by Deborah Jeanne Sergeant
Could your pasture use improvement? Sarah Flack presented “Pasture Improvement and the Grazier’s Toolbox” as a recent webinar hosted by Food Animal Concerns Trust. Her presentation focused on ruminant grazing.
“How can we create higher plant diversity, better plant digestibility, improve the overall quality of our pastures, make it more palatable and how can we make that pasture grazing season longer?” Flack said. “We have to meet the needs of the livestock out on pasture and meet the needs of the plants and soil in this process.”
She said the “grazier’s toolbox” should include observation skills, variable regrowth periods, post-grazing residual, pre-grazing height, stocking rate, stocking density, trampling, fallowing, clipping, tillage, aeration, seeding and fertilization.
Flack said farmers need to look at what their grazing animals “tell” them through their rumen fill, body condition, rate of gain, reproduction, manure scoring, MUNs, milk production, heat stress and behavior.
The farm also “tells” a story. Flack said farmers should look for what’s improving, not improving, and what’s getting worse.
“Catching problems early before they get much worse is really important,” she said. “You might notice a gradual decrease, more annuals than perennials.”
She also listed some earmarks of an improving pasture.
“If your pasture is improving, you will see closer plant spacing and higher plant density,” she said. “You’ll have less bare soil visible, more rapid plant growth, plants growing over a longer growing period, high soil biological activity from manure, manure decomposes more rapidly, more plant species, high diversity, more perennial plant species and good soil structure and fertility.”
“If you’re not doing good grazing management already or setting up the structures to have good grazing management and you’re spending money on seeds, it will revert to the weedy, less productive system you had before,” Flack said.
Good grazing management forms the foundation upon which soil improvements and reseeding rests.
She said grazing guidelines should be based on variable regrowth periods and plant height and stage of maturity. Short periods of occupation create different stocking density and residuals and prevent re-grazing of recovering plants.
“Over grazing damage happens when the livestock graze a plant while it is still growing from energy reserves, rather than from active photosynthesis,” Flack said. “It hasn’t had time to recharge its own energy reserves. It typically happens when animals stay in a paddock for too long or are returned to a paddock too soon.”
She calls over grazing “a death spiral for your pastures.”
Flack listed common over-grazing situations such as taking down interior fences when pasture growth slows in the fall to let livestock clean up pastures; leaving animals in a pasture for too many days in a row; having a fixed grazing rotation; and clipping after regrowth has started.
“People who go out and mow in the fall can cause over grazing damage to plants,” she said.
It may make the pasture look tidy, but it hurts plants that are in the recovery phase. The damage may last a long time as it “trains” the plants to grow shorter to avoid damage and it helps the naturally shorter plants to thrive while taller ones don’t come back.
“Giving it longer rests isn’t going to be enough,” she said.
Overgrazed, clipped pastures may require reseeding to bounce back.
Lowering the herd density may not prevent overgrazing.
“Overgrazing can be done with a few animals in a large pasture,” Flack said. “They may get the whole pasture every summer all summer. It looks like there’s a lot of stuff to eat but there are some areas they go back to every couple of days and many area where there’s weeds or areas where there are plants that aren’t as palatable.”
Grazing an area too short means animals eat the energy reserves in the plant. Instead, Flack encourages farmers to make sure livestock don’t eat the crown, growing points, and plant energy reserves towards the base of the plant.
Additional paddocks mean farmers have more control over the period of occupation, regrowth period, stocking density, trampling and residual.
“If you have livestock out there and it’s wet or muddy, you can get soil compaction,” Flack said.
That’s a problem because it can make it difficult for plants in that area to grow back.
“I’m also a big fan of soil testing,” Flack said. “Stay with a good local lab near you and test regularly, especially in the early years of getting good plants established in your pasture.”
Biological activity — manure — also affects pasture health. Helpful insects such as dung beetles help start the breakdown of dung into the pasture’s soil. Flack said observing how long the process takes can indicate how healthy the soil is.
Flack indicated that many farmers don’t know the difference between stocking density and stocking rate. Stocking density is the number of animals or pounds of animals per acre in the individual paddock at a specific time. The stocking rate is the total number of animals on the whole acreage, which may include both cropland for winter feed and pasture.
“Our stocking density gets higher as we move the animals more frequently in smaller paddocks,” Flack said.
Many farmers encounter the difficulty of having too much manure near the gate. That will mean the gate area will become overgrown and other areas will become stunted from lack of nutrition. Changing the orientation of the gate through moveable fencing may help prevent this issue.
She offered as an example if 50 Jersey cows moved to a new four-acre paddock every three days, that’s 12,500 lbs. of cattle per acre. If they are moved daily into a fresh, 1.75-acre paddock, that’s 40,000 lbs. of cattle per acre. If the farmer moves them twice daily into a paddock that’s .63 acres, there are 80,000 lbs. per acre.
Many farmers wonder about how often they must move their animals. Twice daily or daily are good targets.
“If you’re there full-time on the farm and you have tons of kids who love to move the front fence, that will probably work. You might be able to use tumble wheels where you won’t need as much labor to move the fence.”
Farmers also must ensure they meet the animals’ needs.
“Letting more pasture accumulate and letting the pastures grow taller before you let the animals in there to graze it” represent good strategies, Flack said.
If 82 cows get two acres daily and they average 1,250 lbs. each, the stocking density is 51,250 lbs. per acre. But if they get a fresh paddock after each milking, the stocking density is 102,500 lbs. per acre.
“This is in the range of a very reasonable stocking density for a dairy herd,” Flack said.
Flack also spoke about trampling. Generally regarded as damaging, trampling may actually help farmers if the soil is already in good condition because it can work in manure or even seeds that the farmer has broadcast, providing there’s sufficient rain.
“You can use pigs for trampling, but if you leave them in one area too long, they can break down the soil structure,” Flack added as a warning.
Many farmers like to clip residual after a paddock has been grazed. But Flack said leaving it is “insurance” during a drought year, when the leftovers can help hold moisture in the soil and prevent erosion.
“If you’ve got high performance animals and invasive weed species and you can time clipping before your problematic weeds go to seed” then clipping may be worth it.
Deciding to clip a pasture also depends upon the variety of forage, how long it takes to regrow and the stage of growth it’s in.
“Elongating or jointing grasses tend to elongate the tillers on the grass stems throughout the whole grazing season,” Flack said. “Timothy, brome grasses and the reed canary grass — they grow taller year-round and produce more stemmy material. They don’t tolerate being grazed as short so leave behind the post-grazing material.”
She said allowing grasses to grow too tall too frequently provides too much shade for shorter plants and decreases plant density. Farmers begin to notice more bare spots, which means lower plant diversity in the pasture.
“Plants grow differently at different times of the year,” Flack noted, “so use different stocking densities at different time of the year and leave a different amount of residual to meet your pasture improvement goals. This applies to warm-season perennial grasses and cool-season perennial grasses.”
If a pasture is neglected to the point where the farmer must re-seed it, it’s vital to choose the right plant species to avoid bringing in weed seeds or planting things inappropriate for the climate or soil type.
“It’s more of a last resort,” Flack said of reseeding.
To maximize dry matter intake, Flack recommended higher density of plants with vegetative leaf area, short periods of occupation, and sufficient regrowth time to allow ideal pre-grazing height.