Understanding and treating depression in horses

Introduction

While depression is widely recognised in humans, it is a condition which is often overlooked in animals. The symptoms and clinical signs of depression vary from species to species but recent studies have shown that humans and horses share some characteristic warning signs which are important to recognise.  

Horses are prey animals with a well-developed fight-or-flight response and their behaviours are controlled by the nervous and endocrine system.  Like all animals, behaviour is influenced by many external factors that include genetic predisposition, environment, physiology, experience and learning. Foals are neurologically mature at birth and soon after birth can identify and react to dangerous stimuli, but like humans, the horse’s brain function does decrease with age resulting in increase in anxieties and fears. 

The brain and its neurotransmitters play an instrumental role in the temperament and behaviour of the horse; therefore, abnormal levels of various hormones can lead to a change. Normal survival instincts for the horse fall into two broad categories that includes ‘something to fear and must flee’ and ‘something not to fear and should be explored or ignored’. New research has also demonstrated that there is not a linear dominance hierarchy but rather the herd communicates with positive reinforcement and less from punishment.

In order to achieve the best results when training, it is important to consider these natural behavioural instincts. Maintaining a positive mental attitude in both training and management regimes for the horse will have considerable benefits to performance and reduce negative behaviours. 

What is depression? 

Depressive disorder (also known as depression) is a mental disorder that can occur in horses.  It involves a depressed mood or loss of pleasure or interest in activities for long periods of time.  Depression affects how the horse thinks and behaves and may lead to a variety of potential physical problems.  

While depression is widely recognised in humans, it is an illness which is often overlooked in animals.  The symptoms and clinical signs of depression vary from species to species but recent studies show that humans and horses share some characteristics. With racehorse welfare being a key topic at present, understanding and recognising small behaviour changes can allow for small management adaptations to be made thus enhancing the horses wellbeing. 

The research 

Recent research from France alongside the growing body of research, suggests that horses may develop something similar to depression in a response to physical or social discomfort.   

Researchers have observed horses that become withdrawn because of undergoing a cognitive shift.  It has been found that horses tune out to their surroundings due to physical or psychological stress.  Horses have the cognitive ability to be attentive; however, with the presence of chronic stressors there is a delay in a horse's response as they have “switched off” from their environment and demonstrated sensory inattention. 

Because we do not truly know how the horse is feeling, the hypothesis currently being considered is that the horse develops an “inward-oriented attention” when subjected to chronic disorders.  It must be stressed that this long delay in attentiveness does not indicate a state of calm for the horse but a withdrawal from its surroundings. 

Dr Georgia Mason from The Ontario Veterinary College has suggested that a horse may respond similarly to humans with depression.  It is thought that the horse’s withdrawal can be a result of a ‘learned helplessness’ in that responding to negative stimuli does not make any difference.  Thus depressed people are prone, for example, to judge ambiguous stimuli as being unlikely to be positive and to recall unpleasant memories more readily than pleasant ones.

In addition, a number of studies have assessed cortisol levels in those horses that are withdrawn. Cortisol acts to assist in relieving stress by increasing glucose metabolism to provide energy, which then enables the horse to escape from the stress. In the short-term, cortisol release is beneficial to the horse to help it cope with a stressor. This study found that abnormally low levels of cortisol (hence a physiological depression) were found in withdrawn horses that are in a pathological and depressed state.  These depressed horses also expressed anhedonia, which is the loss of pleasure to feed on an appetent substance.  

Further studies and research are needed to better understand the pathology of depression in horses.  It has been suggested that the life conditions, such as food, space, social conditions and health problems should be questioned and observed in order to identify potential acute or chronic stressors that may lead to depression. 

However, there are reviews that question the current animal models of depression and suggest that ethological models of mood disorders based on animals living under natural conditions need to be improved and developed. 

Symptoms of a depressed horse 

It is important to become acquainted with potential signs of depression in the horse so that you can identify them quickly.  By identifying the symptoms of depression, one can rapidly begin the task of identifying the underlying cause such as an injury, illness, social or environmental stressor.  With these tools, one can reduce the risk of the short-term and long-term negative effects that could ultimately hinder the horse’s health and performance.  

Lack of response

In humans and animals, being attentive is one aspect of subject cognitive abilities and capacities. The delay in responding to stimulation shows that withdrawn horses ‘switch off’ from their environment and show sensory inattention. Such lapses of attention are likely to be associated with the chronic effect of stressors, which might be expected to induce a lowered state of arousal.

