Dry weather this spring has reduced grass production in pastures being grazed continuously at heavy stocking rates down to levels normally found in mid-at a University of Missouri research farm near Linneus.
In spite of the lack of rainfall, there is more grass available to cattle grazing across the fence in paddocks where rotational grazing is used.
That was one comparison shown by Jim Gerrish, research agronomist at the first grazing school of the year at the MU Forage System Research Center.
Thirty-five participants from Missouri and across the nation attended the three-day school.
"The dry spring weather emphasizes the advantages of managed grazing," Gerrish said.
Measurements from the continuously grazed pastures show forage availability of under 1,000 pounds per
acre. In the rotationally grazed paddocks, there is typically 1,400 to 1,500 pounds of forage in the next available paddock that has been rested, Gerrish said.
In management-intensive grazing, large pastures are subdivided into smaller paddocks and the livestock is moved to fresh grass frequently. Rotational management allows grass to grow and rest between grazing periods.
Two grazing studies are under way at the Center that use contrasting rotation schedules. In one, the cattle are moved according to the calendar; in the other, the rotation is "need-based."
This year, on the calendar rotation, with slow grass growth because of the dry weather, the cattle are grazing the grass down to about one inch of residue. That causes slower grass recovery, Gerrish pointed out.
"Calendar based rotation doesn't work," Gerrish told the school participants." "It takes away flexibility, one of the main advantages of this management tool."
Forages in the need-based rotations are showing much more diversity of grass and legume species. The legumes are being grazed out of the calendar-based rotations.
"There is less than 10% legumes in the paddocks under calendar-based rotations."
Forage samples from the rotationally grazed paddocks at any economical stocking rate consistently show 2% higher protein and 3 to 5% higher digestibility, Gerrish said. The rotations add not only quantity but also quality.
In dry weather, Gerrish is observing more paths developing in the continuously grazed pastures. "The cattle are walking back and forth to water more."
He also sees more manure accumulating in those paths. "That means when the rains return, there will be more water channeled into the paths, flushing away both water and nutrients from the pasture," Gerrish said.
The rotational-grazed paddocks have more ground cover, protecting the soil from erosion.
Gerrish called the rotational paddocks "rain ready." There is residue cover, and the forage is still in the vegetative stage before seed heads develop. Additional moisture now would produce high quality forage for grazing animals.
Continuously grazed pastures won't respond as well to rainfall. The heavily stocked paddocks are grazed so short that it will take awhile for recovery after a rain. The under-stocked paddocks have gotten ahead of the cattle and have set seed heads and slowed leaf growth. Stems and seed heads provide poor forage on fescue pastures.
Visitors can see the benefits of management-intensive grazing at four events set this year at the Forage Systems Research Center located northwest of Brookfield, Mo.
Pasture Day, Sept. 28, will report beef-and-grazing research results. The next regular grazing school is Oct. 10 to 12.
Two advanced grazing schools will be on June 13 to 15 and Sept. 19 to 21. Preference is given to those who have attended a regular school.