Clinical features and diagnosis of sacroiliac joint region pain in 296 horses: 2004-2014

Computed tomography of the equine caudal spine and pelvis. Pathological findings in 56 clinical cases (2018-2023)

BACKGROUND

Computed tomography (CT) of the axial skeleton is increasing across many equine hospitals. CT of the pelvis and caudal spine in a large group of clinical cases has not been reported previously.

OBJECTIVE

To describe the pathological lesions identified in the caudal spine/pelvis in horses and ponies undergoing CT spine of this region.

STUDY DESIGN

A retrospective case series.

METHODS

Horses with CT imaging of the caudal spine/pelvis were included. Horses aged under 6 months and those with CT examinations performed post-mortem were excluded.

RESULTS

Fifty-six horses met the inclusion criteria. Ages ranged from 8 months to 20 years and bodyweights from 85 to 680 kg (mean 488 kg). Horses presented predominantly for lameness (30/56) and poor performance (18/56). Osseous pathology was identified in 41/56 horses; including osteoarthritis of the sacroiliac joint(s) (n: 28), pathology of the intervertebral disc joint(s) (n: 12), pelvic fractures (n: 9), osteoarthritis of the coxofemoral joint(s) (n: 8), ventral spondylosis (n: 6), acetabular rim fracture (n: 2), dislocation of coxofemoral joint(s) (n: 2), and dorsal dermal sinus of the sacrum (n: 1).

MAIN LIMITATIONS

The relationship between CT imaging findings and clinical signs in horses remains unclear. Further work is required to describe the relationship between congenital, developmental, and acquired changes in the caudal spine and pelvis, and clinical signs.

CONCLUSIONS

CT of the caudal spine and pelvis can be utilised in horses and ponies for diagnosing a range of clinical disorders that may be causing 'lumbosacroiliac pain', poor performance, hindlimb lameness, and stiffness. The pathologies we observed were diverse and many patients had multiple lesions.

Computed tomography of the equine caudal spine and pelvis: Technique, image quality and anatomical variation in 56 clinical cases (2018-2023)

BACKGROUND

Cross-sectional imaging improves the diagnostic accuracy of complex anatomical regions. Computed tomography (CT) of the pelvis and caudal spine in a large group of live horses and ponies has not been previously reported.

OBJECTIVE

To describe the procedure for acquiring CT images of horses' caudal spine/pelvis under general anaesthesia (GA) and to detail the image quality, artefacts and anatomical variations in this region.

STUDY DESIGN

Retrospective case series.

METHODS

Horses with CT of the caudal spine/pelvis were included. Horses under 6 months and CT examination performed post-mortem were excluded. Protocols, image quality, region of interest, anatomical features and morbidities were analysed.

RESULTS

Fifty-six horses (8 months to 20 years, 85-680 kg) met the inclusion criteria. GA ranged from 10 to 60 min (mean: 30, median: 32). There were no adverse events recorded in any of the horses associated with the procedure. Images of all horses were considered of diagnostic quality. Anatomical variations were common and included the location of diverging (widest) interspinous space, the presence of spina bifida in the lumbar and sacral spine, the shape of the last lumbar vertebra and the location of intertransverse joints in terms of where they were present and the degree of fusion/modelling.

MAIN LIMITATIONS

Not all horses underwent CT examination of the same regions, the upper size limit of horses is unknown and will vary depending on bore size and table infrastructure. Image noise, particularly in large horses and beam hardening artefacts from hardware and pelvis degraded image quality. Images were of insufficient quality in large horses for soft tissue interpretation.

CONCLUSION

CT of the caudal spine and pelvis in live horses with wide-bore CT machines and modified patient infrastructure was safe and produced diagnostic images.

Musculoskeletal Injury and Illness Patterns in British Eventing Horses: A Descriptive Study

There has been little investigation into the health patterns of the eventing horse population outside veterinary clinics. To target health problems in the eventing horse population, it is important to determine the relative impact of different health problems. The objectives were to describe the prevalence and patterns of lameness/illness in registered British eventing horses. An online survey was released for all horses registered with British eventing in 2018. Data were collated and descriptive analyses undertaken. A total of 1677 surveys were completed, among which 49.4% reported a previous lameness/musculoskeletal problem, 26% being in the previous six months. The most frequently reported musculoskeletal problems were in the foot (421), joints (382), wounds (340), back (333), ligament (205), tendon (213), bones (140) and muscles (135). The most frequent non-musculoskeletal problems related to the skin (183), gastric ulceration (173), colic (145) and infection (88). Injuries to the hoof sole/muscles/tendons were most frequently sustained in competition, suspensory ligament/splint bone/stifle/tarsal injuries were more frequently sustained in training and abscess/foot penetration at rest. DDFT injuries were most frequently out of training for >12 months, SDFT/stifle/suspensory ligament for <12 months, tendon sheath/splint bone for <3 months and tarsal/sole bruising/abscess for <2 weeks. A greater understanding of injuries/illnesses frequently sustained could be useful for veterinarians working with event horses.

