Extensive Livestock Production Systems Research Articles

66 Emerging Precision Ranching Technology Is Enabling the Development of a “smart” Biome

Abstract Precision ranching technology is revolutionizing remote data collection from livestock and the land base they depend on, greatly improving our ability to assess the entire biome. Remotely Piloted Aircraft System (RPAS or drone) based remote sensing to date has been used primarily to assess intensive cropping; but RPAS systems equipped with interchangeable cameras: high-resolution visual, thermal, LiDAR, and multi/hyperspectral imagers are now being deployed on rangelands, to monitor subtle changes in the visible, near infrared and infrared spectrums (radiation) that both plants and animals reflect. A single RPAS system can now be used simultaneously for high-quality vegetation mapping and behavioral analysis of animals, providing a suite of comprehensive data-collection tools for studying livestock in a variety of landscapes and rugged terrain. For example, we have used RPAS systems to measure behavioral and physiological indicators of cattle heat stress in feedlots and on pasture (Mufford et al., 2021). These same drones can be utilized for RPAS collection of high-resolution imagery (using multi/hyperspectral imagers and LiDAR) for vegetative and topographical mapping, greatly improving our ability to visualize and characterize habitat attributes such as forage availability, quality (stage of growth) and accessibility. Equipping cattle with new tracking technology, including "smart" GPS ear tags, rumen boluses, and wireless fencing collars (based on low-earth orbit satellites and cellular networks) enable animals to be readily identified and tracked on the landscape, while providing invaluable physiological data, such as internal body temperature to monitor estrous, heat stress, or the onset of disease (Figure 1). Additionally, rapid advances in wireless fencing systems have the potential to improve livestock management through autonomous mustering or the implementation of advanced rotational grazing for use in regenerative agriculture efforts. Wireless fencing may decrease production (infrastructure) costs, while also providing a strategy to better align forage demands with use, and thereby enhance pasture condition at the habitat and landscape level. Finally, non-invasive pasture weighing systems, enabled with or without RPAS technologies, are capable of monitoring key livestock production metrics year-round. Together, these technological advances enabled by this new "smart biome" will improve animal health and welfare while ultimately enhancing the sustainability of extensive livestock production systems.

Sensing and Mapping the Effects of Cow Trampling on the Soil Compaction of the Montado Mediterranean Ecosystem

The economic and environmental sustainability of extensive livestock production systems requires the optimisation of soil management, pasture production and animal grazing. Soil compaction is generally viewed as an indicator of soil degradation processes and a determinant factor in crop productivity. In the Montado silvopastoral ecosystem, characteristic of the Iberian Peninsula, animal trampling is mentioned as a variable to consider in soil compaction. This study aims: (i) to assess the spatial variation in the compaction profile of the 0-0.30 m deep soil layer over several years; (ii) to evaluate the effect of animal trampling on soil compaction; and (iii) to demonstrate the utility of combining various technological tools for sensing and mapping indicators of soil characteristics (Cone Index, CI; and apparent electrical conductivity, ECa), of pastures' vegetative vigour (Normalised Difference Vegetation Index, NDVI) and of cows' grazing zones (Global Positioning Systems, GPS collars). The significant correlation between CI, soil moisture content (SMC) and ECa and between ECa and soil clay content shows the potential of using these expedient tools provided by the development of Precision Agriculture. The compaction resulting from animal trampling was significant outside the tree canopy (OTC) in the four evaluated dates and in the three soil layers considered (0-0.10 m; 0.10-0.20 m; 0.20-0.30 m). However, under the tree canopy (UTC), the effect of animal trampling was significant only in the 0-0.10 m soil layer and in three of the four dates, with a tendency for a greater CI at greater depths (0.10-0.30 m), in zones with a lower animal presence. These results suggest that this could be a dynamic process, with recovery cycles in the face of grazing management, seasonal fluctuations in soil moisture or spatial variation in specific soil characteristics (namely clay contents). The NDVI shows potential for monitoring the effect of livestock trampling during the peak spring production phase, with greater vigour in areas with less animal trampling. These results provide good perspectives for future studies that allow the calibration and validation of these tools to support the decision-making process of the agricultural manager.

