples that tested positive for prohibited medications were 51 out of 230 in 2014, 0 out of 88 in 2015, and 17 (9 were from pleasure horses) out of 26 in 2016. In 2014 the medications most prevalent in the samples were methylprednisolone, a steroid primarily used for treating joint and soft tissue inflammation (26 samples); triamcinolone acetonide, a corticosteroid for treating skin and joint conditions (14 samples); and diclofenac, an NSAID (12 samples). Some samples were found to contain at least two anti-inflammatory medications. The results of the testing in 2015 indicated that all samples were in compliance with the VAC’s medication withdrawal guidelines. In 2016 some samples were found to be noncompliant with withdrawal guidelines for some compounds, namely romifidine, a sedative; phenylbutazone, an NSAID; and stanozonol, a synthetic steroid with anabolic and androgenic properties (S. Stanley, University of Kentucky, personal communication, February 18, 2020).

To the committee’s knowledge, blood testing was done only in these 3 years (2014, 2015, and 2016) at the National Celebration, and the blood samples that were tested came from winners, that is, horses that would not have been allowed to compete if they were found to be sore or to be in violation of other Horse Protection Regulations. This puts into question the usefulness of blood testing in determining if a horse was experiencing soreness when it was entered into a show. Most therapeutic drugs, such as those detected in the blood samples from 2014 National Celebration winners, are generally administered to horses for their overall well-being (Slifer, 2018), so it cannot be assumed that these were given to horses specifically to alleviate pain or inflammation of the limbs. However, NSAIDs, opioids, and local anesthetics may abolish a sore horse’s response to palpation by decreasing mechanical nociceptive thresholds to palpation (Schatzmann et al., 1990; Dönselmann et al., 2017; Söbbeler and Kästner, 2018; Echelmeyer et al.,

___________________

12 The 2014, 2015, and 2016 blood testing reports and the summary report are available upon request to the Public Access Records Office of the National Academies of Sciences, Engineering, and Medicine.

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

2019). Topically applied pain blocking chemicals (e.g., lidocaine or benzocaine) are less likely to enter the bloodstream and the window of their detection is small and depends on how frequently they were applied, the quantity applied, and how much time has elapsed before testing was performed (S. Stanley, University of Kentucky, personal communication, February 18, 2020). Topically applied pain blocking chemicals can be detected by swab testing technology, which is currently being employed by APHIS to check for the presence of prohibited substances on horse limbs (see USDA APHIS Protocol for Detecting Prohibited Substances that Mask Soreness section in this chapter).

Finding 2-8: Blood sampling to test for prohibited medications and medications conditionally permitted but given above therapeutic levels is common in equestrian competitions around the world to protect horse welfare and to ensure fairness in competition. Testing is done according to medication rules and guidelines set by a regulatory body based on data on how the use or overuse of these medications can adversely affect the horse or alter its performance. Regulatory bodies, such as the United States Equestrian Federation (USEF) and International Federation for Equestrian Sports require identification of horses by microchip for identity verification, information sharing, and record keeping.

Finding 2-9: Medications given to TWHs are the same as medications administered to other competition horses and include all of the opioids, sedatives, local anesthetics, and nonsteroidal anti-inflammatory drugs (NSAIDs). These medications (along with their allowable concentrations) have been identified and are tested for by USEF, which has set the standards for medication testing for the entire nonracing equine competition industry in the United States, and other performance horse organizations. Blood testing is not routinely done in TWHs.

Conclusion 2-8: Anti-inflammatory drugs (e.g., NSAIDs), the prevalent type of medication detected in samples from TWHs in 2014, are generally given to horses to treat illness or injury or to alleviate pain in some part of the horse’s body. Research indicates that NSAIDs, as well as opioids and local anesthetics, may significantly reduce or abolish a horse’s response to palpation. Data collected through blood testing to determine presence of NSAIDs, opioids, local anesthetics or sedatives in TWH competitions could be applied to correlate the use of these drugs in horses that are or are not identified as being sore to determine if medications are being used to hinder the detection of soreness via palpation during pre-show inspections.

RECOMMENDATIONS

Recommendation 2-1: In line with the USDA OIG’s recommendation in 2010, the committee strongly recommends that use of DQPs for inspections be discontinued and that only veterinarians, preferably with equine experience, be allowed to examine horses, as is done in other equine competitions.

