Preliminary results suggest an influence of psychological and physiological stress in humans on horse heart rate and behavior

People may involuntarily emit fear or distress signals when around horses, and interpreting how horses respond to these messages is important, particularly for human safety around horses. No studies have been done to determine if horses can differentiate between humans who are physiologically stressed (e.g., after exercising) as opposed to psychologically stressed (e.g., afraid). Horses (N = 10) loose in a round pen were randomly subjected to the presence of a stationary blindfolded human in each of 4 treatments: (1) calm human comfortable around horses (CALM), (2) physically stressed human (PHYS; exercised to 70% maximum heart rate [HR]), (3) psychologically stressed human (PSYCH; afraid of horses), or (4) no human (CONTROL). Both humans and horses were equipped with an HR monitor. Physiological and behavioral observations (gait, head position relative to the withers, distance and orientation toward human) were recorded and analyzed using a mixed model with horse and human as random effects. Increasing human fearfulness was associated with a decrease in horse HR (P = 0.0156). Horses moved at a slower gait in PSYCH (P < 0.0001), and horse head position was lower during PHYS and PSYCH compared with CALM or CONTROL (P < 0.0001). Human HR was highest in PHYS (P < 0.0001) and decreased over time in all treatments. Human HR increased when the horse was facing away (P = 0.0395). Overall, horses appear less stressed in the presence of a stationary fearful or physically stressed human than a calm person. Thus, horses in the presence of fearful humans, particularly where participants may not be comfortable around horses, should not pose any additional risk provided normal safety precautions are used.     

Practical considerations regarding the implementation of a temperament test into horse performance tests: Results of a large-scale test run

Considering the ever-growing demand of various breeding organizations for an objective, inexpensive, reliable, and easily conducted assessment of the behavior of horses, the aim of our study was to implement a novel-object test and a startling test into any kind of breeding performance testing to assess horses' temperament. Additionally, the influence of testing areas (familiar or unfamiliar), riders, and horse factors such as levels of training, breed, and age were of interest. Furthermore, recommendations for the practical implementation concerning the parameters should be given. Therefore, 1,028 horses over a period of 3 years participated in a temperament test consisting of 5 different stimuli. The horses were either ridden (61.8 %) or led by hand (38.2 %) by an unfamiliar professional rider (N = 43) or a familiar rider (N = 20). Live behavioral observations were taken by a trained observer. Overall, horses' scores for reactivity in the present temperament test were distributed over the whole scale, with lower means and higher standard deviations (6.7 ± 2.2-7.6 ± 2.1) than corresponding scores from the conventional personality evaluation in performance tests (7.7 ± 0.8-8.2 ± 0.5; P < 0.01). High correlations (r = 0.3-0.9; P < 0.001) between the scores for reactivity and the other behavioral parameters (emotional expression, activity, time to calm down, rider's aids) show a large influence of these parameters in assessing the horses' temperament. Factors like breed type, sex, and age had significant influences (P < 0.001) on different scores of the temperament test. In most cases, the rider or handler had no influence on the different scores assessed during the temperament test. The training level and the testing modus never had a significant influence on different scores. Only the testing station or location had a small influence on the scores for the stimulus “bridge” in some horses. Based on the results, it could be concluded that an implementation of a temperament tests into performance testing is possible during various types of testing procedure. Especially the assessment of reactivity, emotional expression, interest in the stimulus and rider's aids during and after passing the stimulus, as well as the time to calm down are important parameters for analyzing the horses' personality.     

Cortisol release and heart rate variability in sport horses participating in equestrian competitions

