IES+LSG Grazing Schemes
Grazing Systems for Yearling Cattle on Tallgrass Prairie
Clenton E. Owensby, Lisa M. Auen, Hannah F. Berns, and Kevin C. Dhuyvetter
Abstract
This 9-year study tested steer gains, residual aboveground biomass (AGB) in mid July and early October, and economic returns and risk for tallgrass prairie grazed annually under season-long stocking (SLS) at 1.62 ha steer-1 until early October or intensive early-stocking (IES) at 0.81 ha steer-1 until mid July compared to a composite grazing system. The 3-pasture, 3-herd "IES+ System" is a 3-year fixed sequence of SLS, IES and IES (0.81 ha steer-1) plus late-season grazing (1.62 ha steer-1) until early October (IES/LSG). All grazing treatments began in late April. Average gains per steer for SLS and SLS in the IES+ System did not differ, but were significantly less than gains for steers that grazed the entire season under IES/LSG. Gains per steer in mid July under IES alone or in combination with LSG were similar to the same repeated grazing treatments, but were significantly less than those for steers grazed season long. Gains per ha under SLS did not differ, but were significantly less than those for IES treatments and the IES+ System. Gain per ha in July was similar for IES annually repeated and IES/LSG, but there was greater gain per ha for IES treated pastures rotated within the system. Residual grass and total aboveground biomass (AGB) in mid July did not vary among years and was generally greater on SLS than IES. In early October, grass AGB was similar for all treatments except IES/LSG which had less residual AGB. When pasture rent was charged per head, the IES+ System increased the 20-year mean return ha-1 by $5.98 compared to repeated use of IES and $8.52 compared to using only SLS. Measures of economic risk were generally intermediate for the IES+ system compared to IES, which consistently had the highest risk, and SLS.
A copy of this paper is available as a pdf file.
Two-Year Rotation of SLS and IES+LSG
The system tested here stocks season-long the first year followed by IES+LSG the next year. After six years, results show that the biomass production the year following the IES+LSG treatment is the same as on the SLS control. Steer gains and schematic are shown below.
Schematic of one experimental block and associated treatments. The treatments were season-long stocking (SLS) and intensive-early stocking plus late-season grazing (IES/LSG). The study is replicated three times.
Two-Year Rotation of IES and IES+LSG
The system tested here stocks IES the first year followed by IES+LSG the next year. This system was started in 2007 and steer gains and schematic are shown below.
Schematic of one experimental block and associated treatments. The treatments were season-long stocking (SLS), intensive early stocking (IES), and intensive-early stocking plus late-season grazing (IES/LSG). The study is replicated three times.
