How To Keep Your Horse Healthy In The Rain

horses can handle rain, but blankets can incubate rain rot

Yesterday was unseasonably cold and wet.  I watched my horses shivering in the rain, and I wanted to cover how you can keep your horses healthy in the wet, rainy, and chilly weather. You may be asking;

Are horses waterproof? Horses’ coats consist of a soft, fluffy undercoat and a layer of stiff, guard hairs. These guard hairs help to protect the soft hairs and skin from rain, dirt, and sweat. Horses also produce natural oils that coat the guard hairs to make them even more water-resistant. 

Most horses don’t mind a little rain and will often choose to stand outside getting wet even when there’s shelter available. 

If it starts pouring rain, I usually bring my horses into the garden. Then they can choose to shelter in one of the outdoor sheds. They usually turn their noses up at a shelter, opting instead to huddle together, getting as much protection as they can without being enclosed. Even so, your horses must have shelter within a reasonable distance.

Leaving your horses out in the rain day after day can have some nasty consequences. They may not get cold, but they could develop other problems. (See how to identify and treat horse fungus) Let’s cover other dangers and concerns of rain.

Recognize and Treat Rain Rot

Rain rot, or dermatophytosis, is a bacterial skin disease caused by the bacteria Dermatophilus congolensis. While this microorganism is almost always present on the horse’s skin, it doesn’t cause any problems until aggravated. When a horse is exposed to prolonged periods of heavy rain, the skin’s natural protective barriers start to break down. That allows bacteria to flourish and spread. 

The initial signs of rain rot, or rain scald as it’s sometimes called, include:

  • Matted hair
  • Small bumps on the skin
  • Flaky skin
  • Crusty scabs
  • Hair loss
  • Hair tufts that resemble a paintbrush
  • Sensitivity 
  • Skin inflammation

Many symptoms are reactions the horse’s immune system takes to counteract the bacteria. The bumps and scabs are caused by the white cells and proteins that accumulate in the skin to fight off the bacteria. 

As the disease progresses, the skin underneath the tufts dies. Then the scab drops off, taking the hair with it. These areas of bare skin are vulnerable to a secondary infection which is often more severe than the initial dermatophytosis.

But, it’s not all bad. 

The hair will grow back relatively quickly once the infection is gone. Your horse should be back to normal within a week to 10 days. 

Dermatophilosis is contagious and can be easily transferred from one horse to another via shared grooming equipment, halters, and insects. 

I’ve never observed contagious rain rot, even though I deal with it annually. My two mares seem impervious to the rain. But, my Arab gelding has a thin coat and sensitive skin. 

He develops the first symptoms of rain rot after only a couple of hours of light rain. He needs to be rugged during moderate or heavy rain to prevent him from losing so much hair that he is rendered unrideable. 

Rain can present specific issues for horese (1)

How To Prevent Rain Rot

Horses can get rain rot, even when it’s sunny outside. If you put a blanket on a horse that’s still damp or sweaty from a bath or after a training session, he will be as susceptible to rain rot as one standing out in the rain all day. 

To prevent rain rot, make sure your horse is completely dry before putting a rug on him. Even a horse with a hunter clip can get dermatophytosis on the small patch of hair left under the saddle area. 

You can also reduce the chances of rain rot after heavy rainfall. The day after heavy rain, I sponge off the most vulnerable areas using 50% water and 50% apple cider vinegar solution. 

The acidity makes it hard for bacteria to grow. This approach seems to prevent a mild case of rain rot from developing into something more critical and stimulates recovery.

Other horse owners add undiluted apple cider vinegar to their horse’s feed to prevent rain rot from occurring at all. I haven’t tried this, and there is no research to prove this theory. If you struggle with rain rot, it might be worth a shot. 

You can also prevent rain rot by sheltering your horse or by using a rain sheet.

The Pros And Cons Of Using Rugs To Prevent Rain Rot

Usually, I avoid blanketing my horses wherever possible. But, if it’s pouring, I have little option but to rug my Arab gelding because he’s so susceptible to rain rot.

