How to Avoid Overgrazing

  • How to Avoid Overgrazing

    Posted by Mark Tupman on 19/09/2023 at 2:43 pm

    One of the most important things we can do for soil and pasture health, which translates to livestock health and productivity, is to avoid overgrazing.

    So, what exactly is overgrazing?

    Well, it has more to do with how soon we graze a plant than how much of it is grazed.

    Plants all need to put on good vegetative growth in order to harvest energy from the sun; and develop decent root systems to acquire nutrients and water from the soil. Through these processes, they build up the reserves needed to survive the various circumstances encountered in their growing environment. This is most important at the beginning of a growth cycle, when reserves are low, and as much as possible, plants should be allowed adequate time for establishment.

    Pasture plants are somewhat designed to handle grazing and usually have low and/or numerous growing points from which they can regrow. However, when a significant portion of their foliage has been removed, they have to draw on reserves to support themselves through a phase of initial regrowth. This regrowth usually starts around three days after a graze and the time taken for complete recovery can be anywhere from a few weeks to months. Re-grazing a plant too early exhausts reserves, stunts root development and diminishes its capacity for regrowth. When this occurs, plant vigour is compromised, then a lot more time is required for subsequent recovery and we end up in a negative production spiral.

    Often, larger areas are allocated for grazing to avoid having to move livestock as regularly, but unfortunately, this equates to “selective” grazing. Naturally, if our animals have a choice, they will go for the most desirable species first. When left in an area for more than three days, they will most likely choose to re-graze the tender regrowth on the more desirable species before consuming the less palatable species. This leads to the overgrazing of our best species, which puts them at a significant disadvantage and over time, may result in a less favourable pasture plant profile. Ideally, we want to aim for a more even graze and what is more, with the density required to do this in good time, we get better distribution of dung and urine.

    In spring, annual cool season species start using reserves to set seed and their feed value markedly drops. We can better utilise these pasture species by grazing them or making hay before they start forming seed, which also initiates some vegetative regrowth; but this is best done on paddocks that have had enough time for recovery. Grazing plants that are going to seed before they have rebuilt reserves, results in very poor regrowth, then early senescence, and we end up with scant cover and small root systems. This leaves the soil exposed and prone to erosion for the duration of the harsh non-growing season.

    Further to all of this, herbivores would rather not come back and re-graze the areas they have soiled with dung and urine for quite some time, and the feed value and balance of fibre and sugars and protein is better when plants have properly recovered. The time taken for recovery can vary between species, at different stages of growth and with seasonal conditions. If you’d like to know what recovery looks like for any of the species in your paddocks, let us know and we’ll try to cover it next time.

    Eric Dobbe replied 6 months ago 3 Members · 15 Replies
  • 15 Replies
  • Kate Tarrant

    Member
    21/09/2023 at 9:22 am

    The trick in our short growing season with annuals is to try to keep the pasture in a vegetative state- that can be a challenge if you don’t have enough livestock.

    What do you think about leaving some paddocks to ‘stockpile’ for summer standing feed and focus on the remaining paddocks for quality. By that I mean moving slow enough to ensure recovery but fast enough to keep it vegetative.. at the moment I reckon that’s leaving for only around 40 days, that will speed up as it warms up. A bit of a combo of Dick Richardson’s method with Judi Earls.

  • Mark Tupman

    Member
    21/09/2023 at 4:44 pm

    That’s a great point Kate and I’ve done much deliberating on that matter :-/

    What I’ve come to is that, yes, we can use grazing to prolong vegetative growth of annual species to some degree but it all happens pretty quickly in spring and we can only apply this strategy for a limited period of time.

    The bottom line is that we want our plants to be fully recovered by the time they start going to flower, if we are going to make hay or graze them! Up to this stage, fully recovered plants can still put on another decent flush of growth. We don’t want our plants to be setting seed when they haven’t fully recovered as this is somewhat akin to grazing unrecovered plants – reserves are exhausted, and regrowth and forage quality is poor. If we feel like the paddocks we are grazing in the green season are getting close to this point, it’s time to move on onto the stockpiled/sabbath paddocks. More on that another time.

    If we follow the principles of not overgrazing through the season, we can definitely prolong the vegetative growth of our pastures and we will be rewarded with much richer and faster regrowth. In spring, a stressed (unrecovered) plant is a bolting plant 🙁

  • Eric Dobbe

    Member
    20/10/2023 at 6:09 pm

    Interesting discussion. I believe grazing management is the most important consideration for any livestock system. Our livestock are our employees – they work for us to improve soil function. I agree with your definition of overgrazing.

    Essentially grazing management is all about managing time. I have applied the RCS and probably most grazing recommendations of consuming 60% leave 40 and daily moves. Try and keep pasture in the power growth curve, leaf recovery and adjust recovery time according to time of season (fast growth – fast move, slow growth- slow move). My conclusion for the above after 2 seasons, is that you end up selectively grazing and the recovery period is hard to get right. I couldn’t slow the rotation down sufficiently and ended up with sacrificial paddocks that I supplement fed in.

