Australian Rangeland Research Articles

Electrical stimulation and wet ageing effects on the carcass and meat quality of Australian rangeland goats

Medium voltage electrical stimulation and wet ageing periods effects on the carcasses and meat quality of Australian rangeland goats were investigated. 64 rangeland goats were slaughtered as 2 equal consignments, wherein half were exposed to post-dressing electrical stimulation (300 V, 500 ms pulse width, 45 s) and half were not (control). Carcass and pH decline parameters and glycogen concentration were recorded. At 24 h post-mortem, fresh colour was measured and longissimus lumborum muscles (LL) removed. Within carcass, paired LL were halved and allocated to each of 4 ageing periods (1, 2, 4, or 21 d). There were no significant effects from electric stimulation on LL pH at 18 °C, LL temperature at pH 6, LL pH at 24 h post-mortem, semitendinosus pH at 24 h post-mortem, and LL glycogen concentration. There were no significant interactions between stimulation and ageing period on cooking loss, particle size, purge loss, sarcomere length, shear force, and ultimate pH. Independent to stimulation, shear force, particle size, and cooking values declined as ageing period increased. Purge loss was highest after 21 d of ageing. Colour stability was unaffected by ageing, although all CIE colour coordinates varied across the 74 h total retail display period. There were negative linear relationships found between LL glycogen concentrations and LL temperature at pH 6, ultimate pH, and sarcomere length. These findings suggest there to be little benefit to post-dressing electrical stimulation of rangeland goat carcasses, when applied independent to or in combination with ageing.

A shared purpose: increasing environmental, community and industry resilience in the Australian rangelands through improved natural resource management

In October 2021, the Australian Rangeland Society jointly hosted its biennial conference with Desert Channels Queensland in Longreach, Queensland. This Special Issue of The Rangeland Journal showcases papers from the conference.

Top-predator removal does not cause trophic cascades in Australian rangeland ecosystems

Increased demand for livestock products is exacerbating conflict with predators in many parts of the world, fuelling an increase in predation management practices in many grazing systems. In Australia, exclusion fences are being erected across broad areas to facilitate the sustained eradication of dingoes, an apex predator, prompting concern for possible cascading effects on extant wildlife populations. We experimentally assessed population trends of mammals, reptiles and ground-dwelling birds inside and outside of two large, fenced areas over a five-year period subsequent to the erection of the fences and the removal of dingoes. Wildlife population abundances inside the fences were always higher or the same as outside the fences, and all wildlife species exhibited similar population trends within each treatment over time. The only exception to this was kangaroo populations, which fluctuated widely inside fenced areas but remained relatively low and stable outside fenced areas. Kangaroos exhibited negative relationships with dingoes, although unmeasured variables limited our ability to quantify specific causes for kangaroo population trends. Vegetation trends were virtually identical between treatments, indicating that wildlife population trends are closely linked to vegetation conditions and not predator abundances. These applied, experimental results demonstrate that top-predator removal does not routinely cause trophic cascades (including mesopredator releases) in Australian rangeland ecosystems. We therefore encourage exploration of opportunities for targeted threatened species recovery in predator-free areas on land used for livestock production.

Pastures and Climate Extremes: Impacts of Cool Season Warming and Drought on the Productivity of Key Pasture Species in a Field Experiment.

Shifts in the timing, intensity and/or frequency of climate extremes, such as severe drought and heatwaves, can generate sustained shifts in ecosystem function with important ecological and economic impacts for rangelands and managed pastures. The Pastures and Climate Extremes experiment (PACE) in Southeast Australia was designed to investigate the impacts of a severe winter/spring drought (60% rainfall reduction) and, for a subset of species, a factorial combination of drought and elevated temperature (ambient +3°C) on pasture productivity. The experiment included nine common pasture and Australian rangeland species from three plant functional groups (C3 grasses, C4 grasses and legumes) planted in monoculture. Winter/spring drought resulted in productivity declines of 45% on average and up to 74% for the most affected species (Digitaria eriantha) during the 6-month treatment period, with eight of the nine species exhibiting significant yield reductions. Despite considerable variation in species’ sensitivity to drought, C4 grasses were more strongly affected by this treatment than C3 grasses or legumes. Warming also had negative effects on cool-season productivity, associated at least partially with exceedance of optimum growth temperatures in spring and indirect effects on soil water content. The combination of winter/spring drought and year-round warming resulted in the greatest yield reductions. We identified responses that were either additive (Festuca), or less-than-additive (Medicago), where warming reduced the magnitude of drought effects. Results from this study highlight the sensitivity of diverse pasture species to increases in winter and spring drought severity similar to those predicted for this region, and that anticipated benefits of cool-season warming are unlikely to be realized. Overall, the substantial negative impacts on productivity suggest that future, warmer, drier climates will result in shortfalls in cool-season forage availability, with profound implications for the livestock industry and natural grazer communities.

