There are many reasons for keeping horses inside during the summer months, from preparing for a show to not having the space to turn them out. During the winter months, the climate in many states is such that people often keep horses in a tightly closed barn. If you keep your horse inside most of the time, you need to be aware of some serious health concerns.

Horses need vitamin D which is obtained from sunlight acting on the skin. Horses that are kept totally inside could become deficient in vitamin D, critical to calcium and vitamin A metabolism. Good quality green hay and many supplements contain vitamin D, but that is never as good as the real stuff obtained outside in the sun.

Vitamin E is supplied best in green grass, and some in good green hay. A horse that has no access to the fresh green stuff, may need to be supplemented. Vitamin E has many important uses in the body, including muscle, reproduction and immune system function as well as is an important antioxidant. Natural source vitamin E (d tocopherol) should be used if supplementation is needed. You may need 1000 to 2000 IU per day if your horse has some access to fresh green forage, and up to 5000 IU per day if your horse has no access, especially in the very northern parts of the country where hay is fed for many months.

The mental benefits horses gain from being outside can be critical to our ability to have a safe ride. Horses were designed to run and play – both for their mind and their physical health. Horse that do not get out to play are consistently stiffer and more arthritic than their pasture counterparts. Inside horses need more tranquilizers, herbal relaxers and prayer to keep them sane; the prayer is for our safety as they get tense and try to buck or run away.

One of the more stressful things done to our horse’s respiratory tract is to keep them in a barn with the doors shut. A horse is designed to live outside – that is why he grows a furry winter coat and has a very complex, unique system of shunting blood around to keep his feet warm. When we put our horse in a stall he/she cannot move freely and keep his/her respiratory tract clear. Dust, and ammonia from the urine irritate the respiratory tract. Horses are designed to eat off the ground and the practice of feeding grain, water and hay from buckets and mangers at chest height or higher keeps the irritants in the lungs.

Horses spend a lot of time with their head on the ground, even if they are fed from a manger. Ammonia is a very toxic compound to lung tissue. Ten parts per million (ppm), the level where you can just detect an ammonia smell, is already toxic, and at 30 ppm your eyes will water. In one study, men working a 40-hour week in 11 ppm of ammonia developed ulcers in their lungs. Air circulation studies in English barns point to increased ammonia and dust as significant factors in the development of allergic lung disease such as heaves. Several studies of pigs have shown that their lungs lost up to 2/3 of their capacity in six months of living with high levels of ammonia. Ammonia levels are much higher in urine from horses fed excessive amounts of protein; any feed with 12% protein and above can increase the odor.

Most people do not realize that they have an ammonia problem, because they do not get down to the horse’s level and smell the ground, especially after a horse has spent 12 or 15 hours in the stall. If you walk into your barn in the morning and can smell ammonia there is a severe problem, and in those barns I see a much higher instance of respiratory disease. However, many barns have an ammonia problem and the owner does not know it, because the humans that inhabit the barn have become accustomed to the smell. Ask a friend who has no horses if they can smell ammonia in your barn after it has been closed up all night. Believe their answer; theirs will be the most objective opinion.

We keep barns closed in the winter for one reason – our own personal comfort. In the summer, some barns have good air circulation, while others have nice air flow down the aisle, but the stalls have stagnant air. The ideal barn has stalls open to the outside or big wide spacious aisles with good air circulation, and partial doors, gates or stall guards to allow air circulation at the most critical place – the floor. However there are ways around the dilemma for most barns if you do not have the luxury of the perfect barn.

1. Open the doors and windows in the winter as well as the summer! Close them while you work for your own comfort, then open them and let the sunlight in. If the wind threatens to carry everything away, open only the door opposite the direction of the wind.

2. Clean the wet spot out of the stalls every day. Letting the wet spot build up, then stripping the stall every couple of days or once a week increases the ammonia at nose level for the horse, even though you may not smell it. True deep-letter bedding where you add bedding each day, and only clean out in the spring can work well if you use enough bedding and clean properly.

3. Check your bedding. Straw, though pretty, is not very absorbent, consequently, long before morning, ammonia levels are quite toxic. A base of shavings or something else absorbent may help. Some of the newer pelleted materials may be more absorbent, but you still need to keep them clean. Carefully evaluate the amount of dust your bedding produces and try to reduce it. Sometimes moistening the bedding can help, if something like sawdust is too dry and dusty.

4. Do not skimp on bedding – especially for barns with rubber mats in the stalls. Thin bedding may be enough for cushioning but will not necessarily absorb the ammonia.

5. Use stall guards or screens especially if you have full length doors with small windows and little cross-ventilation. Cross-ventilation is the most important and least practiced item you can do to help your horse’s respiratory tract. The air must circulate at the floor level to be effective, not just 4 to 6 feet up over the top of a door or window.

6. Use an extra Thinsulate™ or other lightweight blanket if your horses are clipped and need additional warmth. These blankets weigh only a few pounds and are warm enough to keep most horses almost sweating in all but the coldest weather. Then you can leave the doors open for the air to circulate.

7. Use lime or soft rock phosphate to help reduce ammonia odors, but they will not cover up heavy ammonia odors; good management is needed for maximum benefit.

8. Use an odor-controlling product, but be careful as just adding a stronger smell to cover up the ammonia does not eliminate ammonia and may increase the amount of chemical irritation in the horses lungs.

9. Avoid the use of blowers when the horses are in the barn. Blowers raise an incredible amount of dust. Try getting some good, old fashioned exercise and use a broom unless the horses are out.

Horses kept outside with shelter from the wind and rain are consistently the healthiest animals I see. My own horses live out though all weather with a run-in shed and extra hay to keep them warm in very cold weather. However, not everyone has pasture with shelters, and there are some horses that really prefer to live inside. If a horse prefers to live in, they should have their needs honored, as horses that are not acclimatized to living out can be quite miserable. Two of the horses at my house spent their first winter going in at night; now, they prefer to stay out.

Most horses will adapt to being out and will do less damage to themselves in the long run. However, if a horse is only turned out occasionally, it will generally run around and act crazy. When this happens, many riders get scared and bring the horse back inside. It is much better to tranquilize them, turn them out regularly and give them time to acclimatize to the new program.

Do not do a disservice to your horses by keeping them in just because you are cold. If you turn them out and the weather is miserable, they will tell you when they are ready to come in. Let them in, it will be their choice, and they will be less likely to tear the barn down. Use common sense, however, when ice is present as it can be dangerous. Horses that go out regularly get into less trouble and are much happier.

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