Corporations use the term “right-sizing” as a kinder, gentler way of saying “layoffs.” The concept has merit though, as companies need just enough people to handle the workload and maintain quality while maximizing profits.
In a cattle operation, right-sizing can apply to the number of cattle turned out to a pasture or maintained on the ranch at a particular time. Too many animals result in overgrazing and potential long-term damage and lost productivity. Too few can result in opportunity costs due to under-utilization of forage. “Just-right” stocking rates optimize forage utilization for sustainability and profitability.
That “just-right” stocking rate, however, is a moving target for any particular ranch, with precipitation causing most of the movement. Ranches in some areas approach this spring in the grips of a multi-year drought. Others are emerging from drought and some others could be seeing early signs of drought settling in.
While most droughts are relatively short-term events, how a rancher responds can influence the long-term impact on the ranch and its forage resource. University of Nebraska range-management specialist Jerry Volesky, PhD, notes that fluctuations in precipitation can dramatically influence forage production on a ranch. Data from the university’s Barta Brothers Ranch in the east-central Sandhills show upland range annual production ranging from 880 pounds per acre in 2002 — a moderate drought year — to as much as 2,360 pounds per acre during 2009, a year with above average spring and early summer rainfall.
Clearly the ideal stocking rates during those years would have been significantly different, but stocking rates often are based more on averages rather than actual forage production. Volesky says 12 years of data from the same location show that annual forage production averages 1,770 pounds per acre, which would support a stocking rate of about 0.75 animal-unit months per acre. Most years though, the actual production is well below or above the average. The best stocking rate based on actual production would have ranged from a low of 0.37 AUM in 2002 to 1.11 AUM in 2009.
Volesky cites another study on mixed-grass prairie in eastern Wyoming where forage production ranged from 100 pounds per acre in a drought year to over 2,000 pounds per acre in a wet year.
Timing of precipitation also plays an important role in forage production, with the ideal timing depending on the location, soil type and mix of plant species on the ranch. Knowledge of these key times, coupled with precipitation records, can help ranchers make stocking decisions early to avoid overgrazing. In the Nebraska Sandhills where warm-season grasses dominate, for example, Volesky says precipitation during May, June and July correlate best with seasonal forage production. In mixed-grass environments in western South Dakota, research shows that April, May and June precipitation is the best predictor of production.