Post-mortem ultrasonographic and computed tomographic features of the anatomical variations and acquired pathological bony changes of the lumbosacroiliac region in a mixed population of horses

BACKGROUND

Transrectal ultrasonography is the best technique for evaluating the ventral aspect of the lumbosacral and sacroiliac regions yet this diagnostic technique does not always lead to a final diagnosis of back pain in horses.

OBJECTIVES

To describe anatomical variations and acquired pathological bony changes (APBCs) in the lumbosacral and sacroiliac regions detected by ultrasonography (US) and computed tomography (CT) examinations on specimens. We hypothesised that age, body mass, previous use and anatomical variations may be correlated with the presence and/or severity of APBCs.

STUDY DESIGN

Descriptive cadaver study.

METHODS

Lumbosacroiliac specimens were obtained from 51 horses that died or were euthanised for reasons other than the study and underwent US and CT examinations post-mortem.

RESULTS

Forty-two specimens were analysed. The most prevalent lumbosacral disc morphology was type 2 (21/42), and protrusions were found in 15/42 specimens. Abnormal echogenicity of the L5-L6 and lumbosacral discs was detected in 11/42 and 30/42 specimens, respectively. Abnormalities in the size of the L5-L6 disc were found in 10/42 specimens and correlated with promontorium localisation (Cramér's V coefficient [V] = 0.42) and lumbosacral disc morphology (type 1: V = 0.41; type 5: V = 0.69). The most prevalent orientation of the L6 spinous process (SP) was convergent (24/42). The promontoria were mostly located between L6 and S1 (36/42). Lumbosacral spondylosis was detected in 24/42 specimens and spondylolisthesis in one. Age was associated with the severity of APBCs in the sacroiliac joints, lumbosacral intertransverse joints, articular process joints, spondylosis and L6 or S1 bone plate irregularities. Lumbosacral spondylosis or L6 extremitas caudalis irregularity was associated with lumbosacral angulation, variability in the size of the L5-L6 disc and localisation of the promontorium, L6 SP orientation and L6 extremitas caudalis irregularity with abnormal echogenicity of the LS disc.

MAIN LIMITATIONS

Lack of information on clinical signs.

CONCLUSIONS

High variability and prevalence of the anatomical variations and APBCs in the lumbosacroiliac region were observed, and correlations between some anatomical variations and APBCs and between APBCs and age were reported.

Equine Nuclear Medicine in 2024: Use and Value of Scintigraphy and PET in Equine Lameness Diagnosis

Scintigraphy and Positron Emission Tomography (PET) are both nuclear medicine imaging techniques, providing functional information of the imaged areas. Scintigraphy is a two-dimensional projected imaging technique that was introduced in equine imaging in the late 1970s. Scintigraphy allows imaging of large body parts and can cover multiple areas, remaining the only technique commonly used in horses for whole body imaging. PET is a cross-sectional imaging technique, first used in horses in 2015, allowing higher resolution three-dimensional functional imaging of the equine distal limb. This manuscript will cover current use and values of these two modalities in equine lameness diagnosis.

Shape change in the saddle region of the equine back during trot and walk

Equine back pain is prevalent among ridden horses and is often attributed to poor saddle fit. An alternative explanation is that saddle fits are technically good but fit to the wrong configuration. Saddles are fit for the standing horse, but much of the time ridden is instead spent locomoting when the back experiences the greatest peak forces. We used an array of cameras to reconstruct the surface of the back and its movement during trot, walk and standing for five horses. We verified the setup's accuracy by reconstructing a laser-scanned life-sized model horse. Our reconstructions demonstrate that saddles sit within a large, relatively low-mobile region of the back. However, saddles do sit adjacent to the highly mobile withers, which demands care in positioning and design around this important region. Critically, we identified that saddle curvature between standing and moving horses is substantially different, where trotting and walking horses have flatter backs than their standing configurations. Saddles designed around the locomoting configuration of horses may improve horse welfare by being better fit and decreasing the focal pressures applied by saddles.

