Harnessing Opportunities, Constraints, and Implications of Integrating Environmental Conservation with Sustainable Ruminant Production

Abstract

The growing demand for animal products exerts pressure on the livestock sector to increase production while minimizing its impact on the environment. The paper explored the impact of ruminant production systems on the environment and opportunities for enhancing production and environmental conservation. A comprehensive review of literature on livestock production, animal nutrition, and environmental conservation was conducted. The review shows that the challenges of ruminant production on the ecosystem are centered around greenhouse gas emissions, land degradation, and water and feed resources. However, manipulation of animal feeding strategies, rotational grazing, precision farming, and integration of crop-livestock systems have the potential to enhance feed efficiency, reduce waste, improve animal health, and nutrition and reduce nitrogen and methane gas emissions. This will also improve manure management, soil health, and biodiversity, which are essential in climate resilience building and resource management by farmers. Development of effective strategies for enhancing animal nutrition and ruminant production while conserving the ecosystem is important.

1. Introduction

Ruminants are a varied group of mammals with a distinct four-chambered stomach allowing them to digest plant material effectively through microbial fermentation and rumination [1,2]. They play a crucial role in human history, contributing to biodiversity and the global economy [3,4]. Ruminant farming remains essential in areas where cropping is not ideal [5,6]. Sustainability in ruminant livestock production requires setting clear, quantitative goals grounded in planetary boundaries [7,8]. The Stockholm Resilience Centre provides insights into the planetary boundaries concept. According to Rockström et al. [9] and Steffen et al. [10], the planetary boundaries framework provides safe operating limits for key earth system processes such as climate change, biophysical systems, and biodiversity loss. These boundaries set critical constraints within which humanity must operate to avoid irreversible environmental changes [11,12]. Agriculture has been identified as the primary cause of overshooting boundaries, which is already beyond six of the nine planetary boundaries [9,13].

Ruminants are expected to reach 9.2 billion by 2050; hence their rearing is significant in agricultural production [14]. By 2050, the global human population is expected to reach 9.6 billion with food demand having increased by 25–70% relative to current demands [15]. There is, therefore, an increasing demand for animal protein-rich food, particularly from ruminant animals such as cattle, goats, and sheep [16,17]. This poses a challenge for sustainable food systems and human well-being due to their higher environmental impact intensities [16,18].

Ruminants play an integral role in promoting soil health and provide manure for fertilization, a positive drive towards agricultural sustainability [19]. However, ruminant production faces scrutiny over its effects on the environment, transgressing several planetary boundaries [8,20,21]. Major concerns include methane gas emissions, deforestation, nitrogen imbalances, water use, land use, and feed-food competition [22,23]. This has raised interest in incorporating conservation into systems to meet sustainability targets [18,24].

Water and energy consumption in agricultural production are major contributors to environmental change [25]. Globally, food systems contribute about 25% to a third of greenhouse gas (GHG) emissions, leading to biodiversity loss, freshwater depletion, and land use changes. Sustainable resource management is necessary to increase resilience and increase production while enhancing food security [25].

To address challenges associated with conventional ruminant production systems, there is a growing interest in integrating environmental conservation with ruminant production. Hence, this study adopts an integrative literature review methodology, which aims to balance productivity with planetary and ecological sustainability, aligning livestock development with climate change adaptation and mitigation goals [26]. Previous studies have shown that there is a potential for sustainable ruminant production integration with environmental conservation to enhance agricultural resilience and mitigate climate impacts, promote biodiversity, and reduce GHG emissions [27,28]. Therefore, this literature review aims to explore the impact of ruminant production systems on the environment and opportunities for enhancing production and environmental conservation. Findings from the literature review will add to the growing body of knowledge on sustainable ruminant production. The article provides a comprehensive review of ruminant production systems, their association with planetary boundaries, their impact on the environment, and challenges and opportunities for sustainable production.

2. Overview of Ruminant Livestock Production

2.1. Diversity of Ruminants

Large ruminants (cattle and buffalo) and small ruminants (sheep and goats) differ significantly beyond body size as they have distinct advantages in production efficiency and environmental adaptation [3]. Small ruminants provide superior economic accessibility through their low production costs, short generation interval, suitability for small areas, and multipurpose use for meat, milk, and fiber [29]. Their small sizes translate to practical management benefits as they are easy to destock and restock and require less labor, feed, and housing [30,31]. Small ruminants have distinct water-saving abilities such as reduced panting and respiration rates that help minimize water loss during stress conditions [29,32,33,34]. This affords them a crucial advantage in water-scarce environments where cattle production becomes unsustainable [35]. Among small ruminants, goats show exceptional heat tolerance with unique abilities to desiccate feces, concentrate urine, and reduce evaporative water loss, making them superior to both sheep and cattle in warm climates [36]. Production system differences also reflect their distinct roles in agriculture. Small ruminant farming is diverse, as the animals can thrive under harsh environmental conditions [37]. Small ruminants have shorter reproductive cycles, indicating that meat and milk gains can exceed those from cattle on a short time frame while their higher birth rates and faster compensatory growth allow quicker recovery from drought conditions [30].

