Knowledge about hooves
Hufwissen

Horse Coat Change

37 Min. Lesezeit

The complete guide for horse owners

In brief: The horse's coat change is not triggered by temperature, but by the length of daylight, regulated by the pineal gland and the hormone melatonin. It begins weeks before the visible hair loss, places a real demand on the metabolism, and can be effectively supported through targeted feeding, consistent coat care and adapted management. In this guide, you will learn everything you need to know as a horse owner – from biology through nutrition to the warning signs that call for a vet.

Horse coat
Table of contents
Horse coat change: The complete guide for horse owners 1. What happens during the coat change? The biology behind it The hair cycle: Three phases, one principle 2. Course of the coat change 3. Spring coat change vs. autumn coat change: The differences 4. Reading symptoms correctly: Normal or concerning? 5. Feeding during the coat change: Which nutrients really count 6. Herbs and natural feed supplements 7. Coat care: Why grooming does more than any supplement 8. Riding and training during the coat change 9. Rugging during the coat change: When useful, when counterproductive? 10. Coat change by horse type: Not every horse has the same needs 11. Problems during the coat change: When the body sounds the alarm 12. Cushing's, EMS and disturbed coat change 13. When to call the vet? The checklist 14. What you can do – and what you should avoid 15. FAQ: The most common questions about the horse coat change

1. What happens during the coat change? The biology behind it

The horse's coat change is not a simple matter of "losing hair". It is a complex, hormonally controlled remodelling process in which – with the exception of mane and tail – the entire coat is renewed. It is about far more than appearance: the skin is the horse's largest organ and plays a central role in thermoregulation and immune defence. An intact skin and coat is the body's first line of defence against cold, wet, UV radiation, parasites and pathogens. Accordingly, the process of completely renewing it is highly demanding. To understand why some horses go through this phase effortlessly while others struggle, it is worth taking a look at the underlying biology.

Light gives the signal – not the cold


One of the most persistent misconceptions about the coat change: many horse owners believe that rising or falling temperatures set the process in motion. In reality, the primary trigger is the so-called photoperiod – the change in daylight duration over the course of the year.

In the horse's brain sits the pineal gland (glandula pinealis), a small, light-sensitive organ. It registers via the eyes whether the days are getting shorter or longer and then regulates the release of several hormones – above all melatonin, but also prolactin, which also plays a regulating role in the hair cycle. Most people know melatonin as the "sleep hormone", but in horses it has a much broader function: it controls the biorhythm, influences reproduction – and the coat change. The interplay of these hormonal signals determines when new hair is formed, how fast it grows and when the old coat is shed.


When the days grow longer again after the winter solstice on 21 December, melatonin production decreases. This hormonal signal prompts the hair follicles to shed the existing winter coat and to start forming a new, lighter summer coat. When the days grow shorter again from the summer solstice on 21 June, melatonin production rises – and the body begins to build up a dense winter coat.

Temperature plays a subordinate but still relevant role: it influences the speed of the coat change and the density of the coat. A cold snap in March can temporarily slow down the process. Horses kept year-round in an open stable, exposed to natural weather conditions, generally develop a noticeably denser and longer winter coat than horses kept in stalls under artificial light. But the starting signal is given by the light – not the thermometer.

The hair cycle: Three phases, one principle

Every single horse hair goes through its own life cycle, divided into three phases:

Phase 1
Anagen phase
Growth phase

The hair root is active, well supplied with blood and produces new hair. In the horse, this phase lasts about three to seven months. During this time, nutrient supply is crucial – deficiencies in zinc, amino acids or B vitamins become visible here because the hair depends on a continuous supply for its growth.
Phase 2
Catagen phase
Transition phase

Hair growth comes to a standstill. The hair root detaches from its blood supply, the hair becomes a so-called club hair. This phase lasts about two to three weeks.
Phase 3
Telogen phase
Resting and shedding phase

The old hair rests in the skin and is finally pushed out by the new hair coming through. During the seasonal coat change, many thousands of hair follicles are simultaneously in this phase – which explains the typical clouds of hair produced when grooming.

What this means in practice: When the first loose hairs hang from the curry comb in February or March, the actual work has long been underway. The new summer hairs were already formed beneath the skin's surface in the depths of winter. The time window in which you can influence the quality of the new coat through feeding therefore lies well before the visible hair loss.

