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Context. Feeding behaviour is an important tool for the early detection of diseases in dairy cows. Aims. The aim of this study was to evaluate whether the variation in time spent feeding in the prepartum and postpartum periods may be used to detect the occurrence of metritis and subclinical ketosis (SCK) before the onset of the clinical symptoms at the postpartum. Methods. The research was conducted in four electronic databases, including Scopus, Science Direct, Pubmed, and Web of Science. The inclusion criteria for citations were original research, evaluation of daily time spent feeding in dairy cows, and use of this indicator for early identification of metritis and/or SCK in dairy cows in the prepartum and postpartum periods. A random-effect meta-analysis (MA) was conducted for metritis with the time spent feeding means of control (healthy) and treated (sick) groups measured in the prepartum and postpartum periods. The analysis was conducted with the values of daily time spent feeding before and after calving in both groups. Key results. In total, 26 trials from six papers, involving 1037 dairy cows, were included in the statistical analysis. No data were obtained for SCK to conduct a MA, while for metritis, 16 trials from six papers (prepartum) and 10 trials from three papers (postpartum) were considered. The heterogeneity between studies on metritis was moderate (I² = 57.5%) in the prepartum period and low (I² = 10.0%) in the postpartum period. The mean difference feeding time for healthy and unhealthy animals was greater during postpartum (21.14 min/day, P < 0.001) than during prepartum (16.36 min/day, P < 0.001). Meta-regression analysis showed that number of daily milkings, sample size, and the place of running trial significantly influenced the time spent feeding by cows. Conclusion. On the basis of available and suitable scientific literature, time spent feeding is reduced at the prepartum and postpartum periods in dairy cows further affected by metritis. Implications. This study evidenced that feeding time might be incorporated into health-monitoring protocols for early detection of metritis in dairy cows. [ABSTRACT FROM AUTHOR]

Context. The aim of farm-systems research is to test concepts in a holistic context that enables results to be as applicable as possible to commercial farmers. A downside of such research has been that it can take several seasons to be confident in the consistency of the outcomes and interpretation of the results. Scientists are often reluctant to communicate outcomes until they have clear conclusions, which conflicts with farmers' desire to see rapid answers and engage with research. Aims. This paper reviews a 3-year farm-systems research project investigating flexible milking strategies for New Zealand dairy farmers. The aims of this paper are to (1) examine the impact of real-time science communication in achieving farm system change, and (2) develop a framework for science communication and engagement in adaptive farm-systems research. Methods. The project involved farmer interviews, a farmlet experiment, a component experiment, partner farms, modelling, and a farmer reference group. We use data from sources such as e-newsletter engagement, webinar participation, web-page engagement, presentation attendance, and farmer feedback to collect insights on the impact of the project. Key results. The analysis highlighted that farmers do not always seek complete information and will follow a project as it evolves, particularly when it is highly topical. We propose a framework for delivering adaptive farm systems research and communication. The framework includes the critical aspects for real-time farm-systems research: credible evidence, rapid results, inclusion of farmer voices, meaningful outcomes, flexible communication channels, iterative feedback loops, and adaptable research design. Conclusion. Farm-systems research can be designed to communicate results to farmers as a project develops, while simultaneously using the engagement with farmers to refine the direction of the research. Implications. This framework can guide scientists leading multi-year farm systems projects to design, implement, and communicate the project outcomes to improve farmer engagement and adoption. [ABSTRACT FROM AUTHOR]

This document is a special edition of Animal Production Science that features a selection of papers presented at the 2022 Australasian Dairy Science Symposium (ADSS). The symposium, held in Queensland, focused on pastoral dairy systems and addressed challenges such as climate change, competition from plant-based alternatives, and resource efficiency. The special issue covers various topics including dairy cattle welfare, heat stress on dairy production, grazing dairy cows, artificial breeding strategies, and greenhouse gas emissions from dairy systems. The ADSS expresses gratitude to the authors, reviewers, and sponsors for their contributions and support. [Extracted from the article]