Liveweight gain and metabolisable energy requirements of young entire male Australian Rangeland goats in response to supplementation

Context High international demand for goat meat and high prices for goat in Australia have resulted in a transition from opportunistic harvesting to more managed production systems for Rangeland goats. There is limited information available to establish feeding strategies to maximise growth rates of Rangeland goats within these developing managed production systems. Aims The aim of these experiments was to determine the response to supplements and the metabolisable energy requirements for maintenance and liveweight gain of young entire male Rangeland goats. Methods Dose–response relationships to various supplements were established in two experiments with young entire male Rangeland goats. In Experiment 1, 54 goats were allocated to rolled-wheat grain, rolled-sorghum grain, or lucerne pellet supplements offered from 0 (control) to 24 g dry matter/kg liveweight.day. In Experiment 2, 24 goats were allocated to a commercial starch-based pellet offered from 0 (control) to ad libitum. In both experiments, goats were held in individual pens and offered their daily supplement allowances with ad libitum access to Mitchell grass hay and drinking water for 70 days. Key results Total intake (30 to 32 g dry matter/kg liveweight.day) increased in a linear fashion with an increasing intake of all supplements. Maximum intake of rolled-wheat, rolled-sorghum, lucerne pellets and the commercial starch-based pellet supplements ranged from 18 to 22 g dry matter/kg liveweight.day. Unsupplemented goats lost liveweight (−20 to −32 g/day), while supplemented goats gained liveweight (0 to 126 g/day) in a linear fashion with an increasing supplement and metabolisable energy intake for all supplements, with the highest response in goats supplemented with the commercial starch-based pellets. Estimated metabolisable energy requirements to maintain liveweight (372 kJ/kg liveweight0.75.day) and for liveweight gain (35 kJ/g) of the goats were the same in both experiments. Conclusion Liveweight gain increased in a linear fashion with metabolisable energy intake, with the maximum rates of liveweight gain occurring when starch-based supplement intake was approximately 20 g dry matter/kg liveweight.day. Implications Supplementation with starch-based rations will increase liveweight gain and decrease age at turn-off of young entire male Rangeland goats; however, the local availability and cost of these supplements need to be considered.

Introduction to the special edition on overabundant macropods

Introduction to the special edition on overabundant macropods

Meat quality characteristics of lot-fed Australian Rangeland goats are unaffected by live weight at slaughter

The effects of live weight on carcass characteristics and meat quality of Australian Rangeland goats were determined. Fifty-two intact-male kid goats were fed Mitchell grass hay and finisher pellets ad libitum for 42 days. Prior to slaughter, kids were categorised into live weight groups: ‘Heavy’ (≈33.1 kg) or ‘Light’ ≈ 24.3 kg). Fifteen kids per group were randomly selected, slaughtered and carcass characteristics measured. The longissimus lumborum (LL) and the biceps femoris (BF) muscles were removed for quality measurements. The Heavy group had higher dressing, hindquarters, non-carcass component and offal percentages (P < 0.05). Live weight had no effect on proportion of carcass cuts, muscle meat colour, cooking loss, Warner-Bratzler shear force, total fat or ash (P > 0.05), but influenced the moisture and protein content in the LL and the moisture content in the BF (P < 0.05). The findings suggest that live weight of entire male Rangeland goats had no effect on meat quality characteristics.

