Is your horse wearing a suitable rug or blanket for this time of year?

You know your horse better than anyone so try not to be influenced by what others are doing when it comes to rugging up. Go with what is best for you and your horse. Understanding how your horse stays warm will also help you decide what rugs are needed.

“Your horse has his own in-built cooling and heating system called thermoregulation. This keeps his body temperature within a certain range,” says anatomy expert Gillian Higgins from Horses Inside Out. “Sensitive nerves and receptors in the horse’s skin, abdomen, skeletal muscles and parts of the spinal cord send messages relating to body temperature to the hypothalamus, which is the thermoregulatory centre within your horse’s brain.”

Horses keep warm by:

• Insulation — your horse will use fat to generate energy and warmth.
• Vasoconstriction — this is when the capillaries under the skin contract, reducing heat loss.
• Shivering — this rapid contraction of his muscles produces heat.

“Your horse’s hair also plays a key role in temperature regulation,” adds Gillian. “He adapts to the colder weather during winter by growing a longer thicker coat. If you remove that coat by clipping it off, you will need to replace that lost layer with a rug. You may also notice that when your horse is cold his hair stands upright. This is to trap an insulating layer of air to warm him up.”

What happens if a horse is over-rugged?

I’ve already mentioned that over-rugging horses can cause problems and it’s generally a well discussed topic. What exactly are these problems, though, and how can you tell if you’re overrugging?

“Knowing when horses need a rug is pretty obvious,” states scientist Dr David Marlin. “If you have a horse who is shivering, losing weight and doesn’t seem very happy, it’s time to consider putting on a rug. On the other hand, if you put your hand under the rug and the horse is sweating underneath, you know you are over-rugging.”

According to Dr Marlin, the difficulty with over-rugging is that it’s not always that obvious. The trickiest thing to judge is when the horse is too hot but isn’t sweating. A study undertaken at Sparsholt College that used humidity sensors under the horses’ rugs found that horses start to sweat at around 25°C. That is the upper limit of the horse’s thermoneutral zone.

“In the study, the upper neutral limit was exceeded on every horse but only one presented with sweat, even though all the horses were severely over-rugged,” adds Dr Marlin. “The key finding from the study was that when trying to assess this by just putting a hand under the rugs, sweating was only detected in one horse who was wearing four or five rugs. So we could tell by feel if a horse was severely over-rugged, but not when a horse was moderately over-rugged.”

Putting on a horse blanket when it’s not needed

The consequences of putting on a horse rug when it’s not needed are that you’re creating a warm, humid environment under the rug.

“These are ideal conditions for bacteria and fungi, increasing the risk of skin infections. There’s also the issue of vitamin D deficiency, because if your horse is constantly rugged, there’s a reduction in the amount of sunlight reaching the skin,” says Dr Marlin.

“An over-rugged horse will also be using less energy to keep warm, which could potentially play a role in obesity. If you have a horse or pony who is overweight, over-rugging is going to exacerbate that. A horse who is overweight has already got a pretty high level of insulation. They don’t need a rug and taking off the rugs will potentially help that horse reduce their bodyweight.”

‘Rugging a horse isn’t natural’

“One of the problems we have with weight management in general is that we mess with the horse’s natural cycle,” continues Dr Marlin. “In the wild, horses will eat everything that’s available in the summer, get well covered, and then lose this extra layer of fat through the winter, so that by spring they are looking on the thin side and the cycle starts again.

“What we try to do is the opposite, which is have them fit and lean in summer when they’re competing, and then over-feed and over-rug them in winter, encouraging horses to get fat, which results in incidences of metabolic syndromes.”

Dr Marlin’s key message is that rugging horses isn’t natural.

“Most cope well in the wild without our help and when we interfere, we often make things worse,” he explains. “As long as they are in good health, have a good body condition score and access to shelter and ad-lib forage, many horses don’t need to wear a rug — or, if they do, they should only be lightweight rain sheets to prevent the horse getting wet and cold.”

Peer pressure is real!

I can remember being at my livery yard one winter’s evening, preparing to leave. I looked around and saw that every other horse had a thick full-neck stable rug on, with an extra layer underneath. This was compared to my little Bee, who just had a standard neck stable rug on. Hmm. I dithered for a bit and questioned my choices. If the chunky Irish Draught and Warmblood types, who dwarfed my 16.2hh Thoroughbred, were wrapped up so well, surely Bee also needed to be?

For the following reasons, I stood firm and didn’t change his rug:

1. Bee was only partly clipped with a blanket clip, while the other horses were fully clipped.
2. He had recently gone from living in a drafty old stable block that was outside (and he did have a thicker rug on then) to this draft-free and very smart indoor barn, which was naturally a lot warmer.
3. It wasn’t predicted to be cold enough to freeze that night (and it didn’t).
4. I’d owned him 10 years, and knew he was a warm little horse.
5. He had ad lib hay, fed from the floor, and never ran out at night. So plenty to eat and fuel his body’s natural heat-producing process. The other horses all had a haynet, so their forage was limited.

Turns out, I made the right decision by doing what I thought was right for my horse, rather than following everyone else’s lead. Bee wasn’t too warm when I removed his rug in the morning, and he went on to winter well.