Deer antlers are unique because they are cast and regenerate each year. They are the fastest-growing structure, reaching an astonishing growth rate of up to 2.75 cm/day in length and more than 20 cm2/day of skin. Surprisingly, no study so far has assessed the metabolic rate of the antler. High metabolic rate needs highly efficient (or large) mitochondria, and it involves a high creation or reactive oxygen species (ROS), origin of oxidative stress. The speed of creation of ROS and the oxidative stress are inversely related to ageing and many diseases such as cancer or age-related diseases. However, antler must have the most efficient anti-oxidant system, as it rarely shows any departure from a perfect growth. This paper examines recent studies showing surprising applications in medicine of growing-antler extracts, or the information regarding its physiology. A recent study (Wang et al. (2019) , Science 364, eaav6335) has shown that antlers have evolved a speed of growth faster than cancer, based on high expression of proto-oncogenes. As a result, deer has evolved tumour-suppression genes to control the high risk of developing cancer. This may explain why several studies have found in vitro and in vivo anti-cancer effects of deer velvet-antler extract in human tumours, such as cell cultures and animal models of cancers such as brain cancer (glioblastoma), prostate cancer, and others. We will also discuss findings in the study of the cyclic osteoporosis of the deer, with unexpected similarities in their proteomics and gene expression with that of the human pathological osteoporosis. Last, we will examine potential applications based on having the highest metabolic rate. If the future studies establish the antler as the tissue having the fastest metabolism and the best antioxidant system, this may have implications for understanding how to fight oxidative stress, which, in turn, will have direct implications for aging and age-related diseases (and others, from cancer to osteoporosis and Alzheimer's for example). It may also show that velvet-antler extract is a general anti-cancer compound, and this may show the path to find an anti-cancer medicine that has no secondary toxic effects in healthy cells. Antler is the only mammal structure regenerating each year, and it is the fastest-growing tissue (much faster-growing than cancer). For this reason, several interesting medical applications are reviewed in this paper, such as anti-cancer activity of growing-antler extract. Studying growing antler may help develop powerful and general anti-cancer treatments without secondary effects, and the high metabolic rate and antioxidant system of the antler may also have other potential medical applications, such as delaying aging- or fight-associated diseases. [ABSTRACT FROM AUTHOR]

The pet-food industry is a significant and rapidly growing market, with global sales estimated at over US$100 billion in 2020. The market size for pet food was estimated at 22.9 million tonnes in 2020. The number of cats and dogs being fed commercial pet food is also on the rise, with an estimated 62% of cats and 68% of dogs being fed commercial pet food in the United States alone with an estimated value of A$2.3 billion in 2020. This represents a growth of 3.3% from the previous year, and the market is expected to continue growing with a forecast compound annual growth rate (CAGR) of 3.4% from 2021 to 2025. The demand for high-quality, specialised pet-food products has led to consistent year-on-year growth in the industry. With this, the increasing demand for commercial pet food on a global scale comes with growing sustainability challenges that must be addressed. In this paper, we will examine some of the opportunities for the use of black soldier fly larvae (BSFL) meal and oil in pet-food formulations to reduce the environmental impact of pet food and pet ownership and deliver nutritional and functional benefits to our pets. The growing populations of urbanised pets have had a significant impact on the environment. In this paper, we will examine the opportunities for the use of black soldier fly larvae (BSFL) meal and oil in petfood formulations to reduce the environmental impact of pet food and pet ownership. [ABSTRACT FROM AUTHOR]

Debate surrounding the adverse consequences of feeding human-edible feedstuffs to livestock can be addressed through calculation of the net protein contribution (NPC) of the production system. If the NPC is greater than 1.0 for the production system, then there are net benefits from the system for human populations with an ever-increasing requirement for protein and amino acids. The aim of this paper was to calculate the NPC for an Australian pork supply chain on the basis of the unique characteristics of Australian ingredients. While calculation of NPC is not complex, intimate knowledge of the source of the nutrients and their quality, and interpretation of their human-edible protein fractions is essential if an accurate estimate is to be achieved. The NPC for an Australian pork supply chain was calculated using (a) actual, published or estimated values for human-edible fractions of feedstuffs, (b) the percentage of protein available within raw materials considered to be human edible, (c) recommended amino acid scoring patterns for infants, adolescents and adults, (d) published, and calculated from standard reference nutrient databases, digestible indispensable amino acid scores, (e) carcase yields and carcase composition from published studies, and (f) actual feed formulations, feed volumes and production data from a large Australian pork supply chain. The NPC for the assessed Australian pork supply chain was 3.26. This means the supply chain generates more than three times the human-edible protein it consumes in the process. This NPC is higher than previously published values, largely because of the composition of Australian pig diets, but demonstrates the positive value that livestock production systems make to human food supply. Livestock systems are often targeted as net consumers of vital nutrients such as protein and amino acids and the diversion of these nutrients from human diets. If production systems focus on the utilisation of waste streams, co-products and human-inedible feedstuffs, then they can make a net contribution to human-edible protein supply. Debate surrounding the adverse consequences of feeding human-edible feedstuffs to livestock can be addressed through calculation of the net protein contribution (NPC) of the production system. This paper calculates the NPC from an Australian pork supply chain to be 3.26. This number is higher than previously published values, largely because of the composition of Australian pig diets, but demonstrates the positive value that livestock production systems make to human food supply. [ABSTRACT FROM AUTHOR]