A French study from the Universite de Rennes, demonstrated that depressed horses that were subjected to a series of five new, unique and unusual sounds were significantly less likely to pay attention to the noises compared to normal horses.  Their findings demonstrated that the withdrawn horses had undergone a cognitive shift that they were so physically or psychologically stressed that they developed sensory inattention. 

Heightened anxiety 

While the depressed horse will often be disinterested in everyday activities, people and companions, they are likely to demonstrate heightened emotions towards challenging situations and new stimuli as they try to express their discomfort. Stimuli that are usually unremarkable to the horse may become uncomfortable for the horse and make them “spooky”, anxious or fearful when they weren’t before. 

Lack of interest in food 

A change in mental well-being in your horse can lead to a loss of appetite.  The potential complications are the loss of weight, condition, muscle development, fitness, energy levels as well as the increased susceptibility to infection and prone to other health conditions such as colic or gastric ulcers. 

There are other illnesses and ailments that can lead to inappetence; hence, it is worth seeking veterinary advice in order to rule out any other physical problems.  

Anhedonia

Dr Carole Fureix looked at anhedonia which is the loss of feeling pleasure from experiences that used to be pleasurable.  This symptom is prominent in the depression of humans. Her study demonstrated that horses who are at times withdrawn are more anhedonic than those that are not withdrawn.  She concluded that this is a key symptom of clinical depression and suggests that withdrawn horses are indeed in a depression-like state.  

The horse may show unwillingness to work or no longer take pleasure in work they used to enjoy. This is especially important when considering rider and horse safety too as a withdrawn horse may not react appropriately to potentially dangerous situations.

Posture

Standing facing the stall wall for periods of time while demonstrating a withdrawn posture showing a fixed gaze, neck stretched out level with back, eyes open but lack of eye and ear movement. This differs from a content horse that is resting and displaying relaxed muscles, laterally rotated ears, the drooping of its eyelids and lips and holding its neck such that it slopes lower and rounder.  

Physical changes are perhaps somewhat easier to spot with a withdrawn posture being one of the typical signs of depression.  A healthy and content horse will stand with their head up and ears moving inquisitively.

Causes of depression 

The domesticated horse is often managed in such a way that they cannot express their natural behavioural instincts, thus exposing them to stressors which can lead to depression.

Lack of adequate positive social interaction with other horses 

A study from Michael Steger and Todd Kashdan explained that dysfunctional social behaviour has been implicated in the experience of depression. 

In addition, Timothy Elmer and Christoph Stadtfeld described individuals with depressive symptoms are more likely to be isolated from their social group(s), which can further increase their symptoms.  

Similarly, lack of social interaction without conscious choice for extended periods of time can lead to depression in humans.

Lack of adequate exercise and/or turnout 

It is well documented in human medicine that exercise and physical activity can improve many health conditions. Research on depression, anxiety and exercise demonstrates that the mental health and physical benefits can help improve mood and lessen anxiety.  The link between depression, anxiety and exercise are not entirely clear.  It has also been shown that exercise and physical activity may help keep depression and anxiety from coming back. 

Companionship reduces stress in the horse, hence naturally  living in a herd.  Horses are able to form companionships with their own species and other animals including humans.  In fact, horses kept in isolation, such as in closed stables, can become anxious, flighty and difficult to manage. 

Exercise releases endorphins which are feel-good chemicals in the body and also allows for more social interaction.  A recent University of London study demonstrated that people with low aerobic and muscular fitness are nearly twice as likely to experience depression.  

Illness or injury that causes pain or discomfort 

In humans studies have found that anywhere between 30-85% of patients suffering from chronic pain are also clinically depressed. Other illnesses in humans such as nutritional deficiencies, cushing’s disease, lyme disease, chronic pain, and insulin resistance can cause depression.

Stress during training, competing or in the daily routine 

If there is chronic stress in which the horse’s physiological stress response is taxed beyond what it is designed to do it can begin to impair the horse possibly leading to depression 

Inflammation and depression 

There is evidence that there is a link between inflammation and depression. Inflammations that lead to serious depression in humans can be caused by infections such as those caused by bacteria, viruses or even parasites.  There is increasing evidence that inflammation can cause depression because of the increase of cytokines setting the horse’s brain into “sick mode”.   

