Rotational grazing offers many benefits
The ideal pasture has fertile soil and a variety of nutritious forage plants, grazed at the proper phases of growth. Your local Extension or Natural Resources Conservation Service folks can provide advice on establishing and maintaining pastures, but how you manage them will determine the ongoing health and quality of those pastures.
Rotational grazing systems are generally the most efficient way to get the best use of pastures and maximum beef production per acre, as well as being healthier for the land and plants. When done properly, pasture rotation can prevent overgrazing, aid optimal regrowth of plants and allow the same piece of ground to be grazed several times during growing season.
John Hall, superintendent of the University of Idaho’s Nancy M. Cummings Research, Extension and Education Center near Salmon, says rotational grazing is always a very positive tool for stock producers, especially on irrigated ground.
“This is a tool you absolutely must use to get maximum beef production on that expensive input,” he says. Irrigated land is high-priced compared to rangeland, and the cost of irrigation in labor and energy input to run a pump or pivot is a major item.
There are many variables regarding the best number of days spent in a paddock. Some stock producers find best results by moving cattle daily or even several times a day. “A person can often get by moving cow-calf pairs just once a week, however. This is something each individual producer must determine, regarding available labor,” says Hall.
Pastures and paddock setups can also make a difference in what’s most feasible. One common method is to create large pastures with permanent fencing and then subdivide them with temporary electric fencing.
Understanding the growth phases of forage, the amount of residual feed to leave and when the animals need to be moved is crucial, especially with cool-season grasses, or they won’t grow back very well. “This means we must be flexible and do some things that maybe weren’t planned,” Hall says.
“If the irrigation system breaks down and takes a few days to fix, or it doesn’t rain, or whatever, we may have to be willing to feed hay at a time of year we hate to feed hay, just to give those pastures enough time to recover,” he explains.
The cost of feeding a little hay may be less than overgrazing pastures to the point they won’t grow back adequately, leaving less forage over the long run.
Maximizing growth phases
Jim Gerrish, American GrazingLands Services, May, Idaho, says grass growth involves three phases. “The first is when grass comes out of dormancy in spring, or after being harvested short. It takes a while to get enough leaf area to capture adequate solar energy for rapid growth,” he says.
Cattle prefer grass in Phase 1 because it’s tender, succulent and high in nutritional quality.
“In a pasture being grazed continuously, without rotation, cattle keep re-grazing the short spots, seeking out Phase 1 grass. This is stressful for plants because they don’t have enough leaf area to support maintenance,” he says.
If the pasture is in a recovery period and not grazed, plants start to accumulate enough leaf area to be able to grow more rapidly. “This Phase 2 growth continues until the mass of the plant is requiring a lot of energy just to maintain its structure. There is also some shading of the lower leaves and some leaves dying.
“At that point, growth rate slows dramatically and the plant goes into Phase 3, which is when we would cut it for hay; it’s as big as it’s going to get,” explains Gerrish.
In a traditional rotation, the producer tries to keep as much of the pasture in Phase 2 as possible, putting cattle into a pasture when grass is fairly high on Phase 2 of the growth curve.
“We take the cattle off when grass is eaten down toward the lower height of Phase 2. If we graze it too hard, all the way back to Phase 1 — stripping the plant of leaves — it takes longer to recover and needs a longer rest period during the growing season,” he says.
“Stockmen who try to do rotational grazing and find they are still running out of grass are usually grazing it too short. This makes the recovery periods longer than they can afford to have,” he says.
Take care not to overgraze
Overgrazing can happen whenever cattle are allowed to return to the same plants, keeping them grazed down into Phase 1.
It’s most common in pastures that are continuously grazed, without rotation — but it can also happen in a rotation program if you leave cattle in a paddock too long, or if your recovery period is too short.
“A common thing you’ll see in continuously grazed pastures is overgrazed areas [Phase 1 grass] right next to mature clumps [Phase 3] that cattle aren’t eating — and no Phase 2 grass. If you do a good job of irrigating and stocking, always keeping grass at 5 to 8 inches in height [always in Phase 2], continuous grazing can work, especially in climates that are very stable, Gerrish says.
