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Is Mob Grazing as Effective as We Thought?

By   /  November 6, 2017  /  15 Comments

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Grazing research is very challenging, and no study can answer all the questions. The research publis
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About the author

Dennis Hancock has been a faculty member in the Crop and Soil Sciences Department and the State Forage Extension Specialist at the University of Georgia since 2006. Dr. Hancock is responsible for the statewide extension and applied research in forage agronomy and associated forage-based livestock systems (beef, dairy, horse, small ruminants). Forage crops are important to the state of Georgia. Forage crops are grown on approximately 4 million acres in Georgia, and the associated forage-based livestock systems have a farm gate value of over $1.2 billion. In addition to his role as the state Forage Extension Specialist, Dr. Hancock also leads the Sustainable Grazing Systems program at UGA where he and his colleagues conduct comprehensive research that assesses best management practices for pasture and grassland crop systems. His goal is to ensure that the forage management systems of Georgia and the Southeast sustain economically viable forage productivity, animal nutrition, and livestock productivity while enhancing stewardship of our natural resources and ensuring a high quality of life for the producers who employ these techniques. Dr. Hancock has many years of experience in research and extension, including as a County Extension Agent and statewide research and Extension Associate, before becoming the Forage Extension Specialist at UGA. He has earned many awards for his Extension service, including both the Georgia Association of County Agricultural Agents’ Junior (2009) and Senior (2016) Outstanding Extension Specialist Awards, the UGA CAES’s D.W. Brooks Award for Excellence in Extension, and the American Forage and Grassland Council’s Merit Award.

15 Comments

  1. Dwayne Somerville says:

    We rotate once per day with 45k#. We did that in the summer and are doing it now. Seems to be working. I need to get a full year experience under my belt to see if it will work this spring.

  2. I am very glad to see RG still viable in this Michigan study. My cool season grasses in New England have supported rates of from 1 day-3 acres-80k to 10 days-20acre-100k with decent gains (1+lbs) . I also have two parcels I overgraze habitually while cows are still calving and coyote pressure is on.
    My cows cycle through each piece 3 times per season with a minimum rest of 30 days, that being the time that seems to work for me controlling parasites. I did get the cycle down to 21 days one year when we had perfect rainfall and I was very proud of my achievement until it all began to unravel and I had to worm the whole herd.
    I think that on a planetary basis mob will be an essential tool to reverse soil degradation and mitigate carbons damaging effect on our environment, but I don’t feel it is as valid a practice where we have ample water and vegetation, this one study seems to confirm my belief.
    I was heartened to hear Allan Savory speak to a group of northeast farmers and say he was not here to convert us because we could do everything wrong and still succeed because of our soil and water resources. He said the same was true in the U.K. But that is not the case for 2/3 of the arable land around the globe.
    For me RG will remain the backbone of my grazing program and I will dabble in Mob to experiment ( we did one .20,.25,80k last year on an oat cover crop)
    This is one study and I assume there will be more. Mob vs. RG is similar to hay vs. stockpiled feed arguments. Time will be the arbiter as the curves of theory and experience either merge or diverge.

  3. carl glazer says:

    A lot of the successful mob grazing systems have rest/recovery for over 100 days many resting a year or more. It gives plenty of time for seed production and plant growth, as well as wildlife and microbial habitat. Also stock density, as Bruce stated, is ‘optimally’ much higher than shown in the research plots. There was no mention of the decreased inflammation in Mob grazed cows, or decreased parasite egg counts as shown in the studies. It also doesn’t mention the better distribution of manure and urine with Mob grazing. This article seemed to pick out some negative stats and dwell on them. Seems quite biased.

  4. Pam Moore says:

    It’s great to see researcher interest in mob grazing. Bruce Anderson commented about researchers’ findings on the benefits often differing from those reported by many producers. Reasons we have seen for this include the way “mob grazing” is defined. This article characterizes long rest periods as a fundamental aspect of mob grazing. That is not what is taught by the “father of mob grazing,” Ian Mitchell-Innes, who connects with producers around the world on this subject. Ian’s approach to Holistic Planned Grazing was coined “mob grazing” years ago, and focuses on optimizing animal performance by grazing vegetative (adequately rested) pastures, typically at higher stocking densities for a short duration of time. Fundamentals in his approach include avoiding taking more than a third off the plant/pasture (ie. no more than one bite of individual plants), which reduces the recovery time needed before the plant/pasture is ready to be grazed again. Too much rest between grazings negatively impacts animal performance and overall pasture productivity (as the plants become overly mature, growth slows and longer recovery periods become necessary). Too little rest may result in protein imbalances that reduce animal performance, and stress to the plants resulting in the need for longer recovery periods.
    As soon as the pasture has recovered it should be grazed, which can be a real challenge at times. Ian talks about buying in livestock to keep up with fast grass growth on his ranch in South Africa. For Northeast U.S. dairies (like ours) with diverse pastures comprised predominantly of cool season perennials it can mean moving cattle very quickly across the farm, with recovery periods of 18 days or less during the spring. Ian also talks about residual, as there will be a good amount of it when pastures are not being overgrazed (as much as 2/3). Higher stocking densities help trample that residue and discourage selective grazing, which also allows for shorter recovery periods.