Review of the clinical diagnosis of sacroiliac dysfunction in horses - Challenges and limitations

Sacroiliac dysfunction (SID) is a condition seen in horses associated with poor performance that affects hind limb gait and impulsion. The condition comprises pain and dysfunction but there lacks clarity around the aetiopathogenesis and whether SID encompasses abnormal joint pathology, abnormal joint movement, abnormal regional biomechanical function, joint laxity and pain, or various combinations of these that may vary over time. Clinical assessment remains challenging for equine clinicians due to the deep location of the sacroiliac joint (SIJ) and surrounding structures which limits access for palpation, diagnostic imaging and joint-specific injection. There is no recognised single reference standard diagnostic test for SID. Clinical diagnosis has been based on ruling out other causes of hind limb lameness, along with combinations of ultrasonography, scintigraphy and periarticular anaesthesia of the SIJ. Recent studies have highlighted the lack of specificity of injections targeting the SIJ, with significant dispersal of injectate into surrounding structures including around the lumbosacral joint (LSJ). Advanced imaging modalities such as computed tomography offers promise for assessment of the structure and pathology of the SIJ and surrounding bony structures. However, there is a need to improve the understanding of the significance of anatomic variation of the sacroiliac region structures, with recent studies reporting detailed anatomic variation in groups of horses with and without SID. There are also limitations around functional assessment of the joint which is still largely reliant on a thorough clinical examination. This review aims to present an update on clinical approaches to the diagnosis of horses with SID, and to consider the challenges and limitations.

Complications following diagnostic and therapeutic sacroiliac joint region injections in horses: A study describing clinicians' experiences

BACKGROUND

There are no detailed data on complications of sacroiliac (SI) joint region injections or on the variability of the methods and circumstances of injections among clinicians.

OBJECTIVES

To describe complications following diagnostic, therapeutic and combined SI joint region injections and the details of how these are routinely performed by a large number of clinicians.

STUDY DESIGN

Cross-sectional questionnaire survey.

METHODS

Clinicians (members of American and European specialist colleges and veterinarians known to the authors), invited by email, who had performed ≥1 SI joint region injection, completed an online questionnaire. Data collected included the clinicians' experience in diagnostic, therapeutic and combined SI joint region injections, details of the injection technique, volume and substance used, and the type of complications seen following SI joint region anaesthesia, medications and combined injections, respectively. Descriptive data analysis was performed and the association between any complications seen and the clinicians' experience, technique, volume and substance used were assessed using binary logistic regression.

RESULTS

Of the 212 respondents, 110 had performed diagnostic, 187 therapeutic and 49 combined injections. More clinicians experienced complications after diagnostic (53/110) than after therapeutic (33/187) or combined (6/49) injections (p < 0.01). The most common complications were hindlimb weakness/ataxia after all types of injections (diagnostic: 44/110, 40%, 95% confidence interval [CI]: 30.8-49.8; therapeutic: 15/187, 8.0%, CI: 4.6-12.9; combined: 2/49, 4.1%, CI: 0.5-14.0). Death or horses requiring euthanasia were reported (after therapeutic injections: 5/187; diagnostic injections: 1/110).

MAIN LIMITATIONS

No prevalence of complications was established; no detailed descriptions of complications were available. Results may be influenced by selection and recall biases.

CONCLUSIONS

Complications were experienced by more clinicians following diagnostic injections than after therapeutic or combined SI joint region injections, but the types and distribution of complications were similar. Results should be interpreted considering the previous reports of low prevalence of complications.

Visually Assessing Equine Quality of Movement: A Survey to Identify Key Movements and Patient-Specific Measures

Outcome measures are essential for monitoring treatment efficacy. The lack of measures for quality of movement in equine physiotherapy and rehabilitation impairs evidence-based practice. To develop a new field-based outcome measure, it is necessary to determine movements most frequently observed during assessment of rehabilitation and performance management cases. An online survey of 81 equine sports medicine veterinarians and equine allied-health clinicians was conducted. The key movements identified included walk and trot on both firm and soft surfaces in a straight line and on a small circle, plus step back, hind leg cross-over, transitions and lunging at walk, trot and canter. The main barriers to observing some movements are access to suitable surfaces and the training level of the horse and handler. Subjective visual assessment of live or videoed horses was the most common method used to track progress of complex movements. The majority (82%) of survey participants agreed or strongly agreed that a modified Patient-Specific Functional Scale would be useful for measuring complex movements. Comments from all professions show a desire to have outcome measures relevant to their needs. This survey identified 24 in-hand movements, which can be used to form the foundation of a simple field-based outcome measure for quality of movement.

