Earlier grazing could lead to a challenging year
With the arrival of spring, graziers are eager to get an early start to get the rotation started.
Geoff Brink, a researcher at the U.S. Dairy Forage Research Center at Prairie du Sac is concerned that because of earlier grazing, 2012 could be a challenging year, especially if the pastures don’t get rain.
Brink and his associates conducted two grazing trials in an attempt to answer some questions that routinely come up at grazing meetings. During a recent seminar in Whitewater he provided some of his findings.
Regarding early grazing he said the researchers looked at the results of grazing when grass reached 3-4 inches in early spring. Annual productivity was compared to grasses always grazed at a normal height of 12 inches.
Brink says, “Although this management practice had an obvious effect on grass yield during the first grazing period, it had little effect on subsequent productivity of pastures.”
As for concerns about the influence of residue grazing height on total pasture production, he comments, “When grass is grazed to a short height, it may increase the yield at each grazing, but it also increases the time needed for the pasture to recover, especially during stress periods.”
Brink says it increases over-all feeding costs and decreases tiller density in the fall and vigor the following spring.
He explains, “Pasture grass would rather start new growth by photosynthesis from the leaves rather than by pulling energy from the roots. If you take the plant down too low there aren’t enough leaves left to regenerate the plant.”
Mob grazing (heavy stocking) of mature pasture has also received a lot of attention by pasture-based producers.
Some graziers like mob grazing because they feel it results in more complete utilization of the pasture, but others wonder how it compares to grazing grass that’s in the vegetative stage.
Brink says, “When grass is allowed to mature before it is grazed, there are fewer rotations, the annual yield decreases, and the potential for wasted feed increases.”
He said their experiments also indicated that with this practice, forage quality decreases and tiller density in the fall decreases along with the vigor the following spring.
“Because of the decrease in forage quality, our research suggests that mob grazing is not a good fit for dairy herds but is better suited for beef herds,” he says. “It’s also a useful management practice for certain situations, such as when renovating a pasture or frost seeding.”
Drought is always a concern for graziers so the researchers also looked at the effect of grazing short, drought-stressed grass.
Brink said, “We found that grazing pastures short (2-3 inches) during summer drought is more harmful to total productivity than grazing in early spring or late fall.”
Grazing height in the last grazing of the fall did not have an influence on the productivity of the pasture the following year.
Brink said in real-world situations concessions need to be made at times. Producers need to decide whether they are managing the pasture for the cows and milk production or for the grass and yield. Weather is also a big factor when making decisions.
Regarding fertilizer, he suggests fertilizing after the first grazing event to get the most benefit.