Proper timing of pasture turnout critical for optimal forage production
Ranchers depend on grass as a primary source of forage, whether it be rangeland, pasture or hay. While they carefully select species to plant as cover crops or plan a total mixed ration, many ranchers do not know the primary grass species their livestock consume.
“Knowing the predominant grass species is important because not all grass is equal,” says
Kevin Sedivec, North Dakota State University Extension rangeland management specialist. “Different species have different growth patterns and nutritional content. Thus, the optimal time to graze these resources varies. To achieve optimal forage and livestock production, plan your grazing system around the type of grazing resources available.”
Native grasslands consist of a mixture of cooland warm-season grasses. Native cool-season grasses begin growing once the average temperature is 32 degrees or greater for five consecutive days, whereas warm-season grasses start growing once the average temperature is 40 degrees or greater for five consecutive days. This results in approximately a one-month difference in when these plants reach grazing readiness.
Pasture, on the other hand, typically consists of cool-season grasses in the northern regions of the United States, and warm-season grasses in the southern regions. Cool-season grasses exhibit rapid growth and need less growing degree days to reach grazing readiness in the spring. This extends the grazing season by enabling ranchers to turn cattle out to pasture earlier in the spring, Sedivec says.
Irrelevant of grass species, grazing before plants reach the appropriate stage of growth for grazing readiness causes a reduction in herbage production by as much as 60%, which can reduce carrying capacity (number of livestock or length of grazing season) and animal performance. Grazing readiness for most domesticated pasture is at the 3-leaf stage, whereas grazing readiness for most native range grasses is the 3½-leaf stage.
“Drought or poor grazing management can further delay grazing readiness of grasses and reduce subsequent forage production,” says Miranda Meehan, Extension livestock environmental stewardship specialist. “This is especially true for coolseason grasses, which develop tillers in the fall. The development of these tillers has a direct impact on plant growth the next growing season.”
NDSU Extension has found heavy grazing use of more than 80% in the fall can reduce forage production of cool-season dominated rangeland and pasture by over 50% the following grazing season.
If livestock grazed tillers of cool-season grasses below the bottom two leaves in the fall, the tillers likely did not survive the winter, Meehan says. If they do survive the winter, plant vigor (health) is low and forage production re