Recommendation 2-2: If the limited budget for HPA enforcement necessitates continued use of third-party inspectors, the committee recommends that they should be veterinarians or equine industry professionals who are screened for potential conflicts of interest and that they be trained to inspect by APHIS, not by HIOs. This is in line with the rule proposed by APHIS in 2016 that was finalized in 2017 but not yet implemented. Training should be done by experienced equine veterinarians, and strict competency evaluations should be conducted to assess the skills and knowledge of trainees before they are given license to inspect horses. Consequences for performing a substandard examination should be strictly enforced and reports of substandard performance and letters of admonishment should come from the APHIS, not HIOs.

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

Recommendation 2-3: APHIS should adhere to the Horse Protection Regulation 9 C.F.R. § 11.4 (h)(2), which states that the reexamination of the horse shall only be granted if the show veterinarian (not the competitor or any other persons) finds sufficient cause.

Recommendation 2-4: In digital palpation of distal limbs, the extent of digital pressure need not be prescribed, provided that experienced equine veterinarians are performing the inspections. Use of palpation from the carpus distally to determine the presence or absence of limb sensitivity is well established in other equine competitions. Horses with limb sensitivity in these competitions must be withdrawn for the welfare of the horse and safety of the rider.

Recommendation 2-5: Owing to physiological changes that occur after repeated stimulation of a painful area, inspection protocols should be based on current knowledge of pain perception and should exclude the requirement that horses must be repeatedly sore in a specific area to be disqualified.

Recommendation 2-6: To detect prohibited substances, swabs should be done on a random sampling of horses or on horses that the VMO identifies as suspect from observations made on the grounds of the horse show.

Recommendation 2-7: Thermography should be reinstituted in the inspection of TWHs.

Recommendation 2-8: Serious consideration should be given to testing blood of TWHs, using USEF’s rules and guidelines as a model, to detect medications administered to alter TWH response to palpation and for overall protection of TWH welfare and ensuring fair competitions. This would include random selection of horses, which are identified by microchip, at shows or sales. Championship shows should require the testing of winning horses as well as randomly selected competing horses.

REFERENCES

AAEP (American Association of Equine Practitioners). 2020. Lameness exams: Evaluating the lame horse. https://aaep.org/horsehealth/lameness-exams-evaluating-lame-horse (accessed May 21, 2020).

AAT (American Academy of Thermology). 2019. Veterinary guidelines for infrared thermography. https://aathermology.org/organization-2/guidelines/veterinary-guidelines-for-infrared-thermography/ (accessed May 26, 2020).

Adams, S. B. 2015. The lameness examination in horses. https://www.merckvetmanual.com/musculoskeletal-system/lameness-in-horses/the-lameness-examination-in-horses (accessed May 28, 2020).

APHIS (Animal and Plant Health Inspection Service). 1978. Animal welfare: Horse protection regulations. Federal Register 43(83):18514–18531.

APHIS. 2020. Horse industry organizations and designated qualified persons. https://www.aphis.usda.gov/aphis/ourfocus/animalwelfare/hpa/ct_hpa_hio_and_dqps. February 2020 (accessed March 26, 2020).

APHIS Animal Care. 2018. Standard operating procedure: Digital palpation to detect soreness. HP-2017-012, Version No. 2. Effective December 12, 2018. Available from the Public Access Records Office of the National Academies of Science, Engineering, and Medicine.

Bussieres, G., C. Jacques, O. Lainay, G. Beauchamp, A. Leblond, J. L. Cadore, and E. Troncy. 2008. Development of a composite orthopaedic pain scale in horses. Research in Veterinary Science 85(2):294–306.

Davis, E. J. 2018. Lameness evaluation of the athletic horse. Veterinary Clinics of North America: Equine 34(2):181–191.

Dönselmann Im Sande, P., K. Hopster, and S. Kaestner. 2017. Effects of morphine, butorphanol and levomethadone in different doses on thermal nociceptive thresholds in horses. Tierarztliche Praxis. Ausgabe G, Grosstiere/Nutztiere 45(2):98–106.

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

Echelmeyer, J., P. M. Taylor, K. Hopster, K. Rohn, J. Delarocque, and S. B. R. Kästner. 2019. Effect of fentanyl on thermal and mechanical nociceptive thresholds in horses and estimation of anti-nociceptive plasma concentration. Veterinary Journal 249:82–88.

FEI (International Federation for Equestrian Sports). n.d. Limb sensitivity. https://inside.fei.org/fei/your-role/veterinarians/welfare/limb-sensitivity (accessed May 28, 2020).

Haussler, K. K., T. H. Behre, and A. E. Hill. 2008. Mechanical nociceptive thresholds within the pastern region of Tennessee walking horses. Equine Veterinary Journal 40(5):455–459.

