Despite the cold temperatures this week, pastures are greening up. As we let animals out to summer pasture, deciding which pastures should be first and when to pull the trigger are important questions to consider.
While the plants we utilize in a pasture developed to withstand grazing, it still puts a certain amount of stress on them when it happens. As leaf material is removed, the plant has to pull upon reserves in the stems and roots to restart growth and build back the area for photosynthesis that was lost.
For all grasses, the period when they first begin initiating growth after being dormant for the winter is a critical time. Their reserves are already low from winter maintenance, and they are counting on the first flush of growth to replenish those energy stores. When an animal comes along and nips this new growth off, the plant is put at a real disadvantage. This stress can push back development and growth for the upcoming growing season. If done repeatedly, the plant becomes weak and can be pushed out of the pasture by more vigorous species around it.
With this in mind, answering the questions of when and where to turn-out for summer grazing can have a bigger impact than we often realize. Let’s look first at the question of when.
Basing turn-out on a specific date is a practice I really discourage folks from doing. Because temperatures and precipitation vary from year to year, the amount of growth available at a specific date fluctuates quite a bit annually. A better idea is to scout your pasture and allow grasses to reach at least 3 full leaves of growth before initiating grazing. This allows time for the plant to store up some reserves for a faster recovery after grazing. This stage of growth will be different for different species, so identify one or two species as your primary focus to guide decisions.
For pastures with species we want to control, this same principle can be used in reverse. Native pastures with aggressive species like smooth brome or crested wheatgrass intermixed can be grazed early as they often green up before our native range. Once the target species has been utilized, pull the animals and allow the desired native species to grow. This early stress on the introduced grasses can limit their spread and actually shrink patches over time.
When we look at the where portion of our turn-out question, rotating that stress of grazing over time becomes important. When there are multiple pastures in our rotation, it may be tempting to turn out onto the same pasture that’s close and convenient year after year. But as we mentioned before, that prolonged stress at the same time annually can have a negative impact on plants. Even hardy species like smooth brome can see a slow but steady decline in vigor and production if grazed hard at the beginning of the growing season year after year. Not only does this mean less forage for our animals, but it also opens up the door for weedy species to establish and become a nuisance.
To prevent this, change the sequence of grazing each year. A pasture that was grazed early last year might not be grazed until fall this year. The last pasture grazed last year during the growing season may be given a rest and not grazed until summer. Once again, knowing what species are in your pasture and when they mature will play a role in this decision. Cool season dominated pastures slump in the summer heat, so should be grazed in the spring annually, but the order in which they are grazed can change. Mixed warm and cool season pasture grazing may be driven by a desire to increase the proportion of either species and adjusted over time as that shift becomes evident.
Spring turn-out is a looked forward to event each year, but takes a bit of planning to ensure that our grazing doesn’t cause unwanted harm. Time turn-out to plant growth, not a set date, shooting for the 3 leaf stage of target grasses. Rotate grazing sequence of pastures throughout the season to prevent stressing specific species annually. Utilize targeted grazing on unwanted species to set them back and give the rest of your pasture a chance to fill in.
-Ben Beckman is a beef systems Extension Educator serving the counties of Antelope, Cedar, Knox, Madison and Pierce. He is based out of the Cedar County Extension office in Hartington. You can reach him by phone: (402) 254-6821 or email: firstname.lastname@example.org