How and what we should use to rug or horses has become a hot debate just lately. As owners, we become cold and wonder if our horses are warm enough. Horses have a wonderful capacity of self-care, of which their internal thermostat is included. Over-rugging actually causes many more problems than those associated with a cold horse and many ‘manmade’ issues can be avoided with correct usage of rugs.
So, what should we be doing about rugging our horses? We need to have a look at the science behind what helps our horses and see if we can be a little more understanding.
Rugging Science.
Before us humans decided to come into play, horses lived freely in the wild, self-regulating their temperature (a process called Thermoregulation) to ensure it remained consistent, sitting between 37.2 and 38.3°C (99-101°F). Horses generally use energy to keep warm, however, studies show that an air temperature must continually sit below 9°C before a horse uses any of its energy maintaining its own body temperature.
Horses graze easily graze for up to 19 hours a day. During this time, the digestion of long fibres and forage in the hindgut continually produces heat through the peristaltic movement. This is the movement in the hindgut and this movement increase the blood flow and ensures a continued heat source for the horse, which is why ad-lib forage is so often recommended, particularly through the colder Winter months.
Over thousands of years, as the horse has roamed and evolved, they’ve learned to adapt to, and deal with, the ever-changing climates. One thing has remained consistent throughout and that is their foraging and grazing manner and their ability to self-regulate their temperature, the two of which go hand in hand. As horses have become domesticated, their body regulation hasn’t changed to the extent in which our management of them has. Despite us often offering them a restricted diet, they still manage to control their temperature, as they adapt to our feeding regimes.
With over rugging it is not only just the overheating that is a problem, continued over-heating can cause colic-like symptoms and also not help with laminitis.
So what happens when my horse is too hot?
Horses have several ways in which they try to cool themselves down, including;
- seeking shelter from direct sunlight during the day,
- sweating, which dilates the blood vessels and increases the respiratory rate,
- the horse lowers its metabolism and will eat less so less internal heat is produced.
A general rule is a skinny horse is more likely to struggle to keep warm whereas a fat horse is more likely to struggle to keep cool
If none of these attempts are successful then the horse’s welfare can be significantly affected as the core body temperature continues to rise. Once this level has been achieved, hormone levels are affected. The result of which can lead to;
- the horse eating less to try to limit the production of heat in the body resulting in undesired weight loss,
- the body may not be able to fight disease as the horse’s immune system drops,
- lactating mares may suffer from milk production,
- breeding stallions may not be able to produce sperm so efficiently,
- an increase in chances of the horse becoming obese,
- a significantly increased risk of Laminitis.
The link with Laminitis
Many believe Laminitis is just a seasonal grass related issue, however, over-rugging can increase your horses chance of developing the disease in Spring. In the wild, horses would gain weight through the Spring and Summer and use that weight to keep themselves warm over the Winter, as they gradually lose the weight. The result is that come Spring, their weight is on the lower side so they can start eating the sugar-rich grass with little problems. When over-rugging through the Winter months, the horse doesn’t use up any of its weight, which throws his hormone levels off balance, which can have a detrimental impact on his health. Laminitis in unfortunately a terminal disease and can be fatal.
Seasonal rugging
Having looked at the detrimental effects of over-rugging, how can you be sure what and when to rug? Spring and Autumn are particularly trying times as the temperature fluctuates so much – the difference between first thing in the morning and the middle of the day can easily be 10°C, making rugging in the morning rather trying. You almost certainly need to change rugs every morning and afternoon if at all possible for these seasons to ensure your horse remains as happy as can be, and the perfect comfortable temperature. Is it better for your horse to be too cold or too hot?
As we have stated above, horses can self-regulate, so if they’re too cold, they can warm themselves up quite easily, however the same can not be said if they’re too hot. Cooling themselves down when they’re over-rugged is practically unachievable. Therefore it is always best to leave your horse naked or to put the lighter weight rug on your horse in Spring and Autumn when the temperature difference is so excessive.
Rugging at nighttime in the Spring and Autumn is entirely dependant on a number of factors including; whether your horse is clipped; is your horse living in or out; is your horse young, old or unwell; has your horse recently been bathed and therefore has had all oils removed the skin?
Very few rugs are required in the Summer months – your rug of choice would most likely be a fly sheet, which due to its colour acts as a heat defensive system, retracting the suns rays, keeping your horse cooler for longer. Alternatively, even in the evening, you may wish for a summer sheet, just to keep the horse’s coat clean.
The table below gives an idea of what to rug when.
| Clipped – stabled | Clipped – lives out | Unclipped – stabled | Unclipped – lives out | |
| 10°C or
higher |
Lightweight or fly rug in Summer months | Lightweight or fly rug in Summer months | No rug/fly rug in Summer months | No rug/lightweight if wet and windy or fly rug in Summer months |
| 5 – 10°C | Medium weight | Medium weight with neck | Lightweight | Lightweight with neck |
| 0 – 4°C | Heavyweight | Heavyweight with neck | Medium weight | Medium weight |
| -10 – 0°C | Heavyweight with neck | Heavyweight with neck and sheet underneath | Medium weight | Medium weight with neck |
| -10°C or colder | Heavyweight with neck and thin stable rug underneath | Heavyweight with neck and stable rug underneath | Heavyweight | Heavyweight with neck |
On the whole, it is better for horses to be slightly too cold than too hot. Horses that are clipped, under the weather or older, will require more rugging through the colder Winter months than ‘good doers’, Native Breeds and those that are unclipped. Every horse is DIFFERENT and should be treated as an INDIVIDUAL case. The table above is a guide only if you’re still unsure please do speak to your Vet. Do try and use your initiative, speak to a professional and you’ll have a happy, healthy horse.
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