Tiller Defoliation in a Moderate and Heavy Grazing Regime

Abstract

An investigation defining the intensity and frequency of tiller defoliation in brownseed paspalum (Paspalum plicatulum), a native perennial, bunchgrass, was conducted with yearling steers in a moderate and heavy grazing regime. Tillers were marked with alternately colored loops of plastic-coated wire so that an individual tiller could be located on successive sampling dates. Tiller height was reduced 50% within 7 days in the heavy grazing regime. The percentage of leaves defoliated per tiller was 63, 78 and 82 following 4, 7, and 11 days of grazing, respectively. Tillers in the heavy grazing regime were uniformly regrazed at approximately 3 to 4 day intervals. A significant reduction in tiller height did not occur in the moderate grazing regime until after 18 days of grazing and tiller height was reduced only 46% at the end of the 33-day grazing trial. The percentage of leaves defoliated per tiller was 5, 9 and 26 following 11, 21, and 33 days of grazing, respectively. By the end of the moderate grazing trial 82% of the tillers were grazed at least once, 31% at least twice and 10% at least three times. The nonuniform frequency of tiller defoliation and wide range of tiller heights at the end of the moderate grazing trial resulted in an inefficient harvest of available tillers.