2.2. Ruminant Livestock Production Systems

Ruminant production systems involve managing and raising animals such as sheep, cattle, and goats for meat, milk, fiber, and draught power [38]. They are commonly categorized based on agro-ecological conditions, demand, availability of resources, and socio-cultural aspects, and have traditionally maintained sustainable equilibrium without external inputs [39,40,41]. Sere and Steinfeld [42] classified livestock production systems into three groups based on agro-ecological zones focusing on the length of the growing period (LGP). These are arid or semiarid (<180 days LGP), humid or subhumid (>180 days LGP), and tropical highlands or temperate regions. Livestock production systems can be further classified as either solely livestock or mixed farming systems [42,43].

Solely livestock systems use over 90% dry matter from rangelands, pastures, and feed with less than 10% non-livestock farming [42,43]. They are further categorized into grassland-based systems, where over 10% of dry matter is produced on farms, and landless systems which produce less than 10% and have high stocking rates. Landless systems can be divided into monogastric and ruminant animals with higher production values for each [44]. Mixed farming systems use over 10% dry matter from crop by-products or non-livestock farming activities [42,43]. They are further categorized as either rainfed or irrigated systems accounting for 90% and 10% of non-livestock farm production, respectively [43,44].

Figure 1 shows typical ruminant production systems categorized into grazing, mixed, and industrial/intensive systems. Grazing systems follow an extensive production system which is widely regarded as a sustainable and animal-friendly method of animal production by society and consumers [41,45]. They extensively depend on natural grazing, where animals normally roam over large areas freely [39,46]. They require low input and output while utilizing marginal land that is not suitable for crop production. It is commonly practiced in arid and semi-arid areas and is practiced in Sub-Saharan Africa and Central Asia [45]. However, grazing systems are vulnerable to climate variability, overgrazing, and land degradation. Mixed systems integrate crops and livestock, utilize crop residues and forages as feed, and integrate manure for crop fertility [43,45]. They require moderate input and management while commonly practiced in Africa and Latin America. They also require feed, water, and veterinary services access which may be challenging [39,45]. Industrial systems are characterized by high input and output, confined or zero grazing, and they rely heavily on formulated and conventional feeds [39,45]. It is commonly practiced under feedlot settings where production is performed for commercial purposes. It is dominant in North America, Europe, and parts of Asia [45].

Ruminant production systems are currently dominated by traditional systems, especially in developing regions, particularly in Sub-Saharan Africa, owing to limited access to capital and inputs [4,45]. Over the years, there has been a shift towards more commercial and intensive systems due to population growth, urbanization, and changing market demand [47,48]. Sustainable development of ruminant production systems requires improved feed resource utilization, genetic improvement, better animal health management, and adaptation to climate change [49,50,51].

2.3. Integration of Ruminant Production Systems and Planetary Boundaries

The schematic interaction of ruminant production systems and planetary boundaries is shown in Figure 1. Grazing systems affect the land system change, biosphere integrity, and freshwater use due to extensive land use for grazing, which often leads to habitat loss, reduced biodiversity, and degradation of vegetation [7]. Overgrazing can also intensify water demand and soil erosion. Key planetary boundaries affected by mixed systems are biochemical flows, land system change, and freshwater use [7]. These systems combine crop and livestock activities, potentially recycling nutrients more efficiently. There is a risk of excessive nutrient loading and land conversion if not managed sustainably. Industrial/intensive systems affect the biogeochemical flows and climate change boundaries. They are often characterized by high stocking densities, feed imports, synthetic inputs, and emissions which significantly contribute to GHG emissions, nutrient imbalances, and pollution [7]. Overuse of antibiotics can also introduce novel entities into ecosystems [10].

2.4. Landscape Management and Biodiversity Benefits of Ruminants

Small ruminants serve as landscape managers providing critical ecosystem services that extend far beyond meat and milk production [3,52]. They contribute to the management and development of landscapes, ecosystem maintenance, biodiversity conservation, and provision of job opportunities from their products and byproducts in the market [29]. Small ruminants contribute to the preservation of landscapes and ecosystems, cooperating with biodiversity conservation and supplying products to niche markets [53]. They are also known to have fire prevention capabilities as they can be raised under short vegetation, thereby mitigating wildfire risks by reducing the accumulation of flammable biomass [54,55]. Small ruminants also provide important soil conservation benefits through grazing and trampling behaviors. Trampling especially by small ruminants, may compact sandy soils, leading to reduced soil erosion risk [54].