Treating depression

Simple changes in management can help treat the underlying cause of depression and can substantially improve the horses well-being thus having a positive impact on performance.

Light therapy

Modern management methods mean that horses can spend a large amount of time stabled which impacts the horse’s circadian rhythm (body clock). 

A study was performed at Nottingham Trent University where trial horses were put under an hour of high intensity broad spectrum light every day for six weeks. Their behaviours regarding feeding, sleep patterns and attitude to being handled and ridden were compared to a group of horses that had not received the therapy. The untreated horses were noted to be sleeping longer, lazier at ridden exercise and grumpier.

Light therapies have many positive benefits that can reduce signs of depression and improve overall well being; better daytime alertness and improved rest and sleep pattern, extending summer coat and body condition and encouraging the body to convert feed to muscle mass, noticeably fewer stable vices such as box walking, cribbing, weaving and reduced bacterial pathogens and fungal load leading to improved respiratory function.

Management

Racing is already making moves to ensure the best welfare conditions for horses, with German trainers now having to comply with regulations regarding size of stable, the amount of light in the stable, the provision of windows enabling horses to socialise and turn out capacity for a minimum two hours per day.

Increasing turnout time is reported to have positive effects on their horses' mental wellbeing, reduces stiffness and lowers the rate of stable vices. It also allows the horse to make social connections whilst allowing them to show their natural instinctual behaviours. 

With horses in varying routines in large yards, this can sometimes become stressful to some individuals. By providing company of other horses when stabled, this can help with social interactions and reduce stress. Stable enrichment and adlib forage can also replicate positive behaviours in the stable. 

It is known that exercise releases ‘feel good’ endorphins, thus, keeping the horse in a regular training regime complimented with the correct nutrition will be beneficial. 

Veterinary advice

It is important to seek veterinary advice should the horse be exhibiting signs of depression to help identify the underlying cause. Diagnostics such as blood tests can ensure there is no infection present and work-ups will highlight any pain or discomfort.

Conclusion 

While depression is widely recognised in humans, it is an illness which is often overlooked in animals. Depression in horses can be significant and harmful regardless of the underlying cause and can be temporary or long term. It is vital to ascertain the underlying cause of depression in a horse in order to treat and remedy the illness. 

How trainers promote best welfare practice across Europe

"Mens sana in corpore sano" - is a well known Italian phrase which translates to “a healthy mind in a healthy body" is a fundamental principle for every athlete, and racehorses are true athletes of the sporting arena. Just like their human counterparts, the performance of a racehorse depends not only on their physical condition but also on their mental well-being. The issue of animal welfare in horse racing is not just a matter of ethics or sensitivity, but the foundation upon which the integrity of the entire sport rests.

The concept of equine welfare extends beyond the mere absence of disease or injury. It concerns the quality of life of the horses, including their daily treatment, living conditions, access to open spaces, appropriate nutrition, and the ability to express natural behaviours. Moreover, it includes ethical training practices that respect the animal's physical limits, avoiding bad training and stress.

In the context of racing, equine welfare is scrutinised not only by industry insiders but also by the public and animal rights activists. Our focus in this section of the article is on the evolution of welfare practices in the leading countries of European horse racing: Great Britain, France, Ireland and Germany. 

The goal is to understand not only the current state in terms of equine welfare but also to identify trends and areas for improvement, reflecting on the importance of an ethical and responsible approach to these extraordinary athletes.

GREAT BRITAIN - HORSE WELFARE BOARD (BHA)

The Horse Welfare Board, inclusive of representatives from the BHA, racecourses, and horsemen, unveiled a five-year welfare plan in 2020 to elevate horse welfare in British racing. This plan is dedicated to ensuring a "life well-lived" for racehorses, with a focus on traceability, safety, well-being, alongside initiating the industry's most extensive data project. It targets enhancing health care practices, ensuring lifelong responsibility, reducing injuries, and fostering public trust through transparency and ethical practices. Additionally, the strategy commits to developing a Code of Ethics and advancing veterinary care and injury prevention. Importantly, the implementation team is collaborating with the industry on 26 strategic projects, backed by funding from the Horserace Betting Levy Board (HBLB) since 2019 and a recent £3 million grant from the Racing Foundation, to realise these goals.

In the array of projects undertaken by the Welfare Board to bolster safety and uphold equine welfare standards, there are a few that stand out as being exceptionally cutting-edge, such as the: Thoroughbred Census, Equine Vision Project, Data Partnership.

