David Marlin

• BSc (Hons), PhD
• Research Director at Animalweb Ltd

Introduction: Bridle-horse-rider interaction is complex and often overlooked in the training and management of horses. Concerns have been raised over the use of double bridles, but there is little quantitative comparison of bridle type (snaffle; double) and comparison of the effects on facial pressures and movement symmetry parameters are not avail...

Background: Dorsal nasal pressures beneath the noseband have been reported to be highest on the lateral aspect of the nasal bone, and noseband design has evolved to include padding beneath this area. However, pressures have been mathematically estimated to be high on the ventral aspect of the mandible. There are no quantitative studies that have si...

Background: The rider's rein aids rely on force transmitted via the reins to the bit and oral structures. Concerns have been raised that two bits may result in an increase in forces applied to the oral structures. Study design: In vivo experimental. Methods: Thirteen dressage horse/rider combinations (Intermediare-II/Grand-Prix) were recruited an...

Background Equine trigeminal‐mediated (TGM) headshaking (HS) is a neuropathic facial pain syndrome characterised by varying intensity and frequencies of head movements and signs of nasal irritation. An accurate method for quantification and/or characterisation of HS severity is lacking. Objectives To develop and validate an objective measure of TG...

Saddles are almost certainly one of the most commonly used pieces of equipment and are used by the majority of riders in many equestrian disciplines. Despite a large number of studies relating to saddle fit and function, there appear to be no published data describing the basic demographics of saddle use, rider preferences or discipline differences...

Anecdotally, horse-riding is a ‘dangerous sport’, often grouped with activities such as motorcycling, skiing, parachuting, bull-riding, and rugby. This opinion is increasingly supported by evidence from retrospective analysis of trauma centre admissions for equestrian related incidents (ERI’s), albeit from relatively low numbers. The most common ap...

Short-term intense and or prolonged medium intensity exercise in conditions of moderate-high environmental temperature or temperature and humidity can result in moderate to marked hyperthermia. This in turn may result in decreased exercise capacity, earlier onset of fatigue and increased risk of falls or injury. Early identification of moderate-sev...

Simple Summary Horse sports are popular worldwide, providing spectator enjoyment, benefiting human health, and contributing substantially to national economies. Training and management practices used to care for sporthorses are generally based on tradition rather than science; this combined with the high-risk nature of equestrian activities led to...

Simple Summary Auditory perception is a key driver in behavioural and physiological responses and as prey species, horses have evolved to identify these stimuli and respond appropriately to maximise chances of survival. Sport horses are required to perform without distraction by external, irrelevant auditory stimuli and to help achieve this, ‘noise...

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 sect...

Background Horse welfare is a priority in the equine sport of endurance riding. Identification and reduction of risk factors associated with elimination and lameness have been the focus of research to date, however, this has centred on international competition. National federations recognise there is a need to consider risk factors for elimination...

Research on human-animal interactions has established that numerous benefits can result from human relationships with diverse companion animal species in the domains of physical, social and psychological outcomes. Therefore, numerous animal-attachment scales have been developed to measure the extent of individual human’s attachment to their compani...

Veterinary eliminations within the equestrian sport of endurance have predominantly been evaluated based on data from international competitions. However, in order to take part in international competition, each horse and rider must qualify by completing rides under their national federation. The aim of this study was to analyse the competitive dat...

Abstract Background The purpose of this study was to investigate the usefulness of salivary cortisol (SC) and eye temperature measured by infrared thermography (IRTET) as biomarkers to manage competitions more effectively and monitor horse welfare in endurance competitions. Based on previous studies, it was hypothesised that pre-exercise baseline S...

A recent survey by the authors of the present study indicated that headcollar (halter, USA) related incidents resulting in horse injuries may be common. From the survey, 134 incidents involving horse fractures and 167 fatalities were reported. Headcollar design and materials vary markedly from traditional leather to “safety” headcollars and safety...

Background Headcollars (halters, US) are one of the most commonly used pieces of equestrian ‘tack’. Despite this, there appears to be minimal information on their use, or more importantly, risk factors for injury of horses/handlers. Objective To explore headcollar use and safety in equestrians. Study design Quantitative cross‐sectional survey. M...

Stirrups aid the rider to stabilise their lower leg allowing it to be used effectively for communication and in maintaining their position in the saddle. Relatively few studies have investigated stirrup forces and to the best our knowledge no studies have reported stirrup forces in jumping. The aim of the present study was to measure stirrup forces...

