Beef cattle production from rangelands in the Southern Great Plains has decreased in concert with declining herbaceous forage production in response to woody plant encroachment over the past 120 years. The combinations of livestock overstocking and fire suppression are considered to be primary drivers of these changes. This experiment evaluated the utility of prescribed fire and grazing management as ranch-scale restoration strategies for Southern Great Plains rangelands that had become dominated by honey mesquite (Prosopis glandulosa Torr.). Here, we document cow-calf production responses over a 7 year period. Strategies tested were continuous grazing, no fire (Cont); 4 pasture-1herd, with fire (4:1F); 4 pasture-1herd, with fire and herbicide (4:1F+H); and 8 pasture-1 herd, with fire (8:1F). All cattle stocking rates were moderate (7.5 to 11 ha/AUY) and all fires were applied during late winter. Beef cattle production variables measured included conception rate (CR), weaned calf percentage (WC), weaning weight (WWT), weight of calf per exposed cow (WtPEC), weight of calf per hectare (WtPHA) and supplement fed per cow (SUPP). All cattle were naïve to rotational grazing, were managed in single age class herds and were handled infrequently prior to inclusion in this experiment.
During the first two years, the Cont strategy had greater (P < 0.05) WC, WWT, WtPEC and WtPHA than the 4:1F and 8:1 F strategies. The 8:1F strategies required greater SUPP the first 2 years than did the other strategies. After this “adaptation phase” where cattle and management were adjusting to rotational grazing, there were few differences among strategies and observed differences were usually caused by the different conditions experienced in each year.
Since animal production was greater in the 4:1F than the 8:1F strategy during the adaptation phase it would probably be advisable to start with fewer pastures before progressing to an 8 pasture strategy. This would provide management and livestock time to adapt to the different management and not forfeit livestock production. The need for personnel unfamiliar with rotational grazing to develop skills and change their grazing management approach for successful adoption of integrated rotational grazing and prescribed fire strategies cannot be overstated.
Based on our findings, animal performance with integrated fire and rotational grazing strategies in the post adaptation phase of both the 8:1F and 4:1F strategies was similar to the continuous-grazed strategy. This occurred even when effective stocking rates in these rotation strategies were de facto 8 to 17% greater in terms of the strategy and cattle herd because that proportion of grazing days were lost in order to provide deferment associated with using fire. Thus, this study demonstrated that the costs for pre and post fire grazing deferment can be internalized within these moderately stocked systems with no loss in animal performance once management and animals adapt to the strategy.
Publications
Pinchak, W. E., W. R. Teague, R. J. Ansley, J. A. Waggoner and S. L. Dowhower. 2010. Prescribed Fire and Rotational Grazing in a Mesquite Savanna: III. Ranch-Scale Cow-Calf Production Responses. Rangeland Ecology and Management (In press)