Grass hay may seem simple, but it’s not necessarily simple. Equi-Analytical Lab sent out a survey to their clients and 90% of the respondents indicated they feed their horses grass hay. However, there are lots of different plants that can make up grass hay. Grasses commonly used for equine forage production are orchard grass, timothy, smooth brome grass, tall fescue, meadow fescue, Kentucky blue grass, perennial and Italian rye, Bermuda grass and even wheat. With all these possible grasses involved, the nutrient value will differ depending on the concentration of grasses involved and their rate of maturity when bailed. Because of this, it is important to identify the grasses in the grass hay you are purchasing so you can compare it to average values that a good quality grass hay should contain.
Also, it is critical to have multiple samples of the hay analyzed to determine the analysis since many hays contain a large range of different grasses. For example, general grass hay and Bermuda grass hay are fairly similar but Bermuda grass is lower in water soluble carbohydrates. If wheat is in the grass hay, the carbohydrate level will be higher; this is important if you have a horse with equine metabolic syndrome because increased carbohydrates can lead to founder in these horses. So the important point is that all grass hay is not equal and before buying it and feeding it to your horses, it is worth the money to have it tested so your can be confident you are feeding the correct hay.