Objective quantification of effort and distress during endurance rides through biomarkers could help manage competitions more effectively and monitor horse welfare through an evidence-based approach. This study aimed to determine if salivary cortisol (SC) and ocular temperature measured by infrared thermography (IRT OT ) are related to the outcome...

Simple Summary On 11 March 2020, the World Health Organization declared coronavirus disease (COVID-19) outbreak a global pandemic and an ongoing public health emergency. In the United Kingdom, quarantine and social distancing measures were implemented with immediate effect on 17 March 2020, resulting in a rapid change to the way owners managed and...

The cardiac recovery index (CRI) is currently a key component of veterinary inspections to assess endurance horses metabolic status and fitness. Originally published by Ridgeway, it instructs veterinarians to subtract from the first heart rate (HR 1 ), collected when the horse is initially presented for examination, a second HR (HR 2 ), taken 1 min...

Performance analysis (PA) involves the systematic observation and analysis of factors identified to enhance performance to improve athlete decision-making in a specific sport. PA is commonplace in human sports, yet despite potential advantages, its application remains limited in equestrianism. This study aimed to evaluate if factors anecdotally ass...

Equine endurance competitions are long races over 1-2 days and horses can be eliminated in international competitions by FEI veterinarians for lameness at any time. Elimination rates due to lameness are high, affect the outcome of the races and commonly elicit objections to the decision from endurance competitors. The aims of this study were: (1) t...

Quantitative assessment of racehorse workload and fitness levels can be achieved through heart rate monitoring (HRM), an established reliable indicator of workload. Using HRM can aid trainers in formulating evidence-based training regimes and evaluating individual horses’ progress during training. Despite this, HRM is not used consistently within r...

The main functions of a saddle are to improve rider stability and comfort, with the stirrups providing support for the rider’s legs. The criteria upon which riders base their choice of stirrup length for different equestrian disciplines does not appear to have been reported. Therefore, this study was designed to investigate the factors that play a...

Although stirrups may be considered an essential part of equestrian equipment, there is little research describing their use and function. The aim of the present study was to compare stirrup lengths chosen for flatwork by novice and experienced riders, and to measure the associated leg position and knee angles. Ten novice and ten experienced riders...

Race pace strategy has been extensively studied in human sports such as running, cycling and swimming. In contrast, pacing strategy appears to have been virtually ignored in equestrian sport despite its potential to contribute to performance optimisation. Previously we have demonstrated that there are significant differences in pacing strategy betw...

Oxidative stress occurs when antioxidant defence mechanisms are overwhelmed by free radicals and may lead to damage to DNA, which has been implicated in processes such as ageing and cancer. The Comet assay allows detection of oxidative DNA damage in individual cells. As horses with recurrent airway obstruction (RAO) have been shown to demonstrate l...

The ability to use oxygen during exercise is determined by a combination of the muscle mitochondrial density, the relative proportion of total body mass consisting of locomotory muscle, the gas exchange surface area and the capacity for conduction of oxygen from the gas exchange surface to the muscle cells, i.e. the heart and circulation. Other fac...

Race pace strategy has been extensively studied in human sports, such as running, cycling and swimming. In contrast, pacing strategy appears to have been virtually ignored in equestrian sport despite the potential for contributing to performance optimisation. The aim of the present study was to analyse data available in the public domain for electr...

The importance of correct feeding practice has been highlighted by the increasing prevalence of obesity in horses. Human research has suggested that voluntary activity (VA) levels may influence digestible energy (DE) requirements, accounting for 15-50% of human daily energy expenditure. Therefore, the aim of this study was to investigate whether le...

Personality has been shown to affect the way individuals think, feel and act, and could impact on the way people behave and perform in a wide variety of activities. Anecdotal evidence suggests that differences in personality exist between equestrians participating in different disciplines and at different levels, but empirical evidence is limited....

Equine exercise physiology is a discipline that emerged in the 1980’s. It has enjoyed tremendous popularity. Areas of popularity in equine exercise physiology research have changed over the past 40 years for a variety of possible reasons, including funding, disappearance of research groups and research interests. We are also now in a position where...

Many consider the English Derby on Epsom Downs to be ‘The Blue Riband of the Turf’. The Epsom Derby has been run annually since 1780 and the colt Diomed was the first winner. Today the Epsom Derby, run over 1.5 miles, is one of five classic races and is the second leg of the English Triple Crown, preceded by the 2,000 Guineas and followed by the St...

