The importance of including ridden exercise in investigations of low-grade lameness and poor performance in horses has been highlighted in a just-published study.
“Horses should be evaluated at all gaits and when performing all movements in their current work repertoire,” Sue Dyson and Danica Pollard said in the journal Animals.
Riders, they said, often become frustrated after recognising a decline in their horse’s performance, because they seek professional advice and are told their horse is not lame based on an examination in hand or perhaps on the lunge.
Dyson, an equine lameness expert, and Pollard, a veterinary epidemiologist, said there is increasing awareness that horses may show gait abnormalities that compromise performance when ridden that are not apparent when assessed moving in hand.
A low-grade lameness observed in hand or during lungeing may not reflect the source of pain that compromises the horse’s ridden performance.
The pair noted that the increasing use of objective gait analysis has prompted discussions about what might constitute the degree of asymmetry that reflects pain-induced gait changes, rather than an inherent asymmetrical movement pattern.
Asymmetry of movement, sometimes referred to as laterality, has been documented not only in adult horses but also in foals.
In their study, Dyson and Pollard set out to describe gait and behavioural changes in horses undergoing routine investigations of lameness or poor performance before and after diagnostic anaesthesia, and a change in saddle if deemed necessary, in a larger group than has previously been documented.
The study centered on 150 horses undergoing routine clinical investigations at a variety of locations in Britain, all showing poor performance.
The horses were investigated consecutively for lameness or poor performance and were evaluated when ridden before and after diagnostic anaesthesia, and, when considered necessary, a saddle change.
The Ridden Horse Pain Ethogram (RHpE), developed to aid the recognition of musculoskeletal pain in horses, was employed in the study.
Dyson led research about five years ago that led to the RHpE. It comprises 24 behaviours, each with strict definitions, that occur more frequently in a horse with musculoskeletal discomfort compared with a non-lame horse.
They include the likes of mouth opening with separation of the teeth for at least 10 seconds, repeated head tilting, persistent tail swishing, an intense stare for five or more seconds, spooking, bucking, rearing, tail clamping, repeated tongue exposure, and putting the ears back for more than five seconds.
The presence of at least 8 of the 24 behaviours is considered a reliable indicator of the presence of an underlying musculoskeletal problem. The higher the tally, the greater the likelihood that the horse has musculoskeletal discomfort which may compromise performance.
It has previously been shown that the most frequent score in non-lame horses is 2 out of 24.
The horses were also given a lameness grade. The most frequent lameness grade was 2 out of 8 – a score that indicates mild lameness. Lameness scores ranged from 0 to 4. It was found that 35% of the horses had no overt lameness but lacked hindlimb impulsion.
RHpE scores were assessed before and after nerve blocks (and, where indicated, a saddle change).
The most frequent RHpE score was 9 out of 24 (with a range of 2 to 15) before the use of nerve blocks. The nerve block, and a saddle change as needed, saw the most frequent RHpE score decline to 2 (with a range of 0 to 12).
The score changes were associated with improved gait quality and rideability.
Dyson and Pollard noted that, in most horses, the RHpE score was 8 or more out of 24 before diagnostic anaesthesia, despite lameness in the conventional sense being low-grade or absent. This, they said, emphasises the value of the RHpE for recognition of the presence of musculoskeletal pain.
“The substantial reduction in RHpE scores after diagnostic anaesthesia verifies the value of the RHpE as a tool to determine if most of the pain-causing compromises in performance has been resolved.”
There was a high frequency of ill-fitting saddles, in 37% of the horses, which influenced performance despite a large proportion of horses having undergone professional saddle fit checks within the previous one to three months, the pair said. However, many riders were unaware of the professional qualifications of the saddle fitter, they noted.
In all affected horses, an improvement in behaviour and/or gait was observed after changing their current saddle to a better-fitting saddle, although paradoxically, in some horses, lameness became apparent or deteriorated. This, they said, was associated with a subjectively assessed increased range of motion of the thoracolumbosacral region and increased oscillation of the tail.
The authors said they had correctly anticipated there would be no association between the maximum lameness grade assigned during ridden exercise and the RHpE score.
“The maximum lameness grade during ridden exercise was unlikely to reflect the degree of discomfort experienced by a horse, because 98% of horses were lame in more than one limb and, in such circumstances, grading cannot reflect the lameness severity.”
Horses adapt to lameness by reducing the range of motion of the thoracolumbosacral region, reducing step length and suspension and increasing duty factor to try to minimise discomfort and effectively conceal lameness.
“This study highlights the importance of ridden exercise in the investigation of poor performance/low-grade lameness and the value of the RHpE to verify the presence of musculoskeletal pain,” they concluded, adding that nerve blocks are vital to determine the sources of pain that compromise performance.
“The high prevalence of ill-fitting saddles, which adversely affected performance in these horses, emphasises the importance of educating riders and trainers about the importance of correct saddle fit for both the horse and rider for optimal performance.”
Dyson, S.; Pollard, D. Application of the Ridden Horse Pain Ethogram to 150 Horses with Musculoskeletal Pain before and after Diagnostic Anaesthesia. Animals 2023, 13, 1940. https://doi.org/10.3390/ani13121940
• Receive a notification when a new article is posted: