Filling the nutrition gap: A veterinary order for supplemented stored forages

Filling the nutrition gap: A veterinary order for supplemented stored forages

When horses can't graze on nutrient-rich grass, supplementing with fat-soluble vitamins is key to preserving health and immunity.
May 31, 2014

When access to fresh pasture is limited, it’s important to supplement stored forages with fat-soluble nutrients to maintain health and immunity. (GETTY IMAGES/LISA VAN DYKE)
Whether they're trail horses or performance athletes on the racetrack, today's horses are often found stabled in confinement. In some areas, harsh winter weather may also keep horses stabled for long periods of time, limiting access to fresh pasture.

Most of these animals eat stored forages, which can be limited in nutrients if not properly supplemented. When comparing these two opposing feeding regimes—fresh pasture versus stored forages—some of the critical nutrients affected are vitamin E and beta carotene, the precursor of vitamin A. And a lack of sunlight may result in vitamin D deficiency.

When fresh pasture is simply not an option, it's important to provide proper supplementation of fat-soluble nutrients to preserve the horses' long-term health and immunity.


For centuries, horses roamed extensive areas of pasture, their natural food source. They traveled over and were adapted to grazing on vast land areas. Unlike other grazing species, such as sheep and cattle, horses are selective and efficient grazers that primarily enjoy grass as opposed to other vegetation. Horses have been observed to prefer young, new growth rather than less-digestible mature grasses that are also less palatable and lower in nutrients. Horses also tend to prefer mixed-grass pastures to legumes and herbs, and they will often move to grazing areas, particularly in the spring, with plenty of new, young growth, regardless of the grass height or thickness.

The National Research Council (NRC) notes that horses spend about 10 to 17 hours each day grazing and that they need to graze for approximately 17 hours daily to meet their nutritional needs. A horse's gender, age and breed all influence its time spent grazing. According to the NRC, forages are the main component of horse diets.1 Whether a horse is fed solely on pasture, given stored forages in confinement or fed a mix of these two, forage and grass intake should be at least 1 percent of body weight per day.

There are some concerns associated with overgrazing lush spring pasture, including the potential for laminitis, colic or obesity in horses prone to metabolic syndrome. Horses turned out onto pasture after winter confinement may overeat because of the enhanced palatability of lush green grass. As a result, the transition to pasture should be gradual.