Open Gate Rotational Grazing

An alternative approach to facilitating wildlife and plant diversity in grazed prairie.

Based on the last 20 years of experience and data collection, the shifting mosaic approach to habitat management seems to support plant and animal diversity and foster ecological resilience in our prairies.  One of the most important parts of our shifting mosaic management is that each patch of prairie goes through a progression of season-long intensive grazing, followed by a multi-year recovery period.  At any time, only part of a prairie is in each phase of the system (intensive grazing, early recovery, late recovery), so there is always a variety of habitat structure available (short, “weedy” and tall) for wildlife.  In addition, as that grazing/recovery progression occurs, plant species experience a different set of growing conditions each year.  Regardless of its competition ability or strategy, each plant is ensured favorable conditions for its growth and reproduction at least once every few years.  Based on our long-term data sets, our management has sustained plant species richness, and both conservative and opportunistic plant species are persisting in our prairies.

A fenceline contrast at our family prairie shows the kind of habitat heterogeneity found in a shifting mosaic approach to prairie management.

Patch-burn grazing is one way to create a shifting mosaic, but it’s certainly not the only way.  While patch-burn grazing has some attributes that make it easy to implement (no need for cross fences or moving animals during the season), it does require regular application of prescribed fire, which can be difficult for some landowners.  In addition, patch-burn grazing is very different from the kinds of rotational grazing systems many ranchers are comfortable with and have set up their pastures for.  We’ve been experimenting with an approach to creating a shifting mosaic that keeps many of the wildlife and diversity-friendly attributes of patch-burn grazing but might fit better within the comfort zone and logistical framework of many ranchers.

For lack of a better idea, I’m currently calling this approach “Open Gate Rotational Grazing”.  It is not a rigid prescribed grazing system, but rather a general and adaptable way of managing multiple grazing paddocks within a prairie.  It’s similar to a traditional deferred grazing strategy, but with one big difference.  In most rotational grazing systems, cattle are moved from one pasture to the next, closing the gate behind them to allow the previous paddocks to rest.  In the open gate system, when cattle are presented with their next paddock, the gate behind them remains open – allowing the cattle to continue grazing the initial paddock even as they have access to new grass.

In a traditional rotational grazing system, cattle are progressively moved through a series of paddocks, closing the gate behind them.  In a deferred rotational system, at least one paddock is usually rested for the season.

Under an open gate approach, gates are left open when new paddocks are made available, allowing cattle to graze both the new paddock and the one(s) they had been grazing before.

The idea started one year when we weren’t able to get a burn done in a prairie under patch-burn grazing management.  Since we didn’t have a burned patch to focus cattle grazing, we instead used electric fence to concentrate the cattle in the area we’d hoped to burn.  We kept them in the enclosure until they had it grazed pretty short.  Then we removed the electric fence and allowed cattle to access to the whole site.  For the remainder of the season, the cattle continued to focus most of their grazing in that former enclosure, attracted by the tender regrowth.  As a result, the overall grazing pattern was fairly similar to what we’d expect with patch-burn grazing.  Seeing how strongly cattle were drawn back to where they’d grazed earlier provided the seed for the open gate rotational system.

On my family prairie, I’ve been using the open gate approach for the last several years.  I have four paddocks, and I basically think of the gates between those paddocks as relief valves.  We start with the cattle in one paddock, and when they have grazed most of the grass down in that pasture, I open the gate to an adjacent paddock so they have more options.  The cattle can keep grazing the regrowing plants in paddock #1, but they aren’t forced to eat more than they want to in that paddock because they have another whole paddock available to them.  If the cattle graze down most of the plants in the second paddock, I can open a gate to a third paddock and provide them with even more options.  I keep the fourth paddock closed off for the entire season so it can rest.  I choose a different paddock to start with each year.

The result of an open gate approach is that one paddock is grazed all season long, one is rested all season, and the others have intermediate levels of grazing.  This results in heterogeneity of habitat structure as well as a wide range of growing conditions for plants.  Each year, grazing starts in a different place, shifting the disturbance regimes among the various paddocks.

The open gate approach can be used with just about any rotational grazing system, as long as there are adjacent paddocks that can be opened up.  One key component of the open gate approach is that paddocks grazed early in the season continue to receive grazing pressure for the rest of that season without forcing cattle to eat progressively lower quality forage as the season goes on.  Instead, cattle can regulate their diet freely, choosing between previously grazed areas and those they haven’t yet grazed.  Typically, when cattle are given that kind of choice, they eat very little other than grasses.  This works out well for pollinators because it means many wildflowers are allowed to grow and flower amongst grazed grasses.

