“The horse’s perception of the surrounding world, an his responses and reactions to changes in environment are determined by the efficiency of his systems of information and control. These systems are the nervous system, the sensory systems of sight, smell, hearing, taste and touch and the endocrine system – a system of ductless hormone-producing glands which control the horse’s pattern of behaviour.” Essential Equine Studies – Anatomy and Physiology
These three systems are often talked about together because they all deal with the transmission of information, messages that are caused by various stimuli and result in a specific response.
“The Equine Nervous System is the most complex system in the body. It controls all of the other equine body systems – consisting of the brain, spinal cord, and sensory and motor nerves. It is also the system that feels pain or other sensations.”
Notes from folder
The nervous system controls and coordinates the equine body’s activities and responses to stimuli through nerve cells (neurons) and the messages they send (impulses). Irrespective of where they are in the body, they all fulfil the same function of transmit- ting information in the form of small electrical signals.
There are three main types of nerve cell or neuron, sensory, motor and intermediate.
The sensory neurons will pass information generated by receptor cells, on to the CNS. Motor neurons carry impulses from the CNS out to muscles and glands throughout the body. They can be extremely long, yet the information travels from the nerve cell out to the muscle or gland in milliseconds. Intermediate neurons connect sensory and motor neurons.
Generally, nerve cells have the same basic set up, a cell body with a nucleus, thin, branch-like growths called dendrites which receive information from other nerve cells, a long, single nerve fibre called an axon which is a transmitter and further branch-like growths at the end of the axon called terminal dendrites.
Neurones can talk to each other, they communicate at the junctions between one neurone’s terminal dendrite’s and another’s cell boy. This is called a synapse.
The Nervous System comprises of three main sub systems, the Central Nervous System (CNS), the Peripheral Nervous System (PNS) and the Autonomic Nervous System (ANS).
The CNS is….Literally the nerve centre of control in the horse – the horse’s “computer”. Made up of the brain and spinal cord, protected by the skull and spinal column.
The PNS is….The system that controls the sensory and motor nerves.
Connected to the CNS and runs throughout the body – the sensory nerves bring messages from sensory organs in to the CNS, the motor nerves take messages from the CNS out body parts, such as contractions of skeletal muscle.
The ANS is….Part of the PNS. Controls involuntary systems.
Made up of two additional sub systems, Sympathetic Nervous System and the Parasympathetic Nervous System.
The Sympathetic Nervous System governs the fight or flight mode in the horse. It will kick in in order to alert the horse to imminent danger, the presence of threats, predators etc. Once activated, the ANS shuts down un-necessary systems such as digestion and reproduction and concentrates on dilating the pupils, raising the horse’s blood pressure, heart rate and supply of oxygen-rich blood to the heart and lungs, ready for him to run.
The Parasympathetic Nervous System in contrast, governs the horse’s down time, the times when blood flow is increased and endorphins are released and he is safe to sleep, relax, digest, process, heal and deal with physical or emotional issues.
As mentioned above, the CNS is comprised of the brain and the spinal cord.
The brain is probably still the least known and understood organ in the human body, let alone the equine one. It is an incredibly complex organ that is organised around centres, or specific groups of nerve cells that are charged with performing specific tasks. It is made up of millions of brain cells (neurons) that the horse is born with and does not ever replace, or reproduce. A neuron is made up of a cell body, an axon and one or more dendrites. These neurons consume 20% of the oxygen in the blood. This is essential in order to keep brain cells alive. Without oxygen, brain cells die and there is no chance for regeneration.
The brain is housed within the protective cranial cavity in the skull. The brain tissue has a buffer of three membranes between it and the bones of the skull called the meninges. It is split into three main sections, the cerebral hemisphere (forebrain), the mesencephalon (mid-brain) and the cerebellum and medulla oblongata (hind brain).
The cerebral hemisphere is thought to deal with all things Sensory, smell in particular, emotions, learning, endocrine functions and expressions of sexual behaviour and is divided into outer grey and inner white matter. The outer grey matter is believed to deal with memory and consciousness. By far the largest white matter structure in the mammalian/ equine brain, is that of the corpus callosum, a collection of nerve fibres that joins the left and right hemispheres within the forebrain and allows communication.