Hersh, M. 2010. Zero-tolerance policy causing total confusion. https://www.drf.com/news/zero-tolerance-policy-causing-total-confusion (accessed August 4, 2020).

Hites, R. A. 2016. Development of gas chromatographic mass spectrometry. Analytical Chemistry 88(14):6955–6961.

Jockey Club. 2014. Raising the standard of testing and enforcement. https://www.bloodhorse.com/pdf/TestingEnforcementFindings10142014.pdf (accessed June 24, 2020).

Keegan, K. G., E. V. Dent, D. A. Wilson, J. Janicek, J. Kramer, A. Lacarrubba, D. M. Walsh, M. W. Cassells, T. M. Esther, P. Schiltz, K. E. Frees, C. L. Wilhite, J. M. Clark, C. C. Pollitt, R. Shaw, and T. Norris. 2010. Repeatability of subjective evaluation of lameness in horses. Equine Veterinary Journal 42(2):92–97.

Kellon, E. M. 2017. The equine lameness exam. https://www.equisearch.com/articles/the-equine-lameness-exam (accessed May 15, 2020).

Kim, K.-R., and H.-R. Yoon. 1996. Rapid screening for acidic non-steroidal anti-inflammatory drugs in urine by gas chromatography mass spectrometry in selected-ion monitoring mode. Journal of Chromatography B 682:55–66.

Lesté-Lasserre, C. 2013. Airflow’s impact on thermographic readings of horse legs. The Horse, May 29. https://thehorse.com/116029/airflows-impact-on-thermographic-readings-of-horse-legs/ (accessed May 26, 2020).

Lynch, K. L. 2017. Toxicology: Liquid chromatography mass spectrometry. In H. Nair and W. Clarke (eds.), Mass spectrometry for the clinical laboratory. San Diego: Academic Press. Pp. 109–130.

Melzack, R. 1975. Prolonged relief of pain by brief, intense transcutaneous somatic stimulation. Pain 1:357–373.

Nelson, H. A., and D. L. Osheim. 1975. Soring in Tennessee walking horses: Detection by thermography. Ames, IA: APHIS Veterinary Services Laboratory. Pp. 1–8.

Oke, S. 2019. Hoof radiographs: More than meets the eye. https://thehorse.com/112777/hoof-radiographs-more-than-meets-the-eye/ (accessed May 27, 2020).

Parks, M. A. 2010. Examination of the equine foot. AAEP Proceedings 56:485–493.

Purohit, R. C., and M. D. McCoy. 1980. Thermography in the diagnosis of inflammatory processes in the horse. American Journal of Veterinary Research 41(8):1167–1174.

Radel, M. 2020. USDA Horse Protection Program prohibited substances. Presentation at committee webinar, April 2.

Robson, J. n.d. Equine thermography—The whole picture. https://holistichorse.com/health-care/equine-thermography-%E2%80%93-the-whole-picture/ (accessed May 19, 2020).

Ross, M. W. 2011. Palpation of the forelimb. In M. W. Ross and S. J. Dyson (eds.), Diagnosis and management of lameness in the horse. St. Louis, MO: Elsevier. Pp. 45–53.

Schatzmann, U., M. Gugelmann, J. Von Cranach, B. M. Ludwig, and W. F. Rehm. 1990. Pharmacodynamic evaluation of the peripheral pain inhibition by carprofen and flunixin in the horse. Schweizer Archiv fur Tierheilkunde (9):497–504.

Slifer, P. 2018. A review of therapeutic drugs used for doping of race horses: NSAIDs, acepromazine, and furosemide. Creative Components 105. https://lib.dr.iastate.edu/creativecomponents/105 (accessed June 30, 2020).

Smith Thomas, H. 2019. Tips for pinpointing lameness—Which leg is lame and why? https://equimed.com/health-centers/lameness/articles/tips-for-pinpointing-lameness-which-leg-is-lame-and-why (accessed May 15, 2020).

Söbbeler, F.J., and S. B. Kästner. 2018. Effects of transdermal lidocaine or lidocaine with prilocaine or tetracaine on mechanical superficial sensation and nociceptive thermal thresholds in horses. Veterinary Anaesthesia and Analgesia 45(2):227–233.

Stanley, S. D., and C. Kollias-Baker. 1997. Review of equine drug testing. AAEP Proceedings 43:211–214.

Stick, J. A., H. W. Jann, E. A. Scott, and N. E. Robinson. 1982. Pedal bone rotation as a prognostic sign in laminitis of horses. Journal of the American Veterinary Medical Association 180(3):252–253.