At our family prairie, the open gate approach seems to be helping with our continuing quest to increase plant diversity in areas formerly dominated by grasses.  New plants are introduced via overseeding (after a season of intensive grazing), and then persist under our grazing management.

In the open gate system, there is great flexibility about when, and how intensively, each paddock is grazed each year, though some of that flexibility depends on how the paddocks are arranged.  Ideally, all the paddocks would be connected through a single hub so the manager can choose to open any gate to any pasture, as needed.  However, my family prairie doesn’t provide that amount of flexibility (the four paddocks are arrayed in a donut-like loop, with no way to connect them through the donut hole) and the approach still works.  Most of the time, the paddock grazed most intensively one year gets complete rest the next.  However, the pattern of grazing each year always depends upon how I think recovery from previous years’ grazing is going.

I think there are great benefits to longer grazing periods and longer rest periods than are typically found in rotational grazing systems.  Certainly, those prolonged grazing and rest periods can provide a greater variety of wildlife habitat conditions, especially on the shorter and taller ends of the vegetation structure spectrum.  In most rotational grazing systems, cattle are moved out of a pasture before grasses are grazed very short, allowing them to recover quickly.  In addition to reducing habitat heterogeneity, that approach can favor strong grass dominance at the expense of wildflowers and plant diversity.

Even when grazing pressure is intense within each paddock of a traditional rotational system, short duration grazing may not foster habitat heterogeneity.  For example, if a paddock is grazed hard in May, it might suppress cool-season grasses, but warm-season grasses won’t be much affected, and once cattle are removed, summer vegetation will fill in quickly, resulting in vegetation structure of moderate to tall height.  The same can happen with summer grazing bouts followed by fall growth of cool-season grasses.  By maintaining grazing pressure for the entire growing season, two things happen.  First, there is sustained short vegetation structure for wildlife that need it.  Second, and perhaps more important, all dominant grasses are weakened by that long term grazing, leading to a fairly long recovery period (1-3 years, depending upon grazing intensity and geographic location), during which wildflowers and other plant species are temporarily released from that grass competition.  That long recovery period creates terrific wildlife habitat and also helps sustain plant diversity.

While prescribed fire isn’t necessary in open gate rotational grazing, it can certainly be incorporated.  The paddock to be grazed all season could be burned before the season starts, for example, which would further add to its attractiveness to livestock (and remove eastern red cedar trees, excess litter, etc.).  At my own prairie, I haven’t been using fire for a variety of reasons, including that I’m so busy burning for work I don’t have time/energy to burn my own place.  So far, I’ve been happy with the way the prairie is responding in the absence of fire, but if I can get myself better organized, I wouldn’t mind doing some burning.  If nothing else, it would mean less time cutting little cedar trees with loppers.

Prescribed fire is not a strategy all ranchers are willing or able to include in their operations.  The open gate approach provides options for creating a shifting habitat mosaic without relying on regular prescribed fire.

I don’t have many years of experience with this open gate approach, or much data to help me understand all the nuances of its impacts on flora and fauna.  However, what I’ve seen from early experiments seems promising.  I’m sharing the idea and our experiences so far, not because I’m endorsing the open gate approach as the next big thing, but because I hope others might find ways to try it and report back.  Because the basic idea is as simple as not closing a gate when opening a new paddock, it can be employed in many different scenarios if people see potential for it.  Also, I’m not trying to claim or patent the idea, and I’d be shocked if there aren’t people reading this that have already tried it in various forms.  If so, I’d love to hear about it.

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About Chris Helzer

Chris Helzer is the Director of Science for The Nature Conservancy in Nebraska. His main role is to evaluate and capture lessons from the Conservancy’s land management and restoration work and then share those lessons with other landowners – both private and public. In addition, Chris works to raise awareness about the importance of prairies and their conservation through his writing, photography, and presentations to various groups. Chris is also the author of "The Ecology and Management of Prairies in the Central United States", published by the University of Iowa Press. He lives in Aurora, Nebraska with his wife Kim and their children.
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11 Responses to Open Gate Rotational Grazing

  1. Polish Hare on the prairie says:

    One thing that has concerned me about grazing in grasslands where grassland songbird recruitment is a goal of management is how grazing may affect cowbird numbers and thus parasitism levels. Are we drawing birds into a seemingly good breeding area only to subject those populations to elevated levels of cowbird parasitism. Do you know if there have been any studies looking at this?