The mesencephalon is also involved in the processing of Sensory information such as sight, hearing and smell, has a part to play in voluntary movement and controls the hind brain sensors.
The cerebellum controls and co-ordinates motor activities such as posture and balance and the medulla oblongata controls breathing and is linked to the horses emotions and behavioural responses, including sleep and stress levels.
However, whilst they can be split into sections in terms of their functional application as we have seen, all sections are interlinked and affect each other in ways that research has not even scratched the surface of in terms of us understanding.
The spinal cord runs down through the vertebral canal from the brain to the tail of the horse. Its job is to link the PNS with the brain, carrying messages to and fro.
It too is made up of white and grey matter, however, it is the reverse of how it is in the brain. The white matter is found on the outside of the spinal cord and is comprised of nerve fibres. All of the nerves that link the horse’s brain with its body, its trunk and limbs, run through the white matter of the cord. The grey matter on the inside, is full of nerve cells, motor neurones that are responsible for innervating the skeletal muscles.
Also, as with the brain, the spinal cord is covered by the same highly protective membrane called the meninges and cerebrospinal fluid.
The PNS is made up of nerve bundles that radiate out from the CNS into the body and the limbs. It is made up of two systems, the somatic, or voluntary nervous system and the autonomic, or involuntary system.
In the voluntary system, receptor cells in the sensory organs, the eyes, ears, skin, nostrils etc. convey messages via sensory neurons to the brain. After processing, the brain sends information down through the spinal cord via motor neurons to the muscles in order to initiate movement or activity, basically, the contraction of muscle.
In the involuntary system, messages are carried by synapses in cell clusters called ganglia. They affect the smooth muscle in blood vessels and glands throughout the body.
As mentioned above, the PNS is divided into two, the sympathetic and parasympathetic systems.
The sympathetic system is the system that kicks in were you to find a bear sitting in your car when you came out of Waitrose, or when the horse you are riding sees a lion behind the traffic cone you have hacked past a million times. It is responsible for the fight or flight response, shutting down unnecessary systems, dilating pupils and bronchioles and diverting oxygen-rich blood to the lungs and heart, ready to run as fast as possible.
The parasympathetic system takes over when the horse is relaxed, usually when it is asleep, or dozing in a safe environment. It takes the opportunity when the horse’s stress levels are low, in the absence of adrenalin, to address issues in the body, to heal, speed up digestion and generally switch off.
As soon as we begin to look at the Sensory system, we see again how these three systems are interlinked.
“Horses have evolved with specialized receptor cells to provide them with information about changes in both their internal and external environment. Many receptor cells are grouped together to form sensory organs.”
Essential Equine Studies – Anatomy and Physiology
It is these sensory receptor cells that supply the central nervous system with the information the horse needs to perceive the world around them. Each and every receptor is a modified nerve ending. Their various types and shapes will influence what kind of stimulus they will respond to. They can occur singly, or in small groups in structures such as muscles, joints, tendons and ligaments, or they can cluster together in larger groups, creating specialised sense organs such as the ears, the eyes and the nose. The skin is also full of them, supplying the horse with a multitude of sensations.
Sight is talked about as the primary sense in terms of informing the horse that they are potential danger. We also, especially if we ride ourselves, know just how influential this sense is on the horse’s general behaviour as a whole. There are a few key facts that back up the claims made about the importance of sight in and amongst the other senses.
The eyes are positioned towards the sides of the head, allowing the horse the panoramic vision that they would have relied on to keep themselves safe in the wild.
The horse’s eyes are actually the largest of any land mammal.
A third of all sensory information received by the brain comes in from the eyes and is reflected by the fact that an abnormally large area of the brain responsible, the cerebrum, is dedicated to processing that visual information.
Vision occurs when the horse’s eyes focus rays of light from objects in their external surroundings, onto the surface at the back of the eye, the retina. The image is actually upside down. Light sensitive cells called photoreceptors take the image and change it into a collection of nerve impulses. The impulses are sent to the brain via the optic nerve in order to be decoded and understood.