Application of the Ridden Horse Pain Ethogram to 150 Horses with Musculoskeletal Pain before and after Diagnostic Anaesthesia

The Ridden Horse Pain Ethogram (RHpE) was developed to facilitate the recognition of musculoskeletal pain. The aim of this study was to document changes in RHpE scores before and after diagnostic anaesthesia was performed to alleviate pain ± when the saddle was changed. One hundred and fifty horses underwent ridden exercise as part of an investigation of poor performance. The RHpE was applied before and after the interventions. Fifty-two (34.7%) horses exhibited a bilaterally symmetrical short step length and/or restricted hindlimb impulsion and engagement. Fifty-three (35.3%) horses had episodic lameness; only forty-five (30.0%) horses were continuously lame. The median maximum lameness grade when ridden was 2/8 (interquartile range [IQR]: 0-3; range: 0-4). Fifty-six (37.3%) horses had an ill-fitting saddle, which was considered likely to influence performance. The median RHpE scores after the interventions (2/24 [IQR: 1-3, range: 0-12]) were significantly lower than before the interventions (9/24 [IQR: 8-11, range: 2-15]) (Wilcoxon signed-rank z = 10.6, p < 0.001). There was no correlation between the RHpE score and maximum lameness grade before diagnostic anaesthesia (Spearman's rho = 0.09, p = 0.262). It was concluded that the absence of overt lameness does not preclude primary musculoskeletal pain. Gait quality and performance can be improved by diagnostic anaesthesia, with substantial reductions in RHpE scores.

Use and repeatability of 3D light scanning to measure transverse dorsal profile size and symmetry in the thoracic region in horses

Equine epaxial muscle size, thoracolumbar profile and symmetry in horses is of clinical interest due to relationships with pain and pathology. Flexible-curve rulers have previously been used to gather reliable, objective measures of thoracic profile, however, 3D light-scanning offers a potential non-contact alternative method to estimate cross sectional area (CSA) of the region. 3D light-scans of the thoracic epaxial region were taken from ten endurance horses (7 geldings, 3 mares; 8±2 years). Total CSA of the combined epaxial musculature, using computer software, was calculated at scapula and T18 levels (depth: 15 cm). Intra and inter-rater (n=3) reliability of CSA measurements was assessed using Friedman’s analyses and post-hoc Wilcoxon rank tests (three repeated measures). Intraclass correlation estimates (ICC ± 95% confidence intervals (CI)) were calculated (mean-rating, absolute-agreement, 2-way mixedeffects model). Paired t-tests assessed differences between right and left areas. No significant differences existed for transverse plane-cuts (scapula, T18 P>0.05) between light-scans. Right and left areas were significantly different at the withers (P=0.012) with the left side larger in 70% of scans, but no significant differences were found between sides at T18. No differences existed for different plane-cuts of the same horse (P=0.53; ICC: 0.76; CIs: 0.43-0.92). While reliability was reduced between all raters (P=0.02; ICC: 0.70; CIs: 0.56-0.82), no significant differences occurred between two different assessors experienced in using the software (P=0.88; ICC: 0.90; CIs: 0.82-0.95). Intra-rater reliability for assessing thoracic profile and inter-rater reliability ICC values with experienced analysts was interpreted as good/excellent. The results suggest 3D light-scanning is an objective, non-invasive method to record size and symmetry of the epaxial region in horses and warrants validity testing against current measurement methods such as the flexible-curve ruler.

Prevalences of lumbosacral articulation anatomic variants identified on nuclear scintigraphy and transrectal ultrasonography of Selle Français Warmbloods, French Standardbred Trotters, and Thoroughbreds and agreement between results from the imaging modalities

OBJECTIVE

To describe scintigraphic and transrectal ultrasonographic anatomic variants of the lumbosacral (LS) articulation in horses and to determine the agreement between results obtained with each imaging modality.

ANIMALS

243 horses (81 Selle Français Warmbloods, 81 French Standardbred Trotters, and 81 Thoroughbreds).

PROCEDURES

A retrospective search of clinical records was conducted to identify horses that had undergone nuclear scintigraphy and transrectal ultrasonography of the LS region of the vertebral column between January 2016 and December 2019. Scintigraphic images were evaluated by 2 observers blinded to the other's results for classification of LS articulation anatomic variants (scintigraphic type); intra- and interobserver agreement were determined. Ultrasonographic images were evaluated for classification of LS intervertebral symphysis anatomic variant (ultrasonographic grade) by 1 observer blinded to horses' identities and scintigraphic findings; agreement analysis was performed between scintigraphic type and ultrasonographic grade. Descriptive and statistical analyses were performed to describe distribution of anatomic variants.

RESULTS

The scintigraphic classification system (scintigraphic type) had excellent intra- and interobserver agreement. Agreement between results for scintigraphic type and ultrasonographic grade was moderate (κ = 0.61; 95% CI, 0.52 to 0.70). Anatomic variants of the LS articulation were observed in all groups. The distribution of variants differed significantly among breeds but not sexes.

CLINICAL RELEVANCE

Anatomic variations of the LS articulation in horses must be known to avoid misinterpreting them as clinically meaningful findings. Further research is needed to determine potential relationships between these anatomic variants and LS lesions, their clinical manifestations, and their influence on athletic performance.