The measurement and prediction of pasture intake in extensive grazing systems, typical of northern Australia, remain elusive after 50 years of research. The aim of this paper is to review research conducted over the past 50 years, highlight advances in understanding, discuss remaining challenges and consider future developments with digital technologies. While the fundamental components of voluntary intake are well understood, their measurement is difficult, particularly in extensive grazing systems, which has limited the development of predictive models that adequately address the interplay of factors influencing intake from the bite to the landscape scale. Ongoing research by the authors is used as an example to highlight the potential application of digital technologies to overcome limitations in measurement and prediction. Digital technologies offer the opportunity for monitoring factors that control voluntary pasture intake at scale and under commercial conditions. However, our ability to ground-truth novel indices of intake remains limited without ongoing development of physical methods. This will limit the accuracy and precision of predictive models incorporating digital technologies that can be applied to the extensive grazing conditions of northern Australia. The advent of precision livestock management for extensive cattle production is essential if the industry is to remain viable in the future where production is transparent, ethically sound and environmentally defensible as well as profitable. Feed intake is fundamental to animal performance and efficiency. Yet, for the cattle industry of northern Australia, our understanding of pasture intake is limited. While much is known about the components of feed intake, it remains difficult to integrate this knowledge into a dynamic and responsive estimation of voluntary intake under typical grazing conditions. This paper reviews the state of understanding, highlights gaps in knowledge and discusses the potential impact of digital technologies that will offer new solutions to old challenges. [ABSTRACT FROM AUTHOR]

Context: Managing people outside the farm family unit is a new issue for many Irish dairy farmers. In the context of rapid growth, the demand for employees has increased, creating the need for Irish dairy farmers to have human resource management (HRM) skills. Aims: This paper explores the extent and type of HRM practices adopted by Irish dairy farmers and the factors that influence their adoption. Methods: A questionnaire was developed, piloted, and issued to farmers on the basis of herd size and location. Data from 203 dairy farmers who employ people were analysed to examine the adoption of different HRM practices and the influence of farm characteristics, farmer demographics and farmer attitudes on their adoption. HRM practices included compliance with employment legislation, health and safety, different approaches to recruitment, workforce management and retention. The questionnaire included one or more variables for each of these HRM practices. Where more than one variable was included, an aggregate variable was developed for that practice. Key results: Whereas, overall, there was a low level of adoption of best HRM practices, farm characteristics such as herd size and number of employees had a significant influence on farmers' adoption of compliance with employment legislation, health and safety, recruitment, workforce management and retention practices. Demographic factors such as age, level of education, and average hours worked influenced farmers compliance with employment law legislation, workforce management practices and retention practices. Conclusions: The study highlighted an overall low compliance with employment legislation and low adoption of best practices in managing staff among dairy farmers in Ireland. Implications: This study highlighted that improvement is needed in all areas of HRM on Irish dairy farms. The findings of this study would be useful to farm advisors who support dairy farmers in improving their management of their businesses. Overall, this study has contributed to a greater understanding of the challenges in managing people in agriculture and how certain factors influences the adoption of HRM practices on dairy farms. The dairy industry's recent growth in Ireland has resulted in a high demand for additional workers, increasing the requirement for farmers to be skilled in Human Resource Management (HRM). This study identified that the adoption of HRM practices is influenced by farm characteristics, in particular herd size, the number of employees on the farm. This study has contributed insights into the prevalence of specific HRM practices on Irish dairy farms, and indicated that there is a significant scope for improvement. A novel aspect of this study was the focus on the potential factors that influence the adoption of HRM practices on Irish dairy farms. The findings of this study could be used by agricultural advisors and those working in HRM to provide tailored advice to support dairy farmers and other small business owners in managing their employees. [ABSTRACT FROM AUTHOR]