There are two types of photoreceptors in the horse’s eye, rods and cones. They are both found on the surface of the retina, but there are more rods than cones and the cones are always situated around the outside of the retina.
Rod cells are very sensitive and can pick up varying intensities of light, making them really useful for seeing at night, or near darkness, but they will not give the horse any information regarding colour.
Cone cells require more light to be activated, so are much better in conditions of bright light. Their strength is in detailed vision and
colour differentiation. The extent to which horse’s can see different colours is still being debated and researched.
The horse’s eye has evolved in so many ways, obvious in so many of its attributes and functions, to ensure that it is primed with all the information a prey animal needs at all times. These can range from the way in which it scans its environment and how it focuses, to adaptations made for changing environmental conditions and protection of the eye itself.
The horse has a spot on its retina called the area centralis. This is an area of acute perception and it is exactly here that the image of whatever the horse was looking at if it was looking at it face on, would fall. So, for example, for a horse grazing, it would clearly see the grass that it was looking directly at. However, being the prey animal that the horse is, it is also equipped with a visual streak which is a second field of acute perception that allows the horse to clearly see and scan the horizon at the same time. The eye has seven muscles that can rotate the eye at will, two are used to keep the eye aligned with the horizon. Horses are thought to be naturally long sighted.
Armed with binocular vision in front that allows him to judge distance, the horse has a horizontal field of vision of 350 degrees and a range in the vertical plane of an amazing 180 degrees. This perhaps is its greatest protection against potential prey. With this field of vision, it is hardly surprising that the horse is often seen to react quickly, unexpectedly and often, in our view (literally), for no reason to things that we have no idea of. More interestingly, it also makes them very sensitive to and wary perhaps of body language and sudden movements, threatening or not.
As a prey animal, however domesticated it might be, horse’s need to be alert day and night. The horse’s eyes have evolved so that vision is maximised both in daylight and nighttime conditions. In daylight conditions, the iris and the pupil and the corpora nigra all work to drastically reduce the amount of light entering the eye. The pupil actually shrinks to a horizontal slit, mimicking the shape of the virtual streak mentioned above. In night conditions, the pupil expands to become a large circle, letting in as much light as possible. We already know that the rod cells in the horse’s eyes work to pick up images in poor light, but an additional element of the equine eye that makes it better equipped to see at night is a layer that sits behind the retina called the tapetum lucidum. If light has passed through the retina and has not been absorbed, i.e., not been “seen”, the tapetum lucidum will reflect it back again, giving the rods and cones every chance to “see” it.
Finally, unsurprisingly owing to the fact that the horse’s vision is such a critical sense when it comes to keeping it safe, the eye is well equipped when it comes to protecting itself. Set into the orbits, bony cavities that protect their position in the skull, the eye is also sat on a pad of fat that absorbs concussion and held in place by the seven muscles referred to above. The eyelid is an obvious element, the tough, fibrous sclera maintains the shape of the eye and protects the more delicate inner workings and liquid released from the lachrymal glands (tears), guard against scratching of the cornea and are anti-bacterial.
Horses have a very well developed sense of hearing, they can hear tones that are higher and softer than humans can perceive. As with their vision, the ability to hear things from a long way away, is essential to their ability to be alert and ready to flee from imminent danger. In addition to the ability to hear sounds from their surrounding environment, hearing allows the horse to communicate with other horses, friend or foe and their riders. Horses also use their ears to display their mood and sometimes, their intent, communicating with us should we choose to observe them.
With the ability to be able to hear such a range of sounds, comes the need to be able to filter it in order to determine what needs action and what can simply be ignored. This filtering is done in the brain and will be dependent on to some extent, the age, sex and breed of the horse and largely on its individual motivations, experience and what it has had exposure to.
The ears are highly mobile, each one being capable of rotating through 180 degrees and being laid flat back. As mentioned above, the ears can be moved in order to demonstrate their mood, shut out sound, or focus the ear on the direction that the sound is coming from. This flicking motion of the ear towards the sound is called the Pryer reflex.
