Crude protein content is an important consideration when choosing grass varieties for hay or pasture. While plant maturity and growing conditions have a huge impact on the amount of protein found in grass at any given time, some species average higher levels than others when tested for crude protein under comparable conditions.
Orchardgrass is a cool-season perennial that averages 13.5 percent crude protein when baled as hay. It is a good choice for mixed grass and legume fields because it matures earlier in the spring than some other common field grasses such as timothy, meaning that it is ready for harvest at roughly the same time as legume forages. It is moderately hardy in winter and drought conditions, and very productive when properly managed.
Bermudagrass is a warm-season grass originally imported from southeast Africa. It averages 12.4 percent crude protein as hay. Unlike orchardgrass, bermudagrass is most productive during the hot summer months. It forms a deep sod of roots and rhizomes that helps it survive dry periods, but it does not tolerate the cold winters of northern climates. Bermudagrass prefers well-drained soil and needs nitrogen fertilization for the best production.
Ryegrass is a cool-season grass grown worldwide for forage and hay production. It is highly productive when grown under optimum conditions, but less tolerant of subpar conditions than many other grasses. With proper management, ryegrass yields a high nutrient value, including an average crude protein level of 11.8 percent. Ryegrass tends to die out over time and require seeding, making it costlier to maintain than more persistent species.
Sudangrass averages 11.6 percent crude protein. An annual plant, it must be reseeded each year for continued production. Sudangrass is heat- and drought-tolerant, though it may go dormant in extreme drought situations. There is a slight danger of toxicity due to prussic acid concentration in sudangrass, but this is normally only a problem in sorghum-sudan hybrids. When properly fertilized, sudangrass is highly productive and may produce up to five hay cuttings in a single season.