Causes and Effects of Stress in Horses

By May 31, 2019 June 13th, 2019 Horses

Horses can experience stress from a variety of environmental and social factors — from their training and feeding schedules to their interactions with other horses in the pasture. Different horses may show stress in different ways, and some horses respond better to stressful situations than others. However, stress can be a serious problem for even the toughest horses as it can lead to health and behavioral issues when left unaddressed. In this piece, we will explore the common causes and effects of equine stress so you can better recognize and prevent stress in your horses.

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What Does It Mean When Your Horse Is Stressed?

Just as humans experience stress in situations that are physically or mentally challenging, horses also experience stress as a natural response to changes or challenges in their environment. In some situations, stress is a helpful reaction that allows horses to cope or adapt. For example, if an unfamiliar animal enters a horse’s pasture, their natural stress response tells them to stay alert and approach that animal cautiously.

What does stress mean for horses?Short term stress helps keep a horse safe, but if stress continues for a long time, it can have damaging effects to the horse’s health and well-being. When we talk about a horse being stressed, we are often referring to this type of chronic stress. Over time, horses can adapt to familiar stresses, such as traffic near their pasture or a new horse joining their pasture. However, when faced with larger changes like a new training schedule or busy show season, horses may be unable to adjust and develop long-term stress.

Chronic stress occurs when a horse’s stress hormone levels rise in response to a stressful situation and then fail to decrease again. Chronically elevated stress hormones can lead to changes in the horse’s behavior and habits as well as cause many health problems.

What Causes Stress in Horses?

Chronic stress in horses is most often the result of changes in the horse’s environment or lifestyle. Management changes, such as a more strenuous exercise routine or new feeding schedule, can also lead to long-term stress. While some horses can adapt to these changes easily, other horses may have a harder time adjusting. Just as different people handle stressful situations differently, some horses are more likely to experience chronic stress than others.

By being aware of what triggers stress in horses, you can take steps to keep your horses healthy and happy. Here are some common causes of stress in horses:

1. Exercise Levels or Changes in Exercise Regimen

Racehorses and performance horses that have a rigorous training schedule with high-intensity exercise are more likely to develop chronic stress. Exercise-induced stress is often proportional to the horse’s competition level — a horse in training may be more stressed than a horse on rest, and a horse that is racing may be more stressed than during training.

Horses can also experience stress if their training schedule becomes more difficult or changes significantly. For example, a horse may struggle to adjust to a particularly busy competition season or more intricate training routine. If a horse feels uncomfortable during exercise for any reason, such as ill-fitting equipment or a new rider, this can also result in elevated stress levels.

On the other hand, exercise has also been shown to reduce stress in horses, while extended rest periods may increase their stress. If your horse is experiencing stress from other factors, taking them out for a ride may actually help to lower their stress levels and help them relax.

2. Poor Diet or Changes in Diet

Horses need a well-balanced diet and regular feeding schedule to stay healthy and fit. A proper diet will include all of the basic nutrients a horse needs, including carbohydrates, fats, proteins, vitamins and minerals. Horses should also consume five to 15 gallons of water each day and eat one to two percent of their body weight in forage. In a healthy feeding schedule, horses are fed frequent small meals throughout the day.

Horses should consume 5-15 gallons of water each day and 1-2% of their body weight in forageIf a horse is fed only feed, does not receive enough forage or their diet is lacking in essential nutrients, this can cause chronic stress. Feeding a horse only twice daily rather than several times is another common cause of stress. When a horse is stalled during rest, they should still be fed regularly with both roughage and feed.

In addition to a poor diet, changes in a horse’s diet or feeding routine can also lead to long-term stress. While traveling, try to keep your horse’s feeding schedule as consistent as possible. Bring your own hay and feed from home so your horses can still enjoy their regular diet while on the road.

