A few simple tools and time out in the pastures will help you understand the types and amount of forage on your ranch this year.
By Ellen H. Brisendine
Take a little time at the beginning of the new year to assemble your forage management toolkit. You will need a yardstick, or meter stick, a set of grass clippers, a camera or a device that serves as a camera, a place to file the photos, a place to spread out grass clippings to dry, and a weigh scale.
Why measure, clip, dry, weigh and record this data? All this effort will give you an idea of how much forage your land is producing, which will then tell you how many cattle, horses, sheep, goats, wildlife or other animal units your ranch resources can support without overgrazing.
Ricky Linex, USDA Natural Resources Conservation Service (NRCS) wildlife biologist, explains stocking rate in the accompanying article about developing your drought plan on page 84 in this issue. Here, he explains why, where, how and when to take forage samples, and what to do with that information for the best use of your ranch resources.
Registration for the 2019 Cattle Raisers Convention opens January 7th. Ricky Linex, USDA Natural Resources Conservation Service, will be part of the speaker lineup in the educational sessions. Come to the Cattle Raisers Convention to discover useful information presented by knowledgeable teachers. Click Here to Learn More!
Why take forage measurements?
Linex quotes what he describes as the old range school policy, “When it comes to vegetation take half, leave half,” he says, but leave half by weight, not by height.
“If you have grass that is 24 inches tall you might think that taking half would mean taking the top 12 inches. But grass is a little heavier closer to the ground. As it shoots up it is producing mostly stems and shorter leaves. That means leaving about 10 inches of stubble in this example,” he explains.
Leftover forage will not be a uniform height. Livestock are selective grazers and can be expected to leave behind a scruffy, untidy pasture.
Linex says research has shown that cattle have a grazing efficiency of about 25 percent. This means that of the half your cattle are “taking,” they are actually eating about half of that, or 25 percent of the total. The other quarter of what the cattle took off the forage plant is lost to being trampled, laid upon and just by being dropped by clumsy eaters.
“Let’s use an example pasture that has 4,000 pounds of forage in it. With a 25 percent grazing efficiency, our cattle are going to use only 1,000 pounds of that total forage. Another 1,000 pounds will be lost to being walked on or trampled,” he says.
With a little more math, you can determine how many animal units (AU) our example pasture can support.
Determine the average weight of the cows in your herd. Many of today’s AU calculations are based on a 1,000-pound cow. However, cattle have been trending bigger and heavier, so it might be a good idea to weigh your cows the next time you run them through the chute.
Daily, cattle will eat 2.6 to 3 percent of their body weight in dry matter. We will say our example cow weighs 1,200 pounds. Multiply 1,200 times 2.6 or 3 percent.
Linex continues, “If your average cow weighs 1,200 pounds, then she will eat about 31 to 36 pounds of dry matter per day.”
In our example, we expect our cow to eat 1,000 pounds of forage and trample on another 1,000 pounds. If the 1,200-pound cow eats 36 pounds of dry matter per day, then one acre of that pasture will support her for almost a month — 27.77 days to be exact.
“If a landowner is just starting out in ranching, it is a very good idea to go through these calculations so he or she can begin to link what they are seeing in the pasture with a number for the amount of forage they are producing,” Linex says. “Many experienced ranchers can ‘eyeball’ their pastures, but I encourage even those with years of experience to sample and weigh their forage from time to time. It is a good exercise to track forage productivity trends,” he says.
Where to sample?
Almost every pasture encompasses different soil types, Linex says. “Usually, you have two, three, sometimes four or five types of soils in a pasture. Each one of those soil types has different capabilities for growing grass. Shallow soils will not grow grass as easily as bottomland soils,” he says.
Analyze your pasture by its soil types, he suggests. “Let’s say you have three soils in a pasture, but one type of soil makes up two-thirds of the pasture. That becomes your key site.
“Then, choose a mid-quality grass within that site — not the most palatable and not the least palatable grass. That grass becomes an indicator or key grass for the entire pasture,” he says.
Do the same for each pasture, finding the most prevalent soil type and choosing a mid-quality grass. “Start watching these sites as indicators of when to move the cattle to the next pasture,” Linex says.
How to sample?
To measure forage production, clip a square yard or a square meter of vegetation all the way to the ground. Dry the forage, weigh it and do a little more math to convert to pounds.
Linex says for ease of calculation use a meter stick or, even better, a meter square.
Many of the USDA NRCS offices have a supply of one-yard range sticks. These square sticks have various useful formulas and species forage requirements printed on the sides. Lay two yardsticks on the ground at a right angle and clip everything within the square to the ground.
Another option is to do some welding out in the ranch shop or get your favorite welder to help. Use one length of 3/8- or 5/16-inch round rod and bend it at one-meter intervals at the inside corners. Weld the square closed at the last corner to make a square-meter frame.
Make a random toss of the frame within your key site and then clip the forage within the square to the ground. “Paint it white, so you don’t lose it in the grass,” Linex says. You can use the frame on the key site in each pasture, or you can “throw that frame out in the pasture to get a random sample. A random sample takes the bias out of your clippings. You are taking whatever is average out there.”
Linex continues explaining the method. “Clip everything a cow is going to eat. Ideally, we would take out the old growth, what we call the litter. This is the standing dead, year-old, or two-year-old grass that might still be there. You want to weigh just the current year’s growth.”
Put the clipped forage in a sack in the barn, or where the cattle cannot get to it, and allow it to dry for a week or 10 days. “You can microwave the grass to dry it, but it will make the next thing you microwave, such as your popcorn, taste like grass. I learned that the hard way,” he chuckles.
Weigh the dried sample to get the grams of weight. Linex says, “If you are in the western half of the state, scales that go up to 200 grams will probably be sufficient. If you are in the eastern half, you will need 400-gram scales.”
If you are clipping from a square meter, multiply the air-dried weight by 10 and that gives you pounds per acre. If you are clipping from a square yard, multiply the air-dried weight by 10.7 to get pounds per acre.
With pounds of production per acre and the required pounds per day per cow, you can start calculating how many animal units your forage resources can support.
When to sample?
“For somebody just getting into ranching, it is a good idea to clip and measure forage before they move the cattle to a new pasture,” Linex says. “Grass grows differently throughout the year.”
Taking samples more than once a year helps the landowner gather information to monitor production trends and gain perspective on forage amounts.
A record of forage production will show if you are producing more or less forage year-over-year. “Did you make any grass grow, or not? The only way you are really going to know is if you regularly collect clippings through the year, over multiple years,” Linex says.
“When you are making those clippings, consider taking pictures at a photo point in those same areas. Eventually, you may get to where you don’t have to clip it to estimate the forage,” he says. Use a t-post or something durable and recognizable as your photo point. Take pictures from that point in all directions, and even straight down at the ground.
Store these images in an organized way. Linex suggests using Microsoft Office PowerPoint as an option. You can begin to build your own digital slide deck in PowerPoint. The program also allows you to insert text on the same slide as the image, so you can document time, date, clipped weight, dried weight, rainfall, or other information.
Linex says, “With pictures from photo points, taken at the same time of year in the same place, I can just go back and look at the photos and compare them to this year, and say, ‘That looks like the same amount of grass we had in 2012 when we had 3,200 pounds. I’m going to base my estimate on that.’ If they’ve done it for a few years, they won’t have to clip forever.”
The other intangible benefit of clipping forage samples is that it gives you a great reason to get out on the ranch and out of the truck. It gives you time to walk the ranch and to gain a greater understanding of the resource under your management.
Organize Your Clipping Kit is excerpted from the January 2019 issue of The Cattleman magazine.
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