Equestrian competitions require both physical activity and mental adaptation in horses. Cortisol, heart rate, and heart rate variability (HRV) are accepted stress parameters and, in this study, have been determined in horses (n = 13) participating in equestrian competitions for up to 3 consecutive days. Participation in competitions caused an increase in salivary cortisol concentrations (e.g., on day 1 from 1.0 ± 0.2 before to 2.2 ± 0.4 ng/mL after the competition, days 1 and 2: P < 0.001, day 3: P < 0.05) and an increase in heart rate (days 1 and 2: P < 0.001, day 3: P = 0.01). A consistent decrease in HRV occurred only in response to the final competition on day 3 (P < 0.01). When horses competing in dressage and show jumping were compared, cortisol release and HRV did not differ between groups, but after the competition, heart rate was lower in dressage than in show jumping horses (P < 0.05). Heart rate increased not only during the actual competition but already when horses were prepared in their stables (e.g., day 1: ?60 minutes, 38.6 ± 2; ?5 minutes, 77 ± 7; competition, 81 ± 10 beats per minute; P < 0.01). In conclusion, participation in equestrian competitions caused an increase in cortisol release and heart rate and a decrease in HRV variables. However, competitions were not a major stressor compared with other anthropogenic challenges such as transport, to which horses are exposed regularly.     

Cortisol release,heart rate and heart rate variability,and superficial body temperature,in horses lunged either with hyperflexion of the neck or with an extended head and neck position

Bringing the head and neck of ridden horses into a position of hyperflexion is widely used in equestrian sports. In our study, the hypothesis was tested that hyperflexion is an acute stressor for horses. Salivary cortisol concentrations, heart rate, heart rate variability (HRV) and superficial body temperature were determined in horses (n = 16) lunged on two subsequent days. The head and neck of the horse was fixed with side reins in a position allowing forward extension on day A and fixed in hyperflexion on day B. The order of treatments alternated between horses. In response to lunging, cortisol concentration increased (day A from 0.73 ± 0.06 to 1.41 ± 0.13 ng/ml, p < 0.001; day B from 0.68 ± 0.07 to 1.38 ± 0.13 ng/ml, p < 0.001) but did not differ between days A and B. Beat‐to‐beat (RR) interval decreased in response to lunging on both days. HRV variables standard deviation of RR interval (SDRR) and RMSSD (root mean square of successive RR differences) decreased (p < 0.001) but did not differ between days. In the cranial region of the neck, the difference between maximum and minimum temperature was increased in hyperflexion (p < 0.01). In conclusion, physiological parameters do not indicate an acute stress response to hyperflexion of the head alone in horses lunged at moderate speed and not touched with the whip. However, if hyperflexion is combined with active intervention of a rider, a stressful experience for the horse cannot be excluded.     

Cortisol release,heart rate,and heart rate variability in transport-naive horses during repeated road transport

Domestic animals are often repeatedly exposed to the same anthropogenic stressors. Based on cortisol secretion and heart rate, it has been demonstrated that transport is stressful for horses, but so far, changes in this stress response with repeated road transport have not been reported. We determined salivary cortisol concentrations, fecal cortisol metabolites, cardiac beat-to-beat (RR) interval, and heart rate variability (HRV) in transport-naive horses (N = 8) transported 4 times over a standardized course of 200 km. Immunoreactive salivary cortisol concentrations always increased in response to transport (P < 0.001), but cortisol release decreased stepwise with each transport (P < 0.05). Concentrations of fecal cortisol metabolites increased from 55.1 ± 4.6 ng/g before the first transport to 161 ± 17 ng/g the morning after (P < 0.001). Subsequent transport did not cause further increases in fecal cortisol metabolites. In response to the first transport, mean RR interval decreased with loading of the horses and further with the onset of transport (1551 ± 23, 1304 ± 166, and 1101 ± 123 msec 1 d before, immediately preceeding, and after 60–90 min of transport, respectively; P < 0.05). Decreases in RR interval during subsequent transports became less pronounced (P < 0.001). Transport was associated with a short rise in the HRV variable standard deviation 2 (P < 0.001 except transport 1), indicating sympathetic activation. No consistent changes were found for other HRV variables. In conclusion, a transport-induced stress response in horses decreased with repeated transport, indicating that animals habituated to the situation, but an increased cortisol secretion remained detectable.     

