Comparison of Productivity and Efficiency of Grass-Only and Grass-Legume Beef Stocker Grazing Systems in the Southern High Plains.

COMPARISON OF PRODUCTIVITY AND EFFICIENCY OF GRASS-ONLY AND GRASS-LEGUME BEEF STOCKER GRAZING SYSTEMS IN THE SOUTHERN HIGH PLAINS

L.L. Baxter and C.P. West

The imminent depletion of the Ogallala Aquifer demands innovative alternatives to prevent dramatic losses of income when water levels are insufficient for irrigated row-crop production in the Southern High Plains. With the goal to optimize sustainability and productivity with pasture-based beef stocker systems, a grass-legume (GL) pasture system employing novel forages and grazing techniques was compared to a previously examined grass-only (GO) warm-season pasture system. Since protein is often the limiting factor in improving performance of stockers grazing warm-season perennial pastures, higher gains are expected with strategic inclusion of legumes such as alfalfa (Medicago sativa L.). Alfalfa was managed as a protein bank so that a limited water resource was concentrated on a small area to produce a high-quality supplement for poorer-quality base pastures. Average daily gains between treatments did not differ in year 1 (P = 0.26). Deferring hay harvests to better utilize forage resources in both treatments extended the grazing season and increased stocker gain per hectare in years 2 and 3 (P < 0.01). After considering rotation frequency and protein bank utilization in the first year, a decision was made to increase the duration but decrease the frequency of rotating stockers into the alfalfa. In years 2 and 3, stocker gains in the GL treatment exceeded those in the GO treatment since longer, more infrequent rotations promoted gains and allowed for better management of high-quality pasture resources (P < 0.01). Inclusion of legume increased stocker gain achieved per hectare in all years (P < 0.01) and increased water use efficiency with the sufficiently long grazing season in year 3 (P < 0.01). The forage-livestock systems created in this research will serve as alternatives for producers transitioning from irrigated row-crops into more resource-sustaining systems.