Australian rangeland futures: time now for systemic responses to interconnected challenges

Australia’s rangelands contain wildlands, relatively intact biodiversity, widespread Indigenous cultures, and pastoral and mining industries, all set in past and present events and mythologies. The nature of risks and threats to these rangelands is increasingly global and systemic. Future policy frameworks must acknowledge this and act accordingly. This paper collates current key information on land tenures and land uses, people and domestic livestock in Australian rangelands, and discusses five perspectives on how the rangelands are changing, in order to inform the development of integrated policy – climate and environmental change; the southern rangelands; the northern rangelands; Indigenous Australia; and governance and management. From these perspectives, more attention must be paid to ensuring a social licence to operate across a range of uses, acknowledging and supporting a younger, more Indigenous population, implementing positive aspects of technological innovation, halting capital and governance leakages, and building human capacity. A recommended set of systemic responses should therefore (i) address governance issues consistently and comprehensively, (ii) ensure that new technologies can foster the delivery of sustainable livelihoods, and (iii) focus capacity-building on a community of industries where knowledge is built for the long-term. All three of these should be undertaken with an eye to the changing demographics of the rangelands.

Challenges, solutions and research priorities for sustainable rangelands

Australia’s rangeland communities, industries, and environment are under increasing pressures from anthropogenic activities and global changes more broadly. We conducted a horizon scan to identify and prioritise key challenges facing Australian rangelands and their communities, and outline possible avenues to address these challenges, with a particular focus on research priorities. We surveyed participants of the Australian Rangeland Society 20th Biennial Conference, held in Canberra in September 2019, before the conference and in interactive workshops during the conference, in order to identify key challenges, potential solutions, and research priorities. The feedback was broadly grouped into six themes associated with supporting local communities, managing natural capital, climate variability and change, traditional knowledge, governance, and research and development. Each theme had several sub-themes and potential solutions to ensure positive, long-term outcomes for the rangelands. The survey responses made it clear that supporting ‘resilient and sustainable rangelands that provide cultural, societal, environmental and economic outcomes simultaneously’ is of great value to stakeholders. The synthesis of survey responses combined with expert knowledge highlighted that sustaining local communities in the long term will require that the inherent social, cultural and natural capital of rangelands are managed sustainably, particularly in light of current and projected variability in climate. Establishment of guidelines and approaches to address these challenges will benefit from: (i) an increased recognition of the value and contributions of traditional knowledge and practices; (ii) development of better governance that is guided by and benefits local stakeholders; and (iii) more funding to conduct and implement strong research and development activities, with research focused on addressing critical knowledge gaps as identified by the local stakeholders. This requires strong governance with legislation and policies that work for the rangelands. We provide a framework that indicates the key knowledge gaps and how innovations may be implemented and scaled out, up and deep to achieve the resilience of Australia’s rangelands. The same principles could be adapted to address challenges in rangelands on other continents, with similar beneficial outcomes.

Building human capacity, capability and future leaders for Australia’s rangelands

Maintaining a skilled, knowledgeable and adaptable workforce in Australian rangeland enterprises and research, development and extension/adoption (RD&amp;amp;E/A) organisations is a varied and challenging task, compounded by trends of sustained losses of human capacity through senior retirements and short-term appointments over the last decade. Concerns for how to fill these gaps while gaining the skills and knowledge needed for a successful career and leadership roles were raised by students and young professionals in the World Cafe session and throughout Early Career workshops and activities at the 2019 Biennial Conference of the Australian Rangeland Society (ARS). This paper responds to these expressed information needs through drawing on literature, experiences shared by session participants, and existing ARS members currently working in the rangelands in diverse roles to provide insights into two main areas: (i) skills and knowledge for personal development and future success in the rangelands across three broad classes of occupation/careers (i.e. advisors, researchers, and producers), and (ii) skills and knowledge that will be expected of future leaders in the rangelands. We outline a variety of options for professional development in the early stage(s) of a career working on aspects of sustainable production systems and pathways to leadership throughout a career in the rangelands. We note the apparent lack of formal rangeland-specific education in Australia, and suggest that this is a major impediment to efforts to build skills and knowledge to ensure the viability of the livelihoods and the integrity of our rangelands. Finally, we believe that the ARS has the potential to play a more central role in inspiring interest and passion for the rangelands, in providing current information on (i) range science and management-relevant education and training opportunities in Australia and internationally, and (ii) leadership development and training opportunities; and in facilitating and supporting mentoring to develop and retain human capacity for a resilient future.

Climate change and variability impacts on grazing herds: Insights from a system dynamics approach for semi-arid Australian rangelands.