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.

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×

Turner, T. A. 1999. The use of thermography in lameness evaluation. https://thehorse.com/14540/the-use-of-thermography-in-lameness-evaluation/ (accessed May 19, 2020).

Turner, T. A. 2011. Thermography. In G. M. Baxter (ed.), Adams and Stashak’s lameness in horses, 6th ed. Sussex, UK: Wiley-Blackwell. Pp. 466–474.

Turner, T. A. 2015. Imaging techniques in equine lameness. https://www.merckvetmanual.com/musculoskeletal-system/lameness-in-horses/imaging-techniques-in-equine-lameness (accessed May 28, 2020).

Turner, T. A., J. Pansch, and J. Wilson. 2001. Thermographic assessment of racing thoroughbreds. In Proceedings of the 47th Annual Convention of the American Association of Equine Practitioners. San Diego, CA: American Association of Equine Practitioners. Pp. 344–346.

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).

Veterinärmedizinische Universität Wien. 2013. Blowing in the wind: How accurate is thermography of horses' legs? ScienceDaily, March 27. www.sciencedaily.com/releases/2013/03/130327092521.htm (accessed September 24, 2020).

Walking Horse Report. 2020. USDA meets with industry—No major changes to inspections. February 12. https://www.walkinghorsereport.com/news/usda-meets-with-industry (accessed April 2, 2020).

Westermann, S., H. Heinz, F. Buchner, J. P. Schramel, A.Tichy, and C. Stanek. 2013a. Effects of infrared camera angle and distance on measurement and reproducibility of thermographically determined temperatures of the distolateral aspects of the forelimbs in horses. Journal of the American Veterinary Medical Association 242(3):388–395.

Westermann, S., C. Stanek, J. P. Schramel, A. Ion, and H. H. F. Buchner. 2013b. The effect of airflow on thermographically determined temperature of the distal forelimb of the horse. Equine Veterinary Journal 45(5):637–641.

Wu, A. H. B. 1995. Mechanism of interferences for gas chromatography/mass spectrometry analysis of urine for drugs of abuse. Annals of Clinical & Laboratory Science 25:319–329.

Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 21
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 22
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 23
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 24
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 25
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 26
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 27
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 28
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 29
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 30
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 31
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 32
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 33
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 34
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 35
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 36
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 37
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 38
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 39
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 40
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 41
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 42
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 43
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 44
Suggested Citation:"2 Methods Used to Identify Soreness in Walking Horses." National Academies of Sciences, Engineering, and Medicine. 2021. A Review of Methods for Detecting Soreness in Horses. Washington, DC: The National Academies Press. doi: 10.17226/25949.
×
Page 45
Next: 3 New and Emerging Methods, Approaches, and Technologies for Detecting Pain and Its Causes »
A Review of Methods for Detecting Soreness in Horses Get This Book
×
Buy Paperback | $52.00 Buy Ebook | $41.99
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

During the last century and today, the Tennessee walking horse has been used primarily for pleasure and show competition. Unique and natural to the breed is a smooth four-beat "running walk" gait. In the 1950s the accentuated or exaggerated running walk, known as the "big lick" became popular at high-level competitions. The combination of exaggerated high-action step in front and long stride behind is still considered desirable in today's horse show competitions, and it is often achieved through soring. Soring is the practice of applying a substance or mechanical device to the lower limb of a horse that will create enough pain that the horse will exaggerate its gait to relieve the discomfort. In 1970 Congress put into law the Horse Protection Act (HPA) to specifically address the practice of soring by prohibiting the showing, exhibition, or sale of Tennessee walking horses that are found to be sore. Sadly, soring is still being done even after 50 years of HPA enforcement.

This report reviews the methods for detecting soreness in horses, in hopes of advancing the goal of ultimately eliminating the act of soring in horses and improving the welfare of Tennessee walking horses. A Review of Methods for Detecting Soreness in Horses examines what is known about the quality and consistency of available methods to identify soreness in horses; identifies potential new and emerging methods, approaches, and technologies for detecting hoof and pastern pain and its causes; and identifies research and technology needs to improve the reliability of methods to detect soreness. This independent study will help ensure that HPA inspection protocols are based on sound scientific principles that can be applied with consistency and objectivity.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    Switch between the Original Pages, where you can read the report as it appeared in print, and Text Pages for the web version, where you can highlight and search the text.

    « Back Next »
  6. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  7. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  8. ×

    View our suggested citation for this chapter.

    « Back Next »
  9. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!