    • carl glazer says:

      There is much less species diversity in grazing vegetative growth consistantly.

      • Pam Moore says:

        That has not been our experience, as only grazing a third of the growth and not taking it down short leaves plenty behind that continues growing (we don’t clip the residual) and creates lots of diverse habitat favoring different species of plants, wildlife and soil critters.

  5. Patrick Tobola says:

    For anyone that is really interested in this subject, I recommend carefully reading chapters 22 and 39 of Savory’s Holistic Management. This is a very complex and misunderstood subject and Savory even complained at least as far back as 1999 that researchers were coming to incorrect conclusions about his work.

  6. Ben Dube says:

    This is a nice summary of the existing (very scarce) literature.

    To quibble a bit: I read the 3 papers from the the Michigan study and it doesn’t seem like a good comparative of Mob-stocking vs lower density rotational grazing.

    First, the non-mob system had irrigation, and the mob didn’t.

    Second: after only 3-4 years, the rotational system had 18.7 t/ac more Soil Carbon and 1250 lbs/ac more soil nitrogen than the exclosure. This is not possible (>300 lbs N/ac/yr accumulation due to grazing management??!!!) and likely indicates that there were substantial soil differences before the experiment started (the researchers didn’t do baseline sampling.) Comparison to rates of gain from converting to pasture would be misleading, because these research sites were pasture for more than 20 years previously.

    If we exclude that study, we are left with the results from Arkansas and Nebraska, which while interesting, are hardly enough to make broad conclusions.

    Thanks fro this.

  7. Rob Havard says:

    Good Article.

    It is interesting that the RG,1,30K seemed to offer the most benefits, which is similar to the system that I use. I sometimes graze a paddock for up to 4 days but not longer. The RG systems are very similar to what Holistic Planned Grazing would lead you towards in a relatively non-brittle environment and echo what Andre Voisin came up with in France 50 years ago with his rational grazing.

    What is missing from this research is a comparison of brittle vs non brittle environments and the impacts of this on the environments.

    Worth adding that the Ultra High Density stuff often falls down when cow size is too big. Nutrition is stretched in these systems and cows with lower maintenance requirements are needed or condition then fertility then profits suffer. All these variables make this sort of presented research a bit like licking your finger and sticking it in the air to find out which way the market prices will blow….

  8. bruce anderson says:

    What is a ‘mob’? If you use the definition of 100,000+ lbs/acre, then one 1,200 lb cow in a pen measuring 10′ x 50′ is a mob that is equal to 87 of those 1,200 lb cows on one acre.
    As research scientists, we have not yet developed the ability to mimic the social behavior of large groups of animals when using small herds. We also place multiple test herds in adjacent or near adjacent paddocks where they interact with each other.
    I have observed ‘mob’ research using small groups of animals and also have tried to use ‘mob’ grazing myself with 60-70 animals. The animal behavior and impact of these small groups is very different compared to producers using 200+ animals in a group.
    I believe this difference in scale is a major reason our research has found less benefit from using ‘mob’ grazing then many producers report. When using small groups of animals as we do in most research trials, we are really just doing a more intensified version of strip grazing rather than true ‘mob’ grazing.
    While I also think some producer reports are unrealistic in their claims of ‘mob’ grazing benefits, research reports that suggest little or no benefits, or even negative results, also overlook some of the methodology limitations.

  9. Luke says:

    What a great article. The mob grazing proponents always speak in generic terms so it’s good to read some real science. I knew the trampled forage instantly turning into organic matter was a bunch of hog wash, but it’s nice to see real data.

  10. curt gesch says:

    Thanks you for making this careful research available to us. Two comments:

    Re: “Their observation was that this was likely the result of having long (300 feet) and narrow (12 feet) rectangular paddocks where animals were stocked so densely they had to regularly move around other cattle to find enough forage.” Perhaps exercise is a good thing. I suspect that small-paddock grazing (like I do) is not the healthiest for the cows. People need exercise; dogs need a run every day. What about cows? One rancher I admire greatly thinks that–unless weather is extreme–his cows might well need a half-mile walk to water each day to maintain health.

    Re: “After all is said and done, no farm production system is “sustainable if it is not profitable.” Who would want to work and go broke, obviously. But the statement itself is not as clear as it may be. If producing food is an “essential service,” like maintaining fresh air, water, or providing medical care, or education, . . . is profit necessary in all those other places in order for them to be sustainable. (I’m not trying to be a smart-ass here, but I live in a world where many, many community organizations flourish as non-profits and are “sustainable.”

    Thanks again for articles that keep us from becoming ideological about one or another good farming practices.

    • Ben Dube says:

      I’ve spoken to dairy farmers who say that milk production goes UP when the cows have to walk a little farther to pasture, and research on dairy cows used for farm work in Germany from the early 20th century showed that a couple hours of moderate work increased milk yields as well.

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