I’m not a fan of blankets as I worry about the extent to which they can disrupt the horse’s natural processes of thermoregulation. 

You may not know that horses have hair erector muscles that enable them to raise, lower, and turn individual hairs in different directions – a process known as piloerection

When blanketed, a horse’s coat lays flat, and he doesn’t activate his hair erector muscles. As a result, these muscles can begin to atrophy. It becomes more difficult for the horse to adapt to cold temperatures, making him more susceptible to hypothermia.

Rain sheets or blankets made from non-breathable fabrics provide a favorable environment for rain rot. They block air movement and prevent a horse’s sweat from evaporating. 

Similarly, putting a rain sheet on a horse that’s already wet prevents moisture from escaping. This breaks down the skin’s natural defense barriers.  

The other issue I have with rain sheets is getting them on in time. By the time I’ve run up the field with a rain sheet, my horse is already wet. I worry that by putting a rain sheet on at this late stage, I’m making the situation worse rather than better. 

A better solution is to provide your horse with a shelter that keeps him dry while allowing his natural methods of thermoregulation to continue.  

This study conducted into the behavior of Nordic horses in different climatic conditions showed that horses are more likely to seek shelter on rainy days than on cold ones. It also revealed that warm-blood horses are more likely to seek refuge than cold-blooded breeds, like Shire horses, Percherons, and Clydesdales.

If you can’t provide your horse with selective shelter, then stable him during heavy rain. As a last resort, use a rain sheet to protect him during showers. Be sure to remove the rain sheet as soon as the rain is over to allow both it and your horse to dry out.

Treat Rain Rot

In addition to apple cider, you can take a more conventional treatment method to treat rain rot. Wash your horse once or twice a week with an antibacterial shampoo that contains chlorhexidine, povidone-iodine, or benzoyl peroxide. 

After shampooing and rinsing him, dry your horse thoroughly. Gently remove the scabs as you go. This process allows oxygen to get to the skin underneath, facilitating the healing process.

For some horses, rain rot is painful. Be cautious when removing the scabs, as this process can be very uncomfortable for the horse. You can also make the process less agonizing by dipping a sponge in a natural oil blend and soaking the scab. Lavender oil is perfect for rain rot as it soothes the sensitivity and has both antibacterial and anti-inflammatory properties. 

In severe cases, your veterinarian will probably recommend a course of antibiotics to combat the underlying bacterial infection. 

Keeping your horse separate from the herd is critical if you hope to prevent the condition from spreading. You also need to clean your equipment carefully after using it on an infected horse.

Once the weather improves, mild cases of rain rot will resolve themselves naturally, especially if the horse is in overall good health. In other situations, untreated rain rot can cause secondary infections and transmit to others.

mud fever is one danger of rain for horses (1)

Identify And Treat Mud Fever

The same bacteria that causes rain rot also causes mud fever. The main difference between the two is where the problems occur on the horse. 

Rain rot usually affects the horses’ rumps, hind legs, backs, withers, and faces. Mud fever, on the other hand, only affects the pastern and heel. Another name for mud fever is pastern dermatitis, and it occurs when horses are exposed to wet or muddy conditions for prolonged periods. 

Rain is a significant factor in mud fever, but it’s not the only one. 

Washing your horse’s legs too frequently removes too many of the natural oils the horse produces for protection, causing a weakening of the barrier that prevents bacterial infections. 

Some deep litter bedding contains ammonia which may irritate your horse’s legs, making him more susceptible to mud fever. Dirty boots and bandages can also cause the condition. 

Also known as greasy heel, mud fever usually affects the pastern or heel and more commonly occurs on the pink skin of horses with white legs. Certain breeds of horses are also more susceptible to the condition. Arabs and Thoroughbreds, for instance, both have comparatively thin skin, which, because it can be damaged more easily, is more vulnerable to bacterial infections.   

