A review of The Ridden Horse pain Ethogram and its potential to improve ridden horse welfare

Do tight nosebands have an effect on the upper airways of horses?

BACKGROUND/OBJECTIVES

The public perception relating to the welfare of horses involved with equestrian sports is associated with training methods used and the presentation of horses at events. In this context, very tight nosebands, which are intended to prevent the horse from opening its mouth, also attract a lot of attention. Various studies have evaluated the impact of tight nosebands on stress parameters, whereas the effect of tight nosebands on upper airway function is unknown. Therefore, the aim of the study was to use overground endoscopy to evaluate changes in pharyngeal and laryngeal function when a tight noseband is fitted. Moreover, the ridden horse pain ethogram (RHpE) was applied to investigate signs of discomfort (Dyson et al., 2018).

STUDY DESIGN

A randomized, blinded, and prospective study was performed.

METHODS

Sixteen warmblood horses consisting of twelve mares and four geldings with a mean age of 11.63 ± 3.53 years were ridden on 2 consecutive days with either loose or tight nosebands (two fingers or no space between bridge of the nose and noseband, respectively) and inserted endoscope in a random order. Videos were taken in a riding arena during a standardized exercise protocol involving beginner level tasks for 30 min in all gaits. For video analysis, freeze frames were prepared and analyzed at the beginning of the expiration phase. Pharyngeal diameter was measured using the pharynx-epiglottis ratio. Other findings (swallowing, pharyngeal collapse, soft palate movements, and secretion) were also evaluated. Moreover, the RHpE was applied. Descriptive statistics and generalized linear mixed effects models were used. Results with a p-value < 0.05 were considered statistically significant.

RESULTS

While the pharynx-epiglottis ratio did not change significantly in horses ridden with loose versus tight nosebands, there was an increase in mean grade and total counts of parameters assessed in the pharyngeal region, for example, grade of secretion (1.5 [±SD 0.89] vs. 3.13 [±SD 0.96]; p = 0.0001), axial deviation of the aryepiglottic folds (0.29 [±SD 0.73] vs. 1.33 [±SD 1.44]; p = 0.01), and pharyngeal collapse (0.69 [±SD 0.87] vs. 1.88 [±SD 1.54]; p = 0.005) in horses ridden with tight nosebands. There was no RHpE score above 8 indicating musculoskeletal pain, but the RHpE scores were significantly higher in horses ridden with tight nosebands (p < 0.001).

MAIN LIMITATIONS

Video quality was limited when horses showed large amounts of secretion. Another limitation was the small number of horses.

CONCLUSIONS

Results add to the evidence obtained in other studies that tight nosebands do not only cause adverse reactions based on the RHpE score such as head behind the vertical or intense staring but also contribute to changes in the pharyngeal region, such as increased secretion and collapse of pharyngeal structures. This may provide further support for future decisions regarding regulations on nosebands.

Comparison of daily heart rate and heart rate variability in trained and sedentary aged horses

Athletic horses are usually retired from equestrian competition at an advanced age. Aged horses may then continue to have regular exercise or are sedentary. The comparison of autonomic regulation between sedentary aged horses (SAH) and trained aged horses (TAH) after retirement remains unpublished. This study compared daily heart rate (HR) and heart rate variability between 11 SAH and 11 TAH over 22 h (07.00 h to 05.00 h on an alternate day) and during the day and night. An increase in mean beat-to-beat (RR) intervals (p < 0.01-0.0001) and parasympathetic nervous system (PNS) index (p < 0.05-0.0001), corresponding to the decreased HR and sympathetic nervous system (SNS) index (p < 0.01-0.0001), was observed at night. Compared to SAH, lowered mean HR and SNS index, corresponding to elevated mean RR intervals and very-low-frequency bands, were marked in TAH during the day (p < 0.05 for all variables). Whereas the standard deviation of the RR intervals index was higher in TAH than in SAH during the day and night (p < 0.05 for both periods). It was suggested that aged horses with different physical activities revealed distinct autonomic responses. TAH demonstrated higher HRV than SAH during the day. A decreased HR in TAH is prone to result from a reduced SNS role, leading to a shift toward more PNS activity during the day. More research is warranted to determine to what extent the autonomic regulation is modulated by accompanying higher exercise volume or programmed exercise in aged horses.

Reported Agonistic Behaviours in Domestic Horses Cluster According to Context

Agonistic behaviours are often directed at other animals for self-defence or to increase distance from valued resources, such as food. Examples include aggression and counter-predator behaviours. Contemporary diets may boost the value of food as a resource and create unanticipated associations with the humans who deliver it. At the same time the domestic horse is asked to carry the weight of riders and perform manoeuvres that, ethologically, are out-of-context and may be associated with instances of pain, confusion, or fear. Agonistic responses can endanger personnel and conspecifics. They are traditionally grouped along with so-called vices as being undesirable and worthy of punishment; a response that can often make horses more dangerous. The current study used data from the validated online Equine Behavioural and Research Questionnaire (E-BARQ) to explore the agonistic behaviours (as reported by the owners) of 2734 horses. With a focus on ridden horses, the behaviours of interest in the current study ranged from biting and bite threats and kicking and kick threats to tail swishing as an accompaniment to signs of escalating irritation when horses are approached, prepared for ridden work, ridden, and hosed down (e.g., after work). Analysis of the responses according to the context in which they arise included a dendrographic analysis that identified five clusters of agonistic behaviours among certain groups of horses and a principal component analysis that revealed six components, strongly related to the five clusters. Taken together, these results highlight the prospect that the motivation to show these responses differs with context. The clusters with common characteristics were those observed in the context of: locomotion under saddle; saddling; reactions in a familiar environment, inter-specific threats, and intra-specific threats. These findings highlight the potential roles of fear and pain in such unwelcome responses and challenge the simplistic view that the problems lie with the nature of the horses themselves rather than historic or current management practices. Improved understanding of agonistic responses in horses will reduce the inclination of owners to label horses that show such context-specific responses as being generally aggressive.

