With the spring season approaching, pasture management issues are foremost in producers' minds. Fertility, herbicide treatments, pasture establishment and, for some, setting up a rotational grazing system are such issues. Questions about rotational grazing generally involve how to get started, where to start grazing this spring and what the benefits are. Let's answer the questions in that order.
How do you get started? First, inventory your resources pastures, forage types, soils, water and livestock, for example. Determine if you are properly stocked. You may need the assistance of a forage specialist to do so, or there are several good publications illustrating this as well (see references at the end of the article). When determining your stocking rate, pasture productivity will be estimated. If you have several pastures in existence already, then, in the simplest form, the rotation is based on a percentage of total productivity multiplied by desired cycle length, which is determined by growing conditions. Cross-fencing would be considered if productivity of some pastures is significantly greater than others, if there are different forage types within a pasture and if there are few or no cross-fences on the property. To make a grazing rotation work, adequate water to meet herd requirements is essential in each pasture. Grazing cycles are determined by growing conditions. As a rule of thumb, speed up the cycle under good growing conditions and slow it down under poor growing conditions. For example, grazing cycles in the spring could be as short as 21 to 30 days and later in the growing season as long as 45 days for introduced forages to 90 days or more for native range pastures. This is an over-simplification of how to get started, as there are many other issues to be taken into consideration. However, there are many good publications on the subject that are worthwhile reading for those interested in rotational grazing.
Where do you start grazing this spring? Where the rotation starts is dependent on several factors: physiological condition of the grazing herd, pasture conditions, forage types and growth rate of forages. For some, the starting point is creating a single herd and shutting the gates to all the pastures. From there, we'll use an example. Let's say your herd is primarily spring calving and you have some cool-season annual grasses, fertilized introduced grasses and some native range pastures. First, focus on pastures that have the greatest cool-season components, and attempt to fully use them. Allow the perennial pastures to accumulate about 6 inches of new growth before initiating grazing if there are few cool-season annuals in the pasture. Once the season has progressed to where only warm-season grasses are being grazed, manage the introduced grasses to maintain appropriate quantity and quality within the stand, especially if fertilized, while maintaining a desirable residual height. If excess pasture is produced, attempt to capture the forage at an optimal stage, balancing quality and quantity. Simultaneously, allow the native range pastures to accumulate excess growth to be utilized later in the growing season.
If you have primarily native range pastures, graze those with the greatest amount of annuals more intensely while the livestock are selecting annuals. Once the livestock begin selecting the warm-season grasses, adjust rotation to maintain a desired residual height of 6-8 inches for the desirable grasses and to account for growing conditions. If properly stocked and with typical spring growing conditions, forage growth should begin to accumulate in excess of what can be grazed. Plan on setting aside, early in the growing season, the pastures that need additional recovery or are in need of extra improvement in condition and then placing them back into the rotation later in the growing season.
What are the benefits of rotational grazing? There are several. An often-overlooked benefit is herd management and ease of observing the livestock. Other benefits include better pasture management, easier assessment of forage reserves, greater grazing efficiencies, improved livestock distribution within pastures and, in many instances, improved production per acre, just to name a few. Again, there are numerous publications written on rotational grazing. Information on rotational grazing also can be found under the names management-intensive grazing (MIG), controlled rotational grazing (CRG), holistic resource management (HRM) and short-duration grazing (SDG). Review associated publications or contact a forage specialist for more information.
References
"Stocking Rate Decisions: How Do I Determine the Correct Stocking Rate?"
http://texnat.tamu.edu/library/publications/stocking-rate-decisions/
Redfearn, Darren D. and Bidwell, Terrence G. "Stocking Rate: The Key to Successful Livestock Production"
http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Rendition-5110/unknown
Hart, Charles R. and Carpenter, Bruce B. "Stocking Rate and Grazing Management During Drought"
http://rains.agrilife.org/files/2011/09/stockingrateduringdrought_10.pdf