2. When does the coat change begin?

The coat change calendar: What happens when


Viewing the coat change as a clearly defined event falls short of the mark. In reality it is a flowing process that extends over months. The following overview shows the typical phases over the course of the year:

The coat change calendar

❄️
December – January
From the winter solstice on 21 December the days grow longer again. Beneath the skin's surface, the hair follicles begin to form new summer hairs. Nothing is yet visible from the outside – the horse stands in full winter coat.
🌱
February – March
The new hairs increasingly push the old winter hairs out. Now the coat change becomes visible: first the long topcoat falls, then the dense undercoat. Many horse owners notice the coat change only in this phase.
🌸
April – May
In most healthy horses, the spring coat change is complete. The short, shiny summer coat lies smooth. Horses still wearing markedly shaggy winter coats now should be examined by a vet.
☀️
June – July
From the summer solstice on 21 June, the days grow shorter again. The body begins to produce the winter coat – at first imperceptibly. The fine summer hair slowly grows longer, and additional undercoat hairs are formed.
🍂
August – October
The autumn coat change becomes visible. The summer coat falls out in soft tufts, while the increasingly dense winter coat pushes through beneath.
🧣
November – December
The winter coat is largely established. The horse stands in its typical plush fur.

How long does the coat change last?


The duration is individual and depends on several factors: breed, age, husbandry, nutritional status and health of the horse. As a guide: the spring coat change usually lasts longer than the autumn one – often four to eight weeks, in some cases several months. The autumn coat change usually proceeds more quickly, since the horse sheds less hair and instead pushes new coat through.


Why the coat change sometimes stalls


A sudden cold snap in spring can temporarily pause the coat change. The body "brakes" the process, so to speak, because the winter coat might still be needed. As soon as temperatures rise again, things continue. Stress – for example through a change of stable, transport or intensive training – can also slow the coat change. A persistently sluggish or incomplete shedding, on the other hand, indicates deeper causes (more on this in the section on warning signs).


3. Spring coat change vs. autumn coat change: The differences

Although the horse changes its coat twice a year, the two phases are not the same.

Spring coat change
🌱 In spring
Complete exchange – high demand

In spring the entire winter coat is shed – topcoat and the dense, insulating undercoat. This happens in stages and produces the familiar mounds of hair that fall during grooming. The metabolic demand is highest in this phase: the body has to shed huge amounts of old hair while simultaneously providing enormous quantities of energy, amino acids and minerals for the build-up of the new summer coat – a double load that makes the spring coat change significantly more taxing than its autumn counterpart. In addition, the spring coat change falls in a season when pastures have not yet reached the vegetative phase – the horse therefore lacks the fresh nutrients from pasture grass while demand is just rising.
Autumn coat change
🍂 In autumn
Equipping – moderate demand

In autumn significantly less hair falls out. The short summer coat is shed while the denser winter coat is pushed through beneath. This is therefore less an "exchange" than an "equipping". The amounts of hair are smaller, but the nutrient demand is still raised – because building up the undercoat costs energy and building blocks.

Good to know: Mane, tail and the tactile hairs around the muzzle and eyes are not affected by the seasonal coat change. They follow their own, much slower hair cycle.

4. Reading symptoms correctly: Normal or concerning?

During the coat change, most horses show typical accompanying signs. The art is to distinguish between normal indications and real warning signals.


Normal accompanying signs


Increased hair loss is the most obvious sign – and entirely natural. Especially during the spring coat change, the amounts of hair can be impressive. Itching is also part of it: the emerging hairs irritate the skin, which is why horses rub, nibble and roll more often in this phase. Mild dandruff can occur because the skin surface renews itself more strongly. And a certain dullness is also normal – the metabolism is working at an elevated level, which means some horses temporarily appear somewhat less ready to perform.


Behavioural changes


The coat change demands not only the body, but can also affect the horse's mood. Some horses are more irritable or less cooperative when ridden during the coat change. Others show reduced appetite or seem generally more restless. Within certain limits this is normal and no cause for concern – provided the symptoms are temporary and not extremely pronounced.


When to take a closer look:


Dull, shaggy coat that shows no improvement for weeks, conspicuous weight loss, persistent cough, round bald patches, markedly swollen legs or distinct apathy go beyond what a normal coat change causes. In these cases you should have the causes investigated (in detail in the section on problems and warning signs).

5. Feeding during the coat change: Which nutrients really count

Much is written in the horse industry about feeding during the coat change, and much of it is driven more by marketing than by expertise. Here is a nuanced view of the nutrients that demonstrably play a role, and a realistic assessment of what your horse really needs.