    This year I have tried a much less known technique called “Total grazing” as promoted by Johan Zietsman and Jim Elizondo. Really liking what I’m seeing with this technique. I now graze to 80-90% utilisation and my rotation has slowed right down to >90 days. Instead of leaf recovery – we are root recovery. I think 4 grazings a year is about right for my environment. We still on daily moves (mostly). We are growing more grass and improving composition as we go. I no longer conserve the “Spring Surplus”, instead I let it stand in the paddock and graze and trample in with high density grazing.

    • Mark Tupman

      Member
      21/10/2023 at 12:08 pm

      Some pics of a stockpiled/sabbath area after a graze. One could argue that there’s wasted feed but the soil microbes don’t think so. I’ll be watching to see what regrowth is like under that mulch. These will be the priority green graze areas next season.

  • Mark Tupman

    Member
    20/10/2023 at 10:26 pm

    Hi Eric,

    Cheers for your input. I couldn’t agree more that the “don’t graze it down too much theory” leads to selective grazing. I’ve done the total grazing course with Jamie Elizondo and got a lot out of it. I’m seeing great benefits from putting the principles into practice in terms of soil health, diversity of species, generation of biomass and animal wellbeing.

    I particularly enjoy seeing the thick layer of carbon and manure on top of the soil after they knockdown the vegetation that was stockpiled over the green season, and how well perennial species are going under this sort of management.

    🙂

    • Mark Tupman

      Member
      21/10/2023 at 12:19 pm

      Who wouldn’t want some of this when everything is drying out.

      Plantain, well and truly recovered as confirmed by the yellowing lower leaves.

    • Eric Dobbe

      Member
      21/10/2023 at 6:59 pm

      That’s awesome Mark to hear someone else’s experience with ‘total grazing’. There wouldn’t be too many around these parts that have heard about it.

      I haven’t yet done the course but am thinking about it. I am going into my first summer under this system and so far so good.

      Everyone around me is cutting silage and now hay, which is early due to a shorter than normal spring. I still have growing pastures. Any rain now will fire up the perennials. The biggest shift has been time of calving. Majority of calving here occurs from feb-may. I have shifted to August, Sep with 6 week joining ( bulls went in yesterday). It’s all about matching demand with supply and livestock production per ha as opposed to kg per animal…

  • Kate Tarrant

    Member
    21/10/2023 at 10:11 am

    Doesn’t the selective grazing really only happen when the stock density is too low? Be great to see a pic of what your paddock looks like when you are ready to move the stock off ..

    So are you saying that to leave 5 to 7 cm of fodder behind is too much, better to graze it hard then not come back for 90 days(Eric) or until the bottom leaves are yellowing (Mark).?

    Having learned with RCS, Dick Richardson, & Judi Earl they all are a bit different but it sounds to me like what you are describing is more like what Dick advocates.

    • Mark Tupman

      Member
      21/10/2023 at 11:59 am

      Hey Kate,

      The premise is that unless you have exclusively ryegrass and clover paddocks, the stock won’t graze it down to a nice even hight, they’ll graze the best and leave the rest, so grazing it to a certain hight is kind of a mute point. They’ll also eat the leaves first and leave the stems. This can mean inadequate fibre intake at certain times of year and regrowth with a poor leaf to stem ratio.

      The other thing with a more complete and harder graze is that you can set smaller breaks and get better utilisation of the forage which buys time on your rotations for recovery of species that need longer than annual ryegrass.

    • Eric Dobbe

      Member
      21/10/2023 at 3:41 pm

      Stock density is really important. I have 70 cow, calf pairs and 20 heifers on about a ha/day to achieve the grazing pressure required.

      It doesn’t matter if you get the daily area a bit wrong. I’m always learning and adjusting according to pasture biomass availability, composition and time of year. The point is you are not grazing the new leaf emergence. Also, by grazing with high use efficiency you will find a higher leaf to stem ratio in your pastures than you would if you leave high residual.

      • Mark Tupman

        Member
        21/10/2023 at 7:21 pm

        Great stuff Eric. Where are you? So good to have working examples underway 🙂

        • Eric Dobbe

          Member
          21/10/2023 at 9:48 pm

          Redmond, WA. Which is 20min out of Albany.

      • Kate Tarrant

        Member
        22/10/2023 at 9:53 am

        Great discussion @Eric & @mark .. so what will be your grazing strategy in the non growing season – will you keep the same density, daily moves & rest periods – I am assuming you are going to have a mix of perennials that are active on the season shoulders in with your annuals that have dried off.

        • Eric Dobbe

          Member
          23/10/2023 at 11:47 am

          Kate, the intention is to match the experience that Mark described earlier regarding utilisation, trampling and manure on stockpiled feed over the non growing season.

          This is best achieved with the high density grazing, which is a combination of small area and frequent moves. The main difference between the growing season and non growing will be no need of a back fence in annual pastures. The perennial dominant pastures might need back fence though – depending on dormancy…

          • Eric Dobbe

            Member
            23/10/2023 at 11:56 am

            Photo is of

            high density vs low density (neighbour) last summer and plantain responding to late summer rain.

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