Stocker beef production on low-water-input systems in response to legume inclusion: I. Forage and animal responses

The imminent decline of the Ogallala Aquifer is encouraging producers in the Southern High Plains (SHP) to seek innovative alternatives to safeguard against dramatic losses of income when pumping capacity is insufficient for irrigated crops. Previous research demonstrated the success of perennial forage grasses in this region, but crude protein (CP) was the limiting factor in improving performance of grazing beef (Bos taurus L.) steers. Possible solutions include integrating legumes into existing warm-season grass pastures and managing small areas of alfalfa (Medicago sativa L.) as a protein bank where irrigation resources can be concentrated. The objective of this research was to compare animal performance in a grass-legume pasture system employing regionally novel forage combinations and grazing techniques to a grass-only system in the water-limited SHP. Three years of research concluded that inclusion of legumes increased CP (P < 0.01) and increased digestibility measures of forages in the grass-legume system. Longer, less frequent rotations into the protein bank resulted in higher average daily gains in Years 2 and 3 (P < 0.05) compared with Year 1 of grass-legume. This translated to higher seasonal liveweight gain per hectare in the grass-legume system in each trial year (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.