Under Australian conditions, many more horses are overrugged than underrugged. To understand why this can be a welfare and even serious health problem, the physiology of homeostasis and sweating must first be explained.
Homeostasis is the ability of warm-blooded animals to maintain their internal environment within tight physiological limits despite changes in the external environment. However, these external fluctuations must not be too severe, otherwise homeostasis cannot be maintained and ill health, even death, will result. An obvious example is extreme heat or cold; both will cause death unless the animal is protected or removed from that environment. The maintenance of homeostasis can be assisted by correct care and management techniques (e.g., by providing protection from the elements), but animals must not be handled/housed/managed in such a way that the natural mechanisms used to maintain homeostasis are disrupted. Inability to lose body heat due to overrugging is a prime example.
Sweating is the mechanism by which horses and many other animals remove heat from the body. If sweating is prevented from occurring by, for example, an impervious rug, the animal will overheat and develop heat stress. In other words, the horse effectively begins to cook in its own juices because homeostasis cannot be maintained and then the body systems will start to malfunction and break down.
One of the most damaging notions ever perpetrated is that fit horses do not sweat. This is absolute rubbish. Horse MUST sweat when they are hot, otherwise they will develop heat stress. The evaporation of sweat from the skin removes body heat with it. The fit-horse-not-sweating myth perhaps arose because soft or “new” horses produce a soapy sweat that lathers easily. As they get fitter, the sweat becomes more watery and evaporates more quickly. An endurance horse, for instance, will continually sweat, dry off, then sweat again - which is what they should do as they approach peak fitness.
Non-sweating in working horses is actually cause for great concern, because it means they have a condition known as anhydrosis (the puffs, puff disease, dry coat). It is common in hot, humid climates including coastal south-east Queensland. It prevents horses being much use at all in countries like New Guinea and severely limits their usefulness in tropical Australia. “The puffs” are well known in the Kimberley region and Darwin; affected horses sweat poorly, puff (pant) after very little work and will collapse if forced to continue. They often recover if moved south to low humidity regions like Alice Springs. It is not difficult to pick horses with some degree of anhydrosis. Although good in the coat, they do not quite have the sheen of their counterparts. Racehorses in the early stages of the disease might perform below expectations and may pant heavily and for a longer period than normal after a race.
Anhydrosis is a progressive inability to sweat, due probably to an initial overstimulation of the sweat glands in conditions of heat and high humidity, then for some reason the sweat glands shut down just when they are needed the most. Affected horses will pant excessively during and after work, but unlike dogs, this is an inefficient way to lose heat, as evidenced by rectal temperatures which will be dangerously high. The immediate treatment for the distressed, anhydrotic horse is to replicate sweating by hosing and placing under a fan or in a current of air. Various dietary supplements have been claimed to assist the condition, including one containing an amino acid specifically involved in sweat gland stimulation and which seems to be affecting a cure in some cases. Most horses cease to display the symptoms anyway once the cooler weather comes or if they are moved to a lower humidity climate. Air-conditioned stables are a solution, though an expensive one, with their own set of management problems.
Additional mention must be made here of the practice of cooling-out, which in essence means assisting a horse to cool down gradually after strenuous exercise. This is usually done by rugging in such a way that the horse cools more slowly than if simply exposed to the elements. For various physiological reasons the practice does have merit, particularly in cool conditions, but the initial rug used should be lightweight and breathable (a “cooler”) and the horse should be walked as well, then as he begins to cool down (or warm down, as the athletes say) a heavier covering can be added. It can take more than an hour for body temperature to return to normal after strenuous exercise.
Unfortunately there is a really crazy and downright harmful belief amongst some horse owners that the correct way to cool-out horses is to pile heaps of rugs on them immediately after exercise then gradually remove them one by one over a period of time. This is exactly the opposite of what should be done, because these horses are desperately trying to lose body heat, which they have no hope of doing efficiently with one rug on let alone several. In fact in hot weather it is downright criminal to put even a light rug anywhere near a hot horse.
Cramping is a possibility if muscles are actually allowed to get cold too soon after competition, and this is where the real art of juggling the correct weight of clothing or rugs lies, but it has nothing to do with catching a “chill” - in the kidneys or elsewhere. What was once known as a chill is actually a cold and is due to viruses. The viruses that cause colds are more prevalent in cold weather, in fact some may become activated by cool conditions, but cold weather itself or being cold or standing in a draft are not the reasons animals and humans contract colds and flu.
In southern Queensland and many other parts of the world as well, winter temperatures often climb into the mid-twenties during the day, much too hot to leave heavyweight rugs on horses, in fact it is downright cruelty. And yet it is not uncommon to see some poor horse sweltering in a paddock in the full sun under a heavy rug, sometimes wearing two as well as a hood, no part of which ever seems to be removed.
As already discussed under homeostasis, all mammals must be able to maintain their body temperature within a narrow critical range in order to remain healthy - and horses are flesh-and-blood mammals like ourselves, not some inanimate object like a car, simply to have a cover put on it to protect its external surface and be forgotten about all week. Certainly horses feel the cold, which they compensate for by growing a winter coat and fluffing it up to trap air if necessary for added warmth, but they can also feel extremely hot. Horses sweat to cool themselves, but the evaporative cooling effects of sweat cannot work if the horse has a rug on. If a mammal becomes too hot its body actually starts to cook and you have the serious medical condition known as heat stress, which in its severest form can be fatal, as with children and dogs locked in hot cars. But aside from heat stress, if horses are unable to lose body heat because of impervious rugs the illhealth problems that can result include dehydration, electrolyte imbalances, lack of vitamin D and finally a total inability to sweat (anhydrosis).
