Grazing Management: Pasture-Based Livestock System

Grazing management is the art and science of optimizing the interactions between the grazing animals, the pasture plants, and the soil, to achieve the desired outcomes, such as animal performance, forage productivity, biodiversity conservation, and ecosystem services.

Grazing management is a critical component of pasture-based livestock systems, which rely on grazing natural or cultivated pastures as the main feed source for ruminant animals, such as cattle, sheep, and goats.

Pasture-based livestock systems are gaining increasing attention and interest as a sustainable and resilient alternative to conventional confinement-based livestock systems, which depend on intensive external inputs, such as concentrated feed, fossil fuels, and synthetic chemicals.

Pasture-based livestock systems can provide multiple benefits and services, such as animal welfare, product quality and safety, soil health, carbon sequestration, water conservation, biodiversity preservation, and rural livelihoods and culture.

However, the success and the sustainability of pasture-based livestock systems depend on effective and adaptive grazing management, which can optimize the use and the regeneration of pasture resources, and can balance the multiple and often competing objectives and trade-offs, such as the short-term animal performance and the long-term pasture productivity and resilience.

Grazing management requires a holistic and systems-based approach, which integrates the ecological, economic, and social dimensions and drivers, and involves the continuous observation, assessment, planning, and adjustment of the grazing strategies and practices.

Principles of Grazing Management

Grazing management is based on a set of ecological and agronomic principles, which describe the fundamental processes and interactions that govern the dynamics and the productivity of the pasture ecosystems. Understanding and applying these principles is essential for designing and implementing effective and sustainable grazing strategies and practices. The key principles of grazing management include:

Plant Growth and Development

Pasture plants, like all plants, have a natural growth and development cycle, which involves vegetative growth, reproduction, and senescence stages. The vegetative growth stage is characterized by the rapid accumulation of the leaf area and the photosynthetic capacity, which enables the plants to capture solar energy and carbon dioxide and produce biomass and carbohydrates.

The reproduction stage is characterized by flowering and seed production, which enables the plants to perpetuate and spread their genetic material. The senescence stage is characterized by the aging and the death of the plant tissues, which enables the nutrients and the organic matter to return to the soil and to support the next generation of plants.

Grazing management aims to optimize the vegetative growth stage of the pasture plants, by maintaining the optimal leaf area and photosynthetic capacity, and by preventing overgrazing and undergrazing, which can reduce the plant vigor and productivity. The optimal leaf area varies by the plant species, the growth stage, and the environmental conditions, but generally ranges from 2 to 4 cm of the compressed pasture height for the temperate grasses, and from 5 to 10 cm for the tropical grasses.

Grazing management also aims to promote the reproduction and the regeneration of the desirable pasture species, by allowing lowering and seed production, and by creating favorable conditions for the germination and the establishment of the new seedlings. This can be achieved by the periodic resting or the deferment of the pastures, especially during the critical reproduction stages, and by the strategic grazing or the trampling of the mature pastures, to enhance the seed-soil contact and the nutrient cycling.

Plant Competition and Succession

Pasture ecosystems are dynamic and diverse communities of plants, which interact and compete for limited resources, such as light, water, nutrients, and space. The plant competition and succession are driven by the differential growth rates, the resource acquisition strategies, and the stress and disturbance tolerances of the different plant species.

In general, the fast-growing and the resource-demanding species, such as the annual grasses and the broadleaf weeds, tend to dominate the early stages of the pasture succession, while the slow-growing and the resource-conserving species, such as the perennial grasses and the legumes, tend to dominate the later stages of the pasture succession.

Grazing management can influence plant competition and succession, by selectively grazing or avoiding different plant species, and by creating favorable or unfavorable conditions for their growth and reproduction. For example, continuous and heavy grazing can favor the grazing-tolerant and the prostrate species, such as the white clover and the bluegrass, while rotational and moderate grazing can favor the grazing-sensitive and the erect species, such as the orchard grass and the alfalfa.

Similarly, frequent and intense grazing can suppress the tall and woody species, such as the shrubs and the trees, while infrequent and light grazing can allow their encroachment and dominance.