The basis: High-quality roughage


Before considering supplements, the foundation has to be right – because a thoughtfully composed ration geared to actual needs is and remains the most effective lever for a smooth coat change. By far the most important feed component for every horse is high-quality, hygienically faultless hay. It provides crude fibre, protein and – with good quality – a portion of the required minerals and vitamins. However, hay loses vitamins and essential fatty acids over the winter months due to storage. The spring coat change falls precisely into this phase – which explains why targeted supplementation often makes sense.

Horses eating hay

The key nutrients at a glance

Essential amino acids – the actual building blocks of the hair ▼
Horse hair consists of around 90 percent of the structural protein keratin. To build it the body needs sulphur-containing amino acids, in particular methionine and cysteine, because they provide the sulphur that stabilises and cross-links the keratin fibres. A key role is also played by lysine: although not directly involved in keratin formation, it is regarded as the first-limiting amino acid in the horse's protein metabolism. Without lysine, the body cannot efficiently use the available sulphur-containing amino acids for hair formation either. Because horses cannot produce these essential amino acids themselves, they have to be supplied through the diet. Good sources are alfalfa, linseed and brewer's yeast.
Zinc – key role in keratin formation ▼
The trace element zinc is involved in cell division and keratin synthesis and is therefore indispensable for the coat change. Since supply through roughage alone is generally insufficient, supplementation via a high-quality mineral feed is advisable – ideally with organically bound zinc, as it is more bioavailable.

Good to know: Inorganic forms such as zinc oxide or zinc sulphate are cheaper, but are less well absorbed by the body and can block each other's absorption in the gut. Organically bound forms – such as zinc chelates, zinc glycinate or zinc methionate – are coupled to amino acids or peptides and therefore use different uptake pathways, which increases their bioavailability.

A look at the declaration: If it says, for example, "zinc glycinate hydrate" or "zinc chelate", these are organically bound forms. If it only says "zinc oxide" or "zinc sulphate", the inorganic variant is present.

Important: Zinc should not be fed in isolation or at high doses on suspicion – an overdose burdens the liver and kidneys and can impair the absorption of other trace elements such as copper.
Copper – for pigmentation and structure ▼
Copper is needed for keratin synthesis and the formation of pigment in the hair. Horses with a copper deficiency sometimes develop the typical "copper spectacles" – light rings around the eye area. Dosage requires a sure touch, since an excess of copper can in turn inhibit zinc absorption.
Biotin and B vitamins ▼
Biotin supports the maturation of the cells that form keratin. In a healthy equine gut, B vitamins are generally produced in sufficient quantities by the gut microbes. If the gut flora is disturbed, however – for example through feed changes, antibiotic administration or inferior silage – supplementation can be useful.

Important: Feeding biotin alone while neglecting all other nutrients achieves little: biotin only unfolds its effect in interaction with the other micronutrients.
Selenium and vitamin E – cell protection ▼
Selenium and vitamin E act synergistically as antioxidants and protect cells from oxidative stress – including the cells of the hair follicles. A selenium deficiency can weaken the immune system and complicate the coat change.

Caution: Selenium is a trace element with a very narrow therapeutic margin: only small amounts separate deficiency from overdose. Dosage should follow the recommendations of the Society for Nutritional Physiology (GfE).
Omega-3 fatty acids – for the skin barrier ▼
The skin is the horse's largest organ and forms the basis for healthy hair growth. Omega-3 fatty acids keep the skin supple, strengthen its natural barrier function and have an anti-inflammatory effect. In the grass-free winter period these fatty acids are often lacking in the ration, since hay contains significantly less of them than fresh pasture grass.

Tip: Linseed oil is the ideal supplement: with around 52 percent it contains a particularly high proportion of alpha-linolenic acid and at the same time offers a favourable omega-3 to omega-6 ratio.
Vitamin A and beta-carotene ▼
Vitamin A promotes blood circulation in the skin and is involved in the regeneration of skin cells. Since horses do not absorb vitamin A directly but synthesise it from beta-carotene in the feed, supply can become tight during the grass-free period.

Home-remedy tip: Carrots with a dash of linseed oil are a simple and inexpensive way to improve beta-carotene supply.

The role of the liver

The liver is often called the body's "central laboratory" – and with good reason. It stores and distributes nutrients, filters toxins and is involved in protein metabolism. During the coat change, protein synthesis runs at an elevated level, which places greater demands on the liver. If it has already been stressed over the winter by inferior feed quality, deworming treatments, medications or hay contaminated with mould fungi, this can show up during the coat change as a dull coat, dullness or skin problems.


