When to Rug a Horse: Judging Need, Fit and Condition

It's a frosty morning, you're standing in the yard with cold hands, and the rug is hanging right there. Before you reach for it, it's worth knowing that too many layers can cause your horse discomfort, just as too few can. There's no single answer for every horse, so this guide covers how to judge the need, check comfort and fit, and recognise when something's wrong.

Start with the horse, not how cold you feel

It's natural to judge by your own cold fingers, but horses don't feel the cold in the same way we do. They're naturally better equipped for cold weather, especially once they've grown a thick winter coat, and many native breeds and cob types cope without a rug when they're healthy, have enough forage and can reach shelter. It's best to assess each one as an individual.

A few questions are worth working through. How much fat is your horse carrying? What does the forecast say, including the 'feels like' temperature and how heavy any rain might be? Can they get to natural or man-made shelter, and are they stabled or turned out? Their health and whether they're clipped matter too.

Forage and movement do a lot of the work. The process of digestion creates heat, so a horse with a constant supply of forage is more likely to keep themselves warm, and movement creates heat as well. If you're thinking of moving to a heavier rug, first consider whether your horse has adequate access to forage.

Wet and windy weather also matters more than dry cold. Horses are more likely to feel cold in a combination of prolonged rain and wind than during dry, cold weather, which is why good shelter makes such a difference.

Which horses may need a rug

Some horses do benefit. Breeds with naturally finer coats, such as Thoroughbreds or Arabs, may need one, as may horses that are older, unwell or have difficulty regulating their body temperature. A fully or partially clipped horse has reduced natural insulation, although some cope fine without a rug if they have a bib or trace clip. Very young horses and older horses may be more likely to need rugs, but weigh up everything else about the individual before deciding.

Body condition matters too. A rug can help an underweight horse by reducing energy loss during cold weather. At the other end, horses carrying too much fat have better insulation, and winter can help overweight horses lose weight naturally because they use more energy keeping warm. So it's best to avoid rugging an overweight horse unnecessarily, unless their individual needs mean they require one.

Using a weigh tape alongside fat scoring every two weeks will help you monitor your horse's weight, so you can see whether they're maintaining, losing or gaining as winter goes on.

If your horse hasn't worn a rug before, build positive associations with the rug and take your time.

The risks of over-rugging

Over-rugging can lead to overheating, limit normal social and self-grooming behaviours, and contribute to obesity. An unsuitable rug can also flatten the hair, which makes it less efficient at trapping heat. A rug that's too warm can trap heat, so your horse finds it harder to cool down, and horses find it easier to warm up than cool down.

World Horse Welfare gives a clear example of how this happens: an unclipped, stabled horse with access to forage all night in a heavyweight rug, with a neck, in mild weather could easily become too hot and start sweating. A native horse with a long, thick mane might not need a rug with a neck cover either, because their mane already provides protection and insulation, and the cover could cause rubbing or pulling of the mane.

Heavier rugs aren't always necessary, so only add rug weight when your horse is showing signs of being cold. Bear in mind that moisture can build up if your horse is over-rugged, even before any dampness can be felt under the rug.

Checking comfort under the rug

The simplest check is to place your hand under the rug behind the withers. Your horse should feel comfortably warm and dry. If you're worried they're cold, feel right next to the skin.

Signs your horse may be too hot include sweating beneath the rug, increased or heavy breathing, lethargy or irritability, frequent rubbing, and warm, damp skin under the rug. If you see these, don't wait for the weather to change: change to a lighter rug or take it off, then check again with your hand under the rug. If you're worried, including about heavy breathing or lethargy, contact your vet straight away. Signs they may be too cold include shivering, a tail tucked tightly against the body, actively seeking shelter, increased movement or pacing, and gradual weight loss.

Conditions may feel cold early in the morning but become significantly warmer by midday. If you're unable to adjust the rug during the day, choose the lightest suitable option and avoid over-rugging.

Fit and rubbing

Rug type matters as well as size. A turnout rug is waterproof and designed for horses spending time outdoors, whereas a stable rug is a rug or sheet used indoors, often made from cotton or fleece. If your horse needs a rug outside, choose a waterproof one.

To measure for a rug, use a soft tape from the centre of the chest, around the widest part of the shoulder and along the side of the body to the point of the buttock. Compare the figure with the manufacturer's size guide, as sizing may vary between brands. Check the fit carefully with a new rug, particularly around the shoulder, withers and chest, and make sure the straps are secure but not overly tight.

If your horse wears a rug, take it off every day to check for rubbing, soreness or discomfort. An ill-fitting rug, or one left on too long, can cause injury, so refit or change it if needed.

When to call the vet

Elderly, very young or sick horses may have different needs, so ask your vet for advice about whether rugging suits them in particular weather. A horse that's lethargic, eating less than normal, standing with their head lowered, tucked in and away from the wind, or seeming unhappy or depressed may not be warm enough, as may one with visible shivering or a body that's cold to the touch under the rug.

If you're worried about your horse's wellbeing, contact your vet straight away.

Shelter matters with or without a rug

Horses and ponies kept outside in winter must have access to shelter at all times. If you can't provide that, you must move or permanently stable them. Thick hedges and tree lines make great natural shelter, but trees that lose their leaves during winter can be inadequate, and without natural cover a field shelter is needed. Field shelters must be dry, draught-free and large enough for the horse to move around comfortably.