A brief note on the information-seeking behavior of UK leisure horse owners

Equine welfare charities have identified the education of (primarily novice) horse owners as the principal route to tackling the majority of equine welfare problems in the United Kingdom. To reach and educate owners effectively, we must understand where they seek advice about issues that arise when owning or caring for a horse. Questions regarding information-seeking behavior were included in an Internet survey completed by a convenience sample of 1,326 UK leisure horse owners, recruited online and through electronic and postal mail shots to equestrian clubs and establishments. The questions asked where the owners sought advice regarding 4 different subject areas: horse behavior, health, stable care, and training. Respondents were asked to select their main sources of information from a list of 7—books/magazines, vet/farrier, instructor, Internet/forums, friends/family, tack shops, and other. Although books/magazines were the most frequently used information source across all 4 subject areas overall, there were differences between the 4 subject areas in the most commonly selected sources (χ² = 992, P < 0.001) and the number of sources consulted (χ² = 254, P < 0.001). Vets/farriers were the source consulted most frequently for health advice (Z = ?13.32, P < 0.001), instructors for training advice (Z = ?3.93, P < 0.001), and books/magazines for advice regarding both behavior (Z = ?9.49, P < 0.001) and stable care (Z = ?8.26, P < 0.001). Despite the survey mode and that many participants were recruited online, Internet/forums were only the third to the fifth most used of the 7 information sources, depending on the subject area. Logistic regression analyses identified significant associations between owner demographics (age, self-rated skill level, and self-reported rider type) and the likelihood of selecting a particular source for advice regarding a specific subject area. The findings have important implications for those trying to reach the horse-owning population to disseminate research findings and ultimately improve the welfare of their horses.     

Effect of turn direction on body lean angle in the horse in trot and canter

Turning is commonly used as a diagnostic aid in equine lameness examinations. Forces experienced on the circle differ from those in a straight line, necessitating an inward lean of the body and asymmetric head/pelvic excursion, which are important parameters for lameness investigations. To better understand gait adaptations to lungeing in normal horses, the effect of turn direction on body lean in trot and in canter warrants further investigation. In this study, it was hypothesised that, on average and independent of gait, the observed body lean angle would be consistent with the ratio between gravitational and centripetal acceleration, but with variations for individual horses showing differences between reins. Twenty horses were fitted with a global positioning system (GPS)-aided inertial measurement unit quantifying body lean angle, speed and circle radius in trot and canter in both directions. The difference between predicted (from speed and circle radius) and observed body lean (Δ_obs,pred) was compared between horses, directions and gaits using a generalised linear model. The mean speed and circle radius were 3.3 m/s and 4.9 m in trot and 4.5 m/s and 5.7 m in canter. Mean Δ_obs,pred was ?1.1° (range ?7.6° to 5.4°) in trot and ?0.8° (range ?7.6° to 8.3°) in canter and was significantly different between horses (P < 0.0001) and directions (P < 0.0001), but not between gaits (P = 0.14). Interactions between horse and direction (P < 0.0001) and horse and gait (P = 0.011) were also significant. Horses leaned marginally less into the circle than predicted. However, this study provides additional evidence for horse specific adaptations, showing significant differences between horses and turn directions but not between gaits.     

Sex differences in the response of yearling horses to handling by unfamiliar humans

In adult horses, pronounced sex differences in behavior exist, and many riders prefer male horses to mares. In the present study, we tested the hypothesis that sex differences in the response of horses to handling emerge before puberty, that is, in sexually immature animals. Warm-blooded yearling horses (6 males and 9 females) were exposed to a stationary human test (exposure to an unfamiliar person for 5 minutes) and a tolerance test (haltering and direct contact with the horse) on 5 consecutive days. The horses' behavior and heart rate were recorded. Male yearling horses displayed significantly less exploratory behavior than females during the stationary human test on days 1 and 2 (P < 0.05). Latency to halter and ease with which horses could be haltered were significantly affected by day (P < 0.05), and a significant interaction of day and sex was detected (P < 0.05; e.g., time for haltering: females, day 1: 23.8 ± 7.8 seconds [±standard error of the mean] and day 5: 21.1 ± 1.7 seconds; males, day 1: 53.6 ± 10.4 seconds and day 5: 19.4 ± 2.2 seconds). Heart rate of the horses in response to the test situations was significantly affected by day (P < 0.01) but not by sex. In conclusion, sex differences in behavior do not only exist in adult horses but are already present in young horses before puberty. When exposed to unfamiliar humans for the first time, male yearling horses display more caution than females.     

