• Effects of dormant-season herbage removal on Flint Hills rangeland

      Auen, L. M.; Owensby, C. E. (Society for Range Management, 1988-11-01)
      Stocking rate effects on intensive-early stocked Kansas Flint Hills range were studied from 1982 through 1987. Rates were 2X, 2.5X, and 3X normal season-long stocking rates for 200-225 kg steers. Study design was a randomized complete block with 2 replicates. Grass and forb standing crop (kg/ha) were estimated at the time of livestock removal (mid July) and again in early October. Plant basal cover and composition were taken in early June the year prior to the study and annually thereafter. Overall growing season precipitation during the study period was below normal, with late-summer precipitation much below normal in the second and third years of the study. Grass standing crop (GSC) in mid July decreased with increased stocking rate, but by early October GSC was similar under the 2.5X and 3X stocking rates, but continued to be lower than that under the 2X rate. There was no consistent response in mid July forb standing crop (FSC) with respect to stocking rate. In early October, FSC was either not affected by stocking rate (1983, 1986, and 1987) or was greater under the highest stocking rate (1982, 1984, and 1985). The major changes in botanical composition and basal cover were a reduction in Indiangrass (Sorghastrum nutans Nash) and an increase in Kentucky bluegrass (Poa pratensis L.) as stocking rate increased. Botanical composition of big bluestem (Andropogon gerardii Vitman) increased under the 2X rate but did not change under the higher rates. Individual steer gains were similar under the different stocking rates, but livestock breed appeared to affect magnitude of the gain. Since individual gains did not differ, gains per ha were substantially increased by the higher stocking rates.
    • Grain supplementation on bluestem range for intensive-early stocked steers

      Owensby, C. E.; Cochran, R. C.; Brandt, R. T.; Vanzant, E. S.; Auen, L. M.; Clary, E. M. (Society for Range Management, 1995-05-01)
      A 4-year study was conducted on Kansas Flint Hills bluestem range to monitor animal gain, grass, and forb standing biomass following grazing, plant population dynamics, and in 2 years, subsequent feedlot performance of steers under intensive-early stocking supplemented with increasing levels of sorghum grain. Each year from 1988 through 1991, crossbred beef steers were stocked at 0.24 ha/100 kg of initial steer weight from 5 May to 1; July. Steers in twice-replicated pastures were given no supplementation, 0.91 kg rolled sorghum grain per head daily, or 1.82 kg rolled sorghum grain per head daily, which corresponded to approximately 0, 0.3, and 0.6% of body weight-1. All steers were implanted with estradiol 17 beta in 1988 and zeranol in 1989-91 during initial processing and had unlimited access to a lasalocid/mineral mixture during the entire trial. In 1989 and 1990, representative groups of steers selected from all treatment/pasture combinations were subjected to a feedlot finishing phase and carcass data were obtained. Grass and forb standing crops were estimated each year at livestock removal in mid-July and again in early October. Pretreatment species composition and basal cover were determined in 1988 and compared to those at the end of the study. In mid-July, when cattle were removed, residual standing biomass of grass increased in direct proportion to increasing level of supplement. Standing biomass of grass at the end of the growing season did not differ among pastures with different supplement levels. Forb standing biomass did not differ among pastures with different supplement levels in July or October. Changes in plant populations among treatments during the course of the study were minimal. During the early portion of the grazing period, sorghum grain supplementation did not significantly influence steer gains, but average daily gain during the latter part of the grazing period increased in direct proportion to increasing level of sorghum grain supplement. Daily gain. feed intake, carcass characteristics, and gain:feed ratio were not different among treatments during the feedlot phase. Although conversion efficiencies may be economically marginal, low-level grain supplementation has the potential to increase the daily gain of cattle grazing early-season tallgrass prairie under an intensive-early stocking program.