Could the Irish dairy industry be more “green” just by grazing differently?

Advantages and current opportunities of mob grazing systems in Ireland

I am currently studying Agri-environmental Sciences at UCD and I made this report for the university by the end of 2021, I feel that there is a movement in Ireland for sustainability that can be supported by the changes proposed to the CAP for the next years in Europe, always with the target of reducing GHGs, enhance soil health, reduce antibiotics usage and at the end, benefit farmers and consumers in the long term.

Do I prefer resilient systems over short-sighted ultra-efficient ways of doing things? Of course, I do. Here is my take on ultra-high density rotational grazing systems

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Savannas: Wide spaced trees growing in vast grassland landscapes.

Big herbivores in nature (e.g. Bison & Wildebeests)
- Savannas: Wide spaced trees growing in vast grassland landscapes.
- Huge herds (millions) in constant movement (food and water).
- Dense packs protects against predators.
- Herds followed by flocks of birds. (Eating maggots from feces).
- Grasses have time between herd intrusions to develop full fisiology (taller grasses, deeper roots.

Introduction

Every farmer is a landscape designer and its guardian, and in general; livestock farmers have a special bond with their animals and the scenery, always trying their best to treat them better whilst maintaining the landscape in better conditions than they found it.

Most current breeding and grazing practices rely on monocultural perennial pastures, high inputs of fertilisers and the constant risk of parasites affecting not only the animal’s health but also the overall returns of the farmer.

Rotational grazing systems offer an alternative management strategy to the most traditional systems of continuous grazing, and especially High Stock Density (HSD), also known as “mob grazing”; if managed well, can improve overall returns for the farmer, while improving the soil fertility and animal health, and even jump-start the carbon storage potential of healthy soils.

Greater number of paddocks, shorter grazing periods in each paddock and longer resting times for the grasses to recover; these three are the principles of mob grazing. A managed take on the natural ecology and relation between big herbivores and grasslands.

Illustration of grazing management: continuous grazing (left), extensive rotational grazing (middle) and management-intensive rotational grazing (right). / iGrow.org

“HSD has intentional impacts on the soils, forages and ultimately livestock production. It implies there is active management occurring with the grazing livestock.” (Aljoe, 2021)

Advantages of High-stock density (HSD) grazing systems

Less economic inputs

After switching and evaluating the performance of the swards, it is possible to cut the inputs of fertilisers, usage of machinery and seeds for longer periods of time. Reducing the risks of worming issues will also reduce the use of antiparasitics and veterinary services. All of this only will be translated into the overall profitability of the farming enterprise.

Soil health and biodiversity

The initial convention of “take half, leave half” of the 90s, later revised in this interview by Greg Judy from Green Pastures Farm (Bright, 2018) now becoming “graze a third, trample a third, and leave the last third standing”, states that livestock will choose the richer top third of the pasture while trampling another third to be considered organic matter to enrich the topsoil for the next growing season. Leaving the soil covered with the last third will avoid erosion by wind or rain. Taller grassland will offer refuge for a variety of species of birds, insects, reptiles and small mammals.
A case study in the UK, shows increases up to 122.7% of soil organic matter (SOM) after 3 years of mob grazing practices, as well as an increase in biodiversity after visual inspection with no data collected (Zaralis et al., 2017).

“The general rule is to graze a third, trample a third, and leave the last third standing”
- Greg Judy (Green Pastures Farm)

Animal health

Rotational grazing systems, in general, promotes diversification in the species composition of the swards as was demonstrated by a recent study (Billman et al., 2020), and the hypothesis of improvement of health performance and production in ewes and lambs in multispecies swards was accepted by researchers in UCD (Grace et al., 2019). Furthermore, studies have shown no substantial differences in blood analysis (overall health) between mob grazed calves in 60 paddocks and calves grazed in 6 paddocks for over a year (Bartimus et al., 2016), another strong suggestion that UHD rotational grazing system can be implemented without sacrificing the health of the animal.

Carbon sequestration

There is strength in diversity, and the potential for capturing CO2 and grounding it in the soil has been studied in 2016 (Skinner and Dell, 2016), with favourable results in systems with 5 species or more. We have reported before that rotational grazing favours the growth of more diverse swards (Billman et al., 2020) and these out-yield and out-performed in their carbon sequestration capacity to single species swards. It is important to remark that allowing grasses to grow taller for longer periods of time between grazing events (as mob grazing promotes) will have a significant impact on their potential capture carbon through photosynthesis.

The general idea behind this management is to mimic what happens in nature in an ecosystem of pastures and big herbivores. (Image: https://holisticmanagement.org/land/mob-grazing/)

Opportunities

A new chapter in the long history of the Common Agricultural Policy (CAP) is currently being written, and with that, a series of consultations have been taken place during the year until the 8th of December 2021, concerning the CAP Strategic Plan for Ireland (CSP) on how funds will be directed and for what activities and schemes.

Although the results and final documents and programmes available will be ready possibly in the second half of 2022, some related schemes were already proposed in the original plan; which will be key to farmers interested in changing their practices regarding grazing.

Eco-schemes under Pillar I, of the proposed CAP for Ireland; regarding activities with goals of reduction of GHGs, carbon sink, improvement of water quality, prevention of soil degradation and better animal welfare, tick all the boxes for rotational grazing practices such as mob grazing. Under the umbrella of “better agricultural practices”, these schemes could be a key support for a farmer to decide to switch to a high-density rotational grazing system.

The Pillar II, with its focus on Agri-environmental schemes and training, will also be an interesting tool for farmers in order to improve their practices, especially under the Suckler Carbon Efficiency Programme, designed to reduce total emission by improving the environmental sustainability of the herd and its genetics.

Conclusions

More studies are necessary to produce knowledge, especially in the long-term economic advantages of these practices; and it is necessary to develop expertise in the management of livestock in the way that this work is detailing, but enough data and analysis are available to start to question if the “best practices” that have taken us where we are today, are really the best practices that will take us to a more sustainable future for us all.