3. A Busy Transportation Schedule

Performance horses that travel frequently during show season are more likely to develop chronic stress. Even if a horse has been transported before, traveling can still be stressful as they are going to an unfamiliar location and are likely experiencing other changes in their routine. As much as possible, a horse’s feeding and exercise schedule should be kept regular while traveling. While on the road, keep your horses well-hydrated and provide ample access to hay to encourage proper gut functioning. If your horses are used to regular turnout, take them on frequent walks to keep them out of their stalls as much as possible.

4. Housing Conditions

The amount of time a horse spends in the field and their stall can impact their stress levels. Regular turnout is important for a horse’s health and can help reduce their stress, so horses should be kept in the pasture as much as possible. If a horse that is usually very active must go on stall rest for injury recovery, keep them entertained as much as possible to prevent stress from boredom and lack of activity.

Horses should be kept in the pasture as much as possible.A horse’s housing conditions can also cause stress when new horses are introduced or if a barn that is typically quiet becomes noisy and crowded. Because horses are social animals, a horse can even develop chronic stress based on which horses are housed next to them.

5. Pregnancy or Reproduction

Horses may experience natural stress during different stages of their reproductive cycle, but this can become chronic stress if not managed properly. When a mare is in estrus, a follicle will develop on one of her ovaries, and she may experience frequent urination. These physical changes can cause discomfort and can lead to chronic stress. Treatments are available that can help reduce the symptoms of estrus and ease a mare’s stress.

A pregnant mare may experience pain or discomfort while giving birth which may be expressed through pawing, pacing, sweating or biting at her stomach. This stress is often relieved after the mare gives birth, but if stress continues after foaling, pain relief medication may be necessary.

What Are the Effects of Stress in Horses?

If a horse develops chronic stress from any of these causes, it can have long-term effects on their health and behavior. Horses suffering from stress may be more likely to get sick or develop gastric ulcers which can lead to more stress. Here are some common signs that a horse is stressed:

1. Weight Loss

A horse that is stressed may experience a decrease in their appetite and will begin to lose weight. This is a common effect if a horse is not receiving a well-balanced diet with quality feed and forage. If a horse is already experiencing gastrointestinal discomfort from a poor diet, they may exhibit a reduced appetite and lack of interest in food. Even if a horse is fed a regular and healthy diet, they may show a decreased appetite due to other stresses. Heat stress or other health problems can also cause weight loss in a horse, so it is important to explore any possible cause.

2. Gastric Ulcers

Gastric ulcers are very common in stressed horses, with about 60 percent of show horses and 90 percent of racehorses suffering from equine ulcers. High-performance horses are not the only ones susceptible to ulcers, however, as horse ulcers can be caused by a poor diet, a busy travel season, stall confinement or any other stressful environment.

Gastric ulcers form when a horse’s stomach lining erodes due to extended exposure to stomach acid. In a healthy horse, regular intake of feed and forage will neutralize this acid to protect the stomach lining. When a horse does not feed regularly, they are at risk of developing gastric ulcers.

Elevated stress hormones can also cause ulcers in horses. When the stress hormone cortisol is released, it reduces the production of another stress hormone called prostaglandin. This lowers the pH levels in the horse’s stomach which weakens the protective lining and makes the horse more susceptible to developing ulcers.

Horse ulcers can be caused by a poor diet, a busy travel season, stall confinement or any other stressful environment.Because horses show very little outward signs when they are suffering from gastric ulcers, they can be difficult to diagnose. A horse with ulcers may show subtle signs such as a decreased appetite or a rough and dull coat. In more serious cases, horses with ulcers may grind their teeth or experience colic.

To test for gastric ulcers, a veterinarian will insert an endoscope into the horse’s stomach to look at the surface. Gastric ulcers are treated by removing stresses from the horse’s environment and ensuring they receive proper nutrition. Medications can also be used to increase pH levels in the horse’s stomach and stop the progression of ulcers.

3. Diarrhea and Frequent Urination

When a horse is stressed, they may produce more manure than usual in a short period of time and may also experience diarrhea. Horse diarrhea can also be caused by a poor diet, which is a common cause of stress in horses. A stressed horse may urinate frequently to relieve their stress and become more stressed if they are in a place where they cannot relieve themselves, such as a trailer.