Context: Australia is renowned for its climate variation, featuring years with drought and years with floods, which result in significant production and profit variability. Accordingly, to maximise profitability, dryland farming systems need to be dynamically managed in response to unfolding weather conditions. Aims: The aim of this study is to identify and quantify optimal tactical livestock management for different weather-years. Methods: This study employed a whole-farm optimisation model to analyse a representative mixed enterprise farm located in the Great Southern region of Western Australia. Using this model, we investigated the economic significance of five key livestock management tactics. These included timing of sheep sales, pasture-area adjustments, rotational grazing, crop grazing and sheep nutrition adjustments. Key results: The results showed that, on the modelled dryland mixed-enterprise farm in the Great Southern region of Western Australia, short-term adjustments to the overall farm strategy in response to unfolding weather conditions increased expected profit by approximately 16%. Each tactic boosted profit by between A$7704 and A$53,171. However, we outline several complexities that farmers must consider when implementing tactics. Conclusions: The financial gains from short-term tactical management highlighted their importance and farmers' need to develop and apply those skills. The tactical skills promote business resilience and adaptability in the face of climate uncertainties. Implications: The study highlighted the economic value of dynamic livestock management in response to climate variations, offering farmers in the Great Southern region the means to underpin profitable and sustainable farm practices. Under Australia's renowned climate variation, it is profitable for farmer to implement short-term tactical management adjustments in response to the unfolding weather conditions. This paper has identified and quantified optimal tactical livestock management for different weather-years for a mixed-farming system in the Great Southern region of Western Australia. [ABSTRACT FROM AUTHOR]

Sciences related to animal agriculture are threatened by agenda-driven scientists. It can be shown that too many peer-reviewed articles have dubious quality, including high-profile ones. Better training and higher review standards for rigour, reproducibility and transparency should help alleviate the problem. However, they will not solve the challenge posed by 'cargo cult scientists', as characterised by Richard Feynman. Such agenda-driven scientists pursue an a priori mission, whose achievement justifies any means, even if it includes to willfully manipulate and interpretate data, or to violate good practices of integrity in the sciences. This review explores in three prominent case studies in animal-sourced food related sciences where the dividing line might be between science being poorly practiced (which can be remedied), and scientific channels being abused for agendas (which should not be tolerated). So as to guard both as the individual scientist and as the discipline against the intrusion of such agenda-driven science, this article suggests adopting the Popperian stance to generally refrain from the concept of seeking or establishing a 'scientific truth', and instead to restrict oneself to presenting the 'scientific evidence', both in terms of what the evidence shows, and what it does not. Three case studies of high-profile scientific endeavours in animal-related sciences are examined on where there is a dividing line between science being poorly practiced (which can be remedied) or science lacking integrity, as characterised by Richard Feynman's as cargo cult scientists (which should not be tolerated). The cases are the WHO IARC 2015 cancer evaluation on red and processed meats, the Global Burden of Disease 2019 and the United Nations Food Systems Summit 2021 cases. [ABSTRACT FROM AUTHOR]

This paper reviews breeding objectives of the current global cattle industry and outlines existing challenges and opportunities for improving sustainability in the livestock sector through genetic selection. Cattle breeding programs have historically been focused on generating profit by selecting for high-producing animals and broadened to include traits related to health, reproduction, fertility, and efficiency. Now, cattle industries around the world are using genetics to reduce their environmental impacts and improve sustainability. Reducing emissions is vital to improve sustainability, and industry leaders have set emission goals to either reduce gross emissions, lower emissions intensity, or reach net-zero. However, additional traits should also be measured and compared in terms of their impact on the broader definition of sustainability. In addition to environmental impact, a sustainable breeding objective must consider profit, animal welfare, farmer wellbeing, and social responsibility. Traits to be considered include direct emissions (e.g. nitrogen and methane), production efficiency (e.g. feed efficiency, growth), closer to biology reproduction and fertility (e.g. oestrous strength and semen quality), health (e.g. calf and transition cow health) and welfare traits (e.g. polled). Many of these novel traits require labour-intensive or expensive phenotyping, resulting in small datasets and low reliability of estimated breeding values. Opportunities exist to overcome this limitation by utilising international collaboration to build large data bases, develop inexpensive and easy-to-measure proxy traits, and expand novel-phenotype reference populations by using female-driven reference populations and young stock and males. Non-economic values can be estimated that quantify the impact that a trait has on societal perspective (e.g. farmer preference) or the environmental impact (methane emissions), and combined with economic weights to calculate aggregate weights for each trait. While validation techniques are still uncertain, the United Nations Sustainable Development Goals may be applied to determine the improvement in sustainability due to genetic selection. This approach allows for various perspectives of sustainability, such as in the developed versus developing world, to be considered. The number and quality of relevant phenotypes are currently the main limiting factors. As confidence continues to grow in the opportunity to improve sustainability through genetic selection, substantial new investment will be required both in phenotyping activities, but also into novel breeding structures and scheme designs that can maximise the value and impact of these phenotypes. This paper reviews breeding objectives of the current cattle industry and outlines existing challenges and opportunities for improving sustainability in the livestock sector through genetic selection. As confidence continues to grow in the opportunity to improve sustainability through genetic selection, substantial new investment will be required both in phenotyping activities, but also into novel breeding structures and scheme designs that can maximise the value and impact of these phenotypes. [ABSTRACT FROM AUTHOR]