EVALUATION OF THE SUSTAINABLE PERFORMANCE OF NATIVE AND INTENSIVE SILVOPASTORAL SYSTEMS IN THE MEXICAN TROPICS USING THE MESMIS FRAMEWORK

<p><strong>Background. </strong>It is agreed that there is a need to work on sustainable extensive livestock production systems. Silvopastoral systems are an alternative for efficient and sustainable grazing systems to increase the provision of ecosystems services and minimize the environmental costs associated to monoculture systems (MS), but the efficiency of intensively managed (IS) and unmanaged or native (NS) silvopastoral systems has never been assessed and compared to MS. The Framework for Assessing the Sustainability of Natural Resource Management (MESMIS) offers a tool to assess sustainability criteria in agroecosystems. <strong>Objective. </strong>To use MESMIS to compare the sustainable performance of NS, IS and MS and determine the system with the best sustainable performance in the Mexican Tropics. <strong>Methodology. </strong>One MS IS and NS per municipality (Tizimin, Merida and Tzucacab) were evaluated in the state of Yucatán, Mexico. Based on the MESMIS approach, the evaluation of the critical points of sustainability resulted in the selection of 19 indicators classified according to the attributes also defined by MESMIS (production, adaptability, stability-resilience, equity and self-management) and by sustainability dimensions (environmental, animal welfare, economic and social). After evaluation, indicator scores were obtained and integrated into attributes and dimensions through the assignation of equitable, balanced weights (W). Finally, attribute and dimension scores were aggregated in amoeba graphs to facilitate visual interpretation. <strong>Results. </strong>NS were better for the dimensions ‘Environmental’ and ‘Economic’ and the attributes ‘Stability, ‘Reliability’and ‘Resilience,’ and ‘Production’. IS were best for the dimension ‘Animal Welfare’ and attributes ‘Adaptability’ and ‘Self-reliance’. MS were better for the ‘Social’ dimension and the ‘Equity’ attribute. <strong>Implications. </strong>The fact that IS appeared to be more sustainable than MS does not leave out the idea of considering NS as a better option for some criteria such as the biodiversity conservation and the prevention of disease outbreaks, than IS. We suggest that more studies are carried on areas of potential improvement for IS as well as NS. <strong>Conclusions. </strong>This information will be useful to continue working on the parametrization of sustainability criteria of cattle extensive systems to be used for more efficient policies.</p>

Cattle Ranching in Colombia: A Monolithic Industry?

This article analyzes literature on the history of cattle ranching and agricultural innovation adoption in Colombia to understand how livestock production systems have evolved from the 1950s until today. Departing from new scholarship that has questioned the idea that cattle ranching has been only a land-grabbing strategy dominated by few elites, this article focuses on the adoption of improved pastures and the role of key institutions such as the CIAT on the transformation of practices and the shortcomings of technification. It shows that Colombia has had big transformations with the introduction of improved pastures, particularly Brachiaria, but these transformations did not translate into a radical change in the dominant extensive livestock production systems. Instead of promoting intensification, the adoption of Brachiaria has allowed producers to expand more, often resulting in large deforestation. One of the main contributions of this article is the analysis of economic, developmentalist, and institutional reports that are not often used to construct historical analysis. It can also serve to scholars interested on adoption of agricultural techniques.