Grazing livestock are an important source of food and income for millions of people worldwide. Changes in mean climate and increasing climate variability are affecting grasslands' carrying capacity, thus threatening the livelihood of millions of people as well as the health of grassland ecosystems. Compared with cropping systems, relatively little is known about the impact of such climatic changes on grasslands and livestock productivity and the adaptation responses available to farmers. In this study, we analysed the relationship between changes in mean precipitation, precipitation variability, farming practices and grazing cattle using a system dynamics approach for a semi‐arid Australian rangeland system. We found that forage production and animal stocking rates were significantly affected by drought intensities and durations as well as by long‐term climate trends. After a drought event, herd size recovery times ranged from years to decades in the absence of proactive restocking through animal purchases. Decreases in the annual precipitation means or increases in the interannual (year‐to‐year) and intra‐annual (month‐to‐month) precipitation variability, all reduced herd sizes. The contribution of farming practices versus climate effect on herd dynamics varied depending on the herd characteristics considered. Climate contributed the most to the variance in stocking rates, followed by forage productivity levels and feeding supplementation practices (with or without urea and molasses). While intensification strategies and favourable climates increased long‐term herd sizes, they also resulted in larger reductions in animal numbers during droughts and raised total enteric methane emissions. In the face of future climate trends, the grazing sector will need to increase its adaptability. Understanding which farming strategies can be beneficial, where, and when, as well as the enabling mechanisms required to implement them, will be critical for effectively improving rangelands and the livelihoods of pastoralists worldwide.

Ultra-high spatial resolution fractional vegetation cover from unmanned aerial multispectral imagery

Vegetation cover is a key environmental variable often mapped from satellite and aerial imagery. The derivation of ultra-high spatial resolution fractional vegetation cover (FVC) based on multispectral imagery acquired from an Unmanned Aerial System (UAS) has several applications, including the potential to revolutionise the collection of field data for calibration/validation of satellite products. In this study, abundance maps were derived using three methods, applied to data collected in a typical Australian rangeland environment. The first method used downscaling between Landsat FVC maps and UAS images with Random Forest regression to predict bare ground, photosynthetic vegetation and non-photosynthetic vegetation cover. The second method used spectral unmixing based on endmembers identified in the multispectral imagery. The third method used an object-based classification approach to label image segments. The accuracy of all UAS FVC and Landsat FVC products were assessed using 20 field plots (100 m diameter star transects), as well as from 138 ground photo plots. The classification method performed best for all cover fractions at the 100 m plot scale (12–13% RMSE), with the downscaling approach only able to accurately predict photosynthetic cover. The downscaling and unmixing generally over-predicted non-photosynthetic vegetation associated with Chenopod shrubs. When compared with the high-resolution photo plot data, the classification method performed the worst, while the downscaling and unmixing methods achieved reasonable accuracy for the photosynthetic component only (12–13% RMSE). Multispectral UAS imagery has great potential for mapping photosynthetic vegetation cover in rangelands at ultra-high resolution, though accurately separating non-photosynthetic vegetation and bare ground was only possible when the data was scaled-up to coarser resolutions.

Australian rangeland futures: time now for systemic responses to interconnected challenges

Australia’s rangelands contain wildlands, relatively intact biodiversity, widespread Indigenous cultures, pastoral and mining industries all set in past and present events and mythologies. The nature of risks and threats to these rangelands is increasingly global and systemic. Future policy frameworks must acknowledge this and act accordingly. We collate current key information on land tenures and land uses, people and domestic livestock in Australian rangelands, and discuss five perspectives on how the rangelands are changing that should inform the development of integrated policy: climate and environmental change, the southern rangelands, the northern rangelands, Indigenous Australia, and governance and management. From these perspectives we argue that more attention must be paid to: ensuring a social licence to operate across a range of uses, acknowledging and supporting a younger, more Indigenous population, implementing positive aspects of technological innovation, halting capital and governance leakages, and building human capacity. A recommended set of systemic responses should therefore (i) address governance issues consistently and comprehensively, (ii) ensure that new technologies can foster the delivery of sustainable livelihoods, and (iii) focus capacity building on a community of industries where knowledge is built for the long-term, and do all three of these with an eye to the changing demographics of the rangelands.