“But the problems we generally have, especially in the West, are temperature extremes — and we can’t always get grass watered when it needs it. The growth rate is very fast for a while, then slows to nothing, so it’s hard to keep everything in Phase 2 in a continuously grazed pasture.
“The goal of rotational grazing is hold the grass in Phase 2 for as much of the season as possible by letting pastures recover periodically,” he explains.
Adjusting recovery periods to encourage maximum grass growth and keep most of it in Phase 2 is a juggling act. Learning how to adjust the grazing and recovery periods is an art.
“This is the part you can’t learn from a book or a workshop. Until you actually do it yourself, you can’t learn grazing management.”
You run into situations each year that you haven’t encountered before, as well as learn from your mistakes. “I’ve been doing this for more than 30 years, and I still make my share of mistakes and learn something new each season,” says Gerrish.
“One of the problems in thinking about rotational grazing is the tendency to think one size fits all, and that there’s a particular way to set up pastures and move cows,” says Hall.
But this won’t work for every operation. The key to rotational grazing or trying to expand the grazing season with pasture management is to try a new idea, on a small scale, before you change your whole system.
“Basic techniques for rotation grazing management can be learned in workshops like the Lost River Grazing School in Lemhi County [Idaho], but then you must adapt those basics to your situation and your particular ranch,” says Hall. Elevation, climate, types of plants, terrain, whether it’s irrigated or dryland, etc., will all be factors.
“We discuss electric fence, but research across the West has looked at controlling cattle use of rangeland without fences. Salt placement was traditionally used to distribute cattle where we want them, but we also use water and supplement tubs as management tools,” Hall says.
On a dry year when grasses become short on protein, cows will readily eat a protein supplement, and you can move the location of their grazing with movement of supplement tubs. This can encourage cows to go places they might not graze otherwise and help with grazing distribution.
Ranchers are limited on public range when trying to graze certain areas at certain times, since there are constraints on when various pastures or allotments can be used. There isn’t much flexibility on turnout and move dates; timing is set on a calendar.
On private range, ranchers have more options to do what might be best for the land and cattle, using innovations and flexibility.
“We still have a lot to learn about how best to use these grasses, especially on rangeland. If there’s good moisture in the spring, how should that change what we do with grazing early in the season? If it turns dry, what should we do differently than if we had a better year?” asks Hall.
Regarding rotation grazing management in general, Hall’s advice is to learn the basics and then try to customize them to your ranch — always keeping the need for flexibility in mind. Try something on a small scale at first, then work your way into it as you discover what works best for you.
How many cattle can a rotational system accommodate? “You need to be able to vary stocking rate seasonally,” says Gerrish.
In a cow-calf operation, this is the greatest challenge for keeping the forage supply and animal demand in balance. If you can run yearlings part of the season, or keep more heifers than you need, selling some after they are bred, you can adjust the stocking rate to try to match the grass supply.
Stocking rate should always focus on forage demand rather than cow numbers. A lactating cow has a much higher demand than a dry cow. If you have superior milking cows, they need almost twice the energy at peak lactation as they did when they were dry. When you go from a dry cow (maintenance requirements) to peak lactation, you’ve doubled the demand on the pastures — even before you add in the calf.
“Ranchers who calve in January and February, hitting peak lactation in March and April, have the highest energy demand before they have good grass. Calving later is one way to shift the energy demand to the time of year you have the best grass,” Gerrish says.
Fences on irrigated pastures
Wheel line irrigation can be compatible with paddock division fences, if you can use portable electric fence. “You can also put up permanent single-strand, high-tensile fence 2 feet tall that you don’t have to move, says Gerrish.
“Wheel lines can cross over [electric fences] because they are not a physical barrier — especially if you run the fence perpendicular to the wheel line path. The pipes are tall enough to pass over the fence, as long as you don’t have the fence where the wheels have to go across,” he says.
Temporary electric fence can be inexpensive and easy to move, partly because no gates are needed. Cattle can be moved just by putting a couple of tall sticks or pieces of PVC pipe in the fence line for a few moments, to raise the electric wire enough for cattle to go under it and into the next paddock. Once cattle learn they can do this, they can be easily moved without gates.