    • Chris Helzer says:

      Hi Jeff, I’m sure there is research on that, but I’m not in the grassland bird literature enough these days to know of it off the top of my head. Of course, cowbirds are just one factor, right? You still need the structural heterogeneity to support the bird community you want, and it can be a lot harder to get the full range of heterogeneity without grazing. Lots of considerations…

  2. Doug Garrison says:

    Chris,
    Good stuff. Thanks for sharing your idea. Hoof action, tearing of forages with the tongue, biology dripping out the front and back end of walking fermentation vats simply cannot be replicated mechanically or chemically. Animal impact is an awesome tool. Now go find some sheep, goats, pigs and chickens to clip, root and scratch more energy into your system.

  3. Patrick says:

    Hi Chris, in this system, how are you establishing the appropriate stocking rate?

    • Chris Helzer says:

      Hi Patrick,
      Stocking rate is still figured on the whole pasture scale. We’re “overgrazing” some areas and “under grazing” others, but balancing stocking rate across the whole site. Practically speaking, we adjust stocking rate from year to year based on how much structure is left on the site vs. what we want to see.

  4. George Shurr says:

    Hey, Chris~
    Really timely. Our renter recently talked about letting the cows decide (“cow psychology”) what parts of corn stubble to feed in, a’la Temple Grandin. He’s been doing rotational grazing for 20+ years and has long advocating letting the cows “decide” on their diet whenever possible. This idea of open gate rotational grazing is helpful because we have not been able to incorporate patch burning into the rotation very easily. This open gate system relies on trusting the cows to know what’s best for them.

  5. Michael Godfrey says:

    Thanks for this thoughtful outline of a an innovative grazing pattern.

    In Virginia’s Shenandoah Valley I rotationally graze 40 cows and calves (+ some heifers and finishing steers) on 100 acres of pasture. I’m a neighbor of Joel Salatin’s and have learned a great deal from him, as well as from other neighbors practicing continuous grazing at lower stocking levels.

    By inadvertence or design I have employed your open gate approach on occasions. The cattle leave a spent paddock as soon as they have an option and never look back. Until the forage and (pardon) repugnance levels in the two boundaries equilibrate. When it does, they mill around and bawl as they would in any spent pasture, making sure I understand they know there is fresh pasture nearby being withheld.

    The observation here is all the cattle, all the time, will stay in the freshest grass. None will return to spent pasture if there is an option. Joel says they won’t graze where they have left any spoor, including tracks. In his management-intensive approach, the idea is fresh pasture in small increments, frequently. It is, in fact, labor insensive, but it puts quality weight on cattle rapidly.

    Do you compare the weight -gain results of open-gate grazing with that on fully-resting boundaries?

    I neglect here the question of benefits to natural systems of rotational grazing. Regarding grassland birds, they take a hit when the cattle maul a stand they are breeding in. My experience is that from mid-May through June I simply have to keep the cattle out of the sections most favored by breeding Bobolinks, Meadowlarks, and (occasional) Dickcissels or the nests get stomped or chomped. The birds are fine foraging in recovering pasture once the young fledge. Unfortunately the prime breeding span coincides exactly with the prime growth span of grasses and few graziers can sacrifice that prime span. Planning grazing moves to accommodate the birds’ breeding cycles is tricky.

  6. James McGee says:

    It is hard to tell the whole story through pictures. However, the picture of your family prairie looks really diverse.

    It will be interesting to see the changes that occur around your pond now that it has been fenced off. After over twenty years of restoration of old cropland some interesting things have been found in wetter areas of restorations in Northeastern Illinois.

  7. Maggi Sliwinski says:

    Thanks for this, Chris!! You’ve taken musings I’ve had rumbling in my head for years and solidified it into something that ranchers might actually try. I’ve struggled with the exact aspect of rotational grazing you’re working to solve here—that grazing can create that short habitat but once you move the cows it goes away! Any birds that nested there because of the short grass are now (potentially) in a trap (I’m not sure anyone has actually looked at this).

  8. I read of a ranch in California that is doing something like this with good success. So much so in fact that the ranch is home to a rare salamander! Great work~I wish you all success.

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