Systems of Growing Cattle on Stargrass Pastures or Sugarcane Bagasse in Peninsular Florida

Florida has a substantial cow-calf industry and provides a major market for beef. The state also has extensive undeveloped resources with potential to produce forage-fed beef. Systems of growing beef steers (Bos taurus × B. indicus) on stargrass (Cynodon nlemfuensis Vanderyst var. nlemfuensis) pasture or a high-roughage diet based on sugarcane (Saccharum officinarum L.) bagasse were compared. The level of supplement fed on pasture was also evaluated. The growing period was followed by a short finishing period for all systems. In Exp. 1, cattle provided a 24% crude protein (CP) corn (Zea mays L.)-based supplement at 1.5% of body weight (BW) during the 161-d winter grazing period gained 0.25 lb/d more than cattle supplemented at 1.0% of BW. Supplementation responses continued through spring, when improved pasture conditions produced much higher gains for all cattle, and even persisted through a subsequent 65-d drylot feeding period on a 40.2%-corn ration. Carcass quality grades of high Standard indicated insufficient finish by current standards for cattle from pasture systems. In Exp. 2, cattle on the bagasse-based ration in drylot made greater (P < 0.05) daily gains (1.75 vs. 1.42 lb) than cattle receiving grain supplement on pasture over a 238-d growing period. Subsequent responses to a 74.7%-corn finishing ration over a 100-d period apparently produced compensatory gains by cattle that had made lower gains on pasture during the growing period. Despite the potential for high yields of quality stargrass forage in spring and favorable responses to supplementation on stargrass pasture in winter and spring, the stargrass pasture systems were limited by unpredictability of spring rainfall and failure of a subsequent short feeding period on a relatively high roughage ration to produce potential compensatory growth and desired carcass characteristics. Research QuestionDespite potential for much higher levels of forage production than currently obtained and local demand for beef, calves produced in Florida are primarily transported out of state, while beef is transported into the state. Lack of locally grown feed grains has been a key limitation to cattle feeding in Florida. Recent changes in consumer preference toward lower fat meat along with the development of methods to enhance quality of beef carcasses, such as electrical stimulation, suggest that cattle grown on forage could provide acceptable beef for the current market. Systems of beef production were evaluated to assess potential for growth of steers on stargrass pastures in peninsular Florida followed by a short feeding period. Literature SummaryStargrass cultivars under intensive management can provide seasonally high yields of quality forage in peninsular Florida. Daily gains of 1.25 to 1.5 lb/head by yearling steers during the spring have been reported at stocking rates of approximately 1.5 head/acre. Additional responses to supplementation also have been obtained during the growing season. A short feeding period on a limited-grain ration could complement such growing systems to produce locally grown beef. Study Description Exp. 1 Recently weaned Brahman crossbred steer calves initially averaged 340 lb. Each pasture consisted of 5 acres of Ona stargrass that was stocked continuously. The site was a flatwoods soil (Ona fine sand) at Ona, FL. Cattle were divided into groups of six head each. Supplement treatments (two replications each): 24% CP-supplement (1.0% of BW) in winter, followed by 12.5% CP-supplement (1.0% of BW) in spring. 24% CP-supplement (1.5% of BW) in winter, followed by 12.5% CP-supplement (1.5% of BW) in spring. Compared with similar cattle confined to drylot and fed a high-roughage (sugarcane bagasse-based) diet. Cattle were subsequently fed a 40.2% corn ration for 65 d and slaughtered. Exp. 2 Similar to Exp. 1 except, Supplement treatments (four replications of each): 26.6% CP-supplement (1.0% of BW) in winter, followed by 0.88 lb/d of a 9.3% CP-supplement in spring. 26.6% CP-supplement (1.5% of BW) in winter, followed by 16.4% CP-supplement (0.5% of BW) in spring. Cattle were fed a 74.7% corn ration for 100 d immediately before slaughter. Applied QuestionAre systems of growing fall-weaned calves on stargrass pasture through spring followed by a short period of limited-grain feeding practical for beef production in peninsular Florida? Cattle performance (Table 1) during the winter was within the range anticipated, although there was an unexplained lack of response to the additional increment of supplement at the high level in the second year (Exp. 2). Gains during the spring differed between years with lower rainfall, limited forage growth, and lower gains in the second year. Daily gains for all cattle in the feedlot in Exp. 1 on a 40.2% corn ration were substantially less than those of cattle grazing spring pasture supplemented at 1.5% of body weight. Apparently the low energy content of the ration did not allow realization of potential compensatory gains, especially for cattle fed the lower supplement level on pasture. In the second year, not only were spring gains on pasture lower than anticipated because of inadequate spring rain, but feedlot performance of all cattle was even lower than in the preceding year, despite being fed a high energy ration. Adverse effects of an extremely humid summer feeding period were probably at least partially responsible for these low feedlot gains. Due to dependence of such beef production systems on unpredictable spring rain for stargrass growth, a feedlot phase during hot humid summer conditions, and failure to realize potential compensatory gains during the limited feeding period, the potentially productive systems of growing beef on stargrass pastures in peninsular Florida were uncertain and less productive than anticipated under the conditions of these experiments. Table 1Gains of cattle during a growth period on stargrass pastures and subsequent gains in the feedlot. Gain on pastureSupplement levelWinterSpringGain in feedlot-------------lb/head/d-------------Exp.1Low1.32a*2.26a2.40aHigh1.57b2.67b2.38aExp. 2Low1.21a1.68a2.10aHigh1.26a1.65a1.99a*Within each experiment means in a column followed by different letters differ (P < 0.05).