The adage "you cannot manage what you do not measure" has many applications, including stocking rate or, more accurately, carrying capacity. However, in the management of beef cattle operations, carrying capacity has traditionally received little attention. There are several factors for this: the development of fertilizer-efficient introduced grasses, cheap fertilizer, cheap hay and several decades of good rainfall beginning in the early 1980s. Fertilizer and hay are now much more expensive. Rainfall has become less dependable with drought reminiscent of the 1950s being experienced in 2011 and 2012. In spite of changing conditions, most producers were reluctant to adjust stocking rate until forced to do so by the drought, and, even then, few have begun monitoring (much less managing) carrying capacity. Now is the time to begin active management of carrying capacity and, thus, your stocking rate.
Where does a producer begin? A good place to start is monitoring monthly rainfall on the ranch using a "water year" table and comparing numbers to the long-term monthly average (Table 1). The water year rainfall table for an operation allows a producer to determine the percentage above or below the long-term average that the actual precipitation is at the end of each month, thus indicating approximately how much to adjust the stocking rate during the growing season (assuming the producer is stocked for an average year).
The second variable to measure is actual forage production. There are several methods to assess forage production. Depending on the type of management employed, the best method will vary. Estimates of forage production need to be determined at critical dates in the operational plan. A few suggested dates for estimating forage production for the Southern Great Plains region are June 1, July 1, Sept. 1 and at frost when, respectively, about 30 percent, 65 percent, 90 percent and 100 percent of annual perennial warm-season grass production is expected to be produced.
A forage assessment form is the tool needed to estimate forage production. There are many different ways to construct a forage assessment form. In Table 2, a reserve herd day approach is used in the assessment, which is often easier when practicing managed rotational grazing. Initial critical information includes identification of critical assessment dates; an estimate of forage demand at critical date assessment and anticipated for the year; an estimate of the total amount of production anticipated for the grazing period (normally a year for cow-calf operations); and an estimate of the amount of forage produced (on-hand, grazed and hayed) at the time of assessment. All forms will include pasture inventory information such as pasture identification, forage type and estimated production.
Adequate rainfall covers up many poor management practices and allows producers to ignore the management of stocking rate. It often takes extreme circumstances - like an extended drought - before stocking rates are adjusted. Unfortunately, adjustment is usually made after the land (forage) resource has been misused to the point that it will take multiple years to recover - if recovery is even possible. However, astute managers can distinguish themselves during periods of extended drought by managing stocking rates to match carrying capacity through the use of tools to monitor rainfall and forage production. The key to sustaining forage resources for long-term optimization of carrying capacity (regardless of rainfall) is active management of stocking rates.