IntroductionDespite the range of oral joint supplements available, there has been very limited research into their efficacy. AimsTo determine effect of an oral joint supplement on orthopaedic, physiotherapy and handler evaluation in horses. Methods Twenty-four mature horses were included in the study. Horses were excluded if they were in poor body...

The Grand National (GN) attracts high profile press and subsequent public attention. This study aimed to establish if factors influential to non-completion, horse-falls and specific fence risk in the GN supported the measures implemented by the British Horseracing Authority (BHA) to improve equine welfare in the GN. Horse, jockey, trainer and race...

This study describes a comparison of the efficacy of the Monty Roberts horsemanship technique (MRT) in comparison with a UK conventional training technique (CT) for the initial training of horses. The sample consisted of 14 untrained horses, between 3 and 5 years old, sourced from a variety of non-competition yards in the UK. Horses were matched on...

Diagnostic tests for some conditions affecting cattle, such as tuberculosis, are often expensive and required over a prolonged period, so that the diagnostic tests involve more than one visit by a qualified vet. An alternative rapid and non-invasive diagnostic-test would be desirable. One possibility is the use of breath testing, which has been sho...

Anecdotal evidence collected by a variety of organisations has highlighted poor welfare in horses transported long distances to slaughter within the European Union. To investigate welfare of horses being transported long distances within the EU to slaughter. Data on transported horses were recorded at 2 assembly centres in Romania and at 4 abattoir...

Human heart rate monitors (HRMs) are frequently used in equine studies to measure heart rate (HR) and interbeat intervals (IBIs). However, to date, the most commonly used HRM (the Polar w system) in horses has not been validated against simultaneously recorded electrocardiogram (ECG) signals during a range of ambulatory conditions. Polar w S810i an...

The aim of the present study was to characterise the quantitative sweating response of the horse to β2-adrenergic stimulation. The sweating responses of 6 horses to the randomised infusion of 8 different adrenaline concentrations (0.025, 0.05, 0.075, 0.1, 0.2, 0.4, 1.0 or 2.0 μg/kg bwt/min), was investigated. Sweating rate (SR) and skin temperature...

The function of the forelimb is fundamental to understanding both sound and pathological locomotion. The precise movements of the equine shoulder are hidden by layers of skin and muscle and hence the shoulder is normally modelled as a simple pivot during locomotion which assumes that any translational motion is negligible. To record and quantify th...

Water treadmill exercise is often incorporated into rehabilitation programmes for horses yet little is known about the biomechanical and physiological responses to water walking. To establish whether stride frequency (SF) reached steady state as a result of 6 introductory water treadmill sessions and then to investigate the effect of increasing wat...

The aim of the present study was to evaluate the capacity of the horse, during low intensity exercise, to increase the contribution of fat oxidation to energy production as a result of a pre-exercise elevation of triglyceride derived plasma FFA. Seven Thoroughbred horses were exercised for 91 min (3.2 m/s for 60 min, 13.4 ± 2.9% V̇O2max) during 2 r...

The pattern and magnitude of respiratory airflow during exercise in healthy horses is largely predictable. Diseases of the upper and lower airways may alter the pattern of breathing and/or the magnitude of respiratory flow variables, such as peak inspired and expired flow rates. These changes may be useful in the diagnosis, treatment, management an...

In vitro titration of muscle homogenates has been used to assess muscle buffering capacity (βmtitr) in a variety of species. In the present study, factors likely to affect the estimation of βmtitr were investigated. Also, values of βmtitr from normal Thoroughbred horses are presented. A non-linear titration curve was obtained with addition of HCl t...

We should like to bring to the attention of the veterinary profession an epidemiological study, recently undertaken in Europe, which examined the trade in long-distance transport of horses for slaughter for human consumption. Anecdotal evidence collected by a variety of organisations, including

Numerous studies have described the cardiorespiratory and kinematic responses of horses running on level and positive gradients, but little attention has been given to exercise on negative gradients, despite the fact that many horses compete over variable terrain. The purpose of this study was to describe the heart rate (HR), estimated net transpor...

Studies investigating the role of oxidative stress in both the ageing process and osteoarthritis (OA) in human beings are limited by the unavailability of samples from healthy subjects. OA occurs naturally in the horse and has been used as a model of human OA. The objective of this study was to determine the effect of ageing and OA on the non-enzym...

Few studies exist regarding the physiological responses of equestrian riders during actual or simulated competition. Interest has proliferated in recent years on the responses of riders, which is mainly due to the fatal tragedies that occurred in eventing in the late 1990s. More emphasis is also being placed on the importance of riders, fitness in...