Chiropractic effects on stride parameters and heart rate during exercise in sport horses

BACKGROUND

Equine veterinarians performing chiropractic treatments are frequently asked to evaluate and treat sound horses to improve their performance and address pain associated with the axial skeleton. Studies describing the effects and mechanisms of chiropractic treatments in horses without overt lameness are scarce.

OBJECTIVES

This study aimed to evaluate the effect of chiropractic treatments on stride rate, length, symmetry, heart rate and rider-perceived quality of the ridden work in sport horses.

STUDY DESIGN

A blind randomised controlled trial with crossover design.

METHODS

Thirty-eight horses ridden in the hunter-jumper discipline were enrolled. Exercise tests were recorded before and after chiropractic or sham treatment while horses were wearing a fitness tracker. Stride length, rate and symmetry, heart rate and the perceived quality of the ridden work were compared.

RESULTS

There was a difference in the qualitative assessment of the ridden work by riders between treatments (odds ratio 33.8, 95% CI [4.68, 458.71], p < 0.01). Stride length, rate, symmetry and heart rate were not different between treatments.

MAIN LIMITATIONS

The quantitative outcomes measured may not be sensitive enough to detect changes that improve the ridden work. Terrain, weather and rider were not standard across horses making small changes difficult to detect.

CONCLUSIONS

Riders participating in a blind randomised controlled trial perceived a positive effect of chiropractic treatments on the quality of the ridden work. There were no differences in stride length, stride rate, stride symmetry or heart rate. The mechanisms, indications and potential benefits of chiropractic treatments in horses need further study.

Comparison of Asymmetry During Trot In-Hand With Evaluations of Discomfort and Pain in Horses While Exercised

Traditional visual lameness assessment is subjective. Ethograms have been developed for evaluating pain and objective sensors to detect lameness. Heart rate (HR) and heart rate variability (HRV) have been used to evaluate stress and pain. The aim of our study was to compare subjective and behavioral lameness scores, a sensor system measuring movement asymmetry, HR, and HRV. We hypothesized that these measures would show related trends. In 30 horses, an inertial sensor system was used to measure movement asymmetries during trot in-hand. A horse was categorized as sound if each asymmetry was less than 10 mm. We recorded riding to observe lameness and evaluate behavior. Heart rate and RR intervals were measured. Root mean squares of successive RR intervals (RMSSD) were calculated. Five horses were categorized as sound and 25 horses as lame by the inertial sensor system. No significant differences were detected between sound and lame horses in the ethogram, subjective lameness score, HR, and RMSSD. Overall asymmetry, ethogram, and lameness score had no significant correlation with each other, whereas overall asymmetry and ethogram correlated significantly with HR and RMSSD during certain phases of the ridden exercise. The main limitation of our study was the small number of sound horses detected by the inertial sensor system. The association between gait asymmetry and HRV suggests that the more gait asymmetry a horse shows during trot in-hand, the more pain or discomfort it probably experiences when ridden with a higher intensity. The threshold for lameness used by the inertial sensor system may require further evaluation.

How to Understand Them? A Review of Emotional Indicators in Horses

Stabled horses often experience negative emotions due to the inappropriate living conditions imposed by humans. However, identifying what emotions horses experience and what can trigger positive and negative emotions in stabled horses can be challenging. In this article we present a brief history of the study of emotions and models that explain emotions from a scientific point of view and the physiological bases and functions of emotions. We then review and discuss physiological and behavioral indicators and cognitive bias tests developed to assess emotions in horses. Hormone concentrations, body temperature, the position of the ears, facial expressions and behaviors, such as approach and avoidance behaviors, can provide valuable information about emotional states in horses. The cognitive bias paradigm is a recent and robust tool to assess emotions in horses. Knowing how to evaluate the intensity and frequency of an individual's emotions can guide horse owners and caretakers to identify practices and activities that should be stimulated, avoided or even banned from the individual's life, in favor of a life worth living. The development and validation of novel indicators of emotions considering positive and negative contexts can help in these actions.

Evaluation of Substance P as a New Stress Parameter in Horses in a Stress Model Involving Four Different Stress Levels

Stress has a significant impact on equine welfare. There are some studies on the stress response in horses ridden with tight nosebands, but little is known about other stress parameters than cortisol, which potentially could address an emotional component. In this study, blood samples of a total of 74 warmblood horses were used to establish reference values for plasma substance P (SP) concentrations. Moreover, 16 of these warmblood horses were included in a stress model. Four different stress levels (level 1: horses ridden with loose noseband, level 2: tight noseband, level 3: loose noseband and overground endoscope, level 4: tight noseband and overground endoscope) were applied to evaluate SP as a potential stress parameter in horses. Blood samples were taken at rest (t0) and directly after inducing stress (noseband tightening, insertion of endoscope; t1), as well as after 20 min of riding at all gaits (t2). A ridden horse ethogram was applied and showed that horses in the tight noseband group resorted to other stress-related behavioral issues than horses with loose nosebands. Serum cortisol showed a linear increase concurrent with the increase in stress levels with a significant difference between level 1 and level 4 (p = 0.043), proving that stress factors were adequate to evaluate the stress response, whereas SP did not show a correlation with the stress levels. Furthermore, concentrations of SP differed widely between horses but stayed within more narrow limits in the individual horse. As a conclusion, SP might not be a reliable stress parameter in horses in the applied minor stress model.