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

Abstract

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.

Application of the Ridden Horse Pain Ethogram to Elite Dressage Horses Competing in World Cup Grand Prix Competitions

“…As hypothesised the median RHpE score was low, consistent with the absence of many of the signs associated with musculoskeletal pain in the majority of horses, and a relatively narrow spectrum of behaviours was observed compared with lame horses [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. The most frequently observed behaviours were the front of the head being behind a vertical position >10° for ≥10 s, mouth opening with separation of the teeth for ≥10 s, an intense stare for ≥5 s and repeated tail swishing, similar to the most common behaviours observed in elite event horses during the warm-up for the dressage phase at 5* three-day events [ 9 ].…”

“…For this reason, this behaviour was retained in the final RHpE. In a convenience sample of 60 horses believed by their riders to be working comfortably, the front of the head behind a vertical position had a 7% higher prevalence in lame versus non-lame horses [ 6 ].…”

“…A Ridden Horse Pain Ethogram (RHpE) comprising 24 behaviours, the majority of which are at least 10 times more likely to be seen in lame versus non-lame horses, has previously been developed [ 1 ]. It has been shown that a RHpE score ≥8 is likely to reflect the presence of musculoskeletal pain [ 1 , 2 , 3 , 4 , 5 , 6 ]. Removal of pain by diagnostic anaesthesia results in significant reductions in RHpE scores [ 2 , 3 ], indicating a causal relationship between behaviour and pain.…”

“…Overall, gait and RHpE data from 491 horses have been assessed and documented. These comprised non-lame horses, lame horses, and lame horses before and after diagnostic anaesthesia had been used to abolish pain causing lameness or abnormalities of canter [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. These data provide strong evidence that a RHpE score of ≥8/24 is likely to reflect the presence of musculoskeletal pain, although some lame horses score <8/24.…”

“…These data provide strong evidence that a RHpE score of ≥8/24 is likely to reflect the presence of musculoskeletal pain, although some lame horses score <8/24. The results of application of the RHpE by 23 assessors have been documented, including skilled assessors [ 1 , 2 , 5 , 6 , 8 , 9 ], equine veterinarians after preliminary training [ 4 ], an equine physiotherapist after on-line training and additional repeatability assessment [ 7 ], and non-trained assessors from a variety of equine-related professions [ 3 ]. When the RHpE was applied to 20 horses by 10 veterinarians and one expert assessor, there was excellent consistency in overall agreement for total scores among raters (Intra-class correlation coefficient (ICC) 0.97, p < 0.001, Confidence Intervals (CI) 0.95, 0.99), and, for exact agreement between individual observers, there was good to moderate agreement (ICC 0.7, p < 0.001, CI 0.56, 0.84) [ 4 ].…”