Pasture measurement can improve management

When the management of grazing is discussed, what are the topics of that discussion? Typically, they involve forage growth, forage varieties, soils, animal nutrition, grazing behavior, and paddock layout and design. These are all valuable topics for a grazier to understand and use to effectively manage his system. Rarely do you hear discussions on the unexciting aspects of management, like planning and control.

Planning is defined as the ongoing process of developing the mission, objectives and goals of the operation. Planning has been discussed in many basic grazing schools. OSU Extension fact sheets address the development of the mission, vision and goals of an agricultural business.

A topic closely related to planning that is rarely discussed is control. Control is a four-step process of establishing standards based on the goals and objectives, measuring and reporting actual performance, comparing the two, and then taking necessary action.

I want to focus on measuring and reporting the actual performance, and how that can be used to make decisions. Please realize that it should be in the context of planning. Taking measurements just as an exercise makes no sense. Taking measurements that relate back to your mission, objectives and goals can help you monitor progress and improve your operation.

Measurement

Let’s first look at measurement. Most graziers are familiar with using measurements related to animal production, like the reading from the bulk tank or the weight of animals on the auction sale receipt. These are good measures to be taken because they relate directly to income but they are not timely enough to help graziers make decisions in their operations. It is amazing that graziers say their focus is on the forage but they don’t measure it.

There are lots of ways to measure forage such as, pasture sticks, falling plate meters, rising plate meters, electric pasture probes, and even the tedious method of cutting. With little expense, graziers can consistently determine how much forage is available by simply walking their paddocks.

Problem

One problem with measuring forage is that it is a dynamic, living community of plants that is highly variable. To overcome the variability, many samples must be taken in order to accurately estimate how much forage is there. This can be time consuming and tedious. Usually 20-30 samples are recommended per pasture or paddock.

The second problem is that the amount of forage available is always changing — animals are consuming leaves and plants are growing. To account for this constant change, measurements need to be taken on a regular basis, usually every seven to 10 days.

The most accurate method used to determine the amount of forage available is cutting. Cutting is simply to take a known area, usually a 1-2 foot square, cut all of the forage in that area, dry it down completely, weigh the sample and convert it to pounds of dry matter per acre. Taking samples in this manner does take time. Most people use it to calibrate some other faster method of measurement. In managing your operation, accuracy is not as important as consistency. Faster methods can give consistent and fairly accurate results.

Height

The easiest measurement of forage we can do is height. There seems to be some common confusion about using plant height to measure forage. Do livestock eat inches of forage or do they eat pounds of forage? Actually they eat pounds. To make it simpler, we take water out of the equation and say pounds of dry matter. Since the primary function of forage is to be used as feed, then converting its measurement into feed terms makes sense.

Using plant height has also confused a lot of people when we talk about the rule of thumb for forage management: Take half, leave half. It refers to dry matter, not inches. If you really look at the profile of grass plants you should notice that there is more vegetative matter the closer you get to the ground. If you are ambitious you could cut and weigh each inch of plant material from the ground up. Depending on the grass species, you would find that the first 2-3 inches has more dry matter than the next 6-10 inches.

Two fact sheets from West Virginia University — A Falling Plate Meter for Estimating Pasture Forage Mass and Estimating Pasture Forage Mass from Pasture Height — are good references for graziers on measuring forages.

The authors do a good job of discussing using a ruler, a falling plate meter and a rising plate meter. Any of those tools could easily give you consistent information that is accurate enough to use in your management.

Big rewards

If you make time to determine average pounds of dry matter per acre for each paddock once a week, it would reward you with huge dividends. It will tell you how much forage you have in each paddock, which in itself is useful information. You will quickly see which paddocks need to be grazed next. If growth has stopped, you can quickly calculate how many days of forage you have left to graze.

Doing it on a weekly basis also allows you to calculate more useful information. Two consecutive weekly measurements can be used to calculate how fast the forage is growing. You can determine if you to a need to change your management because growth has either increased or decreased. Looking at a year of data, you could calculate how much forage you actually grew and if you can carry more animals. It can help you identify the top yielding paddocks and the lowest yielding paddocks. You can determine ways to make the lower yielding paddocks produce more. Using measurements next year will help you determine if what you tried actually worked.

Measuring pastures and using the data is not the most exiting topic in grazing management. But it is one of that will make you effective in your management.

About the Author

Jeff McCutcheon is an Ohio State University Extension, Agriculture and Natural Resources Educator in Knox County. More Stories by Jeff McCutcheon

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