Equine Behavioral Update

Understanding horse behavior research can help you better manage horses and modify owner behavior.
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cribbing horse

One study concluded that five horses equipped with the Quaryka feed dispenser reduced their cribbing behavior compared to the five control horses fed with conventional containers. When the specialized feeder was removed, those horses returned to their previous level of cribbing activity.

Horse owners are “into” the behavior of their horses, and the behavior side of the equine industry (natural horsemanship and training) makes millions of dollars each year. Your owners will appreciate your input when you bring science-based behavioral information to them.

The Effect of Nosebands

The training of horses tends to rely on negative reinforcement to modify a horse’s behavior to the will of the rider. In many riding disciplines, removal of pressure is the reward for when a horse does something favorable.

Pressure comes in many forms, such as halters, bits, spurs and whips. By contrast, a restrictive noseband does not provide negative reinforcement because the pressure never relents or changes in response to a horse’s behavior. Nosebands are commonly used in dressage and eventing pursuits in an attempt to limit a horse’s evasive behaviors.

Studies are currently evaluating the effect of restrictive nosebands on horse behavior. While it is recommended that there be a two-finger available space beneath the noseband, measurements of a study of 750 horses ridden in dressage, eventing and performance hunter disciplines (Doherty, O.; Casey, V.; McGreevy, P.; Arkins, S. (2017), Noseband Use in Equestrian Sports—An International Study. PLoS ONE 12(1)) found that 44% of horses were fitted with a zero-fingers gap beneath the noseband and the horse’s nose. Only 7% of horses were fitted properly with a gap of two fingers.

As a group, eventing horses were found to wear the tightest nosebands, whereas the performance hunter groups had the loosest nosebands in this study. The tendency to tighten nosebands “may reflect riders’ efforts to address behavioral problems rather than putting the required time into training horses to slow, stop or stand still from a rein cue,” noted the study.

A tightly fitting noseband often precludes a horse’s ability to yawn, swallow, chew and even lick sufficiently. Adding rein tension, especially with a double bridle, further intensifies the pressure exerted by a tight noseband. The narrower the noseband width, the greater pressure the horse will feel.

One study (Fenner, et al., The Effect of Noseband Tightening on Horses’ Behavior, Eye Temperature, and Cardiac Responses, PLoS ONE 11(5)) concluded: “The current data indicate that nosebands tightened to the extent that there is no area available underneath them cause a stress response and prevent the expression of normal behavior.” Stress responses were measured by elevated heart rates and increased eye temperature as parameters suggestive of pain and/or discomfort.

Besides behavioral changes, there are other adverse consequences of excessive tightening of a noseband, including breathing restriction, tissue damage and buccal ulceration or laceration from mucosal pressure against sharp edges of premolar teeth. There is some concern that tissue damage and pressure over the trigeminal nerve on the face has the potential to lead to headshaking syndrome.

When veterinarians are asked to examine horses for rider complaints of unwillingness to work or a variety of performance problems, headgear equipment warrants inspection.

A primary objective for riders is to find the least aversive practice that elicits the desired response by the horse for the rider’s demands. Current recommendations are for stewards to be on site to check gear and fit at competition venues, using a specifically designed taper gauge that standardizes measurements.

Feed Dispenser Decreases Cribbing

Cribbing behavior is a stereotypy that might have as its inception a means of coping with stress. A horse experiences stress for many reasons, but one significant variable hinges on modifications to evolved grazing behavior that should have a horse consuming small amounts for up to 16 hours per day.

High-energy rations fed two to three times a day reduce opportunities to consume feed. Condensed meals are presented and consumed in a short period of time, leaving the horse with a desire to forage and chew.

One study (Mazzola, S., et al., Effcacy of a Feed Dispenser for Horses in Decreasing Cribbing Behaviour. Veterinary Medicine International, Sept 2016) examined the effects of a feed dispenser on the amount of time the horses spent cribbing. The feeder (Quaryka) required the horse to rotate a “wheel” with its mouth in order to release food into a feed pan. It didn’t take long to accustom the study horses to using the feeder.

Ultimately, a horse takes a significantly longer time to eats its ration when it has to continually work the wheel to obtain food. Time spent interacting with the feeding dispenser also minimized the amount of time the horses would spend cribbing during mealtime.

The study concluded that five horses equipped with the Quaryka dispenser reduced their cribbing behavior compared to the five control horses fed with conventional containers. When the specialized feeder was removed, those horses returned to their previous level of cribbing activity.

