Browsing Journal of Range Management, Volume 47, Number 3 (May 1994) by Subjects
Now showing items 1-2 of 2
A comparison of frontal, continuous, and rotation grazing systemsTwo 2-year trials were conducted to evaluate and compare frontal, continuous, and 2-paddock rotation grazing systems on 'Plains' Old World bluestem (Bothriochloa ischaemum (L.) Keng.). Frontal grazing allows livestock a continuous opportunity to graze fresh forage via a livestock-pushed, sliding fence which allocates and controls grazing within a pasture. Trial 1 treatments included frontal grazing at a very high stocking density of 13.3 head ha-1 and continuous grazing at 4 stocking densities described as low, moderate, high, and very high. The mechanical design and components of our frontal grazing system were quite adequate in terms of the system's operation and interaction with the livestock herd. Significant (P < 0.05) linear relationships were found for regressions of daily gain on stocking rate and grazing pressure index, and for gain ha-1 on stocking rate and grazing pressure index. Year effects were evident in all regressions. Trial 2 treatments included frontal, continuous, and rotation grazing systems initially stocked at 6.7 head ha-1. Mid-season reductions in stocking density were made in continuous and rotation grazing to ensure that these treatments would have adequate forage to continue until frontal grazing completed its second cycle and to achieve an end-of-season standing crop which was similar in all 3 treatments. Season-long daily gains under frontal grazing were not significantly different compared to continuous grazing (P > 0.05); however, they were less than those under rotation grazing (P < 0.05). Frontal grazing provided about 100 more steer-days per hectare of grazing than either continuous or rotation grazing. However, steer production was not significantly different among treatments and averaged 296 kg ha-1 (P > 0.05).
Tiller defoliation patterns under frontal, continuous, and rotation grazingAn investigation was conducted to characterize the intensity and frequency of tiller defoliation in 'Plains' Old World bluestem (Bothriochloa ischaemum (L.) Keng) under frontal, continuous, and 2-paddock rotation grazing systems. Frontal grazing allows cattle a continuous opportunity to graze fresh forage via a livestock-pushed sliding fence that allocates and controls grazing within a pasture. Nearly 100% of frontal grazing tillers were defoliated at least once during a 3-hour period as the frontal fence was advanced over the transect ares. The initial defoliation intensity of tillers under frontal grazing was also significantly higher and remaining tiller height less than that of tillers under rotation or continuous grazing (P < 0.05). Tillers under frontal grazing were defoliated at a faster rate compared to rotation or continuous grazing, but cattle had access to them for only 6 to 8 days of the entire grazing season. Season-long defoliation frequency was estimated to be 2.4, 4.6, and 4.7 times for frontal, continuous, and rotation grazing, respectively. Tillers that originated from the perimeter of a tussock were initially taller than those arising from the center (P < 0.05); however, frequency and intensity of defoliation was similar for both tiller locations. Significant relationships were also described between defoliation frequency and stocking rate and between defoliation frequency and herbage allowance. Defoliation frequency increased linearly as stocking rate increased; and conversely, defoliation frequency decreased quadratically as herbage allowance increased. Data from this study suggest that the pattern of tiller defoliation under frontal grazing enhanced forage production which allowed the maintenance of higher stocking rates.