  • Frequent leg washing
  • Deep litter bedding with ammonia
  • Arabs and Thoroughbreds are more prone

Recognize The Signs Of Mud Fever 

The first signs of mud fever include:

  • Matted hair
  • Hair loss 
  • The appearance of crusty scabs
  • A thick, creamy discharge between the scabs and the skin
  • Horizontal cracks 
  • Raw, inflamed skin
  • Heat and swelling

Most horses stay outside in the rain (1)

Treat Mild Mud Fever In Horses

Although it may seem counterintuitive to wet a horse suffering from mud fever, keeping his legs clean and free from bacteria is crucial. Wash your horse’s legs thoroughly. Concentrate on the affected areas. Use an antibacterial shampoo and towel dry your horse’s legs afterward.

After washing and drying your horse’s legs, you may need to clip your horse’s feathers. Then, you can access the problem area more easily. It allows air to get to the wounds and accelerate the healing process. 

Crusty, loose scabs can be removed gently to reduce pain. Some horse vets recommend softening the scabs first with coconut oil. The British Horse Society says the use of oils and ointments can exacerbate the problem. You’ll have to watch your horse to see how your horse responds in your specific climate.

Topical ointments that contain benzoyl peroxide, ethyl lactate, chlorhexidine, or mupirocin are the most effective for treating mud fever. 

Once your horse’s legs are clean and dry, apply the ointment and keep your horse in a dry environment, stabling him if necessary. A liquid bandage containing hydroxyethylated amylopectin can also be effective when applied every 1 to 3 days after cleaning.

In severe cases of mud fever, your veterinarian may need to take a blood test to identify the underlying disease, especially if it isn’t responding well to topical treatments. Anti-inflammatories may also be necessary, along with a course of antibiotics.

Prevent Your Horse From Getting Mud Fever

The following tips will help you avoid the underlying causes of mud fever and prevent the condition from occurring:

  • Make sure your horse has somewhere dry to stand for at least part of the day;
  • Avoid washing your horse’s legs. If your horse comes in from the field with muddy legs, wait for the mud to dry and brush it off with a soft-bristled brush;
  • Check your horse’s legs every day for sores and wounds. Treat them immediately with a topical antibacterial ointment to prevent further infection;
  • Use a barrier cream, like nappy rash cream, to protect the sensitive skin around the pastern and create a protective layer between the skin and the mud. 
  • Use turn-out boots made from breathable fabric. Ensure these boots fit correctly, as any rubbing could cause sores to develop.

Get Rid Of Thrush: Diagnosis, Prevention, And Cure

Thrush is a bacterial and fungal infection of the hoof that is easy to identify due to the unpleasantly pungent smell it emits. The condition usually originates in the grooves, or sulci, on either side of the frog. Horses with low heels and deep grooves are more susceptible to thrush than those with correct conformation.  

I have just finished treating a mild case of thrush in my Percheron-cross mare. She loves standing in the pond and eating water lilies. I think the thrush occurred due to having wet legs and feet for so many hours of the day. 

  • The first step in my treatment plan was to move her to a different paddock so she couldn’t give in to the temptations of the waterlilies. 
  • I cleaned her hooves thoroughly with a hoof pick and stiff brush and applied a solution consisting of 50% water and 50% apple cider vinegar to the affected area. After a couple of days, the frog had dried up, and the infection was gone.

With a more severe case of thrush, this approach may not be as successful. More aggressive treatment may be necessary. This process involves removing any necrotic or rotten tissue from around the frog to allow air to access the healthy tissue underneath. Thrush is very sensitive to oxygen, and improving airflow is crucial to the healing process. 

  • Scrubbing the affected area with iodine will also help accelerate the healing, as will the application of commercial products that contain gentian violet.

Conclusion

Although horses have waterproof coats, exposure to heavy rain for a prolonged period compromises the skin’s natural barriers. Rain rot, mud fever, and thrush all take advantage of wet, muddy conditions and can cause severe pain, swelling, and even lameness. Fortunately, by taking the steps we’ve covered, you can protect your horse from those dangers. 

Nicky Hoseck

I’ve been around horses since the age of six and, 15 years ago, leapt at the chance to leave behind my London-based career in journalism and start life on a small-holding in South Africa. Sharing my experiences with horses, goats, and other farm animals allows me to flex my writing skills and help others find their way to a happy, healthy herd.

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