The ear consists of three sections, the outer ear or pinna, the middle ear and the inner ear.
The outer ear or pinna is obviously what we can see. The 180 degree movement mentioned above comes by way of the conchal cartilage and sixteen muscles around each ear that can lift the ears, shut them down and move them forwards, backwards and sideways. The ears can position themselves in order to maximise the amount of vibrations in the air, sounds, that are channelled down into the ear to the eardrum. The inside of the pinna is covered in a layer of hair that protects it and the middle ear.
The vibrations in the air move into the middle ear and hit the eardrum, or tympanic membrane. At either side of the membrane, a eustachian tube runs down to the back of the throat with the intention being to try and maintain an even pressure each side of the eardrum. Three small bones called the ossicles, the hammer or malleus, the anvil or incus and the stirrup or stapes then transmit the vibrations to a membrane that separates the middle and inner ear, called the oval window.
The inner ear is filled with fluid and has two major functions, one is the final stage in the transmission of vibrations that will be processed and perceived as sound and the second is the provision of information to the brain regarding the horse’s head position and movement that it processes in order to retain its balance.
The first function is achieved by the cochlea that takes the vibrations received from the oval window, converts them into nerve impulses that are then fed into the brain through the auditory nerve.
The second function is achieved by three semi-circular canals and two sacs, the utricle and the saccule. The canals are set at right angles to each other in order to give a reading on how the horse moves its head. They are lined with hairs that are stimulated by the calcium carbonate crystals they are filled with, triggering nerve impulses to the brain. In a similar vein, the interconnected utricle and the saccule, are also filled with fluid and calcium carbonate crystals that move with gravity and also send nerve impulses to the brain.
The horse’s head has evolved over millennia to ensure that it is fit for purpose. The length of the head and in some breeds, also the width of the head, allows space for the molar teeth that the horse needs to grind down its food. In order to ensure that the head does not become too heavy, the skull also comprises of nasal and sinus cavities that provide the horse with increased surface areas for detecting odours.
Horses use all of their senses to protect them in the wild. When a horse is investigating something new, he will approach it, looking at it with his eyes, with his ears directed towards it, extending his head and neck to sniff it. The equine sense of smell is used to find water, select and check food and detect predators. It is also used in social behaviour. Stallions will use their sense of smell to track down mares in season, horses in general will use their nostrils and sense of smell as a means of communicating and it is through smelling and the exchange of breaths that mares and foals will recognise each other. In order facilitate their scenting abilities, horses have the vomeronasal organ that helps detect pheromones and chemical signals in the air. The horse will use the flehmen response to expose the vomeronasal organ and draw scent molecules back towards it.
The entrance to the nose, or the nasal chamber are the nostrils. The nostrils are held open by rings of cartilage, but can dilate to become wider and increase the amount of air taken in as the horse breathes in. Just behind the nostrils as the false nostrils, these are a continuation of the skin, but are lined with fine hairs that clean and warm the air that is being breathed in. From here, the air is moved upwards into the turbinate bones that lie at the back of the nasal chamber. They also, are lined with a membrane full of microscopic cilla that secretes a yellow-brown mucous tissue. This mucous tissue contains the olfactory cells that are responsible for smell. It is thought that the filtered, warmed air contains chemical vapour molecules that stimulate the cilla as the air passes over them. This then sets up a chain of events. The cilla pass the message received in the molecules on to the olfactory cells in the mucous membrane, from where it is sent to the cell bodies beneath them in the epithelium. The nervous impulses are carried by the olfactory nerves to the olfactory bulbs in the brain.
The sense of taste is very closely linked to that of smell. Horses will be very suspicious of strange smelling foods, especially those that taste and smell bitter or sour. This is essential to their ability to survive.
At the entrance to the mouth are the lips. Covered with fine hairs and very strong and mobile, they work with the nose to sort through what is edible before using the incisor teeth to bite of what is required.
Within the mouth, taste buds, made up of chemoreceptors and additional cells are found on the tongue within hundreds of papillae, palate and in the throat. The food is mixed with saliva produced by the parotid, sublingual and submandibular glands and is
dissolved into its constitute chemicals. The chemicals stimulate the taste receptor cells in the taste buds and papillae which subse- quently send impulses along the nerve fibres to the brain where they are decoded. The messages will differ depending on where exactly the taste bud is located in the mouth.