3. Environmental Impact of Conventional Ruminant Production

3.1. Greenhouse Gas Emission

The growing population and demand for meat are leading to an increase in emissions from enteric fermentation and manure management due to the increased livestock production [56]. The rise in greenhouse gas concentrations including carbon dioxide, methane, and nitrous oxide, is causing global warming, rising sea levels, and severe weather events [23]. The Kyoto Protocol identified six GHGs (sulfur, methane, carbon dioxide, nitrous oxide, perfluorocarbons, and hydrofluorocarbons), with 90% of total GHGs attributed to carbon dioxide, methane, and nitrogen oxide [56]. Previous studies have shown that ruminants contribute about 40% to global GHG emissions which is approximately 2.3 Pg global warming potential (GWP)₁₀₀ CO₂ equivalents annually [1,57,58]. The carbon footprint for beef production is reported as the highest for any food product estimated at 22.8 kg CO₂ equivalent per kilogram live weight [4,16]. These emissions are higher per protein or calorie compared to non-ruminant livestock or plant-based foods [16]. Methane, a short-lived atmospheric pollutant, has a global warming potential 28-fold greater than CO₂ in a 100 year horizon and 80 times more potent over 10–20 years [59,60,61]. Ruminant livestock are major contributors to GHG emissions [22,57]. Methane is produced during the digestive process known as enteric fermentation and released as a byproduct through belching into the atmosphere [23,60]. Methanogens use hydrogen as energy to degrade cell wall carbohydrates, and methane production depends on the concentration of volatile fatty acid produced [56,62]. Dietary management affects ruminal pH and volatile fatty acids production, with a decrease in pH leading to hydrogen accumulation and a reduction in propionate [56,63]. Methane production in animals is influenced by factors such as digestive system, digestible organic matter, time spent in the rumen, intake level, and carbon source [64]. Management practices and feeding strategies can significantly impact methane release [65]. High-quality forage feed negatively impacts methane production while low-quality feed increases it [56]. Feed type and quality also affect the digestion periods in the rumen with reduced residence time reducing methane production [56,64]. Dietary composition influences methane production, with diets rich in starch affecting ruminal pH and the ratio of methane and fermented organic matter [65].

Livestock manure, including feces and urine, contains organic matter, nutrients, and micronutrients [56]. Urine contains urinary nitrogen, which is a significant source of nitrogen dioxide emissions. Manure is another source of GHG, depending on its management. Manure management systems such as ponds, tanks, or pits promote anaerobic conditions, resulting in the release of methane as a byproduct to the atmosphere [23,56,66]. Nitrous oxide is generated both directly and indirectly during storage and treatment of manure and urine, resulting from the processes of nitrification and denitrification [56,64]. The production and emission of nitrogen dioxide are influenced by factors such as animal feed digestibility, manure management practices, waste management length, and environmental conditions [56,67]. High levels of nitrogen dioxide emissions are typically associated with high feed intake and nitrogen concentrations [68].

3.2. Water and Land Use, Pollution and Biodiversity Loss

Feed production accounts for more than 97% of the water footprint of the livestock industry, making meat products more water-intensive than the majority of plant-based products [45,69]. Approximately 27% of the global human water footprint is attributed to animal product production, with ruminants, products being especially water intensive [45,70]. The water footprint of a product is divided into three components and these are blue, green and gray which represents water used consumed from the surface and the groundwater, rainwater consumed, and freshwater needed to absorb pollutants, respectively [45,71,72]. Most of the water footprint of ruminants in extensive grazing systems is made of green water, which refers to water stored in plants or soil [71,73].

Intensive systems utilize high proportions of blue water for growing feed for feedlots, as they rely on irrigated crops compared to grazing systems, which depend on rainwater [71,74,75]. Blue water use is absent in some regions, and grazing systems can reduce freshwater use strain by about 70% when compared to intensive systems [75]. Grazing contributes to minimizing water footprint by eliminating irrigation of feed crops. This enabling local adaptation of unsuitable land and optimizing water use through sustainable pasture management thereby reducing environmental impacts by promoting infiltration and lowering in runoff [45]. For mixed systems, the blue water footprint is lower than intensive systems, though higher for grazing systems [71]. Feed composition and the origin of the feed influence the blue water in mixed systems. Mixed systems can also increase feed efficiency and balance out increased blue water demand [75]. Additionally, they also optimize land and water use. Water use varies across regions even for similar animal species [72]. However, competition for surface or groundwater and water pollution from livestock production activities can be a challenge [69].