The symposium 'Recent Advances in Animal Nutrition – Australia' (RA) was instigated at the University of New England (UNE) in the early 1970s. In the 1950s and 1960s, under the visionary leadership of Professor G. L. (Bill) McClymont, a talented group of young biochemists and nutritionists was recruited to become the Department of Biochemistry and Nutrition at UNE and quickly developed a strong reputation for nutritional research on ruminant and monogastric animals. Its members were keen to share their findings with relevant industry representatives and to learn about the major industry challenges. The idea for RA emerged ~1970 when Drs Robin Cumming and David Farrell saw the opportunity for regular RA schools, bringing invited experts from Australia or overseas to interact with UNE staff, post-graduate students and representatives of the monogastric and ruminant livestock industries. The first RA school was probably held in 1974. Aided by flexible working arrangements at UNE, David Farrell was able to champion further RA meetings that were held successfully about every 2 years. However, ~1990, the federal Education Minister John Dawkins began a process of amalgamating Australian higher-education institutions that produced detrimental administrative and financial ramifications for UNE and drained staff morale. After the 1993 meeting, Professor David Farrell left UNE, followed soon afterwards by Professor Ron Leng. The future of RA was at a crossroads; its funding and organisation needed overhauling to enable it to survive. A second, more formal phase of RA meetings (13 in all; 1995–2021), was instigated within a newly formed Department of Animal Science at UNE. The meetings became more formalised and even more financially dependent on industry support and sponsorship; meetings were planned by larger organising committees. Soon, papers were being formally refereed and the scope for provocative speculation of the type promoted at earlier meetings was somewhat curtailed in favour of scientific rigour. Organisers experimented with changed meeting dates, formats and venues at UNE, cumulating with a contentious decision to hold this meeting away from UNE. Despite its challenges, RA has grown in stature over 47 years from the small, informal schools of the early 1970s, to become Australia's leading animal nutrition symposium. 'Recent Advances in Animal Nutrition – Australia' has grown in stature over half a century to become Australia's leading nutrition symposium. This history describes how the first 'nutrition school' was conceived at the University of New England, Armidale (UNE), in the early 1970s, and covers the 25 biennial meetings held at UNE; it pays homage to the many organisers, invited speakers and attendees who have focussed on finding innovative solutions to industry-relevant problems, thereby ensuring the symposium's long-term success. [ABSTRACT FROM AUTHOR]

This perspective paper provides industry leaders, researchers and policy developers strategic approaches to ensure that the welfare of dairy cattle is protected at the same time as the industry increases its resilience to climate change. Farm systems and practices will evolve in response to the direct impacts of climate change and/or from responses to climate change, such as mitigation strategies to reduce dairy's greenhouse-gas (GHG) emissions. The five domains framework (nutrition, physical environment, health, behaviour, mental state) was used to assess the potential impacts on animal welfare and strategies to minimise these impacts are outlined. Given that the future climate cannot be certain these approaches can be applied under a range of emissions pathways to (1) ensure that the effects of GHG mitigations on animal welfare are considered during their development, (2) engage with end users and the public to ensure solutions to the effects of climate change and weather variability are accepted by consumers and communities, (3) identify and measure the areas where improved animal health can contribute to reducing GHG emissions from dairy production, (4) ensure those supporting farmers to develop and manage their farm systems understand what constitutes a good quality of life for dairy cattle, (5) ensure effective surveillance of animal disease and monitoring of welfare outcomes and farm-system performance in response to climate change and GHG mitigations. Overall, these strategies require a multidisciplinary co-development approach to ensure that the welfare of dairy cattle is protected at the same time as the industry increases its resilience to the wider impacts of a changing climate. [ABSTRACT FROM AUTHOR]

