Strip grazing stockpiled annual forages: impact on carrying capacity and cattle performance.

Abstract

Strip grazing can increase forage utilization, though it has been shown to decrease individual animal performance. The objective of this study was to evaluate forage utilization and cattle performance when strip grazing (STRIP) vs. continuously grazing (CONT) stockpiled annual forages. Experiment 1 consisted of a mix of Jerry oats (Avena sativa) and Trophy rapeseed (Brassica napus) while experiment 2 was a 17-species mix in which the forage mass was predominantly pearl millet (Pennisetum glaucum), German millet (Setaria italica), and browntop millet (Urochloa ramosa). Fields were divided into six 6.3-ha (experiment 1) or 4.1-ha (experiment 2) paddocks which were blocked by location. Treatment was randomly assigned within block (n = 3 replicates per treatment per experiment). Grazing was initiated in November and terminated in February. This resulted in a total of 83 and 54 grazing days for experiments 1 and 2, respectively. Forage was allocated to STRIP twice a week. The STRIP steers gained 16% less (P = 0.01) per day in experiment 1, but in experiment 2, there was no difference (P = 0.56) between treatments. Compared to CONT, the carrying capacity (AUM/ha) of STRIP was increased (P = 0.03) by 81% in experiment 1 and tended to increase (P = 0.10) in experiment 2. Gain per hectare increased (P = 0.02) for STRIP by 56% in experiment 1 and by 31% in experiment 2. Strip grazing stockpiled annual forages can be an effective way to increase carrying capacity and gain per hectare during the fall and winter months but effects on individual animal performance are inconsistent. Disparities in response to strip grazing could stem from differences in forage quality and allocation. Further research is needed to refine and optimize the utilization of this management approach.