Animal Performance on Limpograss‐Aeschynomene and Nitrogen‐Fertilized Limpograss Pastures

Abstract

AbstractIn vitro digestible organic matter (IVDOM) concentration of ‘Floralta’ limpograss [Hemarthria altissima (Poir.) Stapf et C. E. Hubb.] is high compared to many tropical grasses, but low crude protein (CP) concentration in Floralta may limit animal performance. Aeschynomene (Aeschynomene americana L.) grows well in association with limpograss and may improve animal performance on limpograss‐based pastures. This study compared steer (Bos spp.) average daily gain (ADG), carrying capacity (CC), and gain per hectare from midsummer to early fall on limpograss pastures that were overseeded with aeschynomene (LA) or fertilized with N (LN). Soils were primarily Pomona sands (sandy, siliceous, hyperthermic Ultic Haplaquods). Seasonal ADG (84 d in 1984, and 126 d in 1985 and 1986) was higher for LA than for LN pastures in 1984 (0.69 vs. 0.36 kg), 1985 (0.55 vs. 0.27 kg), and 1986 (0.85 vs. 0.54 kg). Handplucked herbage of aeschynomene had mean CP and IVDOM concentrations of approximately 250 g kg−1 dry matter (DM) and 720 g kg−1 organic matter (OM). Handplucked limpograss CP was marginal for growing steers, averaging 92 and 88 g kg−1 DM in 1985 and 1986, respectively. Mean seasonal CC over the 3 yr of grazing was higher for LN than for LA pastures (2210 vs. 1700 kg liveweight ha−1 d−1). In 1985 and 1986, however, mean seasonal CC did not differ between systems, but from early July to mid‐September LN pastures had higher CC (2240 vs 1540 (1985) and 2450 vs 1930 (1986) kg liveweight ha−1 d−1]. Mean gain per hectare per year was higher for LA than for LN pastures (377 vs. 264 kg) over the 3 yr of grazing. Although LN pastures are easier to manage and have a longer grazing season, these data indicate that gain per animal and gain per hectare can be increased during midsummer through early fall by growing aeschynomene with limpograss.