Recurrent airway obstruction (RAO) is a chronic inflammatory condition in equine lung, which may share a common immunological basis with human asthma, in which dysregulated Th2 responses occur. Mammals express chitinases and chitinase-like proteins, two of which are active enzymes, chitotriosidase and acidic mammalian chitinase (AMCase). Both enzym...

An understanding of the physiological and metabolic demands of competition is essential for the development of training regimens that elicit adaptations appropriate for the sport being participated in. Despite the fact that dressage is a major sport and one of only three equestrian Olympic disciplines, to date there appear to be no studies that hav...

Previously, objective comparisons of surgical procedures to relieve dorsal displacement of the soft palate (DDSP) have been limited by the presumptive basis of the diagnostic measures applied. To assess and compare the efficacy of thermal cautery surgery to conservatively treated controls in racehorses definitively diagnosed with idiopathic intermi...

While there have been several studies of heart rates (HRs) of horses during exercise in water, the effect of exercise in water of different temperatures has not been reported. While the increase in HR during exercise is primarily related to the intensity of exercise and therefore metabolic rate, increasing body temperature can also contribute to el...

The most popular techniques used for studying equine kinematics are videographic recording combined with the analysis using a commercial software package or optoelectronic systems based on emission and detection of infrared or visible light. Such systems can be expensive, complicated to use and their use may be restricted to indoor use (in the case...

The cardiopulmonary effects of an intravenous (iv) medetomidine injection (5 μg/kg) followed 5 min later by its infusion at 3.5 μg/kg/h for 115 rnin were studied in 9 horses and ponies. Five minutes after the end of infusion 60 μg/kg atipamezole were given. Physiological data during infusion were compared with pre-sedation values. Stroke volume was...

Mast cell degranulation is believed to act as a key event in initiating and maintaining airway response to allergen challenge in human asthma. It is hypothesized that the mast cell may play a similar role in equine heaves, which shares many similarities with occupational dust-induced asthma. The aim of this study was to quantify the mast cell prote...

Changes in shape of the equine thorax during locomotion are not well defined, although it has been shown recently that the transverse hemi-diameter changes its dimension by up to 80mm on the side of the trailing forelimb during gallop, despite minimal change in thoracic circumference. The aim of this project was to analyse transverse and dorso-vent...

Objective To evaluate the effect of intravenous lidocaine on coughing and variations in heart rate (HR) and systolic arterial pressure (SAP) at endotracheal intubation in propofol-anaesthetized dogs. Study design Prospective, randomized, blinded clinical study. Animals Eighty dogs, ASA grades I/II. Methods Dogs were randomly assigned to one of two...

Equine recurrent airway obstruction (RAO) has been used as a naturally occurring model of human asthma. However, it is unknown whether there is an early-phase response in RAO. The aim of this study was to determine whether exposure to organic dust induces immediate changes in lung function in RAO-affected horses, which could be mediated by airway m...

Regular monitoring of the heart rate (HR):speed relationship may help evaluate response to training and aid in the early detection of problems. This relationship is normally determined using a treadmill or via a ridden test conducted outside on a track. Simple practical alternative methods to obtain this relationship without access to a treadmill o...

Feeding regimens for horses are usually based on perceived workload (PW) together with body condition. This can lead to inappropriate energy intake and, in particular, excess weight. Therefore, a more detailed understanding of the factors influencing individual energy needs under practical field conditions would be valuable. The purpose of this stu...

BACKGROUND Eventing is often considered to be the ultimate all round test of horse and rider. It consists of: Dressage – a test of discipline and precision; CrossCountry – a test of power, strength, stamina and bravery of horse and rider; Show-jumping – a test of accuracy. The tests of eventing were originally designed to relate to the training and...

The objective of this study was to establish a reference base for respiratory variables (respiratory rate [R(R)], inspiratory and expiratory time [T(i) and T(e)], peak inspiratory and expiratory pseudoflow [PIF and PEF], tidal volume [V(T)], minute ventilation [V(E)] and enhanced pause [Penh]) of healthy cats by use of barometric whole body plethys...

Following a period of airway inflammation the clearance of inflammatory cells along the mucociliary escalator may impose a considerable oxidant load on the trachea. To determine the degree of oxidative stress in tracheal epithelial lining fluid (ELF) in comparison to that present in peripheral airways after an acute exposure to organic dust. Trache...

Several studies have shown that the placement of a face mask on a horse can have effects on ventilation, gas exchange and the cardiovascular system during exercise. The aim of the present study was to determine if airflow and ventilation measured with the same ultrasonic flowmeters were different during exercise between horses wearing half- (HM) an...