A Technological Approach to Support Extensive Livestock Management in the Portuguese Montado Ecosystem

Extensive livestock production systems based on improved pastures under Montado of Holm oaks represent an approach in line with the challenges of sustainability and biodiversity. The increasing incorporation of technologies in the monitoring of this ecosystem allows for a better knowledge of the spatial and temporal variability and, consequently, a more economically profitable management. In this study, between July 2020 and June 2021, soil and pastures were monitored in a 20 ha Montado area located in Alentejo (Southern Portugal) and used for extensive grazing of cattle. The survey of soil apparent electrical conductivity (ECa), the application of algorithms for definition of homogeneous management zones (HMZ), the use of indices obtained from satellite imagery time series to characterize the evolution of pasture quality and the soil and pasture sampling, including the identification of bio-indicator botanical species, were the basis of this exploratory study, allowing a holistic approach to this complex soil-pasture-trees and animals ecosystem. In the near future, this knowledge could represent an important milestone in providing decision-making support systems to farm managers in terms of smart sampling, differential application of fertilizers, amendments or seeds, choosing the best spacing and density of trees in this ecosystem, promoting dynamic grazing, or identifying the animal feed supplementation needs in the critical periods of the year.

Conservation for Effective Management of AnGR in India

Livestock sector forms an important livelihood activity for most of the farmers, supporting agriculture in the form of critical inputs, contributing to the health and nutrition of the household, supplementing incomes, offering employment opportunities, and finally being a dependable “bank on hooves” in times of need. India has vast Animal Genetic Resources (AnGR), which play a vital role in improving the socio-economic conditions of rural masses. AnGR is also of significant social and cultural importance, supplementing family incomes and generating gainful employment in the rural sector, particularly among the landless, small, marginal farmers and women. Global demand for livestock products is expected to double by 2050, mainly due to improvement in the worldwide standard of living. Meanwhile, extensive livestock production systems are being fast replaced with intensive and industrial production system due to change in land use, higher demand of livestock product and more and more keepers shifting to high producing improved breeds. The loss of a breed means the loss of a livelihood strategy and loss of indigenous knowledge. It also emphasizes the need for the active involvement of indigenous communities and the role of local knowledge and institutions in conservation.

Spatiotemporal Patterns of Pasture Quality Based on NDVI Time-Series in Mediterranean Montado Ecosystem

The evolution of dryland pasture quality is closely related to the seasonal and inter-annual variability characteristic of the Mediterranean climate. This variability introduces great unpredictability in the dynamic management of animal grazing. The aim of this study is to evaluate the potential of two complementary tools (satellite images, Sentinel-2 and proximal optical sensor, OptRx) for the calculation of the normalized difference vegetation index (NDVI), to monitor in a timely manner indicators of pasture quality (moisture content, crude protein, and neutral detergent fiber). In two consecutive years (2018/2019 and 2019/2020) these tools were evaluated in six fields representative of dryland pastures in the Alentejo region, in Portugal. The results show a significant correlation between pasture quality degradation index (PQDI) and NDVI measured by remote sensing (R2 = 0.82) and measured by proximal optical sensor (R2 = 0.83). These technological tools can potentially make an important contribution to decision making and to the management of livestock production. The complementarity of these two approaches makes it possible to overcome the limitations of satellite images that result (i) from the interference of clouds (which occurs frequently throughout the pasture vegetative cycle) and (ii) from the interference of tree canopy, an important layer of the Montado ecosystem. This work opens perspectives to explore new solutions in the field of Precision Agriculture technologies based on spectral reflectance to respond to the challenges of economic and environmental sustainability of extensive livestock production systems.

Voluntary intake, milk and colostrum production and lamb growth when ewes are fed high-NaCl diets during pre- and post-lambing