The moral of the story is that if you feel hot so will your horse, probably even more so out in the paddock in the sun where it might be many degrees hotter than it is for you indoors. It is much better not to rug your horse at all if you are not going to be around to take it off or replace it with something lightweight and breathable as the day warms up. Conversely, once you start rugging for the winter you should rug every night. If you have doubts about being able to do this due to work, family or distance commitments, then leave horses to grow their own winter coats and keep themselves warm. Horses that have been clipped are a different story and require very careful management rugging-wise. Clipping in winter assists horses in hard work to sweat more efficiently and dry off more quickly, but they must be rugged adequately and during the day as well unless it is very warm and sunny.
Horses being transported should not be overrugged if they are rugged at all. Much depends on the vehicle. The wind chill factor present on the back of an open truck may be completely absent in a closed float. Even if well ventilated, fully enclosed floats and trucks can become very warm inside due to body heat generated by the inmates. Horses should be checked regularly to make sure they are not too hot and even sweating under rugs, particularly if they were loaded before cooling down properly after competition. Temperature can be judged by feeling with the hand.
Rugging is not a substitute for grooming. In fact habitually rugged horses need much more frequent grooming than their unrugged counterparts. Rugs should be removed a couple of times a day and the horse groomed or given the opportunity to roll. An added advantage is that frequent removal and replacement of rugs ensures they are kept straight and comfortable for the horse.
There are some awful myths around about the benefits of rugging. It will not keep paddock horses in good condition in winter without adequate feed, or make working horses perform better, or make mares produce bigger foals. In fact it is dangerous to rug heavily pregnant mares in case they start foaling with the rug on. Horses do not require keeping “warmer” than any other animal to ensure their good health, in fact being kept overwarm leads to ill-health. Rugging has very little effect, if any, on reducing feed consumption in cold weather. It is much better to let horses grow their own woolly coats and put the money you might have spent on a rug into buying feed.
It is not normal for a rug to rub a horse’s shoulders. A properly fitting, properly lined rug does not do this. The extensive areas of baldness you see on the shoulders of some horses is not something to be accepted as part-and-parcel of rugging, in fact are indicative of what must have been long hours of discomfort for the animal.
Hoods left unsupervised on paddock horses are dangerous because they can slip and blind the horse with disastrous results. Also they can get crooked and pull so tightly that they prevent the horse from grazing. This also applies to rugs which can be so poorly fitting that they slip all to one side and effectively hobble the horse, not to mention the rubbing and discomfort caused.
There are many situations where rugging is appropriate and correct, and there are many types of rug available, from very heavy canvas to ultra-lightweight cotton or satin fly sheets. The standard paddock rug is waterproof canvas with a blanket underlining. It is kept on the horse by a front chest fastening and leg straps crossed between the hind legs and clipped to the back of the rug. Some have a belly fastening that is often less than satisfactory and is best removed before the horse catches a leg in it.
Usually the more you pay for a paddock rug the more waterproof the canvas, the more resistant to tearing, the better the fit and the more extensive the underlining. Rugs are notorious for rubbing on the shoulders, but if the underlining covers that area and there is some pleating to shape the neck (and the rug is the right size in the first place) the problem is largely removed. Rugs are measured from the middle of the chest to the point of the buttock.
Lighter materials than canvas are available for paddock use, some of which have special “ripstop” qualities that prevent rugs getting torn by teeth or on fences. There are all sorts of quilted and fibre-filled rugs of various weights, some of which are breathable and will wick sweat and moisture away from the horse’s coat, as do open-weave cotton “coolers”. Some rugs have tail and neck pieces for added warmth and protection. Stable rugs or blankets are traditionally wool or wool/synthetic mixtures. Jute is a less expensive alternative, it has good wicking properties and makes a satisfactory underrug.
Grooming for hours does not particularly improve a horse’s coat - this comes
from within, through proper feeding and general care. In fact a horse can be
given a thorough grooming in under a quarter of an hour. There are many
different methods and grooming tools but the following routine works as well as
any.
1. Gently remove dried mud with a rubber curry comb. This tool can also be used
to clean brushes.
2. Use a rubberised glove covered in small, smooth projections (e.g., Groom-Mit)
with some firmness all over the body to stimulate the skin and remove dead hair.
3. Tidy the mane and tail with a long-bristled stiff brush (dandy brush) or
metal thick-toothed comb.
4. Brush the horse all over with a short-bristled soft brush (body brush),
wiping it periodically on a dampened towel to remove dust.
5. Give the horse a final wipe over with the dampened towel, including eyes and
nostrils if desired.
6. Clean out the feet with a hoof pick or similar.
A scraper is another grooming tool found in most horse establishments, some are quite elaborate combinations of metal and rubber with a handle, but any thin strip of flexible metal is suitable provided it will not cut the horse. Scrapers are used to remove sweat and water from horses after they have been hosed. If the weather is cool, sweat should be removed with a damp towel rather than hosing.
On the subject of grooming, never should the feather be removed, or the tactile hairs (whiskers) from around the muzzle, or the hair from within the ears. All serve a purpose. The feather takes water away from the heel area, ear hair prevents grass seeds and dirt gaining entry, and the whiskers probably relay necessary tactile information to the horse about objects (e.g. feed, grass) in the vicinity of the muzzle.