This paper presents results from a review of methods of agricultural extension, including the evidence for the effectiveness of methods in supporting farm practice change, how they affect the change process, and the critical success factors involved. Agricultural scientists face challenges in aligning their research outputs to the change process on farm. These challenges are exacerbated by the funding environment for research, development, and extension (RD&E), the complexity of the adoption process and the privatisation and commercialisation of advisory and extension services. To assist scientists in navigating these challenges, a structured literature review of extension methods was conducted, examining the following: group-learning/peer-topeer; technology development; training; information provision; one-on-one advice/coaching; e-extension; co-innovation; best management practice; and social marketing. In addition, two case studies outlining the application of combinations of extension methods in the context of feeding system challenges in the Australian dairy industry, and their effects, are described. While the evidence across the studies reviewed was strongest for the effect on adoption of small group-learning and one to one consulting, it was combinations of methods that resulted in larger effects (for example, in practice change or profitability), which was credited to how they addressed the human and social dimensions of the adoption process. Case studies of adoption in the dairy sector found that scientists influenced adoption by collaborating with the private sector, being directly involved with on-farm trials and demonstrations, and supporting grouplearning approaches to help the adoption of past research. This role for scientists in adoption was enabled by investment in programs of RD&E rather than discreet research experiments, and research designs and methods that incorporated the social dimensions of adoption. This synthesis demonstrates the need for scientists to be proactive in providing guidance for farmers on where to access and source information related to their work, engage with a broad range of advisor types associated with their research field, champion in-field trials and/or demonstrations and be active participants in collaborative approaches to RD&E. [ABSTRACT FROM AUTHOR]

The role of livestock in sustainable food systems and sustainable diets is a complex issue. It should be assessed in terms of its impacts on environmental, economic, and social sustainability, as well as the levels of animal performance, the human food supply, and the human food production system. However, such nuanced analyses are made difficult by the lack of multi-metric, multi-domain modelling frameworks and a lack of data on regional variation in livestock production. This paper proposes a conceptual biophysical modelling framework that could be used as a pathway to address existing methodology gaps and improve sustainability analyses across multiple levels. Realising this modelling framework requires clear, transparent, and enforceable frameworks for multi-scale sustainability assessments, as well as long-term investment into region-specific data collection, particularly from under-represented regions. To ensure representativeness and broader utility, this framework must also be able to model variation in both production systems and consumer dietary patterns, and the feedback loops between producer/consumer decisions and on-farm production. Beyond the level of science, this will also require concerted effort by the various actors in the livestock and food-chain sectors such as governmental bodies, the food production industry and local communities. Once realised, this framework could be used to assess trade-offs between potential food-system changes and to ensure that decisions are being made from a big picture, net-benefit perspective, while exploring methods for building flexible, diverse food systems that are sustainable across multiple scales. For sustainable agriculture to be truly sustainable, it must be sustainable across the domains of environmental, economic, and social sustainability. However, most sustainability assessments focus primarily on environmental impacts, and many current tools and models can model only one or two of these domains, making nuanced, big-picture assessment difficult. This review proposes a holistic modelling framework for nuanced, multi-metric sustainability of livestock systems, while highlighting challenges that must be addressed to realise and implement this framework. [ABSTRACT FROM AUTHOR]

It is clear that the societal role of meat is being challenged with ideological and simplified logic without substantiation from robust data-driven science. With this background, the international summit titled 'The societal role of meat – what the science says' was held in Dublin, Ireland, during October 2022, to provide evidence-based evaluations and the Dublin Declaration was signed by over 1000 scientists. In this paper, we provide a synopsis of the summit and then give context for evaluating the societal role of meat in Australia. The key themes of the summit were the essential roles of meat in (1) diet and health, (2) a sustainable environment and (3) society, economics and culture. Evidence clearly showed the role of meat as a nutrient-dense source of high-quality protein and micronutrients that can be safely consumed by humans. Further, the complementary role of livestock in agricultural systems was highlighted with both plant- and animal-based agriculture reliant on each other to maximise the efficient production of food. Thus, from both an Australian and world perspective, very little food considered to be human-edible is fed to livestock. The role of livestock in rural societies across the world was emphasised to underpin regional and national economies, with particular importance in those countries with developing economies to facilitate growing wealth to 'step out' of poverty and provide gender equality. Meat production, particularly from ruminants, is a critical part of Australian primary production and it is concluded that the Dublin Declaration is highly relevant to Australia. Finally, concern regarding future funding and organisation of research and extension is discussed. There is a need to continue funding highly collaborative programs that bring a broad range of disciplines together, in conjunction with undergraduate and postgraduate teaching to underpin the social license to operate for meat and livestock production. The societal role of meat is being challenged with ideological and simplified logic without substantiation from robust data driven science. The international summit titled 'The societal role of meat – what the science says' was held to provide evidence-based evaluations and the Dublin Declaration. A synopsis of the summit is described and the societal role of meat in Australia is evaluated under the themes of meat for (1) diet and health, (2) a sustainable environment and (3) society, economics and culture. [ABSTRACT FROM AUTHOR]

