Radiographic Abnormalities in Barrel Racing Horses with Lameness Referable to the Metacarpophalangeal Joint

Objective lameness assessment of 235 horses undergoing lameness examination in Brazil: A retrospective study

Lameness, which arises from functional or structural changes in the limbs or axial skeleton, causes asymmetry in the movement of the equine head and/or pelvis. This study aimed to investigate the lameness patterns of horses that underwent lameness examination or monitoring during the years 2016 to 2020. This retrospective study used data from the lameness examination, evaluated using an objective assessment with body-mounted wireless inertial sensors. The lameness examination comprised clinical history, static inspection, palpation, gait evaluation (for which the animals were equipped with a wireless inertial sensor system), flexion tests, lunging examination, diagnostic anesthetic blocks, and imaging examinations. Based on objective assessment data, the condition of lameness, limb with primary lameness, type of lameness, intensity, and location of lameness were determined. Of the 235 animals included in this study, 93,6% presented lameness. Of the animals with lameness, 59,5% had forelimb lameness and 40,5% had hindlimb lameness. The most frequent lameness condition was primary lameness in one limb and secondary lameness in the other. Impact lameness was the most frequent type in both the forelimb and hindlimb. Moderate-to-severe lameness was the most frequent level of intensity. Regarding the lameness location, in the forelimb, the distal region was the most affected, while in the hindlimb, the proximal lower region was the most affected. We conclude that forelimb lameness is more frequent in horses examined in southern Brazil and mainly affects the distal limb region.

Macrophage Activation in the Synovium of Healthy and Osteoarthritic Equine Joints

Synovitis is a major component of osteoarthritis and is driven primarily by macrophages. Synovial macrophages are crucial for joint homeostasis (M2-like phenotype), but induce inflammation (M1-like) when regulatory functions become overwhelmed. Macrophage phenotypes in synovium from osteoarthritic and healthy joints are poorly characterized; however, comparative knowledge of their phenotypes during health and disease is paramount for developing targeted treatments. This study compared patterns of macrophage activation in healthy and osteoarthritic equine synovium and correlated histology with cytokine/chemokine profiles in synovial fluid. Synovial histology and immunohistochemistry for M1-like (CD86), M2-like (CD206, IL-10), and pan macrophage (CD14) markers were performed on biopsies from 29 healthy and 26 osteoarthritic equine joints. Synovial fluid cytokines (MCP-1, IL-10, PGE2, IL-1β, IL-6, TNF-α, IL-1ra) and growth factors (GM-CSF, SDF-1α+β, IGF-1, and FGF-2) were quantified. Macrophage phenotypes were not as clearly defined in vivo as they are in vitro. All macrophage markers were expressed with minimal differences between OA and normal joints. Expression for all markers increased proportionate to synovial inflammation, especially CD86. Synovial fluid MCP-1 was higher in osteoarthritic joints while SDF-1 and IL-10 were lower, and PGE2 concentrations did not differ between groups. Increased CD14/CD86/CD206/IL-10 expression was associated with synovial hyperplasia, consistent with macrophage recruitment and activation in response to injury. Lower synovial fluid IL-10 could suggest that homeostatic mechanisms from synovial macrophages became overwhelmed preventing inflammation resolution, resulting in chronic inflammation and OA. Further investigations into mechanisms of arthritis resolution are warranted. Developing pro-resolving therapies may provide superior results in the treatment of OA.

Injury incidence and locomotor behaviours in polocrosse ponies

There is currently limited information available regarding the physical demands of polocrosse and no information on the specific veterinary problems faced by polocrosse ponies in the United Kingdom. Polocrosse requires the ponies that compete to perform rapid acceleration, sharp turns and sudden halts. The study aim was to explore the injury incidence and type of injury, between the three positions played by polocrosse ponies. Injuries that resulted in withdrawal of a pony during outdoor tournaments in the UK over the 2015 and 2016 seasons were recorded. In addition, GPS data and locomotor behaviours were recorded during winter league tournaments in 2017 and compared between the different position ponies. Ponies that played in the defence position were significantly more likely to become injured (P<0.001) with lameness being the most common cause for withdrawal (P<0.001). Ponies playing in the attack position achieved the fastest speeds and covered the furthest distance. Defence ponies performed significantly more abrupt halts (P=0.007), walk to gallop transitions (P=0.017) and sudden changes in direction (P=0.01) than midfield ponies and more of each manoeuvre than attack ponies, although this was not significant. It is important that the physical demands placed upon polocrosse ponies are investigated further; this will allow identification of injury risk factors, inform training programmes and improve the performance and welfare of the horses involved.