Clinical assessment and grading of back pain in horses

Background

The clinical presentation of horses with back pain (BP) vary considerably with most horse's willingness to take part in athletic or riding purpose becoming impossible. However, there are some clinical features that are directly responsible for the loss or failure of performance.

Objectives

To investigate the clinical features of the thoracolumbar region associated with BP in horses and to use some of the clinical features to classify equine BP.

Methods

Twenty-four horses comprised of 14 with BP and 10 apparently healthy horses were assessed for clinical abnormality that best differentiate BP from normal horses. The horses were then graded (0–5) using the degree of pain response, muscular hypertonicity, thoracolumbar joint stiffness and overall physical dysfunction of the horse.

Results

The common clinical features that significantly differentiate horses with BP from non-BP were longissimus dorsi spasm at palpation (78.6%), paravertebral muscle stiffness (64.3%), resist lateral bending (64.3%), and poor hindlimb impulsion (85.7%). There were significantly (p < 0.05) higher scores for pain response to palpation, muscular hypertonicity, thoracolumbar joint stiffness and physical dysfunction among horses with BP in relation to non-BP. A significant relationship exists between all the graded abnormalities. Based on the cumulative score, horses with BP were categorized into mild, mild-moderate, moderate and severe cases.

Conclusions

BP in horse can be differentiated by severity of pain response to back palpation, back muscle hypertonicity, thoracolumbar joint stiffness, physical dysfunctions and their cumulative grading score is useful in the assessment and categorization of BP in horses.

Gross post-mortem and histological features in 27 horses with confirmed lumbosacral region pain and five control horses: A descriptive cadaveric study

BACKGROUND

There is a lack of understanding of the pathological and/or physiological nature of lumbosacral region pain.

OBJECTIVES

To describe the gross variations of the osseous and soft tissues of the lumbosacral region and report the histological findings of sections of nerve tissue in affected and control horses.

STUDY DESIGN

Descriptive post-mortem case series.

METHODS

All horses had undergone full clinical and gait assessment, including ridden exercise. Horses with a substantial response to infiltration of local anaesthetic solution around the sacroiliac joint regions were included in the affected group (n = 27). Horses for which the source(s) of pain was confirmed by diagnostic anaesthesia to be distant to the lumbosacral region were included in the control group (n = 5). The pelvic regions were isolated and the soft tissues were assessed grossly. Sections of the lumbosacral plexus and cranial gluteal, sciatic and obturator nerves were examined histologically. The osseous specimens were evaluated for anatomical variants and abnormalities. Data were analysed using descriptive statistics.

RESULTS

Gross discolouration of the sciatic or obturator nerves was observed in 7 (26%) affected and no control horses. Grade 3/3 histological abnormality scores were assigned in 22% of nerve sections from affected horses compared with 3% from control horses. Several osseous variants (bifid sacral spinous processes, straight-shaped sacroiliac joint surface, short arrow-shaped sacral alae, left-right asymmetry of sacral alae, sacral curvature, absence of the fourth to fifth and ankylosis of the fifth to sixth lumbar articular process joints, left-right asymmetry of caudocranial position of the fourth to fifth and lumbar-sacral articular process joints) and abnormalities (sacroiliac enthesopathy, extra ventral sacroiliac joint surface, lumbosacral symphyseal periarticular modelling, lumbosacral intertransverse joint pitting lesions) were more frequently observed in affected horses.

MAIN LIMITATIONS

Both control and affected horses may have had preclinical abnormalities.

CONCLUSIONS

Lumbosacral region pain may reflect the presence of a number of pathological changes. Neural pain may play an important role in some horses.

Impacts of DigestaWell NRG Supplementation on Post Exercise Muscle Soreness in Unconditioned Horses, a Pilot Study

Exercising horses are commonly plagued by muscle fatigue and soreness, which can result in reduced performance ability. In the present study, ten unconditioned horses were fed 200g per day DigestaWell NRG, a commercial dietary supplement containing Yucca schidigera and Trigonella foenum-graecum, two herbs shown in other species to reduce post-exercise muscle pain and soreness. A control, unsupplemented group contained ten horses of similar age, breed, and gender. Horses completed a 50 minutes, ridden standardized exercise test of moderate intensity immediately prior to (Period1) and after 28 days of supplementation (Period2). Muscle soreness and tightness were evaluated 24 hours prior to and after each exercise test and used to determine the percent increase in post-exercise muscle soreness and tightness. Blood samples were collected before, and at 10 and 30 minutes, and 1, 4, and 24 hours post exercise. Plasma was analyzed for glucose, lactate, non-esterified fatty acid, tumor necrosis factor-α, and interleukin-1β concentrations. Data were analyzed by repeated measures ANOVA using SAS Enterprise Guide v. 7.1. No changes in plasma parameters were indicated between periods for unsupplemented horses (P > 0.1) during Period2, excepting glucose, which was greater during Period2 (P = 0.018). Supplemented horses had lesser concentrations of tumor necrosis factor-α (P = 0.016) and lactate (P = 0.058) during Period2 than during Period1. During Period2, supplemented horses experienced a smaller percent increase in post exercise muscle soreness (P = 0.031). DigestaWell NRG supplementation may benefit unconditioned horses undergoing moderate intensity exercise through reducing lactate production and inflammation.

Complications following equine sacroiliac region analgesia are uncommon: A study in 118 horses

Background

Diagnosis of sacroiliac region pain is supported by a positive response to sacroiliac region analgesia (SIRA). Varying techniques have been described for SIRA; with clinician preference often dictating method. Potential complications following SIRA include ataxia and recumbency. No study has specifically evaluated the prevalence of complications.

Objectives

To describe the complication prevalence following SIRA in a referral clinic.

Study design

Retrospective cohort study.

Methods

Review of records from horses presented to two of the authors at Rossdales, Newmarket, between January 2014 and December 2018, that underwent SIRA. Injection was performed using a blind midline approach with 20 mL mepivacaine (Intra-Epicaine 20mg/ml; Dechra) infiltrated through a straight 18 gauge 8.9cm spinal needle subdivided into four sub-locations per block.

Results

118 horses were included, with 167 individual blocks. One horse showed a mild hindlimb gait abnormality following SIRA, which resolved uneventfully over 3 hours; complication rate 1/118 horses (0.85%; 95% CI: 0,2.5%), 1/167 joints (0.60%; 95% CI: 0,1.8%). SIRA subjectively improved lameness/performance in 132/167 (79%) joints. 49/118 (42%) received bilateral SIRA with 53/118 (45%) evaluated ridden following SIRA.

Main limitations

Small population numbers with low complication prevalence rate.

Conclusions

SIRA, using the described technique, has a low (0.85%) prevalence of complications.

Associations between Owners' Reports of Unwanted Ridden Behaviour and In-Hand Behaviour in Horses

Simple Summary

Dangerous ridden behaviour in horses, such as bolting, rearing and bucking, are common and may reflect various aspects of the horses’ immediate experience, history and health. They can have a major impact on human safety and horse welfare because of the common misunderstandings of unwelcome behaviour in horses and popular treatments for so-called problem horses. The current study aimed to identify any in-hand behaviours associated with these dangerous ridden behaviours evaluated based on responses (n = 1584) to the Equine Behaviour Assessment and Research Questionnaire (E-BARQ). Declining reports of bolting were associated with decreasing problems loading horses onto transporters, increasing social confidence with other horses and other animals, improved leading behaviour and increased tolerance of restraint. Declining reports of rearing were associated with decreasing loading problems, increasing social confidence with other animals and increasing tolerance of restraint. Declining reports of bucking were associated with decreasing loading problems and increasing social confidence with horses and other animals, improved leading behaviour, increasing tolerance of restraint and increasing tolerance of head handling (when bridling/haltering). Findings from the current study could help riders and trainers predict dangerous ridden behaviour before they manifest fully, allowing for remediation that avoids the escalation of force in the training of misunderstood horses and thus improving safety and welfare for both horses and riders.

Abstract

An evidence-based understanding of dangerous or unwelcome behaviour in horses would greatly benefit both horses and humans who interact with them. Using owner-reported data from the Equine Behaviour Assessment and Research Questionnaire (E-BARQ), the current study investigated in-hand behaviours associated with dangerous or unwelcome ridden behaviours, notably bolting, rearing and bucking. Respondents (n = 1584) to the ridden horse section of the E-BARQ answered 42 demographic questions, followed by 268 behavioural items. Parallel analysis was conducted to group individual behaviours into rotated components to create independent and dependent indices. Multivariable general linear modelling and ordinal logistic regression were used to identify behaviours associated with bolting, rearing and bucking. Results revealed that safety-from-bolt increased as social confidence with horses (Odds ratio (OR) = 1.06; 95% confidence interval (cf = 1.02–1.09) and other animals (OR = 1.08; cf = 1.03–1.12), compliance in-hand (OR = 1.10; cf = 1.06–1.16) and tolerance of restraint (OR = 1.05; cf = 1.0–1.11) increased; and decreased as loading problems (OR = 0.95; cf = 0.92–0.99) increased. Safety-from-rear increased as tolerance of restraint (OR = 1.07; cf = 1.02–1.12) and social confidence with other animals (OR = 1.05; cf = 1.01–1.09) increased; and decreased as loading problems (OR = 0.94; cf = 0.91–0.98) increased. Safety-from-buck increased as social confidence with horses (b-value = 0.011, p < 0.001) and other animals (b-value = 0.010, p = 0.002), compliance in-hand (b-value = 0.015, p < 0.001), tolerance of restraint (b-value = 0.009, p = 0.027) and tolerance of haltering/bridling (b-value = 0.016, p = 0.010) increased, and it decreased as loading problems increased (b-value = −0.011, p < 0.001). By revealing, for the first time, that specific behaviours on the ground are associated with particular responses in the same horses when ridden, this study advances equitation science considerably. Identification of risk factors for dangerous behaviour while under saddle can improve safety for horses and riders and highlights the importance of effective and humane in-hand training.