Changes in cortisol release and heart rate variability in sport horses during long-distance road transport

It is widely accepted that transport is stressful for horses, but only a few studies are available involving horses that are transported regularly and are accustomed to transport. We determined salivary cortisol immunoreactivity (IR), fecal cortisol metabolites, beat-to-beat (RR) interval, and heart rate variability (HRV) in transport-experienced horses (N = 7) in response to a 2-d outbound road transport over 1370 km and 2-d return transport 8 d later. Salivary cortisol IR was low until 60 min before transport but had increased (P < 0.05) 30 min before loading. Transport caused a further marked increase (P < 0.001), but the response tended to decrease with each day of transport. Concentrations of fecal cortisol metabolites increased on the second day of both outbound and return transports and reached a maximum the following day (P < 0.001). During the first 90 min on Day 1 of outbound transport, mean RR interval decreased (P < 0.001). Standard deviations of RR interval (SDRR) decreased transiently (P < 0.01). The root mean square of successive RR differences (RMSSD) decreased at the beginning of the outbound and return transports (P < 0.01), reflecting reduced parasympathetic tone. On the first day of both outbound and return transports, a transient rise in geometric HRV variable standard deviation 2 (SD2) occurred (P < 0.01), indicating increased sympathetic activity. In conclusion, transport of experienced horses leads to increased cortisol release and changes in heart rate and HRV, which is indicative of stress. The degree of these changes tended to be most pronounced on the first day of both outbound and return transport.     

Distances Walked by Long Established and Newcomer Horses in an Open Stable System in Northern Germany

Group housing is claimed to possibly provide horses with a species-appropriate movement possibility, and hence, better welfare. Thus, this study analyzed the daily walked distances of 51 horses held in one group in a “HIT Active Stable” (Hinrichs Innovation + Technik) in Northern Germany by using global positioning system (GPS) technology during a 7 ½-month time span. The daily walking distances of the whole group, as well as newcomers, were investigated. The horses traveled an average of 8.43 km/day. Linear mixed models were applied. The observation day had a significant effect on the daily walking distances (P < .01) due to season and the available area per horse. The age as covariate also had a significant effect (P < .01). The breed had no significant effect (P = .96). No significant differences were found in sex (P = .69), which can be explained by the fact that only mares and geldings were investigated, which do not show increasing locomotion caused by sexual behavior as stallions do. On six of the first nine days, new horses moved significantly more compared to the remaining 24 of the 30 observation days directly after individuals’ inclusion. This is probably due to more exploration and rank-fighting behavior. Similar walking distances were seen among the horses on the single observation days because all horses had to travel the same distance to reach resources. Further, it is suspected that not all horses can sufficiently live out their urges to move, especially in winter, when pasture is inaccessible.     

Effects of different forms of exercise on post inhibitory rebound and unwanted behaviour in stabled horses

Reasons for performing study: It is unknown if different locomotor activities are equally effective at meeting the stabled horse's need for exercise and if they attenuate unwanted behaviour. Hypothesis: Alternative forms of exercise influence the intensity of locomotor activities during a period of turn‐out (the so‐called rebound effect) and the occurrence of unwanted or undesirable activities during standard handling situations. Method: Twenty‐four horses kept in stables were randomly assigned to one of 4 exercise regimes (walker, treadmill, turn‐out and riding) for 4 consecutive days. Because these forms of exercise provide additional environmental stimulation, beyond that provided by exercise, each horse served as its own control in 4 corresponding (no exercise) control treatments presented in a balanced order. Unwanted behaviour was tested by taking horses to weighing scales and loading and unloading them onto a 4‐horse float by an experienced handler and the rebound effect was tested by releasing them into a large arena for a period of 15 min at the end of the exercise and control treatments. Results: Locomotor activities made up a large part of behaviour in the large arena following control treatments and all exercise regimes were sufficient to reduce the intensity of walking (P<0.05), trotting (P<0.01) and cantering (P<0.001) on release into a large arena. Exercise regime reduced the number of bucks (P<0.01) and rolling (P<0.05) during rebound tests suggesting that turn‐out was having a stronger effect than the other 3 exercise regimes. Exercise regimes significantly reduced the amount of unwanted behaviour and the number of commands given by the handler during weighing (P<0.05) but had no effect on these behaviours during loading onto a float. Conclusion: Providing stabled horses with one hour/day of exercise on a walker, treadmill, turn‐out or by being ridden are all effective at allowing expression of locomotor activities in stabled horses. Potential relevance: Providing stabled horses with regular exercise is likely to provide positive effects on horse welfare, training ability and handler safety.     