Although the study involved a limited number of horses, such a feeding device shows promise to modify stereotypic cribbing behavior.

Preconditioning for Learning

The use of negative reinforcement relies on the appropriate release of pressure in response to a horse performing the requested task. Rein tension on the bit is one such means of applying negative reinforcement.

Behaviorists have noted that horses learn better when they are slightly aroused and prepared for their lessons. By contrast, fear responses—such as those evoked by chasing a horse around a round pen—interfere with a horse’s cognitive function.

A study (Fenner, K., et al., Effects of preconditioning on behavior and physiology of horses during a standardized learning task, presented at the 12th International Equitation Science Conference) examined the effect of a preconditioning exercise—giving to bit pressure—on arousal level and learning outcome. Arousal was determined through heart rate and behaviors such as head tossing, while learning was measured by rein tension, time to perform the task, step number and behavior. The objective was to engage the horse in the lesson as a means to improve performance.

The researchers concluded that preconditioning with a pressure-release exercise elicited an increase in heart rate consistent with moderate arousal. Horses treated with the preconditioning exercises “exhibited significantly less head tossing—a response to aversive rein and bit pressure—than their untreated counterparts. This suggested that engaging the horse prior to training might lay the foundation for a better learning experience.”

They also noted that, “Effective use of negative reinforcement depends on timing the release of the applied pressure, and the difference between a good and an average trainer manifests chiefly in that ability.”

Twitching for Restraint

Sometimes it is necessary to use mechanical techniques to subdue a fractious horse for veterinary or farrier procedures. The lip twitch and ear twitch are examples of such restraint measures. It is speculated that a twitch can create analgesia, distraction or pain as a vehicle for obtaining cooperation from a horse.

Measurements of heart rate, heart rate variability and cortisol levels were used to evaluate the effects of the twitch methods on a group of 12 horses (Twitching in veterinary procedures: How does this technique subdue horses? Flakoll, B., et al., Journal of Veterinary Behavior, 18 (2017) 23-28). The study reported considerable differences between using the lip or the ear twitch.

As the lip twitch increases the parasympathetic nervous system activity, the study found it reduces stress levels and “subdues through a calming, probably analgesic effect.” That said, the study also discovered that the lip twitch might be useful only for procedures lasting less than five minutes.

Following five minutes of application of the lip twitch, sympathetic tone significantly elevated in the study horses, possibly due to habituation that then minimized beta-endorphin release. For longer procedures, chemical restraint is likely more appropriate.

By contrast, the ear twitch “significantly raises sympathetic nervous system activity and stress levels, making horses harder to handle both directly after application of the twitch and over time.” Ear twitch restraint is considered “a stressful and aversive mechanism, probably eliciting fear and/or pain,” reported the study.

Horses Facing Unsolvable Tasks

The domestication of the horse has seen an evolution of behaviors that improve interaction between horse and human. One study sought to examine how horses communicate with humans when faced with an unsolvable task, namely obtaining food that is hidden at an unreachable location—i.e., a carrot in a covered bucket (Ringhofer, M., and Yamamoto, S. Domestic horses send signals to humans when they are faced with an unsolvable task. Anim Cogn (2017) 20:397–405).

The project examined how horses communicated about two different problem-solving situations in which a food item was hidden in a bucket that was only accessible to the caretaker and not to the horse. In the first effort, the caretaker was absent when the food was hidden, and therefore ignorant about the hidden food. In the second, the caretaker saw the carrot being hidden so had knowledge of the food and where it was located. The horses witnessed the food being hidden in both instances.

All eight horses in the study used eye contact and touched the human caretaker to convey that they wanted something. But for the experiment in which the horses didn’t think the caretaker knew about the hidden food, they displayed considerably more active efforts to convey to the caretaker that there was a carrot in a covered bucket.

The researchers concluded: “The results suggest the possibility that horses knew what humans did and did not see; moreover, they could Flexibly use this information in their signaling behavior toward humans.”

This study shows that horses possess some cognitive basis for understanding others’ knowledge and are sensitive to a human’s past “attentional” state. Using this information, horses adapt their signaling behavior accordingly to communicate with humans.

Take-Home Message

Knowledge about equine behavior is important not only for managing the horse, but for managing the horse owner, manager or trainer. Teaching the people who regularly handle the horse what research is showing in the areas of behavior can greatly increase your standing with your clients. 

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