Characterization of Stockpiled Limpograss Swards Under Grazing.

The variation in herbage mass (HM) and nutritive value of stockpiled limpograss (Hemarthria altissima [Poir.] Stapf & C.E. Hubb.) pastures during grazing may affect supplementation strategies and animal performance. The objective of this study was to characterize HM and nutritive value of canopy strata of stockpiled limpograss pastures. The experiment was conducted in Ona, FL from January to March 2014. Treatments were limpograss cultivars ‘Floralta’ and ‘Gibtuck’, stratified in three, 25-cm vertical increments (0-25, 25-50, and 50-75 cm from soil level), in a completely randomized design with four replicates. Pastures (0.25 ha) were fertilized with 60 kg N ha^-1 and stockpiled from October 2013 to January 2014. Pastures were continuously stocked at a fixed stocking rate during the experiment. Three forage samples (0.1 m²) were harvested every 14 d. Gibtuck had greater crude protein (CP; 65 vs. 59 g kg^-1) and in vitro digestible organic matter (IVDOM; 480 vs. 450 g kg^-1) and a tendency toward greater HM (6.1 vs. 5.6 Mg ha^-1) than Floralta. Herbage mass was 4.2, 3.3, and 1.0; 2.5, 3.2, and 0; and 3.4, 0.3, and 0 Mg ha^-1 for the 0-25, 25-50, and 50-75 cm layers, respectively, in January, February, and March, respectively. Crude protein concentrations were 58, 58, and 93; 67 and 63; and 63 g kg^-1; and IVDOM concentrations were 380, 470, and 560; 360 and 430; and 360 g kg^-1 for the different layers in January, February, and March, respectively. Leaf proportion in the different layers was 32, 52, and 88; 39 and 57; and 38% in January, February, and March, respectively. In order to meet the nutritional requirements of beef cattle grazing stockpiled limpograss pastures, it is necessary to adjust the supplementation quantity and quality due to the variation in HM and vertical distribution of nutritive value in the canopy.