Effects of posture and accumulated airway secretions on tracheal mucociliary transport in the horse

Tracheal mucociliary clearance was determined in horses by measuring the rostrad transport of the radiopharmaceutical ^99mtechnetium-sulphur colloid following deposition on the tracheal epithelium by intratracheal injection. The effects of head position (head elevated to normal standing position vs head lowered) and of accumulated purulent secretions on tracheal mucociliary clearance were evaluated for the first time in the horse. In normal horses tracheal mucociliary clearance was greatly accelerated by lowering the head so that the cranial trachea was lower than the caudal trachea. Horses confined with their heads elevated for 24 hours developed an accumulation of purulent airway secretions (and associated increased numbers of bacteria) in the lower respiratory tract and showed a decrease in tracheal mucociliary clearance when compared with their previously measured rate when the lower airway contained only normal secretions. These findings have implications for management practices where horses are prevented from lowering their heads, such as transportation and cross-tying, which may therefore contribute to lower respiratory tract disease in horses.     

Riders' application of rein tension for walk-to-halt transitions on a model horse

Rein cues have been used for millennia when controlling horses. Recent research has quantified the range of tensions exerted on the horse's mouth by bit and rein apparatus under a variety of conditions and investigating the tension horses will freely tolerate. Given the importance of rein tension in terms of controlling horses and the potential for welfare issues arising from use of apparatus in the horse's mouth, this study the tensions created by riders (n = 12) performing walk to halt gait transitions on a model horse. The mean tension when applying the deceleration cue of the left rein (mean tension, 8.58 N; standard deviation = 5.15; range = 3.14-28.92 N) was greater than the right rein (mean tension, 6.24 N; standard deviation = 4.1; range = 2.27-16.17 N). Little correlation was found between rider morphometry and rein tension. Although the deceleration cue was significantly higher than the resting tension by 51% for the right rein (P < 0.001) and by 59% for the left rein (P < 0.001), there was large variation between and within riders. These findings suggest the need for greater awareness of the potential for rein tensions to vary from principles of good horse welfare and training principles.     

Effect of manual and motorized dental rasping instruments on Thoroughbred's heart rate and behavior

Inadequate research exists to justify the choice of dental tools used in equine prophylactic dentistry; usage is unregulated, with choice usually based on the practitioner’s preference. Dental procedures could cause stress (through handling or equipment used), as they are potentially painful if contact is made with soft-tissues. Anecdotally adverse reactions are documented and differ when comparing manual with motorized rasping, particularly during rasping the lower arcade. The study aimed to investigate these claims.Forty-five Thoroughbreds were divided into groups: (A): manual rasping, (B): motorized rasping, and (C): control. Horses were accustomed to prophylactic dentistry (6-12 months previously) and required a routine float. A standardized protocol was used; heart rate (HR) and scale-graded interactive behavioral responses (BR) were recorded to evaluate subjects’ stress and pain pre-, peri-, and posttreatment.Increased HR and BR were observed in group A compared with groups B and C (P < 0.001). Motorized rasping produced a significant increase in HR (P < 0.001) and BR (P < 0.001) from the controls. The results support postulation of higher sensitivity in the lower arcades, with these arcades exhibiting significantly higher HR and BR in both motorized and manual groups (P < 0.001). “Bit-seating” recorded higher responses (HR and BR: P < 0.001) compared with routine rasping.The study could inform routine dentistry; motorized rasping produced less-reactive horses, potentially providing a safer working environment for dental technicians and increased welfare for their equine patients.     