Ruminant farming is a significant source of water pollution, primarily due to runoff containing nitrogen and phosphorus from manure and fertilizers [76]. This runoff can lead to eutrophication which is excessive nutrient enrichment of water bodies that causes harmful algal blooms and depleted oxygen, damaging aquatic ecosystems [77]. Conventional ruminant production can lead to biodiversity loss through habitat conversion, overgrazing, and pollution [76]. Intensive grazing and feed crop cultivation can degrade natural habitat, reduce species diversity, and contribute to soil erosion [37,45]. Large areas of land are dedicated to grazing and feed cultivation often contributing to deforestation and biodiversity loss.

Manure from ruminant operations emits ammonia which contributes to air pollution and can cause soil acidification [78]. High-density feedlots and concentrate animal feeding operations can produce excessive manure, leading to local water and air quality problems if not managed properly [79]. Globally, climate change, soil and water pollution, overgrazing, and disease transmission are some of the environmental challenges associated with livestock that pose a serious threat to biodiversity [69]. The expansion of land for farming and pastures has a detrimental effect on biodiversity and leads to habitat degradation and climate change [76,80]. Livestock grazing is widely recognized as the primary cause of biodiversity loss and land degradation in arid rangelands [81]. Overgrazing depletes resources, threatens livestock livelihoods, and destabilizes ecosystems [82]. Undergrazing and overgrazing can cause soil and peat erosion leading to water pollution, and this has negative effects on the environment [83]. Overall, poor grazing management contributes to land degradation [84].

4. Environmental Conservation and Its Relevance to Ruminant Production

Environmental conservation in agriculture focuses on sustainable practices that can protect natural resources while maintaining productivity [85,86]. Its key principles include the following: biodiversity, soil health, and water conservation [87,88]. Promoting species diversification through crop rotation, intercropping, and associations enhances ecosystem resilience and natural biological processes above and below ground [89]. Biodiversity supports pest control, pollination, and soil health contributing to sustainable production [90]. Minimum mechanical soil disturbance preserves soil structure, reduces erosion, and maintains soil organic matter. Maintaining a permanent organic soil cover protects soil from erosion, improves moisture retention, and fosters beneficial soil organisms. Crop diversification supports soil nutrient cycling and reduces pest and disease occurrence [91,92].

Conservation agriculture practices improve water infiltration and reduce runoff leading to better water use efficiency [24,93]. Maintaining soil cover and minimizing disturbance reduces soil erosion and water loss. Reduced tillage and permanent soil cover increase soil organic carbon storage, mitigating GHG emissions [37,88]. Conservation agriculture enhances carbon storage in soil contributing to climate change mitigation [24]. Therefore, healthy soils, diverse cropping systems, conservation agriculture practices, improved water and soil management and carbon sequestration practices enhance forage quality, nutrition, pasture sustainability, and reduced emissions in ruminant production systems [37,88,94].

5. Opportunities for Integrating Environmental Conservation and Ruminant Production

Figure 2 presents a framework for integrating environmental conservation and sustainable ruminant production. Drivers and pressures, constraints, opportunities, and relevant enablers can be identified to allow adoption of an integrated system that is beneficial to the environment, farmers, and the community.

5.1. Sustainable Grazing Systems

Grazing is crucial in the utilization of rangeland for meat and dairy production [82]. Maree et al. [94] reported that grazing systems can be adaptive (rotational) or continuous. Rotational grazing which involves periodically moving livestock between pastures based on pasture conditions, animal requirements, and seasonal variations [95]. It enhances soil fertility, water-holding capacity, and soil organic carbon storage and reduces erosion [94]. By allowing vegetation recovery, this practice increases forage quality and minimizes overgrazing, leading to net carbon sequestration [85]. Continuous grazing allows livestock to graze selectively in large paddocks and has fewer ecological benefits than rotational grazing [94]. Cell grazing, holistic/mob grazing, high-density grazing, and strip grazing are rotational grazing systems that can be incorporated with silvopastoral and agroforestry systems [96].

Silvopastoral grazing systems integrate livestock grazing with trees or perennial systems on the same land unit [84,97]. These systems support ecosystem services such as carbon sequestration, improved water quality, soil conservation, esthetics, and shelter for livestock [4,96]. Some systems use perennial herbaceous legumes for symbiotic nitrogen fixation [84]. Silvopastoral systems improve pasture growth and animal welfare and provide alternative feed during periods of low forage availability [98]. Silvopastoral systems enhance animal welfare by providing nutritionally rich diets, social stability, and social behavior [96]. They promote idleness, grazing, comfort, and environmental diversification [99]. These systems also reduce stress, provide shade, and improve microclimate conditions, contributing to sustainability in tropical farming [100]. Silvopastoral systems also improve nutrient distribution and soil health, as open pastures create hot spots of nutrients and soil compaction, increasing greenhouse gas emissions [98].