Water – the underestimated factor

A nutrient regularly overlooked in discussions about the coat change is water. Yet adequate water intake is the basic prerequisite for cellular metabolism to function smoothly, and therefore also for the nutrient supply of the hair follicles. During the coat change, the metabolism works at an elevated level, which additionally raises the need for water.

The problem: It is precisely during the spring coat change that many horses drink too little. After a long winter they have become accustomed to cold drinking water, and ice-cold water has been shown to reduce willingness to drink. Studies show that horses drink considerably more when the water temperature is between 7 and 18 degrees Celsius than at temperatures close to freezing. At the same time, water intake from fresh pasture grass is missing in the winter half-year, since hay contains only around 10 percent moisture while grass provides up to 75 percent water.

In practical terms this means: make sure the automatic drinker works and is not frozen, temper the water if necessary, and for horses with known low willingness to drink offer soaked hay cobs or a mash to increase fluid intake via the feed


Horse mineral feed

Gut health – the basis of nutrient utilisation

Even the best mineral and protein supply achieves little if the gut cannot efficiently use the nutrients supplied. The horse is a hindgut fermenter: around 50 to 70 percent of its energy needs are met by short-chain fatty acids produced by microorganisms in the caecum and colon through the fermentation of crude fibre. In addition, these gut microbes synthesise B vitamins, which are relevant for keratin formation among other things.

If this microbial community is disturbed – for example through abrupt feed changes, inferior roughage, stress, antibiotic treatments or deworming – it is called dysbiosis. The consequence: nutrient absorption becomes less efficient, B-vitamin production declines and the entire metabolism works below its potential. During the coat change this can show up as a dull coat, slower hair growth or increased susceptibility of the skin to infection.

What supports gut health during the coat change is unspectacular but effective: a stable, roughage-based base ration without frequent changes, sufficient hay of good quality and – if needed – feedstuffs with a prebiotic effect such as linseed or brewer's yeast, which can positively influence the microbial environment in the hindgut.


An honest assessment

In the horse feed industry the coat change is not infrequently portrayed as a medical state of emergency for which this or that special product is urgently needed. The reality is more nuanced: a healthy horse supplied year-round with high-quality roughage and a needs-based mineral feed generally copes with the coat change without elaborate additional programmes. The formation of the new coat extends over months – it is not a sudden nutrient peak but a gradual process.

Targeted supplementation makes sense when the horse belongs to a risk group (seniors, chronically ill horses, sport horses under high stress), when hay quality is below average, or when a blood test actually reveals deficiencies. "More is better" is out of place in supplementation – every excess burdens the organism just as much as a deficiency.

6. Herbs and natural feed supplements

In addition to the basic ration and mineral supply, there is a range of plant-based feed supplements that can support the coat change. Here are the most important – with a realistic assessment.

Linseed and linseed oil – omega-3, protein and digestion ▼
Linseed and linseed oil are among the most valuable natural feedstuffs during the coat change. Linseed provides omega-3 fatty acids, high-quality protein and mucilages that have a positive effect on digestion. Dark linseed should be boiled or ground before feeding, as it contains cyanogenic glycosides – a precursor of hydrocyanic acid, which is rendered harmless by boiling.

Dosage: Linseed oil offers a practical alternative: 30 to 50 millilitres a day, slowly phased in, are sufficient for most horses.
Milk thistle – liver protection and cell regeneration ▼
Milk thistle contains the active substance silymarin, which stabilises the membranes of the liver cells and can promote their regeneration. In the context of the coat change it is often recommended as a "liver herb".

Important: The popular term "detox" is not scientifically defined. A healthy liver performs its detoxification function on its own. Milk thistle can have a supportive effect, but is not an obligatory component for every horse.
Stinging nettle – natural mineral supplier ▼
Stinging nettle is a natural mineral supplier with a high content of iron, calcium, potassium and vitamin C. It promotes blood circulation in the skin and stimulates the metabolism – both can have a supportive effect during the coat change.

Application: Dried stinging nettle can easily be mixed into concentrated feed.
Dandelion – metabolism and kidney function ▼
Dandelion provides vitamins A, B and C as well as copper, zinc and bitter substances. It stimulates kidney function and metabolism and has traditionally been used as a spring cure.