Grazing management aims to maintain the desired plant composition and diversity, by balancing the competitive interactions and the successional processes, and by preventing the dominance of undesirable or invasive species.

This can be achieved by adaptive and targeted grazing, which matches the grazing pressure and the frequency of the growth and reproduction stages of the key plant species, and by integrated pest management, which combines grazing with other control methods, such as mowing, burning, or herbicides.

Animal Behavior and Selectivity

Grazing animals, like all animals, have a natural behavior and selectivity, which are influenced by their evolutionary history, their physiological needs, and their previous experiences. The grazing behavior involves the search, selection, prehension, mastication, and digestion of the forage, and is driven by the animal's hunger, the palatability of the forage, and the physical and chemical properties of the forage, such as the fiber content, the nutrient concentration, and the plant secondary compounds.

The grazing selectivity refers to the differential preference and the consumption of the different plant species, the plant parts, and the landscape patches, and is influenced by the animal's nutritional requirements, the forage availability and quality, and the social interactions and learning.

Grazing management can affect the animal behavior and selectivity, by manipulating the forage quantity, quality, and distribution, and by providing the appropriate stock density, the herd composition, and the grazing duration. For example, the high stock density and the short grazing duration can increase the grazing intensity and uniformity and can reduce the selective grazing and the patch grazing, while the low stock density and the long grazing duration can allow greater selectivity and the diet mixing, and can create the mosaic of the grazed and the ungrazed patches.

Grazing management aims to optimize the animal behavior and selectivity, by matching the animal needs and preferences with the forage supply and quality, and by preventing the overgrazing and the undergrazing of the preferred and the less-preferred species and patches.

This can be achieved by strategic supplementation, which provides the limiting nutrients and the dietary diversity, and by targeted grazing, which directs the grazing pressure to the desired species and patches, using the fencing, the herding, or the attractants.

Soil Health and Nutrient Cycling

Pasture soils are the foundation of the pasture ecosystems, and provide critical functions and services, such as water and nutrient retention, carbon sequestration, biodiversity habitat, and forage growth and quality. Soil health is the capacity of the soil to function as a vital living system and is determined by the physical, chemical, and biological properties and processes, such as the soil structure, the organic matter, the nutrient availability, the pH, and the microbial diversity and activity.

Nutrient cycling is the movement and the transformation of essential nutrients, such as nitrogen, phosphorus, potassium, and sulfur, between the soil, the plants, the animals, and the atmosphere, and is mediated by the soil microbes, the plant roots, and the animal excreta.

Grazing management can impact soil health and nutrient cycling, by altering the plant cover and the litter inputs, the animal trampling and the excreta deposition, and the soil disturbance and the compaction. For example, overgrazing and continuous grazing can reduce the plant cover and the litter inputs, and can increase soil erosion and compaction, leading to the degradation of the soil structure, the organic matter, and the microbial activity.

On the other hand, adaptive multi-paddock grazing and rotational grazing can maintain the optimal plant cover and litter inputs and can promote the uniform distribution of the animal excreta and the soil aeration, leading to the enhancement of the soil structure, the organic matter, and the microbial activity.

Grazing management aims to sustain and improve soil health and nutrient cycling, by optimizing the plant-animal-soil interactions, and by preventing soil degradation and nutrient losses. This can be achieved by regenerative grazing practices, such as high-density short-duration grazing, adaptive multi-paddock grazing, and holistic planned grazing, which mimic the natural grazing patterns and the herd effects of the wild herbivores, and stimulate the soil biological activity and the nutrient cycling.

It can also be achieved by integrated soil fertility management, which combines grazing with other soil amendments, such as compost, biochar, or rock minerals, to replenish and balance the soil nutrients and enhance soil health.

Grazing Management Strategies

Grazing management strategies are the overall approaches and the decision-making frameworks, that guide the selection and implementation of specific grazing practices and the tools, based on the goals, the resources, and the constraints of the livestock operation.

There are several grazing management strategies, which differ in the degree of the grazing intensity, the frequency, duration, and selectivity, and the level of planning, the monitoring, and the adaptation.

