Does short duration grazing work in grasslands?

Does short duration grazing improve livestock production, veld condition and climate resilience compared to other grazing systems in a mesic grassland of South Africa?

Industry Sector: Cattle and Small Stock

Research focus area: Sustainable natural resource utilization

Research Institute: Universtity of Cape Town

Researcher: Dr Heidi Hawkins

Research Team

Title Initials Surname Highest Qualification
Prof S Vetter PhD
A/Prof MD Cramer PhD
Prof V Muchenje PhD
Dr C Mapiye PhD
Mr AS Venter MSc
Ms N Mgwali BSc Hons

Year of Completion : 2018

Aims of the project

  • Overall we wish to test the alleged mechanisms by which short duration grazing (or Holistic Planned Grazing, HPG) “works” explicitly by looking at the underlying mechanisms at the fine scale and overall effects at the camp/farm scale and how these vary and interact with rainfall, temperature, time and specific camps. We wish to apply this understanding to inform efforts being undertaken by government and NGOs to generate sustainable and more commercial red meat production from communal rangelands and land redistribution farms in one of South Africa’s biodiversity ‘hot spots’.
  • At the scale of an experimental farm and experimental plots we test claims that high animal densities in HPG reduces selectivity during defoliation of key plant species leading to conservation of species composition (biodiversity), forage quantity and quality throughout the year
  • At the scale of the farm, plots and pot experiments we determine how grazing intensity (recovery periods /defoliation frequency x defoliation intensity) affects plant recovery.
  • At the scale of the farm and plot we test claims that trampling (from intense hoof action during HPG) results in increased incorporation of nutrients (litter, dung, urine) and water, resulting in increased soil organic matter, nutrients including carbon, microbial activity, soil water infiltration, and reduced compaction and erosion.
  • At the farm scale, we test claims that the increased forage quantity and quality HPG increases animal gain ha-1, meat quality and profit of marketable animals; and at the scale of the individual animal, that HPG results in improved average daily gain per animal, including sufficient nutrition for pregnancy, lactation and re-conception.
  • At the farm and animal scale, we test whether high animal densities alter animal behavior (walking, resting, grazing) and energy expenditure.
  • Also on the individual animal scale, we test whether HPG results in a reduced parasite load (specifically ticks) because of, e.g. rapid movement of animals between camps, and whether the stress of movement compromises disease resistance.

Executive Summary

It has been claimed that Holistic Management (HM) and specifically, Holistic Planned Grazing (HPG, hereafter holistic grazing), can reduce desertification and reverse climate change by using livestock as a tool. At the same time, high animal densities and stocking rates associated with holistic grazing are claimed to result in improved plant and animal production but with little evidence or suggested mechanisms for these changes. The project addressed these gaps in knowledge via a three-year trial and corral studies, fence-line contrasts of existing and long-term practitioners of holistic grazing in the grassland biome, and remote sensing over sub-Saharan Africa.

We found nuanced differences in forage utilization, plant selectivity by animals, litter production, as well as small differences in animal behaviour and more marked differences in forage quality and animal parasites between grazing approaches (continuous, season-long, four camp and holistic planned grazing) in the trial. Some of these differences depended on season, but in all cases the scale of these differences were not enough to affect overall plant or animal production. Thus, the season-long and four-camp approaches were more profitable than the holistic approach due to capital outlay ((fences ands water points for multiple camps, or herders to create virtual camps), with the break-even point for holistic grazing being two years after that for other approaches. Provisional results from a national survey of long-term working farms supported results from the three-year trial. The use of a corrals is associated with holistic grazing in communal livestock systems, and our work showed that if the starting condition of the rangeland was poor with bare ground cover above 12% then basal cover increased under corraling, i.e. at very high animal densities of more than 400 livestock units per hectare, but otherwise increased bare ground so that corraling as a tool may be useful but should be applied with caution. In a remote sensing study, we found that woody plant encroachment has increased by 8% over the last three decades over sub-Saharan Africa and that while this is largely driven by climate, fire and herbivory are important drivers so that judicious use of fire and livestock (possibly at high densities) could help reverse this trend, with implications for the global carbon balance and productivity.

Overall, if animal gain is the priority of a land owner, the additional labour and/or infrastructure associated with holistic grazing is not justified. However, holistic grazing may be useful for rangeland restoration or specific goals.

Useful applications of holistic grazing based on our data may be:

  1. Reduction of under-utilized plant standing biomass and/or creation of a litter layer;
  2. Reduction of external and internal parasite loads (from an already low infestation to slightly lower infestation in our data so the practical usefulness would have to be tested at high infestation rates);
  3. Increased forage quality in some seasons (from normal quality to slightly increased quality in our data);
  4. Possibly, to reduce woody plant encroachment (and runaway fires), especially if browsers are included.

Popular Article

Does holistic grazing improve livestock production, veld condition and climate resilience compared to other grazing systems?

by Heidi-Jayne Hawkins

Director of Research at Conservation South Africa and Honorary Research Associate at University of Cape Town; contacts hhawkins@conservation.org and heidi-jane.hawkins@uct.ac.za

Rangelands, a source of biodiversity and agricultural products, are under threat globally. It has been claimed by the Savory Institute that Holistic Management (HM) and specifically, Holistic Planned Grazing, can reduce desertification and reverse climate change by using livestock as a tool. At the same time, high animal densities and stocking rates associated with holistic grazing are claimed to result in improved plant and animal production but with little evidence or suggested mechanisms for these changes. A recent review of the literature found that holistic grazing has no impact on plant and animal production (Hawkins 2017). In general, any management approach that is adaptive can be expected to sustainably manage rangeland resources by considering both ecological processes and livelihoods. Holistic Management or the Holistic Management Framework (Savory and Butterfield, 2016) is such a framework. While the adaptive approach of HM is not contentious, the livestock management part of this framework has been the subject of debate since the 1980s. Holistic Planned Grazing (HPG; hereafter holistic grazing) describes an intensive, rotational, time-controlled approach much like short duration-, cell-, multi-paddock- and mob-grazing. In South Africa, it is commonly called high-density, short-duration stocking.

