A variety of rangeland, pasture, and forage crop management practices can optimize forage production and utilization while meeting the nutrient needs of the grazing sheep. Sheep are herbivores, and their ability to efficiently convert forages from rangelands and pastures into useful products has defined their ecological and economic niches. The fact that sheep are selective grazers largely determines the type of forages they consume; it may also define how they can best be used in appropriate land management systems.

For our purposes, rangelands are defined as those areas where climate, topography, and other features have resulted in the landsÕ remaining largely in native plant species that can only be utilized through grazing. The U.S. rangelands are generally located in the Southwest, Great Basin, Intermountain, and Great Plains regions. Grazing management must be concerned with protecting the natural resource base as well as sustaining livestock productivity. A significant portion of the nationÕs rangeland resources are located on public lands with multiple use objectives. This increases the number of issues to be considered when developing grazing management systems.

Pastures defined as located in higher rainfall or higher productivity areas of the U.S. can be more intensively managed to increase sheep production through improved forages. Pastures are generally mixtures of introduced or improved plant species, although certain marginal lands may remain in native vegetation and be considered as pastures. Pastures are often part of mixed farming or crop production systems, either on lands not suitable for crops or as a part of crop rotation systems to enhance land use or conservation practices. Forage crops, crop residues, and crops grown in the farming system are often used along with improved pastures to enhance sheep production.

Sustainability of resources must be the primary goal for range management planning. Range scientists have devoted much effort to defining what may be climax and/or desired plant communities within landscapes and ecosystems and to managing rangelands to achieve these plant community goals. A given landscape may contain a wide variety of plant communities, and a given ecosystem may contain a wide variety of landscapes. Increased emphasis is being placed on enhancing biological diversity within ecosystems and landscapes in developing range-management programs.

Because most rangelands are found in arid to semiarid ecosystems, they respond rapidly and negatively to overgrazing or poor grazing management. There is general agreement that unmanaged grazing by any large herbivore can lead to ecological disaster. At the other extreme, lack of grazing for extended periods may or may not enhance plant succession to climax species, and in some situations may reduce plant species diversity. Effective rangeland management planning includes a monitoring program to assess plant community trends and current conditions, defining objectives to achieve (or maintain) desired conditions, an understanding of levels of production within the plant communities, and a grazing management plan to meet rangeland goals.

Sheep are opportunistic and selective foragers, shifting their diet from grasses to forbs to shrubs if various plant species are available. For example, sheep may prefer a high level of succulent grasses and forbs in the spring and summer, then shift to shrubs with their higher energy and protein reserves in the dormant fall and winter months. The plant selectivity of sheep and their willingness to consume certain forbs and shrubs to meet their needs provide opportunities to use sheep to manipulate plant communities in certain rangeland improvement programs. When planning a grazing management program, diet selectivity must also be understood in relation to the available forage resources and the diet preferences of other livestock and wildlife species that may be in the system. If at critical times during the production cycle the sheepÕs nutrient needs cannot be met from available forage, then supplementation must be used.

Pasture and forage crops grazed by sheep can enhance the sustainability of farming systems. Many farms have marginal or unsuitable croplands that can be converted to improved pasture and used in profitable sheep production enterprises. Sustainability can also be improved by incorporating improved pasture into the crop rotation. Improved pastures in rotation can increase soil organic matter and fertility, reduce soil losses from erosion, and break the cycle of crop insects and noxious plants. Adding sheep and improved pasture enhances economic diversity of the farming system. In addition to providing economic returns from the pasture, sheep can convert crop residues to useful products and may provide a more profitable market outlet for other crops produced in the system. Forage crops such as turnips and hybrid sorghum sudangrass may be used as supplements at critical times in the production cycle.

This chapter is divided into two sections. The first discusses rangeland and its management as well as appropriate sheep production systems and management practices to meet both production and land management goals. The second section discusses pasture and forage crop management for profitable sheep production. We would caution the reader that it is not possible to prescribe specific management practices, pasture mixtures, and other factors that may be site specific to your enterprise. We encourage consultation with local extension specialists, experienced producers, and other experts in developing specific management plans and practices.