Thoroughbred Census

The project aims to enhance the traceability of retired thoroughbreds, enabling better support for owners and the adaptation of welfare initiatives by British Racing and Retraining of Racehorses (RoR). It involves a six-month census, in partnership with RoR, collecting detailed information on retired racehorses to improve aftercare and respond quickly to equine disease outbreaks.

Equine Vision Project:

“We try to look through the horses’ eyes” - Mike Etherington-Simth

In 2017, the BHA and Racing Foundation funded research into equine vision to enhance hurdle and fence safety. Horses, seeing fewer colours than humans, struggle to distinguish between hues like red, orange, and green. The study assessed the visibility of orange markers on racecourse obstacles against alternative colours, considering how weather conditions affect perception.

Data Partnership

This project seeks to enhance racehorse safety and welfare by analysing risks and factors leading to injuries and fatalities on racecourses and during training in Great Britain. It utilises extensive data on races and training practices, employing advanced statistical models to identify risk factors. The initiative, in collaboration with industry stakeholders, aims to provide evidence that informs decisions and measures to minimise risks, directly contributing to the betterment of racehorse welfare.

FRANCE - FRANCE GALOP

France Galop is deeply committed to promoting high standards of horse welfare, aligning with the 8 principles outlined in the "Charte Pour le Bien-Être Équin". This commitment is evidenced through various initiatives, including the inspection of facilities by France Galop veterinarians for new trainers who have acquired their flat racing licences. These checks, part of the certification process, aim to ensure that the infrastructure is suitable for housing horses. In 2021, a total of 410 training centres were inspected by the veterinarians of the Fédération Nationale des Courses Hippiques. The vets also check for prescribed medications and substances on site, adhering to a “zero tolerance” policy.

IRELAND - THOROUGHBRED WELFARE COUNCIL (HRI)

“They have horse welfare right at the forefront of everything they do and I would say they are doing a very good job”  Joseph O’Brien

In 2021, the Irish Thoroughbred Welfare Council was assembled to act as an advisor to the Board of HRI and assist in devising policies on welfare matters. HRI gathered 60 industry participants in a co-design project to create a manual called “Our Industry, Our Standards,” aiming to establish a system where welfare standards are verified and measured. These standards include good feeding, good housing, good health and good well-being. Additionally, the Thoroughbred Council is collaborating with IHRB, Weatherby’s, and the Department of Agriculture to create a traceability system that will ensure every horse always has a known link to the responsible person. 

Best-Turned-Out League

To promote and encourage the implementation of good animal care and welfare practices, HRI has introduced the “Best-Turned-Out League,” which aggregates these prizes from across the country into a league table with substantial prizes from six different categories, highlighting the impressive standards maintained across the industry. The primary caregivers, who are often lifelong careerists, are our industry employees. 

GERMANY - DEUTSCHER GALOPP

Deutscher Galopp, has notably advanced equine welfare within racing in recent years. Not only has it raised the quality standards of horse care within stables, monitored through surprise veterinary checks, but it has also started to develop an intriguing project that monitors the physical development of racehorses.

Physical Maturity Check for 2-Year-Olds Before Training

Deutscher Galopp has implemented regulations requiring that every horse must pass specific veterinary checks. These checks are designed to ascertain sufficient physical maturity before a horse enters into training. A second assessment is conducted shortly before the horse can start in a race, to confirm its physical fitness for competition.

For this section of the article, we canvassed opinion from a selection of industry professionals for their perspectives on issues related to equine welfare. 

Q: What role does horse welfare play in your training practices and what specific measures do you implement to safeguard the physical and mental well-being of the horses?

"The welfare of my horses is central to me; it is the most crucial element for the success of my business” asserts Seamus Mullins, a sentiment unanimously echoed by all interviewees who have long regarded animal welfare as a key factor from the outset of their careers in the racing sector. When delving into the practicalities of ensuring each horse's welfare is honoured, Joseph O'Brien highlights the significance of tailoring care to individual needs. "It's crucial not to generalise, as what satisfies one horse might not suit another," he explains. This underlines the necessity of adapting training and rest schedules to cater to their unique preferences and inclinations, guaranteeing their well-being and happiness.

Luca Cumani, who since retiring from training has remained active within the industry, including a term as a director of the BHA and as a pre-eminent breeder emphasises the importance of observation to understand each horse's psychological capabilities and preferences.

