Horse Care | Horse Racing Free Tips

Headshaking And Head Injury: Is There A Connection?

Headshaking in horses is a frustrating condition and can be more than an occasional flip of the nose. The action can escalate to the point that the horse becomes dangerous to handle: he may throw his head up violently or strike at his face.

It's not clear why a horse might become a headshaker, but many cases are believed to be in response to pain in the trigeminal nerve. Other causes for headshaking include poorly fitting tack, dental disorders, nasal congestion, ear ticks or mites, guttural pouch issues, masses in the nasal passages, and equine protozoal myelitis, among others.

Dr. Nadine Ogden and colleagues from the Leahurst Equine Hospital at the University of Liverpool in the United Kingdom found that two cases of headshaking and hypersensitivity at the clinic were the result of head injuries. These injuries involved the infraorbital branch of the trigeminal nerve.

The first case was an 8-year-old Warmblood which presented to the clinic with headshaking and pain upon palpation of the face. The gelding began headshaking the same time the owners found a small wound on his face, which was thought to be self-inflicted.

Ten days before going to the clinic, the horse began to rub his muzzle and flip his head both at rest and while working. An X-ray was completed while the horse was at the clinic and showed a small bone fragment next to the infraorbital nerve.

The horse was sedated and the fragment was removed. He showed no signs of headshaking immediately after the surgery, but clinical signs returned once the horse went home. He returned to the clinic five weeks later because of continued headshaking. An X-ray determined that some bone fragments remained. This time the horse was put under general anesthesia and the bone fragment was surgically removed.

Six months later, the gelding was neither sensitive nor headshaking.

A second headshaking case involved a 6-year-old Welsh mare that was sent to the clinic after the sudden onset of muzzle rubbing. The mare also struggled to eat for 12 hours.

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Imaging found a nondisplaced comminuted fracture of the right hemi-mandible. The fracture line and bone fragments were lying on the mental nerve. The mare was given pain medication and tapering anti-inflammatories to make her more comfortable as the fracture healed.

The mare was showing reduced headshaking and muscle rubbing four months after diagnosis and the onset of treatment.

The researchers note that differentiating injury-induced headshaking from idiopathic headshaking is important in both the horse's treatment and prognosis. Long-term follow-up is needed, they conclude.

Lead By Example: Can Horses Learn By Watching Others?

Similar to children, horses can mimic actions they see others taking in specific situations. This is particularly true if the horse completing the action is more dominant than the horse observing, which can be both good and bad news for equine owners and caretakers.

An EQUUS magazine reader asked Dr. Katherine Houpt of Gaylord, Michigan, if her horse could have learned to unload from a trailer quietly from watching other horses. Houpt cited research out of Germany which indicates that horses possessed the social cognition to learn by watching others. This ability has been shown in cats, chickens, dogs, rats and primates, among other species.

The study found that a horse observing a more-dominant horse approaching a person in the center of a round pen is likely to approach the person more quickly when placed in the same situation than a horse that did not observe the behavior.

The key was that the horse doing the watching, and eventual replication of the action, had to be of a lower social rank than the horse being observed.

Houpf also noted that a potentially frightening action is more likely to be observed and replicated.

Overheating: Common Risk Factors For Thoroughbreds Identified

Hotter, more-humid weather puts racehorses at risk of overheating while racing, and a horse with a history of overheating in hot, humid weather is more at risk of exertional heat illness, new research shows. A horse that overheats is susceptible to heat exhaustion and even death.

Scientists from the University of Bristol recommend that racing officials monitor the wet bulb globe temperature index to help decide if racing should continue. This index is based on temperature, humidity, wind speed, and solar radiation.

Warming temperatures mean that more race days are becoming hotter than in the past, so racing officials in places like Australia and Japan have investigated what factors can lead to heat illness in horses. Thus far, there has been no conclusive way to predict which racehorses may overheat.

Dr. Leah Trigg, from the University of Bristol's vet school, worked with the British Horseracing Authority and University College Dublin to examine data on 704,434 racehorses on British tracks that were recorded in the BHA database between July 2010 and April 2018.

In total, 702 episodes of exertional heat stress or heat exhaustion were recorded during that time, equating to 0.1 percent of the horses.

The scientist modeled the probability that a racehorse would experience heat stress or heat exhaustion (collectively called heat illness) if the horse had a previous heat health incident, race distance, race start time, footing conditions, average temperatures in the five days before the races, and wet bulb globe temperature index.

In total, the model predicted 83.5 percent of exertional heat illness events, though the researchers noted that the model may produce a high number of false positives.

Predictive factors included longer race distances and higher wet bulb globe temperature indices. Horses that have overheated before were 18.59 times more likely to overheat again. Running on heavy or soft ground, or in races before 5 p.m., also increased risk of overheating.

Higher temperatures in the days leading up to the race were associated with reduced risk of overheating, the team concluded. This suggests that racehorses may acclimate to warmer temperatures.

Trigg suggests track officials monitor the wet bulb globe temperature index at race meets to determine whether racing should continue or if additional cooling areas should be provided. She recommends that this data be used to create evidence-based policies to protect racehorse welfare.

Human Diabetes Drug Shows Promise In Treating Difficult Laminitis Cases

Ertugliflozin is a drug that has been used in humans to address hyperinsulinemia and diabetes, but it is also showing promise in helping horses with hyperinsulinemia and laminitis that have not received relief from management changes.

This drug limits the amount of insulin released by the pancreas after a meal.

Horses taking the drug have shown “surprising” improvements in lameness scores and insulin levels in less than a month, reports The Horse. The affected horse's body condition also improved.

Dr. Tania Sundra, owner of Avon Ridge Equine Veterinary Services, in Australia, noted that a lot of the horses were comfortable enough to come off non-steroidal anti-inflammatories 7 to 14 days after beginning to receive the drug.

Sundra presented these findings at the 2022 American Association of Equine Practitioners Convention, held Nov. 18 to 22 in San Antonio, Texas. She also noted that the drug also helped with chronic laminitis cases, even those so severe that the owners were contemplating euthanasia.

Sundra used the drug on 51 horses her practice cared for that had been lame from laminitis for an average of 41 weeks. These horses had not responded to traditional management and diet changes. She treated the horses for 30 days at a dose of 0.05 oz/lb orally.

The scientists found that the average insulin concentrations decreased more than seven-fold and the laminitis scores dropped dramatically (from 10 to 1 on the 12-point Obel scale); some of the horses went entirely sound in just two weeks.

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Sundra notes that the drug is not a replacement for diet and management changes for metabolically challenged horses, and it does have possible side effects to use. Use of the drug nearly doubled the serum fat concentrations in horses in the first 30 days of use, though none developed clinical signs of hyperlipidemia.

Ten of the horses showed excessive urination and thirst, so it's imperative that they have access to clean, fresh water at all times.

Read about some additional drugs used to treat EMS or PPID and their side effects here.