Grazing impacts rangeland productivity and ecological balance by regulating plant growth and community aggregation [96,101]. Moderate grazing has the potential of regulating vegetation growth, reducing wildfire risks, and enhancing soil fertility [82]. It stimulates plant regrowth and improves forage nutritional values while increasing soil nitrogen and phosphorus content [102]. Selecting suitable grazing methods requires thorough assessment of forage yield and quality. Previous research in China showed that the government had implemented policies to combat overgrazing on rangeland, including grazing bans, ecological conservation subsidies, restoration projects, and compensation mechanisms [103,104]. However, the effectiveness of these policies varied across regions. Long-term quantification of grazing intensity can be employed to evaluate these policies and optimize management strategies [76,99]. Grazing intensity assesses livestock utilization of rangelands, considering aspects such as livestock numbers, vegetation, and climatic conditions [105].

Permanent forage cover in grazing systems reduces soil erosion, a primary significant source of agricultural GHG emissions [101]. Integrating ruminants into crop rotation stimulates root exudates, fostering microbial activity and soil organic carbon accumulation [96,106]. Mixed crop-livestock systems repurpose crop residues as feed, reducing reliance on external inputs while recycling nutrients [87]. Appropriately managed grazing land can improve land conditions and enhance natural capital [84]. Effective grazing management should be implemented to prevent overgrazing or land degradation. Zero grazing may be required to allow degraded rangelands to recover and effectively support livestock [94]. However, the duration and approach should be practiced according to specific agro-ecological conditions. Undergrazing can cause problems such as reduced biodiversity and accumulating unpalatable plant species [107,108]. Therefore, it should be balanced with grazing to maintain the healthy condition of the rangeland ecosystems [109,110].

5.2. Improved Feed and Nutrition Strategies

Climate change poses significant challenges to global food security and livestock production [111,112]. Sustainable ruminant production can incorporate climate-resilient adaptation strategies such as improving breeding methods, production systems, and management practices [113]. Improved feed and nutrition interventions involve precision feeding and dietary strategies for livestock [37]. Mitigation measures include carbon sequestration, improved diets, and manure management [96,114].

Reducing GHG emissions from ruminants is a priority for sustainable agriculture [112,113]. The use of low-emission diets and leguminous forages is essential for feed and nutrition strategies [115]. Feeding ruminants with high-quality, less fibrous forage improves rumen fermentation, increases feed intake, and enhances digestibility [116]. This results in higher yields and lower methane emissions per unit product as less methane is produced during the digestion of more digestible feeds [117]. Precision feeding involves formulation of diets for animals based on their requirements at different production stages using feed analysis and ration balancing software [27,113]. It has the potential to optimize nutrient utilization, reduce waste, and minimize GHG emissions [115,118]. Feed additives and naturally sourced alkaloids can also directly inhibit methane production in the rumen, with some additives demonstrating up to 50% reduction in methane emissions [58,62]. Adding oil-rich seeds such as canola and linseed and ionophores such as monensin to ruminant diets can suppress methanogenic microbes and improve feed conversion efficiency, further reducing methane outputs [116,119].

The high protein and carbohydrate content of leguminous forages such as tree legumes, alfalfa, and clover improves dry matter intake and animal performance [120]. Feed value and productivity are increased when low-quality forages are combined with legumes. Secondary metabolites found in some legumes can reduce rumen protozoa, which lowers methane emissions, and are applicable protein supplements during fodder scarcity [121]. Kennady et al. [122] indicated that reduced feed intake and grain replacement are significant in minimizing increased emissions from cattle because poor feed quality can raise methane emissions per unit of energy consumed. Use of locally available alternative feed resources, agro-industrial by-products, neglected crops, and underutilized plants as feed ingredients has the potential of reducing methane emissions without compromising the productivity of ruminants [49,123,124,125,126].

5.3. Animal Genetics and Breeding

Sustainable livestock populations are produced through animal breeding, which selects desirable qualities through natural genetic variation [4,127]. By choosing robustness, disease resistance, longevity, and reduced emissions, modern breeding programs balance environmental effects, animal welfare, productivity, and health [122,128].