Prevalence and Potential Risk Factors of Dermatophytosis in Arabian Horses in Egypt

The objective of the present study was to verify the prevalence and the risk factors associated with dermatophytosis in Arabian horses. For this purpose, a total of 457 Arabian horses in 15 farms were examined. A questionnaire was constructed to include the hypothesized risk factors. Fungal isolation and identification for each horse were carried out by standard microbiological procedures. Logistic regression analysis was used to evaluate the risk factors on both animal and farm levels. Trichophyton spp. was recovered from 50 horses and Microsporum spp. from 27 cases. Trichophyton equinum was more prevalent than Trichophyton mentagrophytes (45 vs. 4) and Trichophyton tonsurans (45 vs. 1). However, Microsporum canis was more prevalent than Microsporum gypseum (21 vs. 5) and Microsporum audouinii (21 vs. 1). On horse level, final multivariate logistic regression analysis showed that there was a significant association between dermatophytosis and horse' age (P < .05; odds ratio [OR]: 1.07; 95% confidence interval [CI]: 1.0–2.69), poor grooming practice (P < .05; OR: 57.11; 95% CI: 2.47–13.44), moist condition (P < .05; OR: 42.77; 95% CI: 2.0–25.18), and farm size (P < .05; OR: 1.06; 95% CI: 1.00–7.05). However, on the farm level, farm size of >30 horses was the risk factor (P < .05; OR: 1.0; 95% CI: 1–3.03). In conclusion, the present results indicate existance of dermatophytosis in Arabian horses. Identification of the potential risk factors associated with the disease may be helpful to construct the ideal preventive measures.     

Effect of Age and Performance on Physical,Hematological, and Biochemical Parameters in Endurance Horses

Endurance horses are subjected to heightened stress even after several conditioning protocols. Hence, the goal of this study was to examine the effect of age and performance on the hematology, biochemistry, and physical parameters after an endurance race. Eighteen horses aged 6-15 years were grouped into 80-km race category. All the horses were physically examined, and blood samples were collected postrace. After physical examination, the poor (n = 9) and good (n = 9) performance horses were identified. Potassium concentration was significantly higher (P < .05) in the good performance horses; chloride concentration was significantly higher (P < .05) in the poor performance horses. The mean blood glucose concentration of the poor performance horses in all the age-groups was significantly higher (P < .05). The mean blood lactate concentration was significantly lower (P < .05) in the poor performance horses. There was significant effect of performance on heart rate (P < .031), capillary refill time (P < .013), and gut motility (P < .05). Univariate Fisher exact test results were significantly higher for skin recoil (P < .03), mucous membrane (P < .03), and gait (P < .04) in the performance categories. In conclusion, the influence of age was seen in the poor performance category in relation to lactate, but age did not influence other physical, hematological, and biochemical parameters of the endurance horses. Thus, further studies are required to determine whether physical, hematological, and biochemical parameters during training could be used to estimate performance in endurance horses based on age.     

The effect of a pressure wrap (ThunderShirt®) on heart rate and behavior in canines diagnosed with anxiety disorder

The effect of moderate-to-deep pressure on soft tissue has been studied in both humans and nonhuman animals with positive results shown in reducing anxiety and promoting relaxation. Canine anxiety disorders are often treated with medications and behavior modification programming. Pressure wraps are sometimes used to treat canine anxiety, but the effects of this investigation have not been rigorously investigated. The aims of this study were to investigate the use of a pressure wrap (ThunderShirt®; ThunderWorks, Durham, NC) on heart rate and behavior in dogs diagnosed with an anxiety disorder. Subjects were 90 dogs (39 males and 51 females) that were diagnosed with Separation Anxiety or Generalized Anxiety Disorder. Dogs were randomly assigned to 1 of the 3 groups, namely Experimental Group 1 (dogs wore the ThunderShirt® per manufacturer's recommendations), Experimental Group 2 (dogs wore the ThunderShirt® loosely without pressure), and Control Group (dogs had no specific treatment). Average and maximum heart rates were measured at baseline and after 15 minutes alone in the kennel. Dogs were video-recorded and analysis completed for 12 behaviors, namely pacing, panting, yawning, tongue-flicking, drooling, elimination, barking, stress whining, howling, licking, door orientation, and calmness. The results were as follows: Dogs in Experimental Group 1 showed significantly less increase from baseline in average heart rate than the Control Group dogs (P < 0.001) and dogs in Experimental Group 2 (P < 0.001). Dogs in Experimental Group 1did not differ significantly from Control Group dogs in maximum heart rate when all dogs were considered, but did differ significantly from the Control Group (P = 0.04) when only those dogs not currently on anxiety medication were considered. There were no statistically significant differences among groups on behavioral outcomes, except that the dogs in the Control Group were significantly more likely to orient toward the door than the dogs in both Experimental Groups 1 (OR = 7.46, P = 0.01) and 2 (OR = 4.42, P = 0.04). Dogs in the Experimental Group 1 presented a trend of less tongue-flicking (P = 0.06) and yawning (P = 0.07) stress reduction behaviors when compared with the other 2 groups. More research should be conducted with the ThunderShirt® on behavioral outcomes. The ThunderShirt® can be used with behavior modification programming and medication as an adjunct treatment option to assist dogs diagnosed with anxiety disorder to reduce heart rate.     

