It's Time to Measure the Forage You Have

The following information is courtesy of The Cattleman Magazine

In November, livestock forage species go dormant. The standing forage in your pastures this month is what will support your cattle until spring. Measure what you have, determine what you’ll need, and buy hay or sell cattle according to what the numbers dictate.

By Charles L. Kneuper, state rangeland management specialist, USDA Natural Resources Conservation Service

We are at the end of the growing season for livestock forage. The grass left in the pastures is expected to carry herds through the coming months. Knowing how much forage you have and knowing how much your herd will need will drive management decisions and will indicate any changes you need to make to your grazing plan.

Now and in the coming months, continue to monitor forage quality. Balancing forage quality with livestock needs is imperative in the production cycle. Further, knowing your forage quality and animal needs will help you make decisions for your winter supplementation program. Monitor key grazing areas and key plants to make sure adequate residue is left to keep your ground covered.

Are you planning to carry out a prescribed burn this winter or early in 2018? Begin preparing fireguards following frost. You certainly want to be ready to go when you get a day that presents the needed conditions for your fire to meet your objectives. Do you have a grazing strategy in place to allow that pasture adequate recovery after the burn?

Edwards Region
By Kason Haby, USDA NRCS rangeland management specialist

As we near the end of the growing season, look at the amount of available forage in your pastures. What you have now is what will be available for livestock use through the winter. Estimate how many animal units (AU) you can carry through winter and, if necessary, selectively cull your herd to avoid purchasing hay.

There are several ways to estimate forage production on range and pasture. See the Texas A&M AgriLife Extension publication “Photo Guide to Forage Supplies on Texas Rangelands (EL-5476)” for comparison pictures for estimating forage production. Another method to estimate forage production is this 3-step process:

Mark off a 1-square-yard area and clip the grazeable forage to the ground in that area.
Air dry the sample and weigh it in gram increments.
Multiply the gram weight by 10.7 to determine production of pounds per acre.

For example, 200 grams x 10.7 = 2,140 pounds of forage per acre.

Clip forage in several representative locations around your ranch and average all samples to get the average forage production for the ranch.

To calculate carrying capacity or the total number of AUs your ranch can carry we must know a few things:

An AU is a 1000-pound cow that consumes approximately 30 pounds of air-dried forage per day, or 10,950 pounds per year.
What is the target harvest efficiency (HE)? What percent of the available forage do we want our livestock to consume? The rule of thumb is 25 percent on rangeland and 35 percent for improved pastures. These numbers account for trampled and wasted forage and leaving enough cover to protect the soil and the plants (take half, leave half rule).
How many grazeable acres do you have? Heavy brush and steep or rocky terrain should be excluded from grazeable acres.

Use this formula to calculate the carrying capacity in AU, then convert AU to cows based on your average cow weight.

Carrying Capacity in AUs =
(Forage in pounds per acre) x (0.25 HE) x (Number of Grazable Acres) / 10,950 pounds of forage per AU per year

For example:
Carrying Capacity in AUs =
(2,140 pounds of forage per acre) x (0.25 HE) x (500 Grazable Acres) / 10,950 pounds of forage per AU per year = 24 AUs
From this example, we see the 500 grazable acres can carry 24 1,000-pound animal units.

Not everyone has 1,000-pound cows. In this example, we see how to convert the carrying capacity to the weight of the animals we may have.

Determine the average weight of your cattle. Divide that weight by 1,000 pounds (AU equals 1,000-pound animal). Divide your carrying capacity by the result to determine how many of your cattle your range should support.

For example:
If your cattle weigh an average of 1,300 pounds, divide 1,300 by 1,000 to get 1.3. In the example above, carrying capacity is 24 AUs. Divide 24 by 1.3 and we see the range in the example can support 18 cows.