Long-term viability and adaptability of livestock systems in challenging conditions depend on indigenous and locally adapted breeds [4,38]. These breeds require less feed and effectively use low-quality forage, and they thrive with limited resources, diseases, and stress [4,89]. For instance, smallholder farmers benefit when indigenous goat breeds outperform local breeds in development and productivity [3]. Breeding practices that enhance cattle productivity and adaptation in developing countries include community-based breeding initiatives such as the Nguni Cattle Project in South Africa, crossbreeding between local and exotic breeds, and genomic technologies [129,130].

5.4. Climate-Resilient Ruminants

Climate change is driving livestock producers to adopt more resilient ruminant species that can withstand harsh climatic conditions [4]. In some regions, camels have emerged as particularly valuable alternatives, especially in arid and semi-arid areas where traditional cattle production is becoming unsustainable [131]. Camels can successfully survive and remain productive under harsh environmental conditions, and during drought periods when milk production from cows and goats becomes inadequate, camels remain a reliable source of milk for pastoralists [30]. Camels have exceptional water efficiency, which allows them to survive extended days without water, qualities that have attracted the interest of non-camel-herding pastoralists towards camel management as an adaptation strategy under a changing climate [30].

In Africa, species substitution patterns highlight the climate adaptation potential of livestock systems. For instance, over the years, camels have replaced cattle in Sahel, and goats have replaced sheep following drought episodes. Traditional cattle farmers in Kenya and Ethiopia have incorporated camels into their livelihood strategies to combat drought, cattle raiding, and disease outbreaks [132,133]. Camels and goats, unlike cattle and sheep, rely on shrubs and trees as their primary feed source, despite any reduction in herbaceous feed availability [133].

The potential for strategic species replacement offers significant environmental and production benefits. Research has shown that increasing goat and camel populations while reducing dairy cattle populations could result in higher milk production with lower water demand and reduced feed resource requirements while reducing dairy emissions [131]. Among small ruminants, goats show exceptional climate resilience, giving them survival advantages compared to sheep [36].

The value of climate-resilient animals extends beyond survival to include their role in supporting food security in marginal areas. Animals such as the Zebu and camels play an essential role in marginal and impoverished regions contributing to food diversity and providing incomes for farming households, with their unique adaptability to specific environments making them valuable alternatives to traditional dairy cows, especially in arid and semi-arid regions [134]. Indigenous and local breeds that have evolved in tropical climates generally exhibit greater resistance to endo- and ecto-parasites, reducing reliance on external inputs such as anthelmintics and antibiotics [38].

5.5. Climate-Smart Livestock Approaches

Climate-smart livestock systems play a crucial role in ruminant production to adjust to climate change while reducing environmental effects [89,135]. Climate risk insurance, pasture monitoring, and early warning systems are essential strategies [112]. Farmers may minimize livestock losses and prepare for extreme weather events by using early warning systems, which provide them with precise climate information [136,137]. Sustainable animal production and grazing management are ensured by advanced pasture monitoring [103]. Precision agricultural platforms for real-time decision support, enhanced feed management, water management strategies, and rotational and adaptive grazing are examples of integrated climate-smart approaches [83,137,138,139]. With the aid of these resources, farmers can preserve the environment, sustain productivity, and adjust to climate change.

5.6. Manure Management and Nutrient Recycling

Manure released by housing facilities varies globally. Herrero et al. [140] reported that in Europe, strict environmental laws have resulted in the recycling of a significant amount of manure for usage in crops, rangelands, and biogas production. Composted manure is mainly used for high-value crops and food in Africa, where mixed and large rangeland-based systems do not handle manure [140]. Manure can be utilized for biogas production, fish pond feed, organic fertilizer, and biofuel [140,141]. Because of the increase in agricultural land, the availability of inexpensive fertilizer, and soil fertility, recycling is not common in North America, where manure recycling is not fully explored [140].

Nitrous oxide and methane are released from feces. Decomposing organic material in manure emits methane [122]. China produced the most methane-treated emissions with an estimated 17.5 million tons of methane emitted annually worldwide [122]. The primary source of nitrous oxide emissions from fertilizer application includes soil infiltration, organic carbon content, pH, temperature, precipitation, and plant uptake rate [79,122]. While industrial output systems emit 90% less nitrous oxide than rangelands, mixed crop fertilizers release 40% more [122].

6. Constraints and Challenges

6.1. Socioeconomic Constraints

The adoption of sustainable strategies in integrating environmental conservation with ruminant production can be hindered by socioeconomic aspects. These constraints include high investment costs, restricted access to economic incentives and market access, knowledge and training, policy support, social and cultural resistance, uncertain operating environments, limited access to financial services and credit, and fragmented extension services support [142,143,144]. Farmers often consider short-term survival ahead of long-term sustainability investments, and adoption is further hindered by a lack of suitable financial services and technical support [87,145]. Small-scale farmers often lack the capital to transition to conservation practices such as rotational grazing or cover cropping [87,139]. However, adopting sustainable ruminant production remains a challenge regardless of long-term benefits.

