The Ecology and Management of Prairies in the Central United States

Appendix 1. Additional Information on Grazing

appendices This appendix provides more detailed information on what you’ll need to set up a grazing operation. Many of the details are general because you’ll need to ask local experts about developing stocking rates, finding lessees, and determining your fence and water needs. However, this quick guide should help you know what kinds of questions to ask. Grazing Stocking Rate The stocking rate of a pasture is a measure of grazing intensity. Stocking rate calculations can be confusing at first, and the decision on what stocking rate to start with can be tricky. Fortunately, there are people in your area available to help you. The Natural Resources Conservation Service (NRCS), a unit of the U.S. Department of Agriculture, has people with expertise who should be able to get you started. Biologists who work on private lands may have similar expertise. See the listing of potential contacts for your area in appendix 6. When asking for help on setting your initial stocking rate, be sure to explain clearly your objectives for the grazing. If you’re trying to suppress smooth brome, your stocking rate will be much different than if you’re trying to create some patchy vegetation structure. People who commonly advise landowners on grazing stocking rates are used to dealing with agricultural production objectives , so it will be critical for you to clarify whether you’re aiming for plant Appendix 1. Additional Information on Grazing 180 appendix 1 diversity, habitat structure, or production. It’s also important to remember that you’ll be able to adjust your stocking rate after the first year if it appears to be too heavy or too light. It’s highly unlikely that you’ll do any permanent damage with a one-year stocking rate that’s too high. If you want to try calculating your own stocking rate, the following two paragraphs will help you. If not, just skip them and work with local experts to get started. Some people talk about stocking rate in terms of the number of cattle per acre, or the number of acres per head. However, a real stocking rate measure also includes the weight of the animals and the length of time they are in the pasture. The most widely used unit of measurement for stocking rates is the animal unit month (AUM). An AUM is the approximate amount of forage a 1,000-pound cow with a calf will eat in one month. The idea is to give you a somewhat quantitative way to estimate how many grazing animals you can support on your prairie. Smaller animals eat less, so your site can support more of them than it can larger animals. The time component of the equation is important too, because it allows you to consider putting more animals on the prairie if you’re going to graze for a shorter time. There is still some inconsistency in how animal units are defined, but table A-1 uses some common definitions. Calves will change weight during the season, so estimate the weight of the animal unit by what you expect it to weigh in the middle of the grazing season. If you were in the cattle business you would try to figure out how many AUMs (consumed forage) you could remove from your pasture each year without hurting your long-term production. For example, you might decide that the rainfall, soil type, and plant composition of your site would allow you to take 100 AUMs per year from the pasture. If you wanted to graze for 5 months, you would be able to graze 20 cows with calves, assuming the pair of them weighed about 1,000 pounds (100 ÷ 5). If the cow-calf pairs weighed 1,400 pounds (more typical) you would then be able to support about 14 pairs (100 ÷ 5 ÷ 1.4). You could then calculate the stocking rate of the pasture as AUMs per acre. For example, if there were 50 acres in the previous example, the sustainable stocking rate for your pasture would be 0.4 AUMs per acre (50 acres ÷ 20 AUMs). However, the appropriate stocking rate for your prairie will depend on your particular objectives and may vary by year as your objectives change. 181 additional information on grazing Keeping a written record of each year’s stocking rate, the weather that season , and the results you saw from the grazing will be...