Is a shiny coat on horses always a sign the horse is healthy inside and out, kept in good living conditions and fed without mistakes? The answer is "no".
Just like in humans, people with all kinds of disorders, including endocrine (metabolic) may still have nice looking hair. The same with horses, the shiny coat is not always a sign of perfect health and good keeping conditions. And non-shiny coat is not always a sign of bad health and bad keeping conditions.
I would like to start with a cool example from my own recent experience of how the human's perception of what is 'healthy' and 'unhealthy' regarding the horses coat can be manipulated through wrong/not enough experience. In my article on the thermoregulation of horses there's this photo:
Coat of an Arabian breed horse on a very cold winter day in Central Europe, where the piloerection mechanism is in use — the hair is raised to increase coat insulation.
After the article was read by participants of a big horse forum (where mostly horse riders participate), the very first feedback I got was a reaction to the photo. One of great surprise and a question "Is this horse ill, or in rehab, or being weaned recently???"
So, the very first thought of a 'regular' horse person upon seeing such a coat was — the horse surely is not o.k... The photo traveled through diaries on that forum, everywhere with the same reaction — 'This is Arabian horse's coat! [shock]'. These people have never had any other experience apart from the using of their poor creatures, who are kept unnaturally and unhealthy in stables, etc... While in the photo, you can see a perfectly healthy and happy Arabian breed horse who is not ridden or used in any other way by a human for years now, only played with, and who is living in species appropriate conditions north of Poland where wintertime can be quite tough. Who grew exactly as much coat as he needed for this winter to feel great, and who was photographed on a brisk winter morning in temperatures of –27 degrees Celsius, when the mechanism of piloerection was in action in his coat. Who in the summer time, looks like this:
Photo © K. Jarczewski
Now I would like to define what is 'healthy, good, correct' for the horse.
Keeping a horse stabled the whole day, or even part of day compromises its welfare. (1) Keeping a horse in conditions which compromise its welfare can in no way be considered 'healthy, good, correct'. It should be obvious that 'healthy, good, correct' for every animal could only be conditions which are proper for that given species in which the animal was designed to live in by nature. Only when kept in such conditions is there a chance for the animal to be healthy physically and mentally.
A human forcing a horse into submission through physical and psychological pressure and pain (join-up, metal bits (9, 10), spurs, whips, etc.) compromises its welfare (1, 2), thus treating a horse using methods which utilize such kinds of techniques, could not be considered 'healthy, good, correct' for the horse.
Using bits damages the horse's health. (10, 11)
Riding itself damages the horse's health. (3)
Competing and training for competitions damages the horse's health. Just like there are no healthy human athletes (those who pay for a win with their own sweat and blood, not that of another living creatures), who suffer many injuries during their life in sport, the same there are no healthy 'horse athletes'. (4)
The horse's digestive system and metabolism only can function correctly when horses natural eating behavior isn't restricted, i.e. when a horse has non-stop free access to food and the possibility to freely move 24 hours a day in a herd. These conditions for the correct digestion and metabolism are never met when a horse is stabled even a part of day. (1, 5, 6, 7)
The common practice of shoeing horses when in the human's care, damages the horses health by blocking/stopping the hoof mechanism and greatly compromising the shock absorption functions of the feet. (8)
Still, many horses who are kept and treated using the above mentioned practices, have shiny coats.
It is just like with the hooves — how often do we see smooth, polished and nice looking hooves on the stabled, many years shoed and badly used horses? The outside horn gives a perfect shiny impression, while on the inside there's a bloody mess, literally.
The hairs of the horses coat and horn of the hooves (as well as humans hair and fingernails) are of the same nature and made of the same material — dead cells the body pushes out. So, just like the hoof horn, the hairs do not have blood vessels, or any other way to be nourished after they are produced. (Btw, just like it is absurd to say 'live sole' when speaking about the solar horn in the hooves, it is absurd when a shampoo ad says something like 'will make your hair alive and shiny after 3 washes' because there's no way hair can be supplied with any topical nutrients, and thus nothing can help them to become 'resurrected').
Shininess of hair is connected to how the hair reflects light. In general the hair looses its ability to shine, when its outer layer (cuticle) gets a mechanical damage and its surface isn't smooth anymore.
Just learn some basic physics, and you can trick your horse into having a super-shiny coat.
When do we have more chances to see a shiny coat on a horse? Usually when a horse has a short summer coat with finer structured hair laying flat to the skin and all in one direction (not erected). Under such conditions, the hair reflects the light the smoothest. Keeping a horse stabled the whole year prolongs the summer season for it. The coat never grows too long, it is usually cleaned and conditioned regularly making the hair lay smooth and it's not allowed to get roughed up from dirt and dust, etc. Regular brushing also stimulates faster coat shedding and growing new hair, so damaged hairs replaced faster by smooth newly grown ones. Rough, course surfaces — ones with many facets — reflect light in many different directions, thus such surfaces aren't look so shiny (compare for example, the chrome Mercedes sign on the front of your Mercedes car and a wool blanket).
Regular brushing intensifies the blood circulation in the skin which stimulates the oil (sebaceous) glands in the skin to secret more oil, which covers each hair in the coat and makes it glossier (or shinier).
Adding oil in feeds may increase the amount of oil secreted by the oil glands in the skin, resulting in an oilier (glossier, or shinier) coat, but feeding oil does not add anything to the horses general health.