Note: As dandelion has a draining effect, water intake should be kept an eye on.
Brewer's yeast – B vitamins, amino acids and gut flora ▼
Brewer's yeast deserves special attention during the coat change: in addition to B vitamins it primarily provides high-quality, easily digestible protein with all essential amino acids – precisely the building blocks the body needs for keratin production. At the same time, brewer's yeast supports a healthy gut flora, which improves nutrient utilisation overall.

7. Coat care: Why grooming does more than any supplement

No supplement in the world replaces regular, thorough grooming. This has solid physiological reasons that go beyond merely removing loose hair.

Circulation as the key


Brushing and currying stimulate blood circulation in the skin. A well-perfused hair papilla – the supply unit at the hair root – produces stronger and healthier hair. At the same time, the removal of metabolic products via the lymphatic system is promoted, which counteracts skin overload.


Mechanical loosening and skin health


Loose winter coat that is not removed can create a damp, warm microclimate under the dense hair layer – an ideal breeding ground for skin fungi and bacterial infections. Regular grooming prevents this, relieves itching and allows the skin to fulfil its protective function (sebum production, barrier function) unhindered.

Horse being groomed

Observation function

Thorough grooming is at the same time the best health check. Skin changes such as dandruff, bald patches, the first signs of mud fever or eczema are noticed early during close contact with the horse – often long before they are visible from a distance.


Practical tips

During the coat change, a shedding curry or shedding tool is better suited than a soft brush to effectively loosen the undercoat. Always work in the direction of the hair and be more careful in sensitive areas – belly, inner thighs, head. The choice of the right tool makes a noticeable difference: rubber currycombs with nubs gently massage the skin and improve microcirculation, while metal currycombs and shedding blades work effectively especially on thick undercoats. Currying with deliberate circular movements combines the removal of loose hair with a massage that stimulates blood flow down to the deeper skin layers – an effect that benefits the nutrient supply of the hair roots. When grooming in the stable, take care that the loose hairs do not end up in the box and get eaten by the horse; better to curry at the grooming spot or outside.


Washing during the coat change: restraint is in order

Full-body washes should be avoided during the coat change wherever possible. The enormous amounts of hair considerably extend drying time, and shampoos can alter the natural skin flora, which plays a particularly important role in fending off skin infections during this phase.


Drainage grooming for the lymphatic system

The lymphatic system transports metabolic products and fluid away from the tissue. During the coat change it works at an elevated level. Targeted drainage grooming – even, gentle strokes towards the heart, especially on the legs – can support lymph flow and counteract the development of swollen legs.

8. Riding and training during the coat change

The coat change is not a reason to send the horse on complete holiday – but it is a good occasion to consciously adapt training to the horse's physical situation.

Training intensity with measure

When the metabolism is additionally taxed by the coat change, less energy is available to the body for top athletic performance. Horses that appear duller or less ready to perform during this phase are not unmotivated – they simply lack the reserves. Instead of stopping training completely, it is advisable to reduce the intensity moderately and watch the horse attentively. Light work and varied movement (hacks, easy trot-canter work, ground work) keep the circulation going without overtaxing the organism.


Sweat sheets and temperature management

One of the greatest dangers during the coat change is cooling down after work. Horses still wearing remnants of their winter coat in spring sweat sooner and more heavily during training. At the same time, the coat is no longer dense enough to effectively warm the horse after sweating. Here sweat sheets are indispensable: put them on immediately after riding and only remove them once the horse is completely dry. Especially in changeable weather or wind, the horse should only return to the paddock or the box once dry.

Goodsmith Klebebeschlag pole work

Warm-up and cool-down phases

Especially in the transitional period, generous warm-up and cool-down phases at the walk are important. In autumn, when horses are already growing dense winter coat but daytime temperatures are still mild, there is an increased risk that the horse will sweat excessively during riding and subsequently catch cold. A warming kidney rug for longer walking phases at cool temperatures can be useful to keep the back warm.

9. Rugging during the coat change: When useful, when counterproductive?

Hardly any topic is discussed as controversially among horse owners as rugging, and during the coat change the debate becomes even more charged. To classify the question soberly, a look at the biology helps.


  • Rugs do not prevent the coat change.

The trigger for the coat change is given, as described in chapter 1, by the length of daylight, not by the outside temperature. A horse under a rug receives the same light through its eyes as a non-rugged horse. It will therefore form a winter coat in both cases and shed it again in spring. What rugs can influence is the density and length of the winter coat: studies show that rugged horses tend to develop somewhat shorter coats than non-rugged ones, although this effect is limited and only measurable in certain time windows. Anyone who really wants to prevent a horse from building up a dense winter coat must work with an extension of the light phase (stable lighting), not with rugs.