The horse’s skin is packed full of sensory receptors – mechanoreceptors that deal with touch and pressure and thermoreceptors that deal with heat and cold. The sensitivity of the skin varies according to age, sex, breed, individuality and location on the body. The location is important because this will dictate just how many sensory receptors are present in that area and what type they are. For example, some receptors are pretty basic nerve endings, whilst others that look like tiny bulbs or discs are a bit more sophisticated and are stimulated by light or sustained touch. The lips, nose and eyes are good examples of parts of the body that are dominated by these receptors, stimulated in most part by stiff, long hairs and whiskers surrounded by nerve endings that warn and protect the horse from close contact.
When the receptors are stimulated, nerve impulses carry the message up the spinal cord to the thalamus in the centre of the brain. From here, having been grouped into similar messages, they are sent through to the sensory cortex where they are analysed in more detail.
If the messages are regarding heat and cold, they will be dealt with by the hypothalamus, the nerve centre that controls body temperature in response to any incoming messages.
We have all heard, or read that a horse is so sensitive that it can detect a fly landing on its skin, so we should be more aware of how we handle them and use our aids etc. Over stimulation of the receptors described above results in pain and discomfort, resulting in the horse taking its own steps to avoid repetition of it, or simply desensitising itself to it if possible.
It is a common belief that horses prefer to be stroked than patted by humans. It is true that when we emulate the ways in which horses use touch to communicate with each other in the herd, to bond or reward, we tend to have happier, calmer horses.
The skin, the tissue covering the entire body is the horse’s largest organ.
The skin has three layers.
The outer most layer is the epidermis. It is made up of lots of layers of cells that are constantly moving up to the surface to provide the skin with its tough, outer coating, only to be shed and replaced by the next cells moving up. It is essential that this process continues and is not hindered in anyway as the skin must be free of the dead scurf. The pores in the epidermis must be clear in order for sweat and oil from the glands below in the dermis to escape and the maximum area of skin should be available for synthesis of vitamin D from sunlight.
The epidermis is covered in hair. The hair helps to control the horse’s body temperature and in the case of whiskers as we saw above, can act as a warning light. When the skin senses cold, the hairs will stand on end in order to trap a layer of warm air against the skin. The hair itself will also adapt, growing longer and thicker in the winter for example.
Beneath the epidermis is the dermis.
Known as the inner layer of the skin, the dermis provides the skin with protein fibres that should keep it healthy, elastic and supple.
It is also contains sebaceous glands that secrete sebum, an oily substance, into the hair follicles. This substance acts as both a lubricant and a weather proofing device as it prevents drying out and makes the skin waterproof. In the winter, more sebum will be produced and secreted in order to make the coat greasier, offering better protection. The sweat glands mentioned above, little coiled tubes, take sweat in order to cool the skin and some waste products, up through the epidermis to be excreted.
Finally, just below the dermis is the subdermal layer. Sitting between skin and muscle, this is a layer of connective tissue that can
also store subcutaneous fat.
Whilst we will see some obvious differences, we will see that the Endocrine system is intrinsically linked with the Nervous system in a number of different ways.
The Endocrine system, also known as the hormonal system, is made up of a great many, varied endocrine glands that secrete a great many, varied hormones. Some glands in the system will release hormones as a result of a change in their environment, such as drop in pressure of the fluid it is surrounded by, or the perceived lack of a substance or nutrient. Others will respond to signals from the Nervous system and yet others will release hormones in direct response to hormones already circulating in the system. Unlike other glands in the body, endocrine glands release their hormones straight into the bloodstream, where they circulate around the body. These hormones are “chemical messenger(s)” which are carried along by the Circulatory system, looking for the “target organs” that contain the receptors they need to attach to in order to get the response that they need. Unlike the nervous system where nerve impulses are delivered to very specific locations, hormones can affect several different target organs in multiple locations in the body. Examples of this would be GH, the growth hormone that affects all tissues, Insulin that affects most tissues, specifically muscles and the liver and PTH that affects bone, kidneys and the intestine.