The skins oils contain the Omega 9 family of fatty acids. You would need to feed a horse oil containing Omega 9 — as the horse's body itself already produces these acids, so the excess would be secreted as more skin oil.
The blocked metabolism in the hooves (through shoeing, incorrect trimming, not enough movement), which is the case with most stabled horses, may result in more intensive hair growth and shedding, as the hair is of the same nature as the hooves — they are built of outworked proteins — this is the way the body excretes its metabolic wastes. When the metabolism is blocked in the hooves, the skin is overloaded with the need to excrete more outworked proteins in the form of hair horn. So, the hairs may grow stronger, and through faster shedding does not have time for each separate hair to get coarse through the longer use.
Have you ever had a chance to observe on a colder windy summer day, or perhaps also at the end of summer, your horse, who looked perfectly shiny the previous day, suddenly had a 'dull' looking coat? It is just because the mechanism of piloerection got to work (through the follicle muscles action, the hair began standing upright) to make the coat warmer by making the air layer thicker in it. Also each hair is turned different a direction, and perhaps also the hair got some stimulation for sudden growth due to the colder weather — so the coat surface just lost its smoothness through these thermoregulation mechanisms, thus light doesn't bounce smoothly from it anymore and the shininess is gone. The longer the colder weather stays, the longer there's no shiny coat, until the body has adjusted to the cold and the now longer hairs are put flat against the body all in the same direction again.
The same way a longer winter coat with its hairs turned different directions, more dust staying in it and with its longer undercoat has less chance to be super-shiny.
A perfect example of the coat not reflecting the real conditions of metabolism in a horse — a horse with summer eczema. Summer eczema is a direct sign of damaged metabolism. If you have ever had a chance to see a horse with summer eczema, then in many cases you could see a horse with a shiny coat on the most of the body, but they would have either no mane or part of the tail, only bloody wounds instead. There could also be no hair and only wounds on some other parts of the body were they have scratched intensively.
Horse with summer eczema.
Or, for example, what can be often seen in stabled horses, there's a shiny coat full of dandruff underneath, if to look closer. Dandruff points to metabolic problems once more, but the coat still looks shiny.
There of course could be cases when the hair horn that is produced is brittle and thus of course means problems inside the body. As for example, when a rescued horse didn't have enough food before, so there was a general lack of nutrients and not enough to 'feed' the hair production. The same 'not enough material' for good quality hair horn production could be in an ill horse or a horse in big pain, who burns all the protein in its body from over-strained (overworked) muscles and for repairing damage to the internal organs that are more important for life. So, such brittle and non-smooth hair does not reflect light evenly.
This horse is believed to be in a perfect form — shiny, athletic body:
While in reality, these abnormally bulged muscles are a sign of something being very wrong with this horse. Normally the horse's body has a smooth, round surface, where no muscles would have a separated look to them. Even in movement, a horse shouldn't look like an illustration from an anatomical textbook by which you could learn all the body muscles. Abnormally bulged — chronically over-strained and cramped muscles are a sign of pain.
Now, using the shininess of the coat as a measure of health, correctness of keeping conditions and feeding, etc., which of the horses in the photo is healthier, better kept, etc.?
This photo is taken in April, when naturally living horses usually shed the last of their long used coarse hairs winter coat.
Horse on the left: 5 yo mare, never broken under the saddle (never had a man on her back), never used any other way by a man, lives in species appropriate conditions and never shoed. Never brushed, shedding naturally her winter coat.
Horse on the right: 6 yo gelding, kept stabled his whole life, ridden, just de-shoed after many years being shoed; one of his disorders which was visible enough to be noticed by an ordinary horsemen was a regular cough he had during the winter season; this photo was taken right after he was brought to this place from the stable to live in species appropriate conditions. Brushed and cleaned regularly, blanketed in winter while stabled.
By the definition, the mare is healthier and kept in the better conditions.
(Here is some info to get more idea which way hair can be 'smooth' or 'course' with the example of the human's hair http://www.hairdressersus.com/under%20the%20microscope.asp)
1. Prof Z. Jaworski, Prof T. Jezierski, "Welfare of horses living in nature reserve conditions in Poland".
2. Dr Z. Wroblewski, "The welfare of horses and its transgressions in horse breeding, sport and pleasure riding".
3. M. Vogt, "Harm of riding study".
4. Editors: E.J.L. Soulsby, J.F. Wade, "Proceedings on a workshop on 'Sporting injuries in horses and man: a comparative approach'", 23–25 Sept, 2004, Lexington, USA
5. Lennart Denkhaus "The Importance of Species Appropriate Feeding and Eating Behaviour of Horses".
6. Dr R. Al Jassim, Dr T. McGowan, Prof F. Andrews and Dr C. McGowan "Gastric Ulceration in Horses"
7. M.J. Murray, E.S. Eichorn, "Effect of intermittent feed deprivation, intermittent feed deprivation with ranitidine administration, and stall confinement with ad libitum access to hay on gastric ulceration in horses."
8. Dr H. Strasser, "Shoeing: A Necessary Evil?".
9. Dr H. Strasser, "Harmful effects of shoeing".
10. Dr R. Cook, "Bit-induced asphyxia in the horse".
11. Dr R. Cook, "Bit-induced pain: a cause of fear, flight, fight and facial neuralgia in the horse".
12. N. Aleksandrova, "Thermoregulation in horses in a cold time of year".