Salmonella enterica isolates from Western Australian rangeland goats remain susceptible to critically important antimicrobials

This study investigated faecal carriage and antimicrobial resistance (AMR) of Salmonella enterica recovered from rangeland goats. Faecal samples (n = 400) were collected at slaughter from four consignments of goats (n = 100 samples per consignment), each from one of four localities in Western Australia. Carriage of Salmonella spp. was detected in 106 samples (26.5%; 95% CI 22.4–31.0%). The rate of faecal carriage for each consignment ranged between 23–30%. PCR assays targeting the STM2755 and STM4497 genes revealed 84.9% (90/106) of the isolates were of serovar Typhimurium. Salmonella Chester (11/106, 10.4%) and S. Saintpaul (5/106, 4.7%) were characterised at invA and ompF genes. Antimicrobial susceptibility testing demonstrated that 84.0% of isolates were susceptible to all tested (n = 13) antimicrobials. Resistance was identified to azithromycin (14.2%), tetracycline (10.4%), ampicillin (5.7%), amoxicillin–clavulanate and cefoxitin (3.8%), trimethoprim/sulfamethoxazole (1.9%), gentamicin and streptomycin (0.9%). No isolate was resistant to four or more antimicrobials, or to critically important antimicrobials such as fluoroquinolones and extended spectrum cephalosporins. This is the first study reporting AMR in Salmonella isolates from Australian rangeland goats. The rate of detection of AMR was very low, some resistance to low-importance drugs was present in the Salmonella population, despite the absence of active selection pressure.

Floristic and structural assessment of Australian rangeland vegetation with standardized plot-based surveys.

We describe and correlate environmental, floristic and structural vegetation traits of a large portion of Australian rangelands. We analysed 351 one hectare vegetation plots surveyed by Australia’s Terrestrial Ecosystem Research Network (TERN) using the AusPlots Rangelands standardized method. The AusPlots Rangelands method involves surveying 1010 one meter-spaced point-intercepts (IPs) per plot. At each IP, species were scored, categorised by growth-form, converted to percentage cover as the input for the plot x species matrix. Vegetation structure is depicted by growth-form configuration and relative importance. The floristic and structural distance matrices were correlated with the Mantel test. Canonical correspondence analysis (CCA) related floristic composition to environmental variables sourced from WorldClim, the Atlas of Living Australia and TERN’s Soil and Landscape Grid. Differences between clusters were tested with ANOVA while principal component analysis (PCA) ordered the plots within the environmental space. Our plot x species matrix required segmentation due to sparsity and high β-diversity. Based on the ordination of plots latitude within environmental space, the matrix was segmented into three “superclusters”: the winter rain and temperate Mediterranean, the monsoonal rain savannas and the arid deserts. Further classification, with the UPGMA linkage method, generated two, four and five clusters, respectively. All groupings are described by species richness, diversity indices and growth form conformation. Several floristic disjunctions were apparent and their possible causes are discussed. For all superclusters, the correspondence between the floristic and the structural or growth form matrices was statistically significant. CCA ordination clearly demarcated all groupings. Aridity, rainfall, temperature, seasonality, soil nitrogen and pH are significant correlates to the ordination of superclusters and clusters. At present, our results are influenced by incomplete sampling. As more sites are surveyed, this pioneer analysis will be updated and refined providing tools for the effective management of Australian rangelands.

Molecular characterisation of Salmonella enterica serovar Typhimurium and Campylobacter jejuni faecal carriage by captured rangeland goats

Western Australian rangeland goats were surveyed for faecal carriage of Salmonella enterica and Campylobacter spp. Faecal samples were collected from 125 goats on four occasions. The first sample was collected immediately upon arrival at a commercial goat depot (feedlot). Subsequent samples were collected at one month intervals thereafter. Frequency of detection and faecal carriage intensity were determined using qPCR targeting the S. enterica outer membrane protein (ompF) and Campylobacter spp. purine biosynthesis gene (purA). Salmonella enterica were identified in 40/500 of faecal samples, with S. enterica faecal carriage detected in 30% (38/125) goats over the duration of the study. Campylobacter spp. were identified in 12/500 of samples, with Campylobacter spp. detected in 10% (12/125) goats over duration of the study. Frequency of detection was highest at the first sample collection for both S. enterica (26%) and Campylobacter spp. (8%). Repeat detection of Salmonella was observed for only a single goat (0.8%). Salmonella qPCR positive samples were characterised at ompF and invA genes as S. enterica. Further characterisation at STM2755 and STM4497 genes confirmed the isolates were S. enterica serovar Typhimurium. Characterization at the 16S rRNA and hippuricase (hipO) genes revealed all Campylobacter spp. positive samples were C. jejuni. This study demonstrates that qPCR can be used for rapid identification of faecal carriage in goat faecal samples and showed evidence of carriage of zoonotic S. Typhimurium and C. jejuni by captured rangeland goats. The findings have implications for management of goats at abattoirs and in confined feeding facilities.