Ultimately, at its most basic, something happens in the body, an endocrine gland “senses” it, releases a hormone in response that is destined for a, or some target organs, the hormone is received by the organ(s) and the desired reaction occurs.
As we know, the same process occurs within the Nervous system, but because nerve impulses travel much quicker than blood-borne ones, the Endocrine systems responses are much slower. Having said that, unlike nerve impulses like the twitching of a muscle, where the reaction is immediate and over with, the reaction caused by a hormone such as stimulating growth, or the reabsorption of water in the kidneys, can last for days.
As described above, hormones are produced by endocrine glands such as the pituitary, thyroid, parathyroid and adrenal glands. However, they can also be produced by organs that also have an endocrine function, such as the pancreas and the sex glands, the ovaries and the testes. There is also a third group of organs whose primary functions would seem far removed from the Endocrine system that are also capable of producing hormones, those include the heart, liver and kidneys.
The pituitary gland is situated at the base of the brain. It is controlled by the hypothalamus to which it is attached by nerve fibres and small blood vessels. This set up is a great example of the Nervous and Endocrine systems being intertwined. The hypothalamus can control the pituitary gland either by releasing hormones of its own, or by sending nerve signals. It is known as the “master gland” owing to the fact that most of its hormone functions control and direct the rest of the Endocrine system. It has two lobes, the anterior and the posterior, the anterior being the most important one, again, in terms of how much of the hormonal system it influences.
The thyroid gland also has two lobes and is situated each side of the larynx. Its job is to produce thyroxine that is needed by the body for regulating the metabolic rate, growth and development, the production of energy in cells, controlling blood cholesterol levels and the take up of sugars in the intestines. It does this by extracting materials such as iodine from the bloodstream and feeding it to the two types of hormone-producing cells it has, follicular and parafollicular.
These cells contain thyroglobulin, which is thyroxine combined with a protein. The pituitary gland releases TSH that is transferred to the thyroid gland where it splits the hormone from the protein and the thyroxine is released.
These cells are found in and amongst the follicular cells. Their job is to secrete calcitonin. This lowers blood calcium by preventing the decalcification, or break down of bones. Unlike the follicular cells that are influenced by the pituitary gland, these cells are controlled by the amount of calcium circulating in the system.
Despite the fact that these four tiny glands are attached to the rear surface of the thyroid gland, they actually have virtually nothing to do with it. What they do, is to produce the parathyroid hormone that is needed, in conjunction with the calcitonin secreted by the thyroid, to control the levels of calcium and phosphate in the blood.
As was mentioned when looking at the Urinary system, the adrenal glands are found one each side of the horse’s spine, very close to the kidneys. Each gland is made up of two layers, the outer layer which is known as the adrenal cortex and the inner layer, or centre of the gland which is known as the medulla. Each layer had its own part to play in the Endocrine system.
The adrenal cortex produces steroid hormones known as corticosteroids. This range of hormones are involved in dealing with issues that range from reactions to stress, the metabolism of carbohydrates and subsequent raising of blood sugar levels and the function- ing of the sexual organs in the male horse.
The medulla, controlled completely by the sympathetic nervous system, produces adrenaline. The fear “perceived” in the frontal lobe of the brain is communicated by nervous impulses to the hypothalamus and directly onto the adrenal medulla. The rapid release of adrenaline raises the heart rate, dilates the pupils, pumps blood to the heart, lungs and muscles, shuts down non-emergency systems like reproduction and digestion and massively increases the metabolic rate.
It is a hormone which is virtually identical to noradrenalin which is produced at the endings of the sympathetic nerves. Both hormones help prepare the horse for fight or flight and are another good example of the two systems working together.
The pancreas has a very important part to play in the Endocrine system – that of maintaining blood-glucose levels. The gland is situated behind the horse’s stomach, next to the duodenum. It secretes a digestive juice and two hormones, glucagon and insulin, produced by loads of tiny cells called islets of Langerhans. The amount of these two hormones into the bloodstream is controlled by the amount of glucose already present in the plasma.
