Beef steer performance on African Bermuda grass pasture overseeded with black oat and annual ryegrass: effects of added irrigation and temperate legumes.

Increasing productivity and resource efficiency through sustainable intensification of grazing systems impose new challenges on crops and livestock. The sustainability of world agriculture is threatened by the degradation of ecosystem services anthropogenic interventions such as reduced biological diversity, water and air pollution, and loss of soil quality. The search for technologies that increase animal productivity with economic and environmental sustainability is necessary. The aim was to determine whether productive systems based on African Bermuda grass, overseeded in rows with annual ryegrass and black oat, would present better beef cattle performance by irrigation and/or inclusion of forage legumes in the grazing systems. We used 72 steers, 24 in each of the 3 years of evaluation, distributed in 12 paddocks under rotational stocking. Each paddock had four sub-paddocks. The experiment was completely randomized in a 2 × 2 factorial arrangement, using irrigation and legumes as factors. Production and chemical composition of pastures and animal performance were evaluated for 3 years in winter, spring, and summer. The irrigation provided promising results in spring, with a higher stocking rate (2194 vs 1254 kg/ha) and live weight gain per area (5.24 vs 2.81 kg/ha/day) in the second year due to water restriction. The forage legumes with irrigation provided a higher average daily gain in the summer than the non-irrigated pasture with legumes. Here we show for the first time that in long-term results (3 years), the pastures with legumes showed a high live weight gain per area (1556 vs 1452 kg/ha/year), and in the third year, the highest difference for the stocking rate in the summer (4134 vs 3311 kg/ha). Legumes or irrigation do not change the pasture's nutritional compounds. The use of forage legumes benefits the grazing system with long-term results. Irrigation, conversely, allows for positive responses during periods of water deficit. [ABSTRACT FROM AUTHOR]