6.2. Technical Constraints

Farmers may lack technical expertise in regenerative practices, highlighting training needs [87]. Availability of relevant infrastructure can be a challenge. For example, fencing for rotational grazing manure management systems requires upfront investment. While implementing regenerative practices requires investments, they are generally lower when compared to intensive systems associated with significant expenditures on infrastructure [146]. Integrated ruminant production is often confronted by difficulties such as veterinary infrastructure, climate change adaptation, GHG emissions mitigation, pasture degradation, water shortages and scarcity, feed optimization, and the utilization of renewable energy resources [136,147]. Effective and relevant strategies are required to mitigate GHG emissions, pasture deterioration, and water contamination [148]. High prices, complexity, and a lack of accessibility hinder the adoption of technologies [26,44]. However, holistic approaches to ruminant production are required to manage environmental impacts, adopt advanced technologies, and build veterinary and energy infrastructures.

6.3. Policy and Market Constraints

Subsidies for conventional practices and weak incentives for ecosystems discourage shifts towards sustainability. Market demands for cheap animal products also prioritize intensive production over ecological methods [87]. Existing policy gaps and weak incentives for sustainable practices can be a barrier to integrating environmental conservation and sustainable ruminant production [93,149]. Limited access to climate finance and carbon markets for smallholder farmers may be challenging [17,88]. Lack of specific policies addressing the environmental impacts of ruminant production, neglected connections between consumption and environmental degradation, financial difficulties, and limitation of small-scale output hinder the adoption of sustainable technologies practical breeding and productivity improvement programs [16,27,38].

Research from the Savory Institute has highlighted that most policies are reductionist, concentrating on specific issues without considering any possible broader consequences [150,151]. Effective policies should focus on comprehensive and nature-linked approaches [150,152]. Governments should concentrate on root causes in line with ex-ante rather than underlying causes or ex-post approaches, and this forms part of policy constraints. Market constraints in promoting sustainable practices, such as incentivizing environmentally damaging practices, influence the success of regenerative management [152,153]. Market systems need to account for externalities such as soil erosion and water security and market support for holistic solutions like grazing and ecosystem restoration [151,154].

6.4. Global Emission Estimates and Discrepancies

Livestock emission calculations are varied and cause challenges due to inherent measurement uncertainties, which affect baseline quantification [155,156,157]. These discrepancies could be attributed to several factors, such as animal dietary changes, management practices, and environmental conditions [155,158]. Current methods can over- or underestimate the baseline of methane emissions in ruminants leading to over- or underestimation in setting goals and implementing policies for methane reduction [157]. The calculations of GHG accounting metrics can also cause quantitative variations, as the atmospheric lifetime and radiative impacts of different climate pollutants differ significantly [155].

7. Implications for Sustainable Ruminant Production and Environmental Conservation

7.1. Environmental Implications

Well-managed grazing systems, especially in regenerative and rotational grazing systems, improve soil health by increasing soil organic carbon, reducing erosion, and enhancing fertility [85,86,159]. This can lead to more carbon sequestration than emissions from the ruminants, thereby mitigating GHG emissions [24,37]. Diverse pasture and cover crops support pollinators and wildlife habitats, therefore enhancing biodiversity [96,160]. Ruminants contribute positively by maintaining rangeland ecosystems, dispersing seeds, and supporting habitats for wildlife [101]. Grazing can control invasive species and restore natural plant communities, enhancing biodiversity and ecosystem resilience [37,139,159].

Improved water infiltration and drought tolerance are significant in mitigating climate risks, especially in arid and semi-arid regions [87]. Integrated crop-livestock systems and the use of cover crops improve water retention and reduce the need for agrochemicals, lowering environmental pollution [24]. Improved feeding strategies, genetic selection for low methane-emitting animals, and better manure management can significantly reduce methane emissions from ruminants, contributing to climate change mitigation.

7.2. Socioeconomic Benefits

Adoption of conservation practices improves long-term farm profitability through higher forage yields and reduced input costs [87]. Environmental conservation and management practices lead to improved natural resource efficiency and increased productivity while reducing production costs due to better soil fertility and pest resistance [109]. Manure management systems that produce biogas can generate renewable energy, reducing farm energy costs and creating additional income [79,161].

