Stem Cells & Hyaluronic Acid for Arthritis

Canadian researchers from the Ontario Veterinary College in Guelph conducted a small, prospective, randomized and blinded clinical trial to test the safety and efficacy of two concentrations of intra-articular stem cells combined with hyaluronic acid (SC+HA) compared with HA alone for the treatment of ankle and knee arthritis.

Twenty-seven performance horses of various breeds (mostly Thoroughbreds, warmbloods and Quarter Horses) were each confirmed to have a grade 2 or 3 out of 5 lameness localized to the ankle (fetlock) or knee (carpus) using intra-articular anesthesia and randomly assigned to the treatment groups. The stem cells used were mesenchymal stromal cells of umbilical origin collected from healthy foals at birth, cultured and frozen until needed.

Lameness scores improved by 1 or 2 grades within both treatment groups over time, but there was little difference between the groups. The proportion of horses returning to work appeared to be higher in the SC+HA groups (7 or 8 out of 9 returned to work) compared with the group treated with HA alone (5 of 9 returned to work); however, these differences were not statistically significant.

A few horses had increased lameness and swelling for 2-3 days after treatment, but there were no serious side effects noted with either treatment. The authors were surprised by the high return to work rates for the group treated with HA alone and concluded that larger studies would be needed in the future to determine whether SC+HA treatments are truly an advantage.

— Luque RM et al. EVJ 2025;DOI:10.1111/evj.14551

A Review of Horseshoe Effects on Gait

While not a report of original research, scientists from the Laboratory for Equine and Comparative Orthopedic Research at Louisiana State University conducted an excellent review of the literature examining the effects of horseshoes on the kinetics (distribution of forces) and kinematics (patterns of movement) of equine gait.

Forty-six studies were included in the review; most used non-lame horses to examine the effects of different types of shoes and shoe modifications compared with barefoot or plain-shod horses. Most of the studies were small, focused on particular breeds and were unable to consider the impact of conformation, hoof shape and health conditions.

While there was a considerable amount of variation in the findings, some common themes started to emerge. Namely, breakover was affected by heel elevation, rolled toes and long toe lengths. Heel wedges and shoe composition tended to impact vertical ground reaction forces.

Ground surface hardness and shoe configuration tended to impact the magnitude and distribution of pressure over the shoe and hoof surface. Unsurprisingly, braking forces were affected by friction coefficients of the shoe-ground surface interactions. In the lower limb, fetlock, pastern and coffin joint angles were most likely to be affected by the presence and shape of shoes. With more than 50 references clearly summarized for the reader, this review could be a valuable resource for practitioners and researchers alike.

— Aoun R et al. Vet Surg 2025; DOI:10.1111/vsu.14162

Pergolide Not a Panacea for Insulin Disorders

Equine Cushing’s disease (also known as pituitary pars intermedia dysfunction or PPID) and insulin dysregulation (ID) are both metabolic disorders associated with increased risk for laminitis. Pergolide is known to be an effective treatment for PPID, but its effects on ID are less clear.

Conducted by researchers from Australia, Germany and the U.K., this study evaluated the effects of pergolide on glucose and insulin responses in horses with ID with and without concurrent PPID. Sixteen horses and ponies, eight with ID-only and eight with PPID+ID, were tested for insulin resistance and insulin-glucose responses after a test meal before and after being treated with pergolide for 4 weeks.

In both the ID-only and PPID+ID groups, none of the parameters examined were affected by the pergolide treatment following the glucose and insulin tolerance test for insulin resistance, which measures insulin sensitivity in tissues.

Similarly, no effects of the pergolide treatment were noted for the insulin responses following the standardized meal test for horses in the ID-only group. Horses in the PPID+ID showed a positive response to the treatment with lower insulin levels following the meal test. These results suggest pergolide is likely to help prevent laminitis by reducing ID, but only when the animals are also affected by PPID.

— Galinelli NC et al. EVJ 2025; DOI:10.1111/evj.14468

Distance Horses Event Best

Faculty from the University of Sydney compared the previous racing performance of Thoroughbreds that went on to higher-level eventing careers with those that went on to eventing but only competed at lower levels.

Other than involuntary retirement due to musculoskeletal problems being an obvious problem, little is known about factors associated with success when schooling retired off-the-track Thoroughbreds (OTTB) into performance horses as a second career. This study of 6,767 OTTB compared the previous racing performance of horses that competed in eventing at or above the EvA95 with those that competed below this level.

Although the difference wasn’t large overall, horses with longer careers and better racing performance (more starts, more win and place finishes and higher earnings) were more likely to only event at the lower levels after rehoming. However, horses that raced at longer distances and waited longer before starting their OTTB career tended to compete at higher levels of eventing.

The authors suggest that when evaluating eventing prospects, in addition to looking at racing performance and distance factors such as stride characteristics, rider-horse partnership and behavior should be carefully considered.

— Bacon EK et al. JEVS 2025; DOI:10.1016/j.jevs.2025.105679