A population-based epidemiological study was conducted between 2007 and 2011 and involved 78 northern Australian commercial beef-breeding herds and in excess of 56 000 cattle concurrently monitored. Cow reproductive performance was described from the biannual assessment of fetal age and lactation status. Both novel and well established measures of performance were used within four broad country types and included the following: percentage of lactating cows pregnant within 4 months of calving; percentage of cows pregnant within an approximate 12-month reproductive cycle (annual pregnancy); fetal and calf loss between confirmed pregnancy and weaning; percentage of cows contributing a calf at weaning and percentage of non-pregnant females retained for re-mating. The results from the present study described the variation in reproductive performance of commercial beef herds across northern Australia and defined typical and achievable levels of performance. The results from the study suggest that a weaning rate of 66% is a more realistic target level of performance for the Northern Forest, while weaning rates of at least 75–80% are realistic for other country types. Female-cattle performance was much lower in the Northern Forest than in the other country types. In absolute terms, there were 15–20% fewer surviving mated cows contributing a calf at weaning in an annual production year and ~4% more missing pregnant cows, which was associated with the ~20% higher retention of non-pregnant cows for re-mating. The reproductive performance of herds varied substantially among and within country types, with a 20–30% variation in reproduction rates and 5–15% variation in fetal and calf loss for half of the herds in all regions. Further analyses were performed and identified the major causes of this variation and are reported in subsequent papers within this series. The results from the present study appear to suggest that substantial opportunities to increase the reproductive performance of northern beef herds exist, providing that the causes of this variation are able to be identified and alleviated. An observational population-based epidemiological study was conducted in commercial northern Australian beef-breeding herds to describe reproductive performance and to quantify the prevalence and impact of the major risk factors. The present paper describes the monitored reproductive performance of ~56 000 cows managed on 78 commercial beef-breeding properties in a tropical region. Reproductive performance varied markedly both within and among country types. The proportion of females weaning a calf annually was much lower in the Northern Forest than in the other country types. [ABSTRACT FROM AUTHOR]

Data concerning the practices and policies of collaborating properties for nutritional, breeding and health management of herds were captured by survey of herd owners/managers (n = 78) at the commencement of a large observational study conducted across northern Australia to identify and quantify the effect of major animal-, management group- and property-level risk factors on measures of reproductive performance. The cooperating herds in this study were considered to be broadly representative of north Australian beef breeding enterprises in terms of geography, size and ownership. Using four broad regional categories, this paper presents descriptive summaries of the management practices and nutritional conditions of cooperating herds in what was known as the Cash Cow project. Property sizes were largest within the Northern Downs and Northern Forest, and smallest within the Southern Forest. The expected average annual growth of yearling steers was >50 kg less in the Northern Forest, compared with the other country types, which also appeared to be associated with the identified production system and turnoff animal. Despite the exacerbated nutrition and environmental challenges and likely increased time required for new managers within the Northern Forest to attain an in depth understanding of the cattle and property dynamics, this region had the greatest incidence of management changes. The nutritional information summarised in this study highlights that available phosphorus during the wet season, as indicated by faecal levels in proportion to dietary energy, was likely to limit animal production within the Northern Downs and Northern Forest. During the dry season, pasture digestibilty and protein levels were likely to be approaching maintenance for cows on ~50% of properties in each country type and that responses to rumen degradable protein were also likely on 50% of properties. Despite this finding, low use of dry season supplements was observed for the Northern Downs, which was partially explained by the high incidence of the management systems based on segregating cows on lactation status and pregnancy. In all country types, the ratio of bulls to cows was higher than the 2.5% recommended for extensively managed situations, while limited use of vaccines to control infectious causes of reproductive loss was also observed. The major conclusion of this study is that there was marked variation in the adaption of interventions to specific businesses, indicating considerable opportunity exists for further adaptation in the region. A large epidemiological study known as the Cash Cow project was conducted in commercial beef breeding herds across northern Australia between 2007 and 2011 with the aim of determining and quantifying the effect of management, nutritional and environmental factors on reproductive outcomes. This paper describes results from survey questionnaires examining their nutritional, breeding and herd health management practices and policies completed by herd managers/owners of participating properties at the commencement of the study. [ABSTRACT FROM AUTHOR]