Application of a Ridden Horse Pain Ethogram and Its Relationship with Gait in a Convenience Sample of 60 Riding Horses

A Ridden Horse Pain Ethogram (RHpE) comprising 24 behaviours has been developed to facilitate the identification of musculoskeletal pain. The aim was to further test the RHpE by its application to a convenience sample (n = 60) of sports horses and riding school horses in regular work and assumed by their owners to be working comfortably. All horses performed a purpose-designed dressage-type test of 8.5 min duration in walk, trot and canter, with their normal rider. The RHpE was applied retrospectively to video recordings acquired in a standardised fashion. Seventy-three percent of horses were lame (≤ grade 2/8) on one or more limbs; 47% had gait abnormalities in canter. Ridden Horse Pain Ethogram scores ranged from 3 to 16/24 (median 9); rider skill score ranged from 2.5 to 8/10 (median 4.75). The effect of horse age, breed, sex, work-discipline, epaxial muscle hypertonicity or pain, an ill-fitting saddle, rider skill score, the presence of lameness or gait abnormalities in canter on the RHpE score was assessed using Poisson regression. Two variables were retained in the final multivariable analysis, rider skill score as a continuous variable (p < 0.001), and lameness (p = 0.008). A RHpE score ≥8 was a good indicator of the presence of musculoskeletal pain.

Generation of Domains for the Equine Musculoskeletal Rehabilitation Outcome Score: Development by Expert Consensus

Simple Summary

Within rehabilitation, measurements taken before, during and after treatments are used to judge patient progress and the effectiveness of prescribed treatments. To know which measurements to use for a given health condition, practitioners must have knowledge of what should be measured, which measurement tools are available and accurate, alongside what they intend to measure. Composite outcome measures (OMs) are tools which use grouped measurement tests to monitor patient progress; they have been tested for a variety of human and canine conditions but none have been designed or tested for use in physical rehabilitation in horses. This study asked leading equine veterinarians, physiotherapists and researchers which measures should be included in an OM for use in the rehabilitation of horses. Using a process to evaluate agreement, ten areas of measurement were included in the final model: lameness, pain at rest, pain during exercise, behaviour during exercise, muscular symmetry, performance/functional capacity, behaviour at rest, palpation, balance and proprioception. Existing reliable tests used to measure these areas were evaluated and potential new measures discussed and now should be taken forward to testing as a composite outcome score to see if they are effective in measuring effectiveness of treatment.

Abstract

Outcome measures (OMs) are a requirement of professional practice standards in human and canine physiotherapy practice for measurement of health status. Measures such as pain and functional capacity of specific regions are used to track treatment impact and can be used to develop optimal management strategies. To achieve comparable patient care in equine physiotherapy, OMs must be incorporated into practice; however, no reliable and valid OMs exist for equine rehabilitation. This study utilised the experience and opinion of a panel of experts working in the equine rehabilitation sphere to gain consensus on the core areas (domains) to be included in a model, to lead to an OM scale for horses undergoing rehabilitation. The Delphi method and content validity ratio testing was used to determine agreement with domains reaching the critical value required for inclusion. The expert panel agreed on ten domains to be included in the OM scale: lameness, pain at rest, pain during exercise, behaviour during exercise, muscular symmetry, performance/functional capacity, behaviour at rest, palpation, balance and proprioception. An OM with these domains would provide a holistic objective assessment tool which could be used by equine rehabilitation professionals in clinical practice.

Comparison of two ultrasound-guided injection techniques targeting the sacroiliac joint region in equine cadavers

Objectives: To compare the accuracy and distribution of injectate for cranial (CR) and caudomedial (CM) ultrasound-guided injections of equine sacroiliac joints.