  • When rugging during the coat change makes sense:

If the winter coat has already been largely shed in spring and a cold snap with wet and wind arrives, a light transitional rug can protect the horse from cooling down, since the new summer coat does not yet offer adequate weather protection. Clipped horses, seniors and horses in poor nutritional condition also benefit from targeted rugging, because their thermoregulation is impaired.


  • When rugging is counterproductive: 

Putting on rugs too early or too warmly in autumn can lead to the horse sweating under the rug without being able to release the moisture effectively. Permanently damp coat under the rug is an ideal breeding ground for skin fungi and bacterial infections – precisely the problems that occur more frequently during the coat change anyway. Rugs also flatten the coat and prevent the horse from using its natural thermoregulation by raising the hairs. Anyone who rugs must be consistent: daily checks of whether the horse is sweating or freezing under the rug, and regular removal of the rug for grooming and airing the skin.

10. Coat change by horse type: Not every horse has the same needs

Older horses and seniors


For seniors the coat change is often the most demanding time of year. The metabolism works less efficiently with age, nutrients are less well utilised, and existing health limitations (dental problems, joint complaints, decreasing liver function) become more pronounced. Older horses more often lose weight during the coat change, because the enormous energy demand for the new coat exhausts the already meagre reserves. It can make sense here to increase energy supply at an early stage – for example via mash, enriched hay cobs or the addition of high-quality oils. Horses kept year-round in open stables, which already use more energy for their own thermoregulation, also often benefit during the coat change from a targeted energetic enrichment of the ration. In addition, seniors should be regularly examined for Cushing's (PPID), since a delayed coat change is one of the leading symptoms of this disease.


Klebebeschlag Goodsmith senior

A factor often underestimated in seniors is dental health. Horses with advanced tooth wear, missing molars or sharp edges can no longer adequately chew hay and roughage. The consequence: feed utilisation declines, and even a needs-based ration does not fully reach the metabolism. During the coat change, when nutrient demand is elevated anyway, this can make the difference between a smooth process and a sluggish coat change with weight loss. An annual dental check by a vet or equine dentist, ideally before the start of the spring coat change, is therefore not an optional measure for older horses, but a fixed component of forward-looking coat-change management.

Sport horses and broodmares

Sport horses that are also worked intensively in winter are often clipped – the seasonal coat change then proceeds less uniformly and less markedly, since clipping influences the natural rhythm. Broodmares, especially those in late pregnancy or lactating, are additionally burdened by the coat change on an already demanded metabolism. Close-meshed nutrient supply is particularly important here.

Dressage horse Klebebeschlag Goodsmith

Young horses and foals

Young horses are still growing and therefore have an elevated nutrient demand anyway. They generally cope well with the coat change – provided the basic supply is right. An adequate protein supply is particularly important during the growth phase, since the body needs amino acids both for muscle build-up and for coat formation.

Foal coat change

Robust breeds vs. warmbloods

Robust breeds such as Icelandic horses, Norwegians, Haflingers or Shetland ponies naturally develop a noticeably denser winter coat than warmbloods or thoroughbreds. The spring coat change can be particularly spectacular and protracted with them. At the same time, as easy-keeping breeds they are particularly at risk for metabolic diseases such as EMS – a fact that must be taken into account when adapting feeding during the coat change. Simply "more feed" is the wrong approach here; instead, deliberately quality over quantity.

Icelandic horse winter coat
Warmblood coat

Husbandry: Open stable vs. box

Open-stable horses, exposed to natural light and temperature conditions, generally develop a denser, more resilient coat and go through the coat change "more naturally" than box-kept horses under artificial light. At the same time, their energy needs in winter are higher, because they have to do their own thermoregulation. Box-kept horses with thinner coats often shed more quickly, but are more sensitive to unexpected cold snaps after the coat change.

11. Problems during the coat change: When the body sounds the alarm

 

Cough and respiratory problems


Coughing during the coat change has two common causes. On the one hand, the immune system is less effective due to the increased metabolism, so horses become more susceptible to respiratory infections. On the other hand, the load of fine hair particles and dust rises considerably in closed stables when many horses are shedding at the same time. Persistent cough should always be examined by a vet, since a neglected respiratory issue in the horse – unlike a cold in humans – can have serious consequences.