During holistic grazing, livestock are kept at high densities using fences or herders with the intention of mimicking free-moving herds of herbivores that are migrating or bunched by predators; and grazing rather than fire is generally favoured as a way of recycling soil nutrients. Our recent article (Venter et al 2017) discusses the great numbers, densities and diversity of herbivores that occurred in the past before mass extinctions and hunting associated with humans spreading over the earth, and it is indeed reasonable to think that higher densities or animals would be ecologically appropriate and that the current use of fire to manage rangelands could in part be replaced by herbivores including livestock. However, the claims made by Savory go beyond this and need testing. Considering the renewed debate and existing threats to our rangelands including grassland and savanna, we examined the evidence for claims and tested various possible mechanisms that could underly these claims ((increased production, nutrient cycling, plant utilization and reduced plant selectivity).

The project addressed these gaps in knowledge via a three-year trial and corral studies, fence-line contrasts of existing and long-term practitioners of holistic grazing in the grassland biome, and remote sensing over sub-Saharan Africa. The research was a collaboration between Conservation South Africa and academics including five researchers and five students from the University of Cape Town, Stellenbosch University and the University of Fort Hare.

The controlled study was conducted on sections of a private farm (30.351767°S, 29.043433°E near Cedarville Flats and 30.394363°S, 29.020521°E on slopes near Goedhoop), called Merino Walk within the Matatiele Local Municipality, Eastern Cape in the grassland biome. Each flats and slopes section was divided into holistic grazing, conventional four-camp rotation, and continuous season-long grazing treatments with the same overall HM management and stocking rate but different animal densities. A national survey of working holistic farms and their neighbours allowed us to broaden the scope of the work from the scale of a local trial to the national scale. Also, the survey allowed us to assess holistic farming over longer time periods than the three years farm trial, as well gain insights into real farms. The questionnaire can be found at https://www.surveymonkey.com/r/grazing_research_survey .

We found nuanced differences in forage utilization, plant selectivity by animals, litter production, as well as small differences in animal behaviour and more marked differences in forage quality and animal parasites between grazing approaches (continuous, season-long, four camp and holistic planned grazing) in the trial. Some of these differences depended on season, but in all cases the scale of these differences were not enough to affect overall plant or animal production and in winter animal production in the rotational treatments was relatively low. Provisional results from a national survey of long-term working farms supported results from the three-year trial.

The season-long and four-camp approaches were more profitable than the holistic approach due to capital outlay (fences ands water points for multiple camps, or herders to create virtual camps), with the break-even point for holistic grazing being two years after that for other approaches.

Looking closer at animal behaviour, there was no evidence that holistic grazing increases dung trampling, the number of steps taken or selectivity at the plant or patch scales. An interesting effect of holistic grazing was a reduction in tick infestation that is thought to be associated with the rapid movements of animals between the mobile camps, so that ticks do not have time to complete their life-cycles. Out of the three grazing treatments, tick counts were higher in the continuous herd compared to the holistic grazing and four-camp herd in spring and summer. In general, internal parasites were very low with faecal egg counts being highest in the hot-rainy season. Both tick and faecal egg counts were not at levels of concern for animal health regardless of treatment effects.

The use of a corrals is associated with holistic grazing in communal livestock systems, and our work showed that if the starting condition of the rangeland was poor with bare ground cover above 12% then basal cover increased under corraling, i.e. at very high animal densities of more than 400 livestock units per hectare, but otherwise increased bare ground increased, so corraling should be applied with caution.

In the remote sensing study, we found that woody plant encroachment has increased by 8% over the last three decades over sub-Saharan Africa and that while this is largely driven by climate, fire and herbivory are important drivers so that judicious use of fire and livestock (especially browsers, possibly at high densities) could help reverse this trend.

Implications

From our results in a mesic grassland:

  • Holistic grazing may be useful as a tool for specific purposes such as increasing the litter layer and reducing tick loads but does not increase production;
  • High-density grazing practices are less profitable than conventional season-long grazing or the four-camp approach;
  • Corrals at animal densities over 400 LSU ha-1 may be a useful disturbance regime for restoration of bare ground and increasing phosphorus concentrations for cropping but only on already disturbed ground;
  • Browser/grazer mix and fire may be useful tools managed to reduce woody plant (bush) encroachment (and runaway fires).

Information sources

Hawkins H-J. 2017. African Journal of Range and Forage Science 34: 65-75.

Savory A, Butterfield J. 2016. Holistic Management. A commonsense revolution to restore our environment (3rd edn). USA: Island Press. ISBN 9781610917445 (e-book).

Venter, ZS., H-J Hawkins, MD Cramer 2017.  Ecosphere 8 (10), http://dx.doi.org/10.1002/ecs2.1946

Venter ZS, Cramer MD, Hawkins H-J 2018. Nature Communications 9, 2272 http://dx.doi.org/10.1038/s41467-018-04616-8

Please contact the Primary Researcher if you need a copy of the comprehensive report of this project – Heidi on heidi-jane.hawkins@uct.ac.za