Methods: Both sacroiliac joints from 10 lumbo sacropelvic specimens were injected using cranial parasagittal (CR; curved 18 gauge, 25 cm spinal needles) and caudomedial (CM; straight 18 gauge, 15 cm spinal needles) ultrasound-guided approaches. Injectate consisted of 4 ml iodinated contrast and 2 ml methylene blue. Computed tomo-graphical (CT) scans were performed before and after injections. Time for needle guidance and repositioning attempts were recorded. The CT sequences were analysed for accuracy and distribution of contrast.

Results: Intra-articular contrast was detected in sacroiliac joints following 15/40 injections. The CR and CM approaches deposited injectate ≤ 2 cm from sacroiliac joint margins following 17/20 and 20/20 injections, respectively. Median distance of closest contrast to the sacroiliac joint was 0.4 cm (interquartile range [IQR]: 1.5 cm) for CR approaches and 0.6 cm (IQR: 0.95 cm) for CM approaches. Cranial injections resulted in injectate contacting lumbosacral intertrans-verse joints 15/20 times. Caudomedial injections were perivascular 16/20 times.

Limitations: Safety and efficacy could not be established.

Clinical relevance: Cranial and CM ultra-sound-guided injections targeting sacroiliac joints were very accurate for periarticular injection, but accuracy was poor for intra- articular injection. Injectate was frequently found in contact with interosseous sacroiliac ligaments, as well as neurovascular and synovial structures in close vicinity of sacroiliac joints.

Alterations in thoracolumbosacral movement when pain causing lameness has been improved by diagnostic analgesia

Lameness, thoracolumbosacral pain and reduced range of motion (ROM) often coexist; better understanding of their relationship is needed. The objectives were to determine if thoracolumbosacral movement of horses changes when pain causing lameness is improved by diagnostic analgesia. We hypothesised that reduction of lameness will increase ROM of the thoracolumbosacral region. Thirteen horses with different types of hind limb lameness were trotted in straight lines and lunged on a 10m diameter circle on left and right reins before and after lameness was subjectively substantially improved by diagnostic analgesia. Inertial sensor data were collected from the withers, thirteenth (T13) and eighteenth thoracic (T18) vertebrae, third lumbar (L3) vertebra, tubera sacrale (TS), left and right tubera coxae. ROM of flexion-extension, axial rotation, lateral bending, dorsoventral, lateral-lateral motion and vertical movement symmetry were quantified at each thoracolumbar site. Hiphike difference (HHD), maximum difference (MaxDiff) and minimum difference (MinDiff) for the pelvic sensors were measured. Percentage changes for before and after diagnostic analgesia were calculated; mean±standard deviation (SD) or median [interquartile range] were determined. Associations between the change in pelvic versus thoracolumbar movement symmetry after each local analgesic technique were tested. After resolution of lameness, HHD decreased by 7% [68%] (P=0.006). The MinDiff decreased significantly by 33% [61%] (P=0.01), 45±13% (P=0.005) and 52±23% (P=0.04), for TS, L3 and T18, respectively. There was significantly increased ROM in flexion-extension at T13, in axial rotation at T13, T18, L3 and in lateral-lateral ROM at L3. Thoracolumbosacral asymmetry and reduced ROM associated with lameness were both altered immediately by improvement in lameness using diagnostic analgesia.

TRANSRECTAL ULTRASONOGRAPHY OF EQUINE LUMBOSACRAL NERVES: PILOT STUDY IN 28 HEALTHY WARMBLOOD HORSES

A noninvasive method for visualizing lumbosacral nerves would be helpful for horses with suspected lumbosacral plexopathy or injury. The aim of this prospective descriptive pilot study was to characterize the ultrasonographic appearance of the lumbosacral nerves in a sample of healthy horses, and expand on the technique for image acquisition. Horses were recruited for inclusion if they were determined to be healthy and sound based on clinical and lameness evaluation. Transrectal ultrasound images of the lumbosacral nerves (L6, S1, and S2) were obtained for both sides. Landmarks for localization, and techniques for nerve identification and measurement were described. Effects of sex, age, side, and nerve on measured thickness were statistically tested. Twenty-eight warmblood horses were sampled (15 males and 13 females). Ages ranged from 5 to 15 years. Ventral nerve roots from L6 to S2 appeared as tubular structures with a characteristic hyperechoic linear echo pattern. There was no significant difference in nerve vertical diameter between left and right sides. A three-way interaction was found among sex, age and lumbosacral nerve. The L6 nerve in males was significantly larger than S1 only in the youngest group. The S2 nerve was significantly smaller than L6 or S1 regardless of age group or sex. In conclusion, transrectal ultrasound was a feasible method for visualizing and measuring equine lumbosacral nerves. Wide ranges of sizes for each nerve were found between horses, however nerves were bilaterally symmetrical within horses. Side comparison is therefore recommended when nerve pathology is suspected.