Glucagon encourages the breakdown and use of glycogen which raises the blood-glucose level.
Insulin encourages the uptake of glucose which is converted to glycogen and fat. By hindering the breakdown of glucose, insulin lowers the level of blood-glucose in the body.
The Gonads are sex glands that produce the hormones that give female and male horses their characteristics. LH, luteinizing hormone and FSH, follicle stimulating hormone is released from the anterior pituitary gland and sent to the ovaries and testes. The ovaries produce oestrogen and progesterone, the testes, testosterone. In addition to the role played by oestrogen and progesterone in the mare’s reproductive cycle, all three elements are essential to the behaviour or the horse.
Hypothyroidism is where there is a shortage of iodine in the body and therefore, the thyroid gland cannot access enough to manufacture thyroxine. Symptoms can range from lacking in energy and a tendency to feel the cold more, to compromised physical and mental development.
In direct opposition to that is hyperthyroidism which is characterised by everything that goes with an increased metabolic rate – elevated heart rate, high blood pressure and extreme weight loss. Some people may have a goitre, a visibly enlarged thyroid gland.
Owing to the fact only small quantities of parathyroid hormone is released at any one time, it can end up with calcium being laid down in the bones rather than remaining in circulation. This is of particular concern for mares in foal. It is essential that mares are closely monitored for levels of calcium in the blood as there is a danger that she might lose some of her own skeletal calcium deposits and density to her developing foal.
Diabetes can occur if insulin cannot be produced in enough volume, meaning that blood sugar levels are consistently high. However, this is very rare in horses.
The horse’s nervous system is the most complex of the systems in the body in that it also controls all of the others systems.
The nervous system and all of the other systems in the body rely on the ability to communicate with each other in order to function in balance. The horse is reliant on the correct messages getting to its brain and back out again and the correct functioning of the nerves, glands and muscles in order to interpret and action those messages accordingly.
Locked, stiff, or scar tissue in the fascia at all depths and at any point in the horse’s body, around muscle, ligaments, tendons and organs, can disrupt communication and therefore, the effcient working of systems.
Bowen can help release this fascia and allow the correct functioning of the nerves within it. By opening up the lines of communication, the ingoing messages should be correct and the subsequent outgoing messages should be ones of healing and action to remedy the issue.
The lymphatic system is very closely integrated with the circulatory system which pumps blood around the body through arteries and brings it back through veins. Thin tubes called ‘lymph vessels’, or ‘lymphatic vessels’, run through the fascia, parallel to the blood vessels and as they do, reach all parts of the body, organs and tissues. However, instead of carrying blood, the lymphatic system circulates lymph, a transparent, yellow-coloured liquid.
The system drains, filters and fights infection.
This balancing act is primarily achieved by the kidneys.
It is not a coincidence that a lot of the Bowen moves correspond with areas of the horse’s body in which lymphatic nodes are located. Being embedded in the fascia and communicating through it as it does, means that the effective functioning of the lymphatic system is reliant on the fascia being healthy, flexible, pliable and able to do its job of facilitating fluid movement and encouraging structural integrity of the body as a whole.
Bowen can help detox and boost the immune system. One of the outcomes of a Bowen treatment is the expelling of urine and faeces as the lymphatic system gets a reboot and wants to get rid of waste material.
The main function of the urinary system is to remove excess water and liquid wastes containing nitrogen, salts, excess sugars, and other unwanted substances as urine. It’s role therefore, is to ensure the correct balance of salts and fluids in the body.
This balancing act is primarily achieved by the kidneys.
The kidneys constantly filter the blood, removing some substances, reabsorbing substances that need to remain in the body and collecting waste to be eliminated as urine. The kidneys also adjust the temperature of the body and are part of the system that controls blood pressure. They play an important role in lymphatic drainage, the health of the immune system and are seen as regulators for a general healthy balance in the body.
As the “master chemists” as Julian Baker referred to them in Bowen Unravelled, the kidneys are often the dumping ground and fixer/ mopper-upper for all of the stresses we willingly and unwillingly put our bodies under.