Seamus Mullins discusses the regular turnout of horses in individual paddocks while ensuring they are always in association with other horses. The stables are varied to suit different preferences, emphasising the need for regular updates to training methods and facilities to keep the horses in the best condition possible.

Peter Schiergen, Nastasja Volz-Degel, and Alessandro Botti all share this commitment to horse welfare, implementing daily routines, wellness programs, and training methods tailored to the individual needs and physical aptitudes of each horse. They focus on creating a comfortable environment for the horses, using modern facilities such as solariums, water treadmills, and magnetic blankets for massage, highlighting a collective effort to maintain high welfare standards in the racing industry.

Q: How do you educate your staff or team members about the importance of animal welfare?

"I always said to the riders: the relationship with the horse you ride should be viewed as a partnership, akin to that with your wife or daughter, and should be treated with the same respect and care" Cumani explains with a touch of warmth. The stable staff plays a pivotal role in the implementation of animal welfare, which is why, as the interviewees emphasise, it's crucial to focus on their education and enhance their knowledge to the fullest. "We want our staff to become better horsemen," states Schiergen. 

Beyond the training provided internally within their stables, some trainers, like Alessandro Botti, with the support of AFASEC (the Association de Formation et d'Action Sociale des Ecuries de Courses - which roughly translates to Association for Training and Social Action of Racing Stables), have decided to offer courses in equine ethology led by experts brought in from outside. This initiative not only sparked significant interest among their staff but also led to an improved approach to working with horses.

Q: The risk of injuries is an inherent component in all sports, including horse racing. What is your opinion on this statement, and what specific actions do you take to minimise the risks?

"Risks are everywhere, especially in competitive activities, whether involving humans or animals, there's a significant element of risk," are the words of Cumani, which also resonated with others we interviewed. 

The consensus is that, unfortunately, injuries are inevitable despite efforts to minimise them through practices and care that respect the physical state of the horse. "We try to minimise the risks by checking every horse before a race and during training, we never push the limit of a horse if he isn't ready enough” underlines Schiergen, “we have to get the message across that we are doing all our best to minimise the risks at all accounts”, adds Mullins.

Q: What role do you believe transparency plays in communicating to the public the importance placed on the welfare of racing horses in daily activities, and how do you ensure that this information is effectively shared with the general public?

“There are fewer and fewer people growing up with animals and in farming, and as a result, this is why we need to show through platforms what we do because things we take for granted, someone who has never been to a racing yard may not realise what happens,” says O'Brien. He adds, “It is important to give people access to behind the scenes, and this is why we try to be quite active on social media and encourage people to come to our yard, so that they realise the amount of passion that staff puts in their daily work.”

Public involvement, to make them part of the daily practices of stable life, is crucial, as our interviewees from various parts of Europe maintain. Thanks to numerous activities promoted by the racing authorities of the interviewees' respective countries, Open Day events allow the public to participate in stable life. 

Many trainers, like Seamus Mullins, have noticed a significant increase in participation in recent years, “Ten years ago, participation in the UK was about 100, while in 2023 it was more than 500. Moreover, people who participate often express surprise at how well race horses are treated.” However, all the trainers, like Alessandro Botti affirms, it is necessary to increase content on social media, to give the possibility to everyone, every day and in every part of the world, to participate in the daily life of horses in various stables.

Q: What do you think will be the future trends in horse welfare in Racing in the coming years?

All the trainers interviewed are convinced that the standards of equine welfare in racing are already very high. However, they unanimously believe that social pressure from activists will continue to grow, making it necessary to increase transparency and public engagement. Joseph O'Brien emphasised the importance of education: "What I think really has to be put to the forefront is educating people who are not involved in racing; this will be the biggest challenge." 

Given the insights on how Racing Authorities operate in terms of Horse Welfare and the daily interest and commitment of trainers, the trend seems to be very positive and reflects very high standards. It is essential, however, that countries collaborate with each other to inspire one another, further improving equine welfare practices, as Helena Flynn, the British Horse Welfare Board Programme Director emphasises "We love these animals and do our best to ensure they are protected, and thus it would be beneficial if the results of various state projects could contribute to inspiring everyone internationally." Therefore, the issue of equine welfare in racing is a complex mosaic of care, respect, and dedication towards the thoroughbred racehorse. Recognising and acting for their welfare is not just a moral duty but the foundation on which to build a fair, sustainable, and most importantly, animal-respectful racing industry.