Some of the common grazing management strategies include:

Continuous Grazing

Continuous grazing is the simplest and the least intensive grazing management strategy, which involves the grazing of the livestock in the same pasture or paddock for the entire grazing season or year, without any planned rest or rotation. Continuous grazing allows the maximum selectivity and the diet mixing by the livestock but can lead to the overgrazing of the preferred species and patches, and the undergrazing of the less-preferred ones. Continuous grazing can also result in soil compaction, bare ground, and weed invasion, especially under high stocking rates or poor pasture conditions.

Continuous grazing can be appropriate for extensive and low-input livestock operations, which have large and heterogeneous pastures, low animal density, and minimal labor and infrastructure. However, continuous grazing can limit forage productivity, utilization efficiency, and ecosystem services, and can be unsustainable in the long term, especially under variable and stressful environmental conditions.

Rotational Grazing

Rotational grazing is a more intensive and controlled grazing management strategy, which involves the grazing of the livestock in multiple pastures or paddocks, in a planned sequence and duration, with periodic rest or recovery periods for each paddock. Rotational grazing can optimize the forage utilization and the regrowth and can reduce the selective grazing and the patch grazing, by matching the grazing pressure and the frequency to the forage growth and the recovery rates.

Rotational grazing can also improve soil health and nutrient cycling, by promoting the uniform distribution of animal excreta and litter inputs, and by reducing soil compaction and erosion.

Rotational grazing can be implemented with different levels of intensity and complexity, depending on the number and the size of the paddocks, the length and the frequency of the grazing and the rest periods, and the stocking density and the herd composition.

Some of the variations of rotational grazing include:

  • Deferred rotational grazing: Deferred rotational grazing involves the delaying of the grazing in some paddocks until the key forage species have reached the desired growth stage or the seed maturity, to allow their reproduction and the stand establishment. Deferred rotational grazing can be used to improve the pasture composition and productivity, and to stockpile the forage for later use.
  • Rest-rotation grazing: Rest-rotation grazing involves the complete rest or the non-grazing of some paddocks for the entire grazing season or year, to allow their full recovery and seed production. Rest-rotation grazing can be used to restore degraded pastures, enhance the wildlife habitat, or provide a drought or emergency reserve.
  • Intensively managed grazing: Intensively managed grazing involves the use of high stocking density, the short grazing duration, and the frequent rotations, to maximize the forage utilization and the animal performance, while minimizing the selective grazing and the patch grazing. Intensively managed grazing can be used to improve pasture productivity, soil health, and economic returns, but requires a higher level of planning, monitoring, and infrastructure.

Adaptive Multi-Paddock Grazing

Adaptive multi-paddock grazing is a holistic and dynamic grazing management strategy, that combines the principles and practices of rotational grazing, adaptive management, and ecosystem management. Adaptive multi-paddock grazing involves the use of multiple paddocks, flexible stocking density and herd composition, short grazing duration, and variable recovery periods, based on continuous monitoring and adaptation to the changing forage, animal, and environmental conditions.

Adaptive multi-paddock grazing aims to optimize the multiple ecosystem services and the resilience of the pasture-based livestock systems, by enhancing the diversity, productivity, and stability of the pasture plants and the soil biota, and by mimicking the natural grazing patterns and the disturbance regimes of the wild herbivores.

Adaptive multi-paddock grazing can provide several benefits, such as:

  • Increasing the forage production, utilization efficiency, and animal performance, by matching the grazing pressure and the frequency to the forage growth and the recovery rates, and by preventing overgrazing and undergrazing.
  • Improving the pasture composition, diversity, and resilience, by promoting the growth and reproduction of the desirable forage species, and by suppressing the weeds and the invasive species.
  • Enhancing the soil health, carbon sequestration, and nutrient cycling, by increasing the plant cover, litter inputs, and microbial activity, and by reducing the soil compaction and erosion.
  • Conserving the water quantity and quality, by increasing the water infiltration and retention, and by reducing the runoff and the sediment and nutrient losses.
  • Providing the habitat and the resources for the wildlife, the pollinators, and the other beneficial organisms, by creating the mosaic of the grazed and the ungrazed patches, and the different vegetation structures and compositions.

