weak | Horse Racing Free Tips

Noticing Asymmetry Under Saddle? The Solution Could Come From A Single Bell Boot

Though all horses have some degree of asymmetry, a rider can make a slight asymmetry better by placing something loose around the fetlock of the weaker leg, according to a report from the archives of The Horse. The horse will feel it and work harder to engage his limb, said Dr. Adrian P. Harrison, who works with Copenhagen University in Denmark.

The fix could be as simple as occasionally using a bell boot on the weaker leg; the boot uses proprioception to remind the horse that the weaker leg is still there. Proprioception is the awareness of body parts, and knowing and remembering where they are and what they are doing. The bell boot helps a horse “remember” his leg is there.

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This correction could resolve issues relating to an old injury or dominant limb. Old injuries can sometimes cause horses to be unwilling to fully engage a limb for fear of pain; the bell boot trick helps them realize they are pain free.

Harrison created a study using eight sound dressage horses that had slightly weaker left hind limbs when measured using acoustic myography (AMG). AMG measures how muscle and ligament fibers move, and how much power the central nervous system must exert to get a muscle to contract.

Riders of the horses placed a cob-sized bell boot on the horse's weaker limb when the horse was ridden for 60 minutes every three days for six weeks. At the end of the study, AMG shows that the asymmetries had resolved.

Study Examines Prevalence of Quarter Cracks in High-Performance Horses

Like equine athletes in all disciplines, Thoroughbred racehorses face hoof-related challenges, including quarter cracks. In an effort to better understand this hoof wall abnormality, researchers investigated the incidence, clinical presentation and future racing performance of Thoroughbreds with quarter cracks over a nine-year period.*

A quarter crack is a full-thickness failure of the hoof capsule between the toe and heel that may extend the entire height of the hoof, from coronary band to ground. The separation often results in unsoundness due to instability of the hoof wall or infection of the deep dermal tissue, though many horses remain free of lameness despite the presence of a quarter crack.

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Quarter cracks are thought to arise for many reasons: innate hoof weakness; improper hoof balance; injury or trauma to the coronary band; or infection of the corium, part of the internal vascular network of the hoof. Poor farriery may contribute to hoof imbalance, which could contribute to crack formation. A common finding among horses with quarter cracks is sheared heels, an unevenness of the heels that causes unequal weight-bearing on the bulbs and creates a shearing force absorbed by the hoof capsule.

During the nine-year study period, just over 4,500 horses in a training center were followed. Seventy-four horses had at least one quarter crack during the study period. Twenty horses had two or more quarter cracks. Almost half of all horses with quarter cracks were lame at the onset of the defect.

An overwhelming number of cracks occurred in the front hooves and there was a proportional difference in the number of cracks in the left rather than right front hooves. Most of the cracks came about on the inside of the hooves.

The quarter cracks identified in this study were treated in various ways, though the principle treatments included corrective shoeing with a heart-bar shoe, wire stabilization, and the use of epoxy or acrylic. Treatment goals centered around correcting the hoof imbalance and eliminating uneven movement.

Racing performance following treatment was available for 63 of the 74 horses. Of the 63 horses, 54 horses had at least one start after treatment. When compared to control horses, there was no significant difference in the number of career races, career wins and career placings for horses with quarter cracks.

As mentioned previously, horses genetically predisposed to weak hoof walls might be susceptible to quarter cracks. Racehorses are generally well-nourished, as trainers know the importance of sound nutrition in conditioning an athlete. Aside from high-quality forage and fortified concentrates, horses inclined to poor-quality hooves should be given a research-proven hoof supplement. Biotin should be a primary ingredient in the supplement, but other ingredients will further support hoof health. A high-quality hoof supplement also contains methionine, iodine and zinc.

*McGlinchey, L., P. Robinson, B. Porter, A.B.S. Sidhu, and S.M. Rosanowski. 2020. Quarter cracks in Thoroughbred racehorses trained in Hong Kong over a 9-year period (2007-2015): Incidence, clinical presentation, and future racing performance. Equine Veterinary Education 32 (Suppl. 10):18-24.

Can A Horse That Has Had EPM Have A Relapse?

Equine protozoal myeloencephalitis (EPM) is a potentially devastating disease caused by a protozoa that horses ingest. Once the horse has been infected, the organisms can migrate to the central nervous system, causing inflammation and tissue damage to the spinal cord and brain.

A horse that has EPM can be incoordinated, lame or weak. Treatment involves the use of antiprotozoal or antiparasitic medication like diclazuril, ponazuril or sulfadiazine and pyrimethamine. These can reduce or eliminate the signs of EPM. Most cases of EPM respond to treatment, but horses may need more than one round of treatment weeks or months after their initial treatment.

EPM-causing protozoa are good at evading the immune response and surviving immune attacks, which makes them hard to eradicate. Additionally, a horse's immune response in the central nervous system is not as strong, additionally complicating treatment. Because of this, horses that have had EPM can relapse, though it is unclear how often this happens. One study showed a relapse in about 8 percent of horses within 90 days after the initial EPM treatment concluded. Evidence of relapses after longer periods of time also occur.

Multiple factors are involved in an EPM relapse, including the dose and type of drug used, as well as the variability of the individual horse to clear the organisms. A veterinarian caring for a horse that has another episode of EPM should investigate lengthening the duration of treatment.