Evaluation of assays for troponin I in healthy horses and horses with cardiac disease

Cardiac troponin I (cTnI) is a marker for detection of myocardial damage in horses. Many cTnI assays exist and medical studies have shown that the clinical performance of assays differs. The aim of this study was to compare two different cTnI assays in horses. Serum samples were taken from 23 healthy horses (group 1) and 72 horses with cardiac disease (group 2). Cardiac troponin I was determined using assay 1 in laboratory A (limit of detection, LOD, 0.03 ng/mL) and assay 2 in laboratories B and C (LOD 0.01 ng/mL). In group 1, a median cTnI concentration of <0.03 (<0.03–0.04) ng/mL and <0.01 (<0.01–0.15) ng/mL was found with assays 1 and 2, respectively. A higher median value was demonstrated in group 2 for both assays (assay 1: 0.11 ng/mL, range 0.03–58.27 ng/mL, P < 0.001; assay 2: 0.02 ng/mL, range 0.01–22.87 ng/mL, P = 0.044). Although a significant correlation between assays existed, large mean differences that could be important for clinical interpretation of test results were found. A small mean difference was found between laboratories B and C. A significant optimal (P < 0.001) cut-off value for detection of cardiac disease could only be determined for assay 1 (0.035 ng/mL, sensitivity 70%, specificity 91%). Assay 1 performed better for detection of cardiac disease in horses in this study.     

A Randomized Blinded Crossover Clinical Trial to Determine the Effect of an Oral Joint Supplement on Equine Limb Kinematics,Orthopedic, Physiotherapy,and Handler Evaluation Scores

Despite the range of oral joint supplements available, there has been very limited research into their efficacy. The study aimed to determine the effect of an oral joint supplement on limb kinematics, orthopedic, physiotherapy, and handler evaluation in horses. Supplement S or placebo P was fed to 24 horses for 21 days each in a random order. Horses were evaluated at days 0 (baseline), 21 (after first treatment), and 42 (after second treatment). Assessments included the following: clinical orthopedic evaluation for straight line/lunging circle in walk and trot; high-speed motion capture determined hindlimb kinematics for straight-line trotting; grading of limb range of motion (ROM) and muscle tone based on standardized physiotherapy criteria; handler grading of specific criteria during pasture, groundwork, and ridden exercise. Effect of treatment, sequence, limb, and interactions were investigated using linear-mixed models. S was associated with significantly lower lameness grade in a straight line (P = .001) and circle (P = .010), with individual horses improving up to 2/10 grades over P/baseline. S was associated with significantly improved ROM and muscle tone. Ridden/groundwork scores were significantly higher with S compared to P/baseline. With S, horses were graded significantly higher for “ease of movement” at pasture compared with P/baseline. For horses with hindlimb lameness, S was associated with significantly greater tarsal flexion than baseline (4.2% greater, P < .020) or P (2.7% greater, P < .037). S was associated with less lameness and improved physiotherapy scores, ridden/groundwork scores, and pasture “ease of movement.” Increased midstance tarsal flexion of lame limbs may indicate improved mobility/comfort during peak loading, supporting a positive effect of S.