In the horse, the adrenal glands are situated just in front of the kidneys in the lower back. It is their job to manage stress by produc- ing the anti-inflammatory hormone cortisol, as well as the hormone adrenalin when the sympathetic nervous system kicks in and the horse moves into fight or flight.
Horses that are prone to being anxious, or stressy, or who are being forced to react in that way by external factors such as bad riding, management or treatment, will suffer from adrenal fatigue and kidneys that are having to work overtime. These horses can present with chronic fatigue, interspersed with almost manic episodes of energy and excitement, they become unpredictable and difficult to handle.
The strain experienced by the adrenal glands and the kidneys cannot be contained long term and many horses suffering in this way may go on to develop stomach ulcers and colic, along with a marked depression of the immune system and therefore, an inability to deal with things such as vaccines, worming treatments or insect bites.
There isn’t a kidney procedure in Equine Bowen Therapy. However, Bowen is a holistic treatment and the renal fascia will be reached, perhaps most pertinently by work done on bottom and top stoppers, closing and opening the back and the vast majority of the work done on the hindquarters.
The musculoskeletal structure is made up of the skeleton, bones, joints and connective tissues: muscles, tendons, ligaments, fascia, main muscles, tendons and ligaments that run throughout the body.
Bowen therapy helps to release any tension and pull in the horse’s muscles, allowing re-alignment of both muscle structure and of the skeletal structure in totality.
“Just as an engine needs a chassis, muscles need the skeletal frame to turn the power of movement into the reality of locomotion. Nevertheless, whereas the application of the body’s muscles is physically ingenious, the structure of the skeleton is a mechanical tour de force.”
The Horse’s Muscles in Motion, Sara Wyche
Yes. There isn’t a “Digestive System” move within Equine Bowen therapy. However, when you look at how the system stretches from the mouth, down though the thorax, between the lungs and through the diaphragm, into the abdomi- nal cavity, you begin to realise just how many other “moves” within a treatment will come to have an effect on it.
Issues ranging from potential TMJ and chewing issues and insufficient movement in the diaphragm, to an acidic, stressed stomach and a system perhaps under pressure from excess gaseous build up or having to work too hard.
We would never treat a colicing horse. We should definitely treat a horse in recovery from an episode, or with a history of colic, alongside all of the expected management recommendations, such as what to feed, when, exercise, turn out etc.
Bowen can obviously not cure ulcers in a horse. However, alongside good management as mentioned above, there is a very strong argument to say that physiologically, it may help with pain relief in the form of natural endorphins.
Perhaps more interestingly, in horses deemed to be at risk of ulcers as a result of behavioural characteristics, whether that is eating too fast, or stress stereotypies such as crib biting and wind sucking, there is definitely a case to be made for Bowen as a powerful way of inviting the horse’s body to relax, both mentally and physically.
“While all of the horse’s body systems work together to keep the animal alive and active, the circulatory and respirato- ry systems have a special relationship. The flow of blood and oxygen can make the difference between a champion and an ordinary horse, or when problems develop, it can mean the difference between life and death.”
Lotty Merry – Equine Bowen Study Notes
Yes. Both systems are utterly central to the general health and wellbeing of the horse and its ability to move. Owing to the interconnected nature of the horse’s fascia throughout the body, Bowen has a big potential part to play in helping and maintaining of both systems.
Bowen therapy can deal with the initial physical issues, but also plays a large part in helping to mediate the stress response that occurs as a result of those physical issues.
The Respiratory move which is designed to help address the fascia in and around the lungs and thoracic cavity, helps horses with breathing issues caused by dust in hay or straw and allergies caused by things like pollen. This works particularly well with the TMJ procedure in terms of ensuring that airways are open and muscles are relaxed and functioning correctly.
Central to the Circulatory system is the muscle of all muscles, the heart. All muscles, tendons, ligaments, organs and
bones in the body are encased by and run through by fascia, both superficial and deep. Bowen can help restore full capacity by addressing fascia that has become stuck or sticky, resulting in tight and restricted heart, lungs, diaphragm and abdominal muscles.