Botanical Composition of Diets of Cattle Grazing South Florida Rangeland

Abstract

The botanical composition of the diets of 5 esophageal-fistulated steers in summer (June to August) and winter (January to March) on a south Florida range was studied in order to point out those plants or groups of plants that warrant management. Diets of steers grazing 3 ecosystems were compared: pine palmetto (Typic and Arenic Haplaquod soils), fresh-water marsh (Terric Medisaprist soil), and transition area around the marsh (Spodic Psammaquent soil). In addition we wanted to know if diets of steers regrazing a summer-grazed pasture in the winter were the same as diets from a pasture grazed only in the winter. A total of 320 diet samples were analyzed microhistologically, and out of 109 species, steers were found to eat 42 species. Steer diets were significantly different between summer and winter, while diets were similar on the regrazed-winter and winter-only pasture. Differences between summer and winter diets were mainly a decrease in Panicum hemitomon on the marsh and a decrease in Lachnanthes caroliniana in the winter diets on the pine-palmetto area, an increase in the proportion of shrubs in the winter diet on the pine-palmetto area, and an increase in Xyris spp. and Solidago fistulosa in the late-winter on the marsh and the transition area around the pond. These diet changes were the result of changes in plant availability or palatability, which was the case with P. hemitomon. These data indicated that Andropogon spp. and Schizachyrium stoloniferum were major components of the pine-palmetto area diet of cattle and should receive management to increase their yields. Forbs, though seasonally available, should be encouraged by shrub control, careful use of selective herbicides, and promotion of natural reseeding. Shrubs, especially Serenoa repens and Ilex glabra should be available as winter foods.