Articles on forages, animals, and grazing systems
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Extension Forage Specialist
University of Kentucky
Phone: (859) 257-3358
Fax: (859) 323-1952
Although grazing warm-season annuals can be extremely beneficial throughout the hot summer months, many are reluctant to use them. The cost and extra time and labor required to seed these forages each year is the main reason. Grazing warm-season perennials may be a good option for some operations.
Warm-season perennials best grow between late spring and early fall, at temperatures between 80° F and 90 °F. Although the forage quality of these species tends to be considerably lower than that of cool-season grasses, they continue to be highly productive through the summer months. While frosts kill warm-season annuals, warm-season perennials become dormant throughout the winter and reinitiate growth when temperatures rise in the late spring. There is potential for winter kill in Kentucky if temperatures get extremely low. Purchasing winter-hardy varieties when available will decrease this possibility. Warm-season grasses should be planted between mid-May and early-June, after risk of frost. Seeds germinate when soil temperatures are above 55° F. These forages are not preferred for high-producing dairy cattle or other high performance animals but supply adequate feed for replacement heifers, dry animals, sheep, goats, and beef cattle. Some common warm-season perennials used for grazing include native species such as big bluestem, eastern gamagrass, Indiangrass, and switchgrass. The most common non-native warm-season perennial is bermudagrass.
Native Warm-Season Perennials
Big bluestem is a tall growing bunchgrass used for hay and grazing. Although big bluestem has a lower yield potential than switchgrass, it is a higher quality forage and more tolerant of poor soils and drought. It also stays palatable and nutritious longer as it matures. A specially modified seed hopper may need to be used or seed will need to be debeared prior to seeding. This grass is often preferred for hay production as it dries quickly and produces good quality hay.
Eastern gamagrass, a bunchgrass which is often preferred over other warm-season perennial grasses, is one of the highest in quality and palatability. This grass can be used for good quality grazing, hay, or baleage. High levels of seed dormancy are often an issue and a method such as wet-chilling may be necessary for good germination. Treated seed is commonly sold to help prevent seed dormancy issues.
Switchgrass is a tall growing grass with short rhizomes that is used for grazing and hay. As it matures, the stems quickly become thick and digestibility and quality quickly decrease. Harvesting at an immature stage is important for forage quality. Switchgrass can be seeded easily with most drills. This grass is also often used for biomass production. Switchgrass and eastern gamagrass are not recommended for horses.
Indiangrass is a tall growing bunchgrass with a yield comparable to big bluestem that is best for grazing but sometimes used for hay. This very drought tolerant species grows well on steep, shallow soils and makes good wildlife habitats. Like big bluestem, seed needs to be debearded for seeding unless a modified seed hopper is used.
These native warm-season species have some qualities which affect the way they are managed. They are slow to establish and there are few options for chemical weed control to allow proper establishment. It is important to seed into a weed-free seedbed. It is suggested that seedbed be prepared by tilling one month prior to seeding and lightly tilling again directly before seeding. Following the second tilling, use of a cultipacker will help kill weeds. It is possible to use a no-till drill if weeds are controlled. It also may be possible to broadcast followed by cultipacking if on a well prepared seedbed. It is important that seed is not planted too deep.
Non-Native Warm-Season Perennials
Bermudagrass, a sod-forming grass used for grazing and hay, is often preferred due to its ability to produce high yields of good quality forage and its ability to tolerate high traffic. It is established through sprigging or seeding. Various varieties can only be planted by sprigging as they do not produce viable seed. Springing is the process of incorporating rhizomes and stolons into a prepared seedbed or using specialized sprig-planting equipment. It is important that sprigs are not covered too deep. Cultipacking after sprigging firms soil and improves establishment. Seeded varieties should be planted into a prepared seedbed. Additionally, only plant a seeded variety that has good winter survival under KY conditions.
For more information see Native Warm-Season Perennial Grasses for Forage in Kentucky (AGR-145).