By Patrick Keyser, Professor and Director, Center for Native Grasslands Management
Most recommendations for grazing native grass forages are based on some form of rotational grazing. That approach to native grass management and its benefits was discussed in the publication “Managing Native Grass Forages.” However, continuous grazing may also be used effectively with native grasses. In fact, in the Great Plains where a great deal of native grass grazing occurs, this is a common practice. As is the case with rotational grazing though, the key to successful continuous grazing of native grasses is maintaining the proper canopy height.
Native grasses are tall growing and to remain vigorous they require maintenance of a higher canopy – especially under continuous grazing – than what is required by most other common forage species. For big bluestem and indiangrass, canopies should be maintained between about 15 – 20 inches tall throughout the summer grazing period. For switchgrass, canopies should be kept between 20 – 30 inches for lowland varieties such as Alamo and Kanlow. Eastern gamagrass heights should fall between that for switchgrass and the other natives, about 18 – 24 inches.
Under continuous grazing, maintaining canopy heights lower than those described above will result in weakened stands, reduced gains, reduced yields, and increased weed pressure. However, research conducted at the University of Tennessee and elsewhere has demonstrated that continuous grazing is a viable strategy – as long as minimum canopy heights are diligently maintained.
Two other cautions should be observed in continuous grazing with native grasses. First, do not allow the canopy to get too tall or the grass will get stemmy and unpalatable. In that case, grazing will be concentrated on the more heavily grazed portions of the pasture where the grass is shorter and more vegetative. If not corrected, the result will be patches that are overgrazed (grazing camps) and others that have gone to seed and are not grazed at all. Of course, the key to managing canopies that are not too short or too tall is appropriate stocking. And this leads to the second caution for continuous grazing.
Native grasses grow rapidly during early summer and then slow down in mid- to late-summer. This is particularly true of switchgrass, but also occurs with the other species. You need to be prepared to make some adjustments in stocking during late June to ensure that you do not ‘overshoot’ the carrying capacity for the later part of the grazing season. Typically, stocking will need to be reduced by about one third during this time. Also, be sure to rest the stand after September 1 under continuous grazing.
Continuous grazing will allow you to effectively manage your native grass pastures with less time invested in moving cattle during the summer than is required under rotational grazing. However, you must still carefully monitor the condition of the pasture and be prepared to adjust stocking as needed (especially in late June). Remember, it’s all about canopy height