 

Mud fever and faecal water


Mud fever occurs more frequently during the coat change, especially in autumn. The skin as the largest organ is heavily taxed in this phase and therefore more susceptible to bacterial infections that settle in the damp fetlock crease. Faecal water can also occur in connection with the coat change, since the increased metabolic activity also influences the gastrointestinal tract.

 

Swollen legs and lymphatic congestion


The lymphatic system, which transports metabolic products away from the tissue, works at full speed during the coat change. Congestion can develop especially in the hind legs, showing as thick but neither warm nor pressure-sensitive legs. Regular movement and drainage grooming prevent this. If the swellings are warm, react painfully or do not recede, a veterinary examination is necessary.

 

Weight loss


Some horses lose noticeable weight during the coat change because the energy demand for coat production exceeds the amount of feed taken in. Hard keepers and seniors are particularly affected. Here energy supply should be adapted early on – not only when weight loss becomes visible.

 

Skin fungus and bald patches


Round, scaly, hairless spots in the coat are not a normal coat-change symptom but a clear indication of a fungal infection. During the coat change the risk is increased because the skin barrier is weakened. Clean grooming tools, rugs and saddle pads are particularly important during this phase to minimise the risk of transmission. If skin fungus is suspected, the vet should be consulted.


12. Cushing's, EMS and disturbed coat change

Cushing coat horse neck
Cushing coat horse

A delayed or absent coat change – especially when the horse wears long, curly coat well into summer – is one of the best-known leading symptoms of Equine Cushing's syndrome (PPID, Pituitary Pars Intermedia Dysfunction). This is a functional disorder of the pituitary gland that causes an excessive release of the hormone ACTH and throws the horse's entire hormone balance off course.


In addition to the disturbed coat change, Cushing's horses often show muscle loss, conspicuous fat deposits (especially on the mane crest and above the eyes), increased thirst, increased susceptibility to infections and an increased risk of laminitis. Studies suggest that a considerable proportion of horses over 15 years old are affected by PPID – many of them without obvious symptoms in the early stages.


Important: Not every slow coat change automatically means Cushing's. But if an older horse repeatedly has trouble shedding its winter coat in time, an ACTH blood test should be carried out by the vet. Cushing's cannot be cured, but with the medication pergolide and an adapted diet (low in sugar and starch) it can be managed well if the disease is recognised early. In addition, the horse can be supported with coordinated hoof care and a suitable choice of the right hoof protection.


The Equine Metabolic Syndrome (EMS) often occurs together with Cushing's and is characterised primarily by overweight, insulin resistance and susceptibility to laminitis. In EMS horses too, the coat change can proceed with difficulty, since metabolism as a whole is impaired. Feeding for affected horses must be particularly carefully tailored: reduced in sugar and starch, with adapted energy supply and regular exercise.

Laminitis icon

Laminitis in horses – causes, symptoms & treatment

Laminitis Goodsmith Klebebeschlag

Laminitis therapy with Goodsmith

13. When to call the vet? The checklist

Not every problem during the coat change requires an immediate vet visit. But there are clear situations in which professional help is important. Have your horse examined if one or more of the following signs appear:

  • The coat change is not complete by May and the horse is still wearing distinct winter coat

  • The horse is losing noticeable weight although it is getting enough feed

  • Round bald patches or strong dandruff indicate skin fungus

  • Persistent cough for more than a few days – particularly together with dullness

  • Markedly swollen legs that are warm or pressure-sensitive

  • General apathy, refusal to perform or susceptibility to infections beyond the normal coat-change tiredness

  • Suspicion of Cushing's/PPID: long, curly coat in summer, muscle loss, increased drinking (especially in horses from around 15 years of age)

  • Mud fever or eczema that does not improve despite care

Tip: A blood test (mineral and hormone status) in most cases provides quick clarity about the cause and enables targeted treatment instead of supplementing on suspicion.

