Flexible stocking with Grass-Cast: A new grassland productivity forecast to translate climate outlooks with ranchers

Authors: Peck, Dannele; Derner, Justin; PARTON, WILLIAM - Colorado State University; HARTMAN, MELANNIE - Colorado State University; FUCHS, BRIAN - University Of Nebraska

Submitted to: Western Agricultural Economics Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/2018
Publication Date: 3/29/2019
Citation: Peck, D.E., Derner, J.D., Parton, W., Hartman, M., Fuchs, B. 2019. Flexible stocking with Grass-Cast: A new grassland productivity forecast to translate climate outlooks with ranchers. Western Agricultural Economics Association. 17(1):24-39.

Interpretive Summary: Matching animal demand with available forage is quite challenging for land managers. Flexible stocking is capable of both reducing losses during drought and increasing profit during wet years. By incorporating a yearling enterprise into an existing cow-calf only operation, the number of yearlings can be “flexed” up or down, both within and across years, in response to current and anticipated or forecasted forage availability. Economic returns from flexible stocking are dependent on high accuracy climate outlooks, which are currently lacking for the timeframes (e.g, 3-10 months) relevant for decision-making. Translating current conditions in the spring and short-term (1-3 month) climate outlooks into a forecast of grassland productivity would be directly useful to ranchers. A team of researchers recently developed a new Grassland Productivity Forecast, or “Grass-Cast”forecast (released in May 2018) for ranchers in the Great Plains region. Grass-Cast forecasts the productivity of how much rangelands, currently at the individual county level, are likely to produce using current climatic conditions to date for the year and precipitation outlooks for the May-July period during the growing season using above-normal, near-normal, or below-normal estimates, relative to the individual counties’ 34-year history. Grass-Cast maps are updated every two weeks from mid-May to the end of July, with new observed weather data and updated climate outlooks used as they become available (http://grasscast.agsci.colostate.edu/). Producers could use the early-May Grass-Cast maps to help inform their initial late spring grazing and marketing decisions. Furthermore, as the growing season progresses unfolds and Grass-Cast’s three maps are updated every two weeks, and evolve in response to new weather data and outlooks, producers could continue using this decision tool to be adaptive in their flexible grazing strategy.

Technical Abstract: Matching animal demand with available forage is quite challenging for land managers in highly inter- and intra-annual variable environments as forage responses to precipitation are dynamic. Livestock producers have traditionally been encouraged to practice light (defined here as 25 to 30% forage use) to conservative (defined here as 35 to 40% forage use) stocking rates, but these light to conservative stocking rates can also reduce financial gains during wet years by underutilizing abundant forage. An alternative strategy for advantageous matching of animal demand with forage availability is that is capable of both reducing losses during drought and increasing profit during wet years is flexible stocking. First, it involves increasing enterprise flexibility by incorporating a yearling enterprise (i.e., retaining weaned calves, both heifers and steers) into an existing cow-calf only operation, which requires the operation to reduce the size of the cow herd. Second, once the yearling enterprise is established in place, the number of yearlings can be “flexed” up or down, both within and across years, in response to current and anticipated or forecasted forage availability. If high-quality seasonal to sub-seasonal climate outlooks had high accuracy, flexible stocking with yearlings through the addition of a yearling enterprise and then actively managing its size within and across years could an increase economic returns from a modest 23 to percent to as much as 100 percent. Unfortunately, economic returns from flexible stocking are dependent on high accuracy climate outlooks, which are currently lacking for the timeframes (e.g, 3-10 months) relevant for decision-making on retaining numbers of weaned calves. Thus, currently the practicality of implementing flexible stocking with imperfect information about future forage availability (i.e., imperfect seasonal to sub-seasonal climate outlooks) limits application of this strategy by ranchers. Translating current conditions in the spring and short-term (1-3 month) climate outlooks into a forecast of grassland productivity would be directly useful to ranchers. A team of researchers from Colorado State University, U.S. Department of Agriculture-Agricultural Research Service, the National Drought Mitigation Center, and the University of Arizona recently developed a new Grassland Productivity Forecast, or “Grass-Cast”forecast for ranchers, and other rangeland managers, in the Great Plains region. Grass-Cast, released in May 2018, uses over 30 years of historical data about weather and vegetation growth (much of it from the U.S Department of Agriculture’s Long-Term Agricultural Research (LTAR) network)—combined with seasonal precipitation forecasts—to forecast the productivity of how much rangelands, currently at the individual county level, are likely to produce using current climatic conditions to date for the year and precipitation outlooks for the May-July period during the growing season using above-normal, near-normal, or below-normal estimates, relative to the individual counties’ 34-year history. Grass-Cast maps are updated every two weeks from mid-May to the end of July, with new observed weather data and updated climate outlooks used as they become available (http://grasscast.agsci.colostate.edu/). Producers could use the early-May Grass-Cast maps to help inform their initial late spring grazing and marketing decisions. Furthermore, as the growing season progresses unfolds and Grass-Cast’s three maps are updated every two weeks, and evolve in response to new weather data and outlooks, producers could continue using this decision tool to be adaptive in their flexible grazing strategy.