Chemical immobilisation and rangeland species: assessment of a helicopter darting method for Australian cattle

Chemical immobilisation (darting) is increasingly being used for the capture of rangeland animals. The aim of the present study was to assess a newly developed helicopter-based chemical immobilisation method for free-ranging Australian rangeland cattle (Bos taurus and Bos indicus). Eighteen cattle were darted from a helicopter in north-western Australia in September 2015 using a combination of xylazine and ketamine, partially reversed with yohimbine. Following a recently published framework for assessing helicopter darting methods, we quantified several animal welfare measures designed to quantify the severity and duration of stress imposed by the procedures. The duration of the procedures was generally short (median total duration 41 min), but for 33% of animals total duration exceeded 60 min. Although the sample size was small, mortality rate on the day of capture was 17% (three animals) and 28% (five animals) required physical restraint to achieve recumbency. We describe this newly developed method and discuss its relatively poor animal welfare outcomes compared with other validated helicopter darting methods. Legislation restricts veterinary chemicals that may be used for food-producing species in many countries, including Australia. Chemical immobilisation regimens other than the one chosen in the present study may produce superior animal welfare outcomes but would not be compliant with legislation in Australia. As a result of these restrictions, we suggest that development of an improved helicopter darting method for Australian cattle may prove difficult. Rangeland managers should carefully consider animal welfare impacts before undertaking chemical immobilisation programs, especially for food-producing species.

Innovation in Australian rangelands. A special issue from the 18th Biennial Conference of the Australian Rangeland Society

This special issue highlights organisational innovations and new insights about challenges of living successfully in Australian rangelands through a diverse set of papers from the 18th Biennial Conference of the Australian Rangeland Society. Key themes in the papers are collaborations for innovation and adapting to change. The papers indicate a shift to increased interdisciplinary and transdisciplinary research and greater diversity in the perspectives being voiced about rangeland futures.

Rangeland pastoralism in northern Australia: change and sustainability

Australian rangeland pastoralism is now a marginal economic activity. To survive as an industry, it must retain critical mass and to do that, the majority of producers need to be financially sustainable. Significant change has taken place in the past 40 years to facilitate this, but this change appears to have had limited enduring value for much of the industry. The productivity of the average northern rangeland beef herd in absolute terms is poor and is far from being competitive now, let alone in the future. If preservation of the natural resource base is included as a sustainability criterion, the industry outlook becomes even more uncertain. The conundrum is that it has never been more opportune to succeed in rangeland pastoralism, but the evidence is that most producers do not. The conclusion is that the lack of financial literacy and business skill remains the biggest impediment to most pastoralists achieving financial sustainability.

Energy, water and space use by free-living red kangaroos Macropus rufus and domestic sheep Ovis aries in an Australian rangeland

We used doubly labelled water to measure field metabolic rates (FMR) and water turnover rates (WTR) in one of Australia's largest native herbivores, the red kangaroo (Macropus rufus) and one of Australia's dominant livestock species, the wool-breed Merino sheep, under free-living conditions in a typical Australian rangeland. Also, we used GPS technology to examine animal space use, along with the comparisons of urine concentration, diet, diet digestibility, and subsequent grazing pressures. We found smaller space-use patterns than previously reported for kangaroos, which were between 14 and 25% those of sheep. The FMR of a 25-kg kangaroo was 30% that of a 45-kg sheep, while WTR was 15% and both were associated with smaller travel distances, lower salt intakes, and higher urine concentration in kangaroos than sheep. After accounting for differences in dry matter digestibility of food eaten by kangaroos (51%) and sheep (58%), the relative grazing pressure of a standard (mature, non-reproductive) 25-kg kangaroo was 35% that of a 45-kg sheep. Even for animals of the same body mass (35kg), the relative grazing pressure of the kangaroo was estimated to be only 44% that of the sheep. After accounting for the energetic costs of wool growth by sheep, the FMRs of our sheep and kangaroos were 2-3 times their expected BMRs, which is typical for mammalian FMR:BMRs generally. Notably, data collected from our free-living animals were practically identical to those from animals confined to a semi-natural enclosure (collected in an earlier study under comparable environmental conditions), supporting the idea that FMRs are relatively constrained within species.