Hay is nothing more than dried grass, but unfortunately, during the drying process, some things are lost. Especially vitamins and fatty acids. If your horse is on pasture for less than four hours a day, or wears a grazing mask, it is necessary to supplement with some nutrients. For example, with a supplement or a balancer. Hay alone is really not enough, not even for hardy breeds!

Vitamin A for the eyes, growth and fertility

Vitamin A and vitamin E are the most important vitamins to consider when a horse has limited or no access to pasture. Vitamin A plays a crucial role in vision, fertility, reproduction, and the development of young horses. In the horse's body, carotene from grass is converted into vitamin A. Green grass contains enough carotene, along with a small amount of fat needed for conversion. However, after the grass is harvested, the carotene content quickly decreases. Hay contains almost no carotene after several months of storage. Many people give their horses carrots in the winter. Not a bad idea per se, as carrots contain carotene. But it's not enough: you would need to feed a horse about 7 to 10 kilograms of carrots per day to meet the daily requirement. Considering the sugar content of carrots and the risk of diarrhea, this is not a good option!

Vitamin E

Vitamin E is a very important vitamin, especially for muscles, the nervous system, and immunity. It acts as an antioxidant against tissue damage and aids in recovery after exertion. Horses cannot produce vitamin E on their own. Therefore, it must be included in their diet. Just like with vitamin A, a small amount of fat is needed for the body to absorb vitamin E. Grazing horses usually get enough fat from green grass to meet this need. Green grass also contains more than enough vitamin E. Vitamin E is quickly lost during the drying of roughage. The vitamin E content in hay can vary widely. Horses can store a small amount of vitamin E. If horses are on pasture for about eight to ten months per year and do not have to make significant efforts, their own store may be sufficient to get through the winter. However, young horses, pregnant mares, and sport horses need more and are more likely to experience a vitamin E deficiency if they are not on pasture. A deficiency can lead to muscle weakness, stiffness, and poor immunity. Therefore, it is wise to supplement growing horses, pregnant mares, and sport horses with vitamin E if they don't have full access to grass.

Vitamin C

Fresh grass, like other fresh 'vegetables', contains a fair amount of vitamin C. This vitamin has antioxidant properties and a positive effect on the body's recovery function. The skin and connective tissue especially need vitamin C. Additionally, this vitamin is important for energy metabolism and hormone cycles. Healthy horses are not likely to have a vitamin C deficiency quickly because they can produce it themselves in the liver. Humans cannot do this. However, horses may have a compromised liver due to stress, for example. In that case, the production may be less efficient. Additionally, horses with reduced liver function due to illness or old age may experience a deficiency in vitamin C if they do not eat fresh grass. Therefore, older horses or those under stress, with skin issues, or liver problems may require extra vitamin C.

Vitamin D

Vitamin D is necessary for calcium and phosphate absorption and the formation of strong bones. It is also important for the liver, sugar metabolism, and immunity. Vitamin D is produced on the skin under the influence of daylight. Horses with summer eczema or other allergies, prone to acidosis, undergoing significant growth, or are elderly, may require more vitamin D. If horses do not spend much time outdoors or wear a (insect/UV) blanket permanently, vitamin D supplementation may be necessary for them.

Omega-3 fatty acids

Fresh grass contains omega-3 fatty acids. As mentioned before, a small amount of fat is important for the absorption of vitamins A and E. However, omega-3 fatty acids, especially DHA, are important for other reasons. They contribute to a healthy coat, proper immune function, and reduced muscle fatigue. The same as with vitamins, growing horses, older horses, and sport horses need more. If your horse does not have access to fresh grass, make sure to supplement their diet with omega-3 fatty acids. It is preferable to use easily absorbable EPA and DHA, found in, for example, salmon oil and algae powder. Flaxseed oil only contains ALA, which the horse's body still needs to convert to EPA and DHA.

Summary: Deficiencies with limited pasture access

When a horse has no or limited pasture access, resulting in less than four hours a day of grazing, there is a deficiency in several important nutrients. Hay does not provide enough vitamin A, vitamin E, and potentially leads to deficiencies in vitamin C, vitamin D, and omega-3 fatty acids. Therefore, it is crucial for all horses to receive a balancer or vitamin supplement in addition to hay during the winter. Keeping a horse on a restricted diet may be wise, but do not go too far. Especially if you expect physical exertion from your horse, or if they are in a growth phase or are older! Reduced immunity, muscle stiffness, and loss of energy could result from deficiencies in vitamin A, C, D, and E or from a lack of omega-3 fatty acids. If you notice any of these symptoms in your horse, consider using a balancer or supplements!