Nutritional requirements at the end of gestation in ewes carrying multiple fetuses are rarely fully met in pasture production systems. Thus, concentrate feeds entail an alternative for increasing herd productivity. However, daily offer of complementary feed in extensive livestock production systems is not always possible due to climatic or geographic constraints or to labor shortages. One alternative is to offer large amounts of concentrate feed with the addition of NaCl that limits voluntary consumption, eliminating the need for daily supplement delivery. Our objective was to evaluate the effect of high salt levels added to concentrate feed on pre- and post-lambing twin-gestating ewes and their responses on feed intake, colostrum and milk production and composition, plasma biochemical profile variation and lamb growth. Twenty-four adult Corriedale females were housed in individual stalls and divided into four treatments: S13: ad libitum concentrate feed plus 13 % of salt; C13: the same amount of concentrate feed consumed by S13 ewes the day before, but without salt; S17: ad libitum concentrate feed with 17 % of salt, and C17: the same amount of concentrate feed consumed by S17 ewes the day before, but without salt. Fresh water and forage were offered in ad libitum amounts. Treatments were applied in the period of highest ewe nutrient demand, from day 123 of pregnancy to day 21 of lactation. The four percentage points in salt content resulted in a decrease of organic matter daily intake of concentrate (23 % of reduction in pre-lambing and 35 % of reduction in post-lambing for S17 relative to S13; P = 0.0134 and P = 0.0164, respectively). Lamb birth weights were similar between S13 and C13 (P = 0.1002) and between S17 and C17 (P = 0.8449) treatments. Colostrum and milk production did not differ between S13 and C13 (P = 0.9776 and P = 0.8928, respectively) or between S17 and C17 groups (P = 0.4943 and P = 0.7705, respectively). Plasma insulin, hematocrit and total protein levels were not influenced by the treatments and these parameters remained within normal physiological limits. Thus, the addition of 13 or 17 % of salt to concentrate feed did not affect the reproductive capacity of ewes or offspring growth, showing that ewes are able to withstand high doses of NaCl and supporting the potential of salt as a limiter of voluntary intake in pre- and post-lambing diets.

Increases in extreme heat stress in domesticated livestock species during the twenty-first century.

Anthropogenic climate change is expected to have major impacts on domesticated livestock, including increased heat stress in animals in both intensive and extensive livestock systems. We estimate the changes in the number of extreme heat stress days per year for animals raised outdoors that can be expected in the major domesticated animal species (cattle, sheep, goats, poultry, and pigs) across the globe during this century. We used the temperature humidity index as a proxy for heat stress, calculated using temperature and relative humidity data collated from an ensemble of CMIP6 climate model output for mid and end century. We estimate changes in the proportions of different livestock species that may be at increased risk of extreme heat stress under two contrasting greenhouse gas emission scenarios. Results are discussed in relation to changes in the suitability of different climate conditions for domesticated livestock during the current century. We find that by end century, extreme heat stress risk is projected to increase for all livestock species in many parts of the tropics and some of the temperate zones, and to become climatically more widespread, compared to 2000. Although adaptation options exist for both intensive and extensive livestock production systems, the increasing pervasiveness of extreme heat stress risk in the future will seriously challenge the viability of outdoor livestock keeping, particularly in the lower latitudes in lower and middle‐income countries where the costs of adaptation may be challenging to address.

The nutritive value of different Mediterranean browse species used as animal feeds under oak silvopastoral systems in Northern Portugal

Oak woodlands (OW) have historically been important in the Mediterranean region since they provide an important amount of goods and services, such as fodder and shelter for extensive livestock production systems. However, OW lost relevance as a fodder supplier due to the specialization and intensification of livestock production. Nowadays, with the challenges emerging from climate change and other environmental concerns, OW are regaining interest as silvopastoral systems. The aim of this study was to evaluate the seasonal variation of the chemical composition and the in vitro organic matter digestibility (IVOMD) of key browse species in grazed OW in the north of Portugal. Additionally, the feeding value was compared with the requirements of goats’ maintenance and late pregnancy. The browse species evaluated were Quercus suber, Q. rotundifolia, Q. faginea, Juniperus oxycedrus, Cytisus scoparius, C. multiflorus, Genista falcata, Cistus ladanifer, and Lavandula stoechas. The data were analysed by a two way analysis of variance focusing on species and season and their interaction. The results obtained varied significantly among the species studied regarding the crude protein content (CP) (41.6–195.9 g kg−1 dry matter (DM)), fibres (neutral detergent fibre (NDF): 316.7–632.5 g kg−1 DM; acid detergent fibre (ADF): 246.0–468.0 g kg−1DM; acid detergent lignin (ADL): 90–210.5 g kg−1 DM), IVOMD (33.02–71.34%), and metabolizable energy (ME) (5.78–11.42 MJ kg−1 DM). Both C. ladanifer and Q. rotundifolia have inadequate ME and CP levels to meet the nutritional needs of goats with 45 kg of live weight. Only leguminous shrubs cover CP needs in late pregnancy.