However, adaptive multi-paddock grazing also requires a higher level of knowledge, skills, and labor, and the initial investment in the fencing, the water systems, and the other infrastructure. It also requires the continuous monitoring and record-keeping of the forage, the animal, and the environmental indicators, as well as the flexibility and adaptability to the changing conditions and the goals.

Targeted Grazing

Targeted grazing is a specialized grazing management strategy, that uses livestock as a tool to achieve specific vegetation management or landscape restoration goals, such as weed control, fuel reduction, invasive species management, or habitat improvement.

Targeted grazing involves the strategic and controlled grazing of the specific plant species, the plant communities, or the landscape areas, using the appropriate livestock species, the class, the stocking density, the timing, and the duration of the grazing.

Targeted grazing can be used alone or in combination with other vegetation management tools, such as mowing, burning, or herbicides, depending on the target species, the site conditions, and the management objectives.

Targeted grazing can provide several benefits, such as:

  • Controlling the weeds, the brush, and the invasive species, by the selective and repeated grazing of the target plants, and by the trampling and the incorporation of the seeds into the soil.
  • Reducing the wildfire risk and the intensity, by the removal or the reduction of the fine fuels, such as the grasses and the forbs, and by the alteration of the fuel continuity and the structure.
  • Improving the habitat quality and the connectivity for the wildlife, by the creation of the mosaic of the grazed and the ungrazed patches, and by the modification of the vegetation structure and the composition.
  • Enhancing the soil health and nutrient cycling, by the incorporation of the plant litter and animal excreta into the soil, and by the stimulation of microbial activity and decomposition.
  • Providing economic and social benefits, through the generation of income and employment from livestock production and ecosystem services, and by the engagement and education of the landowners, the managers, and the public.

However, targeted grazing also requires careful planning, coordination, and monitoring, to ensure the effectiveness, safety, and sustainability of the grazing practices, and to minimize the potential negative impacts, such as overgrazing, soil compaction, or wildlife disturbance. It also requires knowledge and experience of livestock behavior, plant ecology, and landscape dynamics, and collaboration and communication among different stakeholders, such as livestock producers, land managers, conservation organizations, and regulatory agencies.

Grazing Management Practices and Tools

Grazing management practices and tools are the specific actions and techniques, which are used to implement grazing management strategies and to achieve the desired outcomes and goals. The grazing management practices and tools can be divided into several categories, based on their main functions and applications, such as:

Fencing and Water Systems

Fencing and water systems are the essential infrastructure for grazing management, which enable the control and distribution of livestock grazing, and the provision of clean and reliable water sources. Fencing can be used to create paddocks or pastures of different sizes and shapes, delineate riparian areas, sensitive habitats, or other exclusion zones, and facilitate livestock movement and handling.

Water systems can include natural sources, such as streams, ponds, or springs, or artificial sources, such as wells, pipelines, or troughs, and can be designed to provide adequate water quantity and quality, and to minimize the livestock concentration and the impacts on the water resources.

The type, design, and location of the fencing and the water systems can influence the grazing patterns, the distribution, and the behavior of the livestock, as well as the forage utilization, soil health, and ecosystem services. For example:

  • Electric fencing can allow more flexible and adaptive grazing management, by enabling the rapid and easy adjustment of the paddock size and the configuration, based on the forage growth, the animal needs, or the management goals.
  • Permanent or semi-permanent fencing can provide more secure and long-term boundaries and can be used for perimeter fencing, exclusion fencing, or the subdivision of the larger pastures into smaller paddocks.
  • Movable or temporary fencing, such as the poly wire, the tape, or the nets, can be used for strip grazing, mob grazing, or targeted grazing, and can be easily set up, moved, or removed as needed.
  • Water systems can be designed to provide multiple, well-distributed, and easily accessible water points, encourage uniform grazing and livestock distribution, and reduce the distance and energy expenditure for water access.
  • Water systems can also be designed to minimize the livestock concentration and the impacts on the water quality and the riparian areas, by using the off-stream water sources, the hardened access points, or the exclusion fencing.

Stocking Density and Herd Composition

Stocking density and herd composition are the key grazing management decisions, that influence the grazing intensity, selectivity, and distribution of the livestock, as well as the forage utilization, the animal performance, and the ecosystem impacts.

