Equine stress

What is stress?

Stress can be defined as a mental or physical pressure which can result in a reaction. Some stress is useful in a horse’s life to protect them from potential danger and allows a horse to learn and adapt to their environment. However, too much stress can cause a negative impact to their health and well-being.

Acute stress is caused by short term stressors, for example; a plastic bag blowing in the wind, which causes the horse to spook.

Chronic stress is caused by long term stressors such as being restricted to a stable or the horse experiencing pain over a prolonged period.

Advice on understanding donkey behaviour is available from The Donkey Sanctuary.

Stress response

Stress in the horse can be broken down into two elements:

1. Physiological (physical) stress
2. Psychological (mental/emotional) stress

The fight and flight response can be useful as a short-term measure to move the horse away from an undesirable situation. However, when the stressor is continually repeated or always present, the stress hormones cortisol and adrenaline can cause a permanent feeling of stress that the horse then needs to have an outlet for.

A freeze response can also be observed in horses, this is when the horse will suddenly stop and become completely immobile. The horse in the ‘freeze’ stance will often be very alert with an increased heart rate, and head and neck held high. As prey animals the freeze stance would often confuse the predator into letting them go or if being stalked, the predators kill instinct wouldn’t be activated. An example of the freeze response in domesticated horses would be when the horse is subjected to high levels of confusion or fear, such as leg pressure not being released when ridden. Often, when a horse freezes it’s followed by a reactive response for example spinning and bolting away from the perceived danger.

Horses have two ways of coping (either combined or in isolation) - active coping (proactive) or passive coping (reactive)¹. The active coper will try to take control of the situation by taking flight and moving away, while the passive coper will freeze or become withdrawn. This has implications for welfare, safety and training.

Recognising stress

Horses are individuals and will show differing signs of stress and may show more than one sign at a time. Horse owners and carers need to be able to recognise these signs to identify the cause and improve the horse’s situation.

Some signs to look out for are:

• Change in personality, for example becoming grumpy
• Unexplained weight loss
• Stereotypical behaviour - box walking, wind sucking, crib biting
• Yawning² - this should be taken in context, as a sleepy horse stood yawning in the sun is perfectly normal, however a horse in a stressful situation such as being isolated may yawn repetitively
• Tooth grinding
• Poor ridden behaviour, change in ridden behaviour, bucking, stopping at a fence
• Equine Gastric Ulcer Syndrome (EGUS) - the signs of this can be subtle but include reluctance to work, reactive when doing up the girth, loss of appetite and dullness
• Licking and chewing³, for example, a horse licking and chewing when they hear their dinner being made is probably keen to eat, however a horse in a stressful situation such as a friend being turned out without them, may lick and chew as a way of coping with the stress
• High pulse and respiration rate, this may be for a moment when a horse is startled or longer when the horse is in a stressful situation. However, if you see this and there is no obvious explanation, a vet should be called
• Apathy⁴ - a lack of enjoyment or wanting to participate
• Increase in droppings (usually of loose consistency)
• Facial tension such as around the muzzle.
  
  

Causes of stress

Below is a list of some potential stressors, it’s important to know that each will have an influence on both physical and mental health of the horse and that as prey animals they’re incredibly stoic and therefore may outwardly show no signs of stress at all⁵:

• Travelling - the source of stress could be poor driving, uncomfortable temperature, confinement, unsuitable flooring or being separated from other horses
• Exercise - if a horse is showing very mild signs of discomfort or signs you may not relate to being ridden, like pulling faces when you do the girth up, horses can become anxious at the thought of movement that will cause pain. Harsh training methods cause anxiety and tension, some horses can even become fearful of their rider or handler causing aversive behaviours
• Competing - the horse when competing uses all their strength and energy to complete the task asked of them so a lack of fitness will put a lot of stress on the body. Mentally, some horses are very calm, and some are keen and excitable. This raises the stress hormones but if this happens frequently it can become a source of stress for the horse
• Isolation from other horses or from a friend for a prolonged period of time, for example a horse on box rest
• Illness or injury has two potential causes of stress. The physical impact of the horse being ill or having an injury and the presence of a vet or being at a veterinary hospital. When a horse is in a stressful situation, the effects can build on top of one another; known as the stacking effect. For example, the horse has a wound on their leg and is in pain, the owner is anxious and worried about their horse, and an unfamiliar person/vet is trying to clean the wound. Each of these individually may be manageable for the horse but when you add one on top of another the horse experiences overload and reacts⁶. An example of stacking and how to manage this can be found here
• Extremes of temperature – the horses’ digestive system creates heat in the hindgut due to the break down and fermentation of fibre and this helps to maintain their body temperature. The metabolism, which is the change of food into energy, will stay constant between 5°C and 20° If the temperature drops or rises above these parameters horses need to use their metabolism more to either warm themselves or cool themselves by sweating
• Poor welfare - this can relate to their training, health, or care. For example, inappropriate use of training aids will have a physical impact on the horse and have the potential if repeated to cause a stress response. Health issues such as poor hoof care or being overweight will place strain on the systems of the horse⁷
• Poor handling methods - every interaction with a horse is a chance for them to have a positive experience. If a horse is repetitively handled in a way that scares them, for example, the handler is being repeatedly forceful, they will anticipate this experience happening again when in similar scenarios
• Clipping - most horses learn that being clipped isn’t going to harm them but for some horses the sound and sensation of clipping can be very scary causing the horse to be acutely stressed

Boredom – when horses can’t perform natural behaviour, they can easily become frustrated. They need to be kept mentally stimulated especially when they aren’t able to be frequently exercised, are stabled or turned out in a restrictive paddock. Enrichment can help prevent this by creating a greater variety and choice and positively contribute towards a horse’s physical and mental needs.

For the horse’s welfare it’s important to create an enriched environment to help satisfy their innate behavioural needs with ample foraging opportunities, turnout and social interaction and companionship.

Be mindful that an active coper is likely to show clear behavioural signs of both acute and chronic stress, whereas a reactive coper may appear calm and relaxed when they’re actually withdrawn, unresponsive and emotionally blunt. These types of horses are equally or even suggested to be more stressed than an active coper who is physically trying to control the situation. By trying to reduce the effect of acute stressors on the horse it could help to prevent the development of chronic stress and stereotypical behaviour, therefore helping to improve welfare.

For further information visit the Understand Horses website.

To learn more and search for an equine behaviourist visit the Animal Behaviour and Training Council.

Supported by:

Justine Harrison CEBC ABTC-AAB. IAABC certified Equine Behaviour Consultant, ABTC Accredited Animal Behaviourist, FearFree® Certified Professional.

Rosa Verwijs MSc FHEA CEBC ABTC-AAB. Senior Lecturer at ARU Writtle, IAABC Certified Equine Behaviour Consultant, ABTC Accredited Animal Behaviourist.

Get in touch – we’re here to help 

The BHS Horse Care and Welfare Team are available to offer you advice and support with any questions or concerns you may have. 

Don’t hesitate to call us on 02476 840517* or email welfare@bhs.org.uk – You can also get in touch with us via our social media channels. 

Opening times are 8:35am-5pm from Monday – Thursday and 8:35am-3pm on Friday. 

*Calls may be recorded for monitoring purposes.