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
An advanced rotational grazing system should provide forages for livestock to graze year round. It is important to plan ahead and utilize several forage species to supply adequate amounts of quality forage and to increase the length of the grazing season. As the environmental temperature increases, cool-season forages begin to go dormant and production decreases. Warm-season grasses and legumes should be incorporated into grazing systems in order to reduce overgrazing paddocks and supply ample amounts of high quality grazing throughout the summer months. These forages grow best between late spring and early fall when temperatures are between 80° F and 90 °F.
Several options exist when deciding what warm-season forages to add to your grazing system. Commonly used warm-season annual forages in Kentucky include sorghum, sudangrass, sorghum X sudangrass hybrids (Sudex), and millets. These species are highly productive in the hot summer months and provide high quality feed when grazed in a vegetative state. Nitrate accumulation and Prussic acid poisoning can be health risks to animals grazing these forages after drought or frost or when grazing young regrowth. Millets do not produce prussic acid. For more information on prussic acid poisoning see http://www2.ca.uky.edu/grazer/October11_Prussic_Acid.php.
Warm-season perennials commonly used include native species such as big bluestem, Eastern gamagrass, switchgrass, and Indiangrass. Bermudagrass is a common non-native species that has been increasingly used for pastures in Kentucky. These species are often difficult to establish, but once established, can produce a thick stand for many years. Because they are lower in quality, it is not recommended for grazing animals with high nutritional needs, but can be ideal for grazing dry dairy cows, beef cattle, replacement heifers, and small ruminants through the hot summer months.
When the temperature increases and cool-season forages decrease in production, grazing warm-season forages is useful to provide large amounts of quality feed. Warm-season perennials are seeded as early as mid-April while warm-season annuals are planted as early as May 1st. Be sure to plant after risk of frost when seeding any warm-season species. Using winter-hardy varieties can also be advantageous as winter kill is a possibility for warm-season perennials in Kentucky. For more information on warm-season annuals see http://www.ca.uky.edu/agc/pubs/agr/agr88/agr88.pdf. For more information on warm-season perennials see http://www2.ca.uky.edu/grazer/May12_warm_season_perennials.php.