Stocking density refers to the number of animals per unit area of the pasture at a given time and can be expressed as the animal units (AU) per hectare or acre, based on the standard animal unit equivalent, such as one mature cow or five sheep.

Herd composition refers to the species, the class, the age, and the physiological status of the grazing animals, and can influence their nutritional needs, the grazing behavior, and the social interactions.

The optimal stocking density and the herd composition depend on several factors, such as:

  • The forage quantity and quality can vary by the season, the weather, the soil fertility, and the management history.
  • The animal performance goals, such as the daily weight gain, the milk production, or the reproductive efficiency.
  • The grazing management strategy and the objectives, such as the forage utilization, the weed control, or the ecosystem services.
  • The labor, the infrastructure, and the other resources available for grazing management and animal husbandry.

Some of the principles and practices for stocking density and herd composition include:

  • Matching the stocking density to the forage supply and the growth rate, and adjusting it based on the seasonal or annual variability, to ensure adequate forage intake and animal performance, and to prevent overgrazing or undergrazing.
  • Using the higher stocking density for the shorter duration, followed by the adequate rest period, to improve the forage utilization and the regrowth, and to reduce the selective grazing and the patch grazing.
  • Using mixed species grazing, such as cattle and sheep, or goats and horses, to increase forage utilization and weed control, and to reduce the parasite loads and disease risks.
  • Grouping the animals by class, age, or physiological status, enables targeted grazing management and supplementation, and minimizes social stress and competition.
  • Incorporating herding, low-stress handling, or guardian animals, to improve livestock distribution, grazing efficiency, and predator protection, and to reduce the fencing and labor requirements.

Monitoring and Adaptive Management

Monitoring and adaptive management are the essential components of grazing management, which enable the continuous assessment, learning, and adjustment of grazing practices and the tools, based on changing conditions, new information, or unexpected outcomes.

Monitoring involves the regular and systematic collection and analysis of the data on the key indicators of the forage, the animal, and the ecosystem performance, such as:

  • The forage height, density, composition, and nutrient content, can be measured by the visual estimation, the pasture stick, the rising plate meter, or the forage analysis.
  • The animal weight, the body condition, the reproductive status, and the health, can be measured by the scales, the visual scoring, the breeding records, or the veterinary exams.
  • The soil cover, the compaction, the infiltration, and the biological activity, can be measured by the visual assessment, the penetrometer, the infiltrometer, or the soil tests.
  • The water quality, the quantity, and the flow can be measured by water sampling, flow meters, or remote sensing.
  • The biodiversity, the habitat quality, and the ecosystem services can be measured by the species surveys, the vegetation structure, the habitat assessment, or the ecosystem service valuation.

Adaptive management involves the use of the monitoring data and the feedback to inform the decision-making, experimentation, and innovation in grazing management, and to improve the effectiveness, efficiency, and resilience of the grazing practices and tools.

Adaptive management can be facilitated by:

  • Setting clear and measurable objectives and targets for grazing management, based on the goals, the values, and the context of the livestock operation and the ecosystem.
  • Developing the grazing plans and the contingency plans, which outline the grazing strategies, the practices, the tools, and the triggers and the responses for the adaptation, based on the monitoring data and the thresholds.
  • Implementing the planned grazing management, and documenting the actions, the observations, and the outcomes, using the grazing records, the maps, the photos, or the sensors.
  • Analyzing and interpreting the monitoring data and the feedback, and comparing them to the objectives, the targets, and the benchmarks, to identify the successes, the challenges, and the opportunities for improvement.
  • Adjusting the grazing plans, the strategies, or the practices, based on the monitoring results and the insights, and testing the new or the modified approaches, to enhance the performance, resilience, or innovation.
  • Sharing and communicating the monitoring data, the lessons learned, and the success stories, with the peers, the stakeholders, and the public, to foster the learning, the collaboration, and the adoption of the adaptive grazing management.

Benefits and Challenges of Grazing Management

Grazing management, when properly planned and implemented, can provide multiple benefits for livestock production, ecosystem health, and human well-being.