Limited information exists about the physiological changes and clinical problems that occur in elite horses competing in high-speed 160 km endurance races. To provide initial data describing changes in physiological and laboratory measurements in horses competing in a high-speed, 160 km endurance race under temperate conditions and to compare data...

Heart rate is one of the most commonly measured variables in equine exercise physiology and relative exercise intensity commonly expressed as % of maximal heart rate. A number of influences affect maximal heart rate (HRmax), including age of the horse but other factors have not been described. To determine if fitness, health status, gender, breed,...

The prevalence and severity of cardiac arrhythmias during exercise in athletic horses presented for poor performance is not well described. To describe prevalence and severity of ventricular and supraventricular arrhythmias immediately before, during and immediately after standardised incremental treadmill exercise tests (IET) to fatigue in Thoroug...

During high intensity exercise, the very high pulmonary artery pressure (Ppa) experienced by Thoroughbred horses is considered a major factor in the aetiology of exercise-induced pulmonary haemorrhage (EIPH). Recently, endothelin-1 (ET-1), a potent vasoconstrictive hormone, has been found to increase Ppa in horses at rest via binding to its ET-1A r...

Pulmonary capillary stress failure, largely as a result of high pulmonary vascular pressures, has been implicated in the aetiology of EIPH. However, the role of the respiratory system in determining the magnitude of EIPH has received little attention. Horses breathing a gas of greater density than air will exhibit greater transmural pulmonary arter...

Inspired air is warmed to body temperature and fully humidified by the upper airway mucosa under normal resting conditions. This conditioning process may not be completed by the upper airways during conditions of increased minute ventilation or when the inspired air is unusually cold, resulting in cooling and desiccation of lower respiratory surfac...

Classic descriptions of rib motion during ventilation include three-dimensional movements that are tied to the locomotor pattern. It is still not clear how chest wall and diaphragmatic movements contribute to ventilation. The purpose of this paper was to evaluate how gait affects local thoracic geometry in horses. Hemispherical markers were placed...

The aim of this study was to test the hypothesis that pulmonary inflammation and emphysema induced by cadmium (Cd) inhalation are associated with pulmonary oxidative stress. Two groups of Sprague Dawley rats were used: one vehicle-exposed group undergoing inhalation of NaCl (0.9%, n = 24) and one Cd-exposed group undergoing inhalation of CdCl(2) (0...

Effects of acute airway inflammation induced by organic dust inhalation on pulmonary antioxidant status were investigated in healthy horses and horses affected by recurrent airway obstruction. Exposure to organic dust induced acute airway neutrophilia, which was associated with increases in elastase and decreases in ascorbic acid concentrations in...

The proposed biological mechanisms for exercise-induced pulmonary haemorrhage (EIPH) are many and varied. Better knowledge of risk factors should lead to achievable measures to reduce the incidence. To identify risk factors associated with epistaxis following racing in UK Thoroughbreds, to gain possible insights into the pathogenesis of the conditi...

Collection of exhaled breath condensate (EBC) is a noninvasive method for obtaining samples from the lungs. EBC contains large number of mediators including adenosine, ammonia, hydrogen peroxide, isoprostanes, leukotrienes, nitrogen oxides, peptides and cytokines. Concentrations of these mediators are influenced by lung diseases and modulated by th...

Inhaled ozone can induce oxidative injury and airway inflammation. Horses affected by recurrent airway obstruction (RAO) have a decreased pulmonary antioxidant capacity, which may render them more susceptible to oxidative challenge. It is currently unknown whether RAO-affected horses are more susceptible to oxidative stress than those unaffected by...

Diminished basal plasma cortisol concentrations and a blunted cortisol response to exercise have been observed in human asthmatics. In horses with recurrent airway obstruction (RAO), plasma concentrations of cortisol at rest are not significantly different from those of healthy horses, but the effect of exercise on endogenous cortisol concentration...

The objective of this study was to describe a standardised and non-invasive method for exhaled breath condensate (EBC) collection in cats and to test whether determination of hydrogen peroxide (H(2)O(2)) in EBC might be used as marker of lower airway inflammation. The technique of barometric whole body plethysmography for cats was combined with a s...

It is estimated that more than 50 million cattle are infected with Mycobacterium bovis worldwide, resulting in severe economic losses. Current diagnosis of tuberculosis (TB) in cattle relies on tuberculin skin testing, and when combined with the slaughter of test-positive animals, it has significantly reduced the incidence of bovine TB. The failure...