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Why rotate pastures?
Grass is the cheapest feed out there. Are you and your cattle taking advantage of it?
That’s a question posed by Dennis Hancock, Extension forage specialist at the University of Georgia. He’s watched and helped beef farms and grazing dairies in his state push grazing efficiencies to new high levels. He contends that grazed forages are your cheapest feed resource for cattle (which are outlined in the table on the following page), giving pastures a natural advantage today.
Here are eight reasons why Hancock says farms and ranches can benefit from rotational grazing.
1. You can better utilize forage resources.
A continuous stocking system, where animals have access to all the pastureland all the time, is only about 30% to 40% efficient.
“Of every 100 pounds of forage produced, only 30 to 40 pounds actually get into an animal,” Hancock says.
A slow rotation through three or four paddocks gets that up to about 60%. Push that to a strip system where animals are moved to new grass every day, and the efficiency can be twice the continuous rate.
2. You can optimize the growth rate of the forages.
Grazing plants go through three stages of growth: early vegetative phase, exponential rapid vegetative phase, and a reproductive phase where growth levels off.
“We want to start and stop grazing in the rapid-growth phase,” says Hancock. “We’d like to perpetually keep the pasture there and keep it growing fast.”
3. You can get higher stocking rates.
This is the number of animals per acre over all acres for the long haul, not to be confused with stocking density (animals on a certain area at any one time).
“What we want is higher overall stocking rate,” says Hancock. “At least 12 places I know of have looked at this, and rotational grazing gives at least a 30% increase in stocking rate.”
In a Georgia study, it was 38% higher stocking rate and 37% more pounds of beef produced per acre.
4. You can harvest and feed less hay.
This may vary from north to south in the U.S., but studies show that by keeping forages in their rapid-growth stage more of the time, rotational grazing reduces the need to feed hay by about 30%. That doesn’t include the benefits of stockpiling grass in the field for fall or winter grazing.
“Hay is only about 30% to 70% efficient,” says Hancock. “In my state, it’s about 50%. Half of the hay made is lost in the field, in storage, or at feeding time. We need to get as far away from harvested hay as possible.”
5. You can save forage roots.
“What you don’t see in a pasture is the roots,” says Hancock. “When you overgraze, the roots die back, and you can kill out a stand. In my area, people have overgrazed Bermuda grass and killed it out. That’s almost impossible to do.”
He points to a demonstration at a recent field day where grass plants had been clipped every other day to simulate continuous grazing. When the roots were dug, they went down only about 8 inches. In a rotation pasture, they were over 4 feet deep.
“With adequate rest, the roots of a plant will go down about as far as the uncut plants grow up,” he says.
6. You get better persistence of desirable forages.
In a rotation program, with more biomass left after a grazing cycle, photosynthesis continues at a higher rate. Plant vigor is enhanced. The persistence of legumes, like clover and alfalfa, are especially helped by rest periods to regrow.
7. You get better weed suppression.
Weeds are opportunistic. In the absence of competition, they flourish. When you do things to encourage vigorous growth of desirable forages, weeds may disappear.
8. You get better manure distribution.
One grazing dairy that Hancock follows in Georgia increased soil organic matter from 1% to 2% in three years of rotational grazing, forcing the cows to get to all parts of the farm. In continuous grazing, manure tends to be concentrated around mineral feeders and waterers.