Eastern gamagrass (Trypsacum dactyloides), a warm-season perennial bunchgrass indigenous to Oklahoma and much of the southeastern United States, is capable of producing forage of high quantity and quality. However, lack of producer familiarity, high seed costs and necessary grazing management practices have reduced the acceptance of eastern gamagrass in this region.
This native grass was a component of plant communities primarily in the eastern half of Oklahoma prior to European settlement and can still be found in areas not subjected to grazing pressure. It is adapted to most soil types, but is best suited to clay loam soils with moderate to good drainage. While this grass was once an important part of Oklahoma rangeland, it is now isolated mainly to areas that are seasonally grazed or not accessible by livestock. Eastern gamagrass will not persist under overgrazed situations or situations with limited grazing management. This grass will produce very significant amounts of forage that will meet the needs of most classes of livestock when grazing is planned to manage for proper rest and sufficient leaf area remaining after grazing. This is a phenomenal native grass when managed correctly as evidenced by the efforts of the late Dr. Chet Dewald of the USDA-ARS Southern Plains Range Research Station in Woodward, Okla. Dr. Dewald was responsible for much of the research available on this grass and was noted as the primary expert on eastern gamagrass in the world.
Though eastern gamagrass has many outstanding qualities, such as perennial high productivity with little or no added fertilizer or soil amendments, it also has the previously mentioned limitations that, in my estimation, will confine eastern gamagrass to applications that fit certain niches, rather than it being a major forage species, until factors such as inherent seed dormancy, weed control, seed cost and delayed stand development can be improved upon. Efforts over the past decade by several USDA-NRCS Plant Material Centers (PMCs) have resulted in the release of four new eastern gamagrass germplasms. "Medina" and "San Marcos" were released from PMCs in Texas. It will be interesting to see the performance of these releases compared to the commercially available "Pete" and "Iuka." Establishment of eastern gamagrass pastures was initiated in 1998 at the Noble Research Institute's Red River Demonstration and Research Farm (RRDRF) in Burneyville, Okla. About 85 percent of the pasture is planted to Iuka IV, with the remaining area comprised of abandoned demonstration plots of Medina, San Marcos, Jackson and Pete.
In the spring of 2000, a five-year project was initiated on this area with the main objective of demonstrating that a combination of eastern gamagrass and double-cropped cereal rye and Red River crabgrass can be managed as the forage base for a sustainable summer stocker cattle program. Projected average daily gains are expected to fall within the range of 1.5 to 2 pounds for all of the forages over the course of the program. This is one of the necessary criteria that have to be met for this program to be adopted by producers. In each of the last three years, the grazing demonstration was initiated with preconditioned stocker steers averaging 450 lbs./head and terminated with cattle ranging between 750 lbs. and 800 lbs./hd. Grazing protocol (adjustable) for this project includes grazing rye pasture from Feb. 15 to April 15, eastern gamagrass pasture from April 15 to June 15, and Red River crabgrass pasture from June 15 to Aug. 15. Stock density on the eastern gamagrass is about 8,000 lbs. of liveweight/acre. Graze periods are seldom over two days per rotation, and rest periods range from 15 to 18 days. Livestock are rotated prior to eastern gamagrass reaching an average stubble height of 8 inches. Figure one illustrates the average daily gain (ADG) on the three forages over the last three years. Red River crabgrass was not grazed in 2000.
So far, we are disappointed with the animal performance on eastern gamagrass in this project. We suspect that animal performance in 2001 was negatively affected by a sudden, severe infestation of internal parasites, which is not uncommon at that time of year. In addition to production through grazing, the eastern gamagrass in this project has averaged an additional 5,176 lbs. per acre of hay production over the last three years. Based on several other grazing studies that have shown better animal performance, we have hope for increasing ADG through better grazing management.
However, preliminary results indicate that the long-term use of this forage is better suited for mature cattle rather than stocker cattle. I hope this article has shed some light on some of the advantages and disadvantages of eastern gamagrass. We will update you over the next few years on the progress of this project.