Roger Gates: Flexible grazing strategies
December 3, 2010
I learned the other day that Dec. 1 marks the start of “meteorological winter.” It’s also a confirmation that, from a pasture growth standpoint, we’re well past the accumulation phase and in the midst of the depletion phase. This time of year, it’s useful to begin anticipating next year’s accumulation phase; and developing a plan to allocate pasture resources to support livestock.
Creating grazing schedules would be straightforward if vegetation growth could be predicted reliably. The challenge faced by grazingland managers in semiarid regions is that precipitation is erratic, and plant production therefore is extremely variable. For example, production estimates for a clayey range site in western South Dakota with a typical plant community range from: 800 pounds per acre in an unfavorable year, to 2,400 pounds per acre in a favorable year – a threefold difference!
Another characteristic of semiarid regions is that rainfall is below average more often than it’s above average. The likelihood of drought demands a grazing strategy that acknowledges and accounts for this risk.
A study recently reported in Rangeland Ecology and Management by New Mexico agricultural economists (L. A. Torell, S. Murugan and O.A. Ramirez) addresses this need for rational grazing strategies in drought prone areas. Several typical responses to drought were acknowledged: reducing numbers; leasing pasture; temporary overgrazing; and increasing supplemental feed.
It was suggested that there are two basic approaches to stocking level planning in an environment where production is variable:
1. Stock at very conservative levels so that destocking is seldom required, or
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2. Anticipate and respond to fluctuating production by building stock numbers during favorable years and destocking quickly during dry periods.
Conservative stocking limits uncertainty, but sacrifices potential revenue that could result when vegetation remains unharvested in favorable years. A common recommendation to deal with variable forage is to allocate to breeding animals only what is likely to be available in unfavorable years (50-70 percent of total carrying capacity) and allocate the balance to yearling animals, which can be liquidated most easily.
The research used computer simulation procedures to answer the question, “Is it most profitable to use a conservative, relatively constant stocking strategy, or to adjust stocking levels in response to forage availability. Additionally, researchers evaluated options of stocking only with cows and calves versus the inclusion of yearlings in stocking alternatives.
Initial conditions were defined by an existing New Mexico ranch and multiple scenarios, production levels and price situations were evaluated in a complex but comprehensive simulation. The environment evaluated is rangeland dominated by warm-season short grass with a summer dominant precipitation pattern. The conclusions reached, therefore, are not directly applicable to the Northern Plains, but I believe they are instructive.
In addition to adjusting stock numbers, alternatives considered included: leaving pastures ungrazed; leasing pasture to other operators; leasing additional pasture to support livestock owned; selling calves in fall; wintering calves to run the following summer; and purchasing yearlings in spring. Initial conditions included a cowherd of about 540 Animal Units and also allowed for $35,000 of annual off-farm income.
Average values generated from multiple scenarios and runs for a 40 year period lead to several generalizations:
• Borrowing occurred infrequently for any scenario, at most 3.5 percent of years.
• Conservative stocking with cows only led to lowest average net returns – $55,000.
• Maintaining conservative stocking, but including yearlings increased average net returns to $63,000.
• Allowing stock numbers to track forage production, with cows alone, yielded average net returns of $69,500.
• Including yearlings in a flexible stocking strategy further increased net returns of $115,000.
• The number of years with negative returns was similar for conservative and flexible stocking alternatives, both with and without yearlings, varying from 18-26 percent of years.
• It was always more profitable to sell calves in the fall and purchase yearlings in the spring than to winter calves.
• When yearlings could be included in stocking alternatives, there was a progressive increase in the allocation of forage to yearlings and consequent decrease in number of cow-calf units over the 40-year time span.
Researchers pointed out that both flexible stocking strategies and/or the inclusion of yearlings increased costs, sometimes dramatically. This also magnified risk levels.
One very hypothetical scenario that was included for evaluation eliminated variation in forage production (although price variation remained). Not surprisingly, this led to high net return and nearly eliminated years with negative returns.
While scenarios were developed from Southern Plains data, the report also mentioned the advantage available to producers in the Northern Plains. Unlike the summer dominant precipitation and warm-season dominant vegetation of the Southern Plains, our precipitation comes primarily in the spring and there is a very large component of the vegetation that is cool-season.
Research in South Dakota, Montana and Wyoming has demonstrated that spring precipitation (April-June) is a reasonable predictor of growing season production. This provides the opportunity to purchase yearlings in the spring as a “flexible stocking” strategy, with greater confidence than producers in the Southern Plains may have.
While it potentially increases costs and risk, including yearlings as part of a flexible stocking strategy may be a means to effectively harvest pasture forage in favorable years and enhance returns. It simplifies destocking decisions when drought develops and reduces the risk of damaging the vegetation resource.