Diets and Liveweight Changes of Cattle Grazing Fall Burned Gulf Cordgrass

Abstract

We investigated effects of fall burning of gulf cordgrass (Spurtina spartime) rangeland on winter diets and liveweight gains of cattle on the Texas Coastal Prairie during 1979-1981. Gulf cordgrass dominated steer diets (21-76s) regardless of burning treatment. However, Texas wintergrass (Stipa leucotricha) on adjacent upland sites accounted for 13 to 36% of animal diets during winter growth periods. Burning increased dietary crude protein content from January to March in all years and increased in vitro organic matter digestibility during February and March. Cattle gained or maintained weights on burned pastures but maintained or lost weight on unburned pastures. Weight gains of animals with access to burned gulf cordgrass, but not Texas wintergrass, equaled gains of animals grazing unburned gulfcordgrass and Texas wintergrass. Burned gulf cordgrass can provide alternative green forage that will improve diet quality of cattle when cool-season species are absent. Gulf cordgrass (Spartino spartinae), a perennial warm-season species, provides abundant but poor quality forage for cattle grazing the Texas Coastal Prairie (Gould 1975, McAtee et al. 1979 a, b). Oefinger and Scifres (1977) and McAtee et al. (1979 a,b) determined prescribed burning or shredding could enhance nutritional value of gulf cordgrass without damaging stand integrity. However, it remains uncertain whether burning results in direct benefits to grazing livestock. This study was undertaken to test 3 hypotheses: that gulf cordgrass rangeland burned during fall provides greater dietary crude protein and energy during winter than unburned gulf cordgrass; that fall burning increases the proportion of gulf cordgrass in the diet of free-ranging cattle during the winter; and that cattle grazing fall burned gulf cordgrass rangeland have greater gains in liveweight than cattle grazing unburned areas.