14. What you can do – and what you should avoid

Recommendation
Sensible and recommended


Groom regularly and thoroughly – during the coat change at least every other day, ideally daily

Keep an eye on hay quality – after a long winter the nutrient content of hay may have dropped significantly

Use mineral feed according to needs – a good basic mineral feed with organically bound trace elements (zinc, copper, selenium, manganese) covers the basic supply

Ensure protein supply – lysine, methionine and cysteine are the actual building materials of the hair, not zinc or biotin alone

Supplement linseed oil or linseed – for omega-3 fatty acids that support skin and coat quality from within

Adapt training – a horse that seems more sluggish during the coat change deserves understanding, not more pressure

Use a sweat sheet – use it consistently after riding until the horse is dry

Rug during cold snaps – if the winter coat has already been largely shed and another frost is coming
Caution
Question critically


"Coat-change bundles" and complete packages – a healthy horse with good basic feeding does not necessarily need a special product; targeted individual supplements are often more sensible and cheaper

Indiscriminate supplementation – zinc, selenium and other trace elements in the wrong dosage can be toxic or block each other in absorption

"Detox cures" as a mandatory programme – the term is not scientifically defined; liver-supporting herbs can be useful as a supplement, but a healthy organism detoxifies itself

Deworming and vaccinations in the middle of the coat change – if the timing is flexible, it is gentler to place these in the "quiet phase" when the coat change is at rest

Wet washes during the coat change – change the skin flora and considerably extend drying time due to the dense amounts of hair

15. FAQ: The most common questions about the horse coat change

When does the coat change start in horses?

The coat change is controlled by the length of daylight and begins inside the body as early as the winter solstice (21 December). It usually becomes visible from January to March (spring coat change) and September to November (autumn coat change).

How long does the coat change last in horses?

The duration varies depending on breed, age, husbandry and state of health, ranging from a few weeks to several months. The spring coat change usually lasts longer than the autumn one.

How can I support my horse during the coat change?

The three most important measures are: ensure high-quality basic feed, check mineral and protein supply, and groom regularly. In addition, linseed oil, linseed and, if needed, a herbal cure (milk thistle, stinging nettle) can be used.

What to feed during the coat change?

The basis is high-quality hay in sufficient quantity. In addition, a good mineral feed with zinc, copper and selenium, linseed oil or linseed for omega-3 fatty acids and protein-rich additions such as brewer's yeast or alfalfa as needed.

Why is my horse so sluggish during the coat change?

The formation of the new coat demands the metabolism, the immune system and the circulation. As a result, less energy is temporarily available for athletic performance. A moderate reduction in training intensity is appropriate in this phase.

Why is my horse coughing during the coat change?

Possible causes are an immune system weakened by the coat change and an increased dust load from loose hair in the stable air. Persistent cough should be examined by a vet.

What does a disturbed coat change mean?

If a horse still wears distinct long, curly coat in summer, a metabolic disease such as Cushing's (PPID) may be present. A blood test at the vet brings clarity.

When should I call the vet about the coat change?

In the case of strongly delayed coat change (May with still full winter coat), conspicuous weight loss, round bald patches, persistent cough, swollen legs or suspicion of Cushing's.

May I clip my horse during the coat change?

Yes – for older or sick horses that sweat excessively under the dense winter coat and develop circulatory problems, clipping can make sense. Clipped horses must then be rugged accordingly.

Which herbs help during the coat change?

Milk thistle can support liver function, stinging nettle provides minerals and promotes blood circulation, dandelion stimulates kidneys and metabolism, and brewer's yeast supplies B vitamins and essential amino acids.

Does rugging interfere with the coat change?

No. The coat change is triggered by the length of daylight, not by temperature. Rugged horses change their coats just as non-rugged ones do. Rugs can only influence the density and length of the winter coat slightly. It is important that the rug is removed regularly to air the skin and avoid sweat patches.

How much water does my horse need during the coat change?

A large horse drinks around 20 to 40 litres of water per day under normal conditions. During the coat change, demand may rise due to the increased metabolic activity. At the same time, willingness to drink declines in winter when the drinking water is very cold. Tempered water between 7 and 18 degrees Celsius is demonstrably accepted better. Soaked hay cobs or mash can additionally supplement fluid intake.

Does gut health play a role during the coat change?

Yes. The majority of nutrient utilisation in the horse takes place in the hindgut, where microorganisms ferment crude fibre and produce, among other things, B vitamins. A disturbed gut flora – through abrupt feed changes, stress or medications – can impair nutrient absorption and show up as a dull coat or slower hair growth. A stable, roughage-based diet is the best basis for a healthy gut flora.

Klebebeschlag icon

What is a Klebebeschlag?

Hoof protection yes or no?

Does my horse need hoof protection – and if so, what kind?

15. List of sources


This article serves general information purposes and does not replace individual veterinary or feed-specialist advice. If you have doubts about your horse’s health, feeding or supplementation, consult your vet or a qualified feeding advisor.