4. Weakened Immune System

A chronically stressed horse will have high levels of cortisol which can disrupt its normal bodily functions. Too much cortisol can weaken a horse’s immune system, making a stressed horse more likely to catch an infectious disease or become seriously ill.

5. Stereotypic Behavior

If a horse is experiencing stresses, such as too much time in their stall or a poor feeding schedule, they may begin to exhibit stereotypies. Common stereotypes include cribbing, chewing, wall kicking, stall walking, weaving and fence walking. While this stereotypic behavior is not always tied to stress, it may be an indicator that a horse is not adjusting well to a change in their environment or routine.

6. Yawning

The reason horses yawn is not entirely clear, but yawning has been connected to stereotypic behaviors and may be a sign that a horse is stressed. Yawning could provide an endorphin release that helps horses cope with a stressful situation. If your horse yawns frequently, ask yourself if there may be a reason that your horse is stressed.

7. Behavioral Changes

When a horse is stressed, they may develop a poor attitude and become resistant to training or exercise. A horse that is usually enthusiastic about work may become unmotivated or appear depressed. Horses that are stressed may also act out by bucking, bolting, biting, rearing or pawing, even if they are generally even-tempered and well-behaved.

8. Tooth Grinding

As mentioned above, tooth grinding can be a sign that a horse has gastric ulcers. Horses may also grind their teeth if they are experiencing other physical pain or discomfort. Physiological stress can also cause horses to grind their teeth while they are in their stall or being ridden. If a horse does not have any dental issues, tooth grinding is likely a result of a stressful environment.

9. Trembling, Sweating and Elevated Pulse

During a stressful situation, a horse may exhibit many of the same physical signs that a person does when they are stressed. The horse’s heart rate and breathing increase and they may begin to sweat. Horses may also tremble when they are in a stressful environment such as during transportation or when visited by the veterinarian. These signs of stress will normally disappear whenever the stressful trigger disappears. However, if a horse shows these signs of stress in an ordinary situation, that may indicate chronic stress.

How to Make Your Horse’s Life Less Stressful

If your horse shows any of these signs of stress, there are several measures you can take to create a more comfortable and healthy environment. First, try to identify what may be causing your horse to feel stressed, and then consider ways you can adjust their lifestyle to relieve that stress. Here are a few options for how to reduce stress in horses:
How to Make Your Horse's Life Less Stressful

  • Maintain a consistent daily routine: Horses enjoy a regular schedule, so aim to keep their feeding and exercise schedule as consistent as possible, even while traveling.
  • Create a healthy diet and feeding schedule: Ensure your horses are receiving good nutrition with the proper balance of feed and forage. Horses should have access to plenty of clean water and be fed several times during the day.
  • Increase pasture time: If your horses spend a lot of time inside their stalls, try to increase their turnout as much as possible.
  • Adjust exercise schedules: Make sure your horses are receiving the right amount of exercise and appropriate level of training. Proper exercise routines help prevent injuries and can reduce stress in horses.
  • Monitor social interactions: If you believe your horse may be stressed due to social factors, watch how the horse interacts with other horses in the pasture and barn. If the horse seems uncomfortable while in the barn, consider moving it to another stall.
  • Take care when traveling: When transporting your horses, try to keep the trailer ride as smooth as possible. Provide ample hay and water to keep the horse’s stomach settled while traveling. Bring hay and feed from home so your horse’s diet stays consistent.
  • Perform preventative care: Keep your horses up-to-date on vaccines and take them for regular health exams. If your horse shows any signs of stress-induced health problems, talk to your veterinarian about possible treatments.

By recognizing the causes and effects of stress in horses, you can take steps to relieve their stress and create a happier environment. At Pro Earth Animal Health, we are dedicated to helping you keep your horses healthy and stress-free. We are proud to offer the all-natural equine supplement Zesterra, which is designed to reduce the effects of stress in horses and help prevent gastric ulcers. Contact Pro Earth Animal Health to learn more about Zesterra and how it can benefit your horses’ health.

© 2019 Pro Earth Animal Health.

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