Achieving drought resilience in the grazing lands of northern Australia: preparing, responding and recovering

Northern Australia is characterised by high rainfall variability and extended droughts that challenge sustainable and profitable management of grazing properties. To achieve drought resilience, emphasis must be placed on supporting livestock managers to prepare for drought as well as implementing appropriate drought response and recovery actions. Here we describe insights and learnings gained from working with scientists, industry development and extension officers, and property managers, to enable more profitable and drought resilient extensive livestock production systems across northern Australia. We provide examples from the modelling and analysis of hypothetical grazing properties representative of enterprises across northern Australia. To prepare for drought, we principally propose the application of the farm-management economics framework to identify investment strategies which can improve enterprise resilience through building wealth over the longer term. The critical first step in drought preparedness for beef businesses was the implementation of management strategies to achieve the optimal herd structure, steer sale age, and breeder body condition. Other key strategies to improve profitability across northern Australia were (1) addressing a phosphorus deficiency for cattle through effective supplementation and (2) establishing adapted perennial legume-grass pastures to improve steer nutrition. In addition, we identify the benefits of working closely with livestock managers and industry to gain adoption of proven technologies that effectively improve decision-making capacity and the drought preparedness of extensive livestock production systems. The usefulness of the farm-management economics approach to assess the relative value of alternative tactical destocking and restocking decisions during drought response and recovery is also discussed. These latter analyses can highlight important differences between options in terms of future profit and cash flow, as well as the ability to rapidly return the property to the most profitable herd structure and age of turnoff, with consideration of production and financial risk. Additionally, integrating pasture growth models with herd or flock economic models can provide insights into the effects, on profitability and sustainability, of alternative destocking and later restocking strategies over the longer term. Combined, the farm-management economics framework approach can support more informed decision-making by livestock producers and hence enable more profitable and drought resilient extensive livestock production systems. However, achieving drought resilience in the grazing lands of northern Australia will require emphasis on drought preparation, in addition to appropriate action in response and recovery phases of drought. Key to this approach is increasing the adoption of strategies that enhance drought preparedness.

Measurement of selenium in two Algerian chenopods (Atriplex canescens (Pursh.) Nutt. and Suaeda fruticosa (Linn.) Forssk)

Neutron activation analysis laboratory (NAA measurement) was applied for the determination of selenium (Se) contents in two perennial forage species (Atriplex canescens (Pursh.) Nutt. and Suaeda fruticosa (Linn.) Forssk) used in extensive livestock production systems, in arid rangelands of Algeria. Se content was estimated in leaves and in the soil in which the plants were grown. The vegetal and soil samples were irradiated for 6 h duration with a thermal neutron flux of 4.5 × 1013 cm−2 s−1 of Es-Salam research reactor (Berine, Algeria). The daily intake of Se was determined and compared with the values recommended by National Research Council (NRC) guidelines. Result showed that the highest contents of Se were found in the rainy period (January–15 winter) for both species. By way of contrast, for the surrounding soil this metalloid was higher during dry season (July–15 summer). The maximum uptake of Se was predominantly recorded in A. canescens (0.16 ± 0.07 μg g−1) compared to S. fruticosa (0.07 ± 0.03 μg g−1). The bioaccumulation factor (BFSe) from soil to plant showed a high enrichment of Se especially for A. canescens. In conclusion, this study envisages that A. canescens can be gazed by livestock in winter season as a source of Se; however the problem of Se deficiency was expected during the other seasons for animals grazing A. canescens and S. fruticosa.

Rural household chicken management and challenges in the Upper River Region of the Gambia.

