• Integrated Ecological and Economic Analysis of Ranch Management Systems: An Example From South Central Florida

      Swain, Hilary M.; Boblen, Patrick J.; Campbell, Kenneth L.; Lollis, Laurent O.; Steinman, Alan D. (Society for Range Management, 2007-01-01)
      Developing sustainable ranch management systems requires integrated research that examines interrelations among ecological and economic factors. In south central Florida, where phosphorus (P) loading is an overriding environmental concern, we established an interdisciplinary experiment to address the effects of cattle stocking density and pasture type on P loading and other ecological and economic factors in subtropical Florida ranchlands through a partnership including ecologists, agricultural faculty, agency personnel, and producers. Here we present an overview of all project components detailed in 3 accompanying papers in this issue of Rangeland Ecology Management. We describe the experimental design, which included 2 replicates of 4 different cattle stocking density treatments (control, low, middle, and high [0, 15, 20, and 35 cow-calf pairs per pasture]) maintained on 8 improved summer pastures (– 20 ha each), and 8 seminative winter pastures (– 32 ha each) from 1998 to 2003. Stocking densities did not significantly affect P loads and concentrations in surface runoff, soil chemistry, or soil nematode communities, but did affect cattle production and economic performance. Cattle production was greater at the high than at the middle or low stocking density; economic performance declined significantly with decreasing stocking density (break-even was 1.89 kg-1 for high and 2.66 kg-1 for low density). Pasture type significantly affected environmental factors; average P runoff from improved summer pastures (1.71 kg P h-1 y-1) was much greater than from seminative winter pastures (0.25 kg P ha-1 y1), most likely because of past P fertilizer use in improved pastures. We integrate results from all the papers within the context of a conceptual model and a P budget, and emphasize that management practices targeted at specific environmental factors on beef cattle ranches, such as nutrient loading, must include consideration of economic impacts and broader ecosystem implications. 
    • Integrating Ranch Forage Production, Cattle Performance, and Economics in Ranch Management Systems for Southern Florida

      Arthington, J. D.; Roka, F. M.; Mullahey, J. J.; Coleman, S. W.; Muchovej, R. M.; Lollis, L. O.; Hitchcock, D. (Society for Range Management, 2007-01-01)
      The presence of grazing cattle near open waterways has created environmental concerns related to the potential for water contamination. In Florida the removal of cattle from grazing landscapes or decreasing stocking density is being investigated as one option to improve the quality of surface water runoff draining into Lake Okeechobee, Florida. The objective of this study was to determine the effects of stocking rate on cow-calf performance, forage availability and quality, and ranch economic performance. Experimental pastures were established on a southern Florida cow-calf operation with stocking rates of 0.58, 1.01, and 1.35 ha cow-1 on summer pastures and 0.93, 1.62, and 2.16 ha cow-1 on winter pastures, corresponding to high, medium, and low rates, respectively. The study was conducted over 4 consecutive production years. Cow body condition scores (BCS), pregnancy rate, and calf average daily gain were used as measures of animal performance. Forage utilization was estimated by measuring the difference between forage yield inside and outside grazing exclusion cages and forage quality by crude protein and in vitro organic matter digestibility. Forage yield, utilization, and quality were not significantly affected by stocking rate. Although statistically not significant (P = 0.17), cattle in the high stocking rate experienced a numerically greater loss of BCS following the winter grazing period, but stocking rate did not affect pregnancy rate or calf gains. Production (kg weaned calves ha-1) was increased (P < 0.01) for a high stocking rate compared with medium and low stocking rates. Overall ranch profitability will decrease as stocking rates decline. Ranch revenues decrease one-for-one as stocking rates decrease. At the same time, unit cow costs increase at an increasing rate as fewer brood cows are left to support the ranch’s fixed cost structure.