In developing countries, integrated systems enhance food security by diversifying income streams. Sustainable ruminant farming supports economic viability by balancing productivity with environmental conservation, therefore ensuring long-term farm profitability and resilience against climate and market pressure [38,88]. Promoting the involvement of farmers in farmer associations and improved knowledge through training programs on environmental conservation will aid in their adoption of better ruminant production strategies [148].

7.3. Livelihood Benefits

Ruminant production contributes to food security by enhancing access to animal-source foods. They also support marginalized communities by promoting equitable access to natural resources. Integrating environmental conservation with ruminant farming enhances the resilience of farming systems to climate variability and ecological stressors, thereby protecting livelihoods. Mixed crop-farming systems enable efficient recycling of nutrients, for instance, using manure as fertilizer, reducing dependency on external inputs, and supporting food production in developing countries.

7.4. Policy Implications

The integration of environmental conservation and ruminant production has significant policy implications [24,86,109]. Agricultural subsidies should be redirected towards regenerative practices. Farmer-led training on rotational grazing and manure management can bridge knowledge gaps [87]. Compensation of farmers for carbon sequestration and biodiversity benefits could be prioritized [87]. Promoting sustainable intensification and diversification, lowering methane emissions, encouraging regenerative grazing and agroecosystem management, supporting mixed farming and circular systems, addressing supply chain and trade impacts, creating legal and institutional frameworks, capacity building, and implementing economic tools and incentives should be considered [162,163]. Implementation of these policies will be significant in mitigating climate change, improving biodiversity, sustaining rural livelihoods, and balancing ruminant productivity and sustainability goals [16,37]. Holistic management, policy reform, and market transformation approaches are required to address environmental challenges [152,153]. There is advocacy for a systems-thinking approach focusing on ecological, economic, and social complexity and encouraging government adoption of long-term policies and market reforms [151,152].

7.5. Emission Quantitative Accuracy and Implications

Addressing quantitative issues and measurement challenges requires specific approaches that should be considered [156,157]. These include verification and consideration of authoritative data sources, clarifying system boundaries and scope using standardized emission factors and conversion methods, providing step-by-step calculation transparency, acknowledging and quantifying uncertainties, comparing multiple methodological approaches, addressing temporal and regional variations, and reconciling discrepancies with existing literature [157,158].

8. Future Directions for Integrating Environmental Conservation with Sustainable Ruminant Production

Future research should promote the advancement of precision agriculture and digital technologies in agricultural production. Adopting artificial intelligence, the Internet of Things, and robotics in ruminant production will enable precise monitoring of animal health, pasture conditions, and resource use, optimizing production while minimizing environmental impacts. These technological advances can facilitate data-driven decisions to enhance sustainability. Innovations in feed additives such as natural probiotics and methane inhibitors are gaining prominence to reduce enteric methane emissions from ruminants without compromising productivity. Therefore, future research should explore antibiotic alternatives and precision nutrition to support animal health and environmental goals.

Regenerative agriculture and agroecological farming practices should be scaled up. Regenerative agriculture, emphasizing soil health restoration, biodiversity, and carbon sequestration, is expected to become the cornerstone of sustainable ruminant production. Expansion of practices such as rotational grazing, silvopastoral systems, and cover cropping will enhance ecosystem services and resilience. Linking ruminant output with renewable energy technologies such as biogas from manure and water recycling can reduce the sector’s carbon footprint and resource consumption, creating a circular bioeconomy.

Strengthening policies incentivizing ecosystem service payments, carbon credits, and subsidies for sustainable practices will be critical to overcoming economic barriers and encouraging adoption, especially among smallholder farmers. The rise in alternative proteins will complement sustainable ruminant production by reducing pressure on land and resources, contributing to food security and environmental goals. Future research should also integrate animal welfare considerations with ecological sustainability, recognizing their interdependence for sustainable ruminant systems. Continued research, innovation, and development into improving feed conversion efficiency and breeding low-emission ruminant breeds will support sustainability targets by reducing resource inputs per unit.

9. Conclusions

Greenhouse gas emissions, land degradation, and water and feed resource utilization are challenges associated with conventional ruminant production. The integration of environmental conservation with sustainable ruminant production presents an effective and promising approach for improving animal production, ecosystems, and rural livelihoods. Sustainable ruminant production involving manipulation of animal feeding strategies, rotational grazing, precision farming, and integration of crop-livestock systems has the potential to mitigate climate change, restore degraded land, and improve food security. However, successful integration requires technical innovation, enabling policies, and stakeholder participation. Policy makers, researchers, financial institutions, extension services, smallholder support, capacity building, payment for ecosystem services, coherent policy integration, and localized research should be prioritized to maximize the benefits of integrated ruminant production.