Systematic assessment and documentation of extensive livestock production systems are necessary to design or review breeding programs, extension services, and policies. This study therefore examined management practices and challenges concerning village chicken production in the Upper River Region of the Gambia. The data gathered with 45-variable semi-structured questionnaires were analyzed based on the household head's education status and gender. Illiteracy level was high, and only 38% indicated that they attended certain schools. There was a significant relationship (p < 0.05) and phi coefficient of 0.35 between household heads' education status and record keeping. None of the examined management practices had a statistically significant relationship (p > 0.05) with household heads' gender. Children (10-14years) were mostly responsible for providing care to the chickens. Foundation and replacement stocks were mainly acquired through purchase (78%). Many households (74%) indicated supplementary feeding of their flocks but only 34% provided separate houses apart from the household dwellings. Newcastle (68%) was the most common disease. Sick birds were recognized by restlessness (34%) and diarrhea (28%). External parasites were mainly controlled through local practices (52%) while the most common way to dispose dead birds was to throw them away (88%). Up to 90% indicated no formal training on disease management and access to extension agents was also low (20%). Control of chicken movement was occasionally done to protect birds from predators (60%) and then, to avoid contagious diseases (38%). Individual farmers and their associations need to be supported by stakeholders to access relevant information and uptake improved management techniques.

Self-feeding improved animal performance of calves grazing native grasslands during winter on extensive livestock production systems

Self-feeding improved animal performance of calves grazing native grasslands during winter on extensive livestock production systems

Agroforestry for ruminants: a review of trees and shrubs as fodder in silvopastoral temperate and tropical production systems

Among the oldest agroforestry systems, silvopastoralism uses shrubs and trees to feed ruminants. The practice is common in extensive livestock production systems, whereas the intensification of grass-based systems in the past century has led to the removal of woody species from agricultural temperate landscapes. In Europe however, woody species are promoted again on grasslands through environment-friendly policies due to the ecosystem services they provide such as carbon sequestration, control of soil erosion, limitation of airborne pollutants and biodiversity conservation. Positive effects of browse on rumen digestion and parasite control have also been documented across different plant species and regions. Under optimal conditions, feeding ruminants from woody fodder sustains animal production. Nonetheless, limitations can restrict the use of woody forage into animal diets, such as the presence of anti-nutritive and toxic compounds. The incorporation of this resource in ruminant feeding systems raises the question of the management of the interface between the plant and the animal. Various management systems are practiced. Temperate species such as Salix spp. and Populus spp. are fed to sheep and cattle in fodder blocks or by pruning trees in New Zealand, and Fraxinus spp. or Corylus avellana in hedgerows supply forage to livestock in Belgium, whereas Leucaena leucocepahala and Desmanthus spp. browsing is common in Australia. Nowadays, ensiling and pelleting techniques are being developed as a way to store browse forage. As the renewed interest in using shrubs and trees to feed ruminants is recent, especially in temperate regions, additional research about the optimal introduction of this resource within systems is needed.

Livestock and human use of land: Productivity trends and dietary choices as drivers of future land and carbon dynamics

Land use change has been the primary driving force of human alteration of terrestrial ecosystems. With 80% of agricultural land dedicated to livestock production, the sector is an important lever to attenuate land requirements for food production and carbon emissions from land use change. In this study, we quantify impacts of changing human diets and livestock productivity on land dynamics and depletion of carbon stored in vegetation, litter and soils. Across all investigated productivity pathways, lower consumption of livestock products can substantially reduce deforestation (47–55%) and cumulative carbon losses (34–57%). On the supply side, already minor productivity growth in extensive livestock production systems leads to substantial CO2 emission abatement, but the emission saving potential of productivity gains in intensive systems is limited, also involving trade-offs with soil carbon stocks. If accounting for uncertainties related to future trade restrictions, crop yields and pasture productivity, the range of projected carbon savings from changing diets increases to 23–78%. Highest abatement of carbon emissions (63–78%) can be achieved if reduced consumption of animal-based products is combined with sustained investments into productivity increases in plant production. Our analysis emphasizes the importance to integrate demand- and supply-side oriented mitigation strategies and to combine efforts in the crop and livestock sector to enable synergies for climate protection.