Some of the key benefits of grazing management include:

  • Improving the forage quantity, the quality, and the utilization efficiency, and reducing the feed costs and the external inputs.
  • Enhancing the animal health, the welfare, performance, product quality, and marketability.
  • Increasing the soil organic matter, fertility, water holding capacity, and carbon sequestration.
  • Conserving the water resources, the biodiversity, and the habitat quality, and providing the ecosystem services, such as pollination, pest control, or recreation.
  • Diversifying the income sources, the products, and the markets, and enhancing the profitability and the resilience of the livestock operations.
  • Engaging the consumers, the communities, and the public, and building the trust, support, and demand for sustainable livestock products and practices.

However, grazing management also faces several challenges and barriers, which can limit its adoption, its effectiveness, and its scalability.

Some of the key challenges of grazing management include:

  • The lack of knowledge, skills, and experience of grazing management principles, strategies, and practices, among the livestock producers, the extension agents, and the other stakeholders.
  • The high initial costs and the investments for the fencing, the water systems, the livestock, and the other infrastructure, and the limited access to the capital, the credit, or the cost-share programs.
  • The variability and the uncertainty of the weather, the forage growth, the animal performance, and the market conditions, can affect the grazing management outcomes and the economics.
  • The land tenure, the leasing arrangements, or the public land policies, can constrain the grazing management flexibility, the duration, or the access to the resources.
  • The social norms, cultural values, or peer pressure, can favor the conventional or the intensive livestock production systems, and resist change or innovation in grazing management.
  • The regulatory, the policy, or the market barriers, can limit the recognition, the valuation, or the compensation for the ecosystem services and the externalities of the grazing management.

To overcome these challenges and to scale up the adoption and the impact of grazing management, there is a need for concerted and collaborative efforts among the different stakeholders, such as:

  • Increasing the research, the education, and the extension on the grazing management, and developing the practical and the context-specific guidelines, the tools, and the case studies, to build the capacity and the confidence of the livestock producers and the advisors.
  • Providing the financial and the technical assistance, the incentives, and the risk management tools, to support the transition and the adaptation to the grazing management, and to overcome the initial costs and the uncertainties.
  • Fostering peer-to-peer learning, networks, and mentoring, to share knowledge, experiences, and innovations, and to build the social capital and collective action for grazing management.
  • Engaging the consumers, the value chain actors, and the policy makers, to create the demand, the recognition, and the enabling environment for sustainable grazing management and products, through market differentiation, certification, payment for the ecosystem services, or other mechanisms.
  • Developing the monitoring, the evaluation, and the learning systems, to assess the outcomes, the impacts, and the trade-offs of the grazing management, and to inform the adaptive management, the innovation, and the scaling up strategies.

Conclusion

Grazing management is a powerful and multifunctional tool for sustainable livestock production, ecosystem stewardship, and human well-being. By understanding and applying the principles, strategies, and practices of grazing management, livestock producers and managers can optimize forage and animal productivity, soil health, biodiversity conservation, and other ecosystem services, while improving profitability, resilience, and social acceptability of livestock operations.

However, the adoption and scaling up of grazing management requires concerted and collaborative efforts among the livestock producers, the researchers, the extension agents, the policymakers, the value chain actors, and civil society, to overcome the knowledge, financial, social, and institutional barriers, and to create the enabling environment and the incentives for the grazing management.

The adaptive and participatory research, education, and innovation on grazing management, which engage diverse stakeholders and perspectives, and integrate scientific and local knowledge, experiential learning, and the co-creation of solutions, can play a key role in fostering the transition and the transformation towards the sustainable and the resilient livestock production systems and the landscapes.

Grazing management, as a nature-based and regenerative approach to livestock production and ecosystem management, can contribute to multiple Sustainable Development Goals, such as food security, poverty alleviation, climate change mitigation and adaptation, biodiversity conservation, land degradation neutrality, sustainable consumption, and production.

By recognizing and valuing the multiple benefits and the synergies of grazing management, and by investing in capacity building, innovation, and partnerships, we can unlock the potential of grazing management to create positive and lasting change for the people, the animals, and the planet.