Animal and Vegetation Response to Modified Intensive—Early Stocking on Shortgrass Rangeland

Abstract

A comparison of animal gains and vegetation trends was made from 2002-2008 between a continuous season-long stocking (SLS) system and a modified intensive-early stocking system (IES) with late-season grazing (IES 1.63 + 1; 1.6 times the number of animals of the SLS system from May 1 to July 15, and 1 times the number of animals of SLS from July 15 to October 1) on shortgrass native rangeland of western Kansas. The continuous season-long stocked system placed animals at a density of 1.37 ha steer-1 from May through October, or 2.63 animal unit months (AUM) ha-1, whereas the intensive-early stocked system with late-season grazing (3.33 AUM ha-1) stocked pastures at 0.85 ha steer-1 from May through the middle of July, and then stocked pastures at 1.37 ha steer-1 for the remainder of the grazing season by removing the heaviest animals mid-July each yr. Average daily gains (0.78 vs. 0.70 kg d-1, P = 0.039) and total animal gain (58 vs. 52 kg, P = 0.042) were different between the continuous season-long stocked and the intensive-early stocked animals during the first half of the grazing season. No difference was found between average daily gain (0.61 vs. 0.62 kg d-1, P = 0.726) and total animal gain (48 vs. 49 kg, P = 0.711) for the continuous season-long stocked and intensive-early stocked with late-season grazing animals during the last half of the season. Total individual animal gain (106 vs. 101 kg, P=0.154) and average daily gain (0.70 vs. 0.66 kg d-1, P = 0.152) was not different between the continuous season-long stocked and the intensive-early stocked system animals that were on pasture the entire grazing season. Total beef gain on a land-area basis (96 vs. 77 kg ha-1, P = 0.008) was greater for the modified intensive-early stocked system with late-season grazing with greater animal densities. Changes in residual biomass and most key vegetation components at the end of the grazing season were not different between the two systems.