Extensive livestock farming in Morocco: From marginal territories to major social and environmental roles

Recent developments in the supply of animal products in Morocco revealed a sharp decline of the contribution of extensive livestock farming systems. In a con­text of marked demographic expansion (from 15.3 to 32.9 million inhabitants from 1956 to 2013) associated to rapid urbanization (almost 60% of the pop­ulation lives in urban centers), consumption habits have changed. There has been a shift from a patriarchal structure of the society, which meant that meals were consumed at home, to more individualistic behaviors. As a consequence, the nature of animal products consumed by large sections of the population has notably changed. Dairy and poultry products appear to be most suited to these changes, as they can easily be used in fast-food preparations. On another hand, the consumption of beef and mutton from extensive systems has been stagnating. Extensive livestock systems, however, still use many fibrous feeds, from rangeland resources to cereal by-products. Traditionally, this has enabled them to ensure strategic functions such as the regional development of marginal areas, natural resource management, efficient water productivity through livestock products in a country experiencing acute water scarcity, and the creation of wealth and job opportunities. The shift of interest from these systems to more intensive ones raises many questions. It puts tremendous pressure on natural resources in areas of intensive production. In addition, the supply of animal products has become highly fragile as it depends on imported inputs, from animal genes to feeds (e.g. soya and maize for poultry). These changes mean that more attention should be given to extensive livestock production systems, as they promote a greener way of production and enhance large rural areas. These systems will hold a strategic position in the near future, when the time comes to face issues such as sustaina­bility of the animal protein supply and natural resource preservation, and to bal­ance the development of the various regions of the country.

Assessing the magnitude of impact of volcanic ash deposits on Merino wool production and fibre traits in the context of a drought in North-west Patagonia, Argentina

Environmental variability is a key feature of arid and semiarid rangelands worldwide. Drought is one of the main sources of variation in most extensive livestock production systems in arid environments, with biophysical and socioeconomic implications. The effect of non-climatic disturbance factors, such as volcanic eruption and ash deposits, has been less documented in arid environments. The aim was to assess the magnitude of impact of volcanic ash deposits on Merino wool production and quality that took place in the context of a drought, by making a comparison along a gradient of ash deposition before and after a volcanic eruption. It was found that volcanic ash deposits in the context of a regional drought significantly affected Merino wool production and fibre quality traits in farms from North-western Patagonia, Argentina. The magnitude of the impacts differed among wool traits. It is argued that further research is needed on the impact of ash deposits on wool weights and quality, and that measures of livestock production should be included in environmental monitoring systems at regional and farm levels.

An integrated approach to assessing the farm and market level impacts of new technology adoption in Australian lamb production and marketing systems: The case of large, lean lamb

New technology adoption is an important source of productivity gains in Australia's extensive livestock production systems because of the opportunities it offers producers to achieve sustainable cost reductions. Widespread technology adoption which leads to permanent production increases can be expected to have industry-wide effects because of the competitive nature of the Australian livestock industries. Assessing the potential economic benefits of new technology adoption therefore requires the use of a model which considers both the farm and market components of these industries. This paper describes the development of such a model and its ex-ante application in assessing the benefits of a new technology programme in Australian lamb production. Based on parameters derived from the model's farm and market level components, the introduction of this technology was found to offer significant annual benefits to both Australian lamb producers and lamb consumers (of between $4 and $30 million) according to several assumed market scenarios for the product.

The identification and evaluation of disease constraints for extensive livestock production systems

AbstractThe types of constraint caused by disease on extensive livestock production systems are described. Various approaches by which these constraints may be identified, quantified and evaluated are proposed and the advantages and disadvantages inherent in these different approaches are discussed.