The quadrennial International Deer Biology Congresses reflect the world-wide interest in the ecology, biology, and conservation biology of deer and use of cervine products. The origins and development of the International Deer Biology Congress are described in this article. The International Deer Biology Congresses grew out of a series of international conferences on deer biology. The origins and development of the International Deer Biology Congress are described in this article. [ABSTRACT FROM AUTHOR]

The periodically detached and regenerated antlers are a diagnostic trait of deer (family Cervidae) and represent the most rapidly growing bones of mammals. During their species-specific and seasonally fixed growth period of a few months, antlers can accumulate large amounts of 'bone-seeking' elements that are incorporated into the bone mineral. This makes antlers 'naturally standardised' environmental samples that can be used to monitor environmental pollution of deer habitats by these elements. The present contribution reviews studies utilising hard antlers as environmental archives to reconstruct temporal and spatial variation of contaminant levels in different geographic regions. We further discuss the use of lead isotope signatures in antlers for source apportionment of environmental lead and the impact of excess fluoride uptake on antler mineralisation. In addition, promising areas for future research using antlers as bioindicators are discussed. Antlers are a unique trait of deer and can be used as 'naturally standardised' environmental samples for monitoring ambient levels of bone-seeking pollutants. The present paper reviews basic aspects of antler growth and the history of using antlers as monitoring units in environmental research. Furthermore, we identify promising approaches for future studies using antlers as bioindicators. [ABSTRACT FROM AUTHOR]

The global goat meat sector is advancing and contributes to long-term food security, especially in meeting the protein demands of the growing human population in developing countries. Spanning all countries, Australia, is the largest exporter of goat meat, although it has negligible consumption. However, Australia does potentially have a secure future as an innovative, profitable, and resilient world leader in goat production, provided some challenges are addressed. These challenges facing the goat meat sector require suitable strategies and interventions for better profitability and acceptance of goat meat consumed in Australia and as an export product. Limited research on goat meat quality and the lack of an adequate grading system for goat meat quality are two of the major issues that need attention from the industry and researchers. Some of the most critical areas that need further research to enable growth of the goat meat industry are the influence of genetics and age of animals on meat quality, standardisation of the ageing period of various goat meat cuts, cooking innovations, consumer acceptance and sensory analysis of goat meat (both farmed and rangeland goats). This paper reviews the status of the goat meat sector and identifies the opportunities for the goat meat sector, particularly in Australia. In addition, we highlight several key issues requiring further research and interventions to enhance the growth of the goat meat industry. [ABSTRACT FROM AUTHOR]

Context: Selenium deficiency occurs all over the world. Therefore, the research and development of selenium supplements has been a focus for relevant scholars. Organic selenium is safer and more efficient than is inorganic selenium. In fact, China's sika deer resources are of high quality, but the utilisation rate of deer blood is very low. Research has found that deer blood is a reasonable peptide source for the preparation of selenium-chelate supplements. The abundance of deer blood resources provided conditions for this study. Aim: To provide new selenium supplements for humans, and further develop and utilise China's sika deer industry, which to some extent also improves the utilisation rate of deer blood resources. Methods: Peptides were hydrolysed by protease, and the best hydrolysates were screened. Single-factor experiments and response-surface methodology were used to study the effects of pH, temperature, time and peptide:selenium mass ratio on selenium-chelating activity. The sika deer blood polypeptide–selenium was characterised and analysed through ultraviolet spectrum, infrared spectrum, amino acid analysis, molecular-weight determination, scanning electron microscopy, and particle-size and potential analysis. Also, thermal-stability and acid–base-stability tests were conducted. Key results: The chelating activity of alkaline protease hydrolysate was the highest, being 73.1 ± 0.16%. The pH value, temperature, time and peptide:selenium mass ratio had influence on selenium-chelating activity. Because of the cross-linking of selenium ions, the chelated selenium aggregates into larger particles with a more compact structure. The determination of amino acid and molecular weight showed that the metal-chelating activity of small-molecular peptides was very strong. Glutamic acid (Glu) and aspartic acid (Asp) play an important role in the binding of selenium ions. At the same time, the chelated SDBP–selenium had acid–base stability and thermal stability. Conclusion: Studies depicted that SDBP–selenium is suitable as a new type of selenium supplement. Implications: The preparation of deer blood polypeptide-chelated selenium provides a scientific basis for the development of new selenium supplements and the practical application of deer blood resources. In this paper, we studied the chelation of sika deer blood polypeptide with selenium ion to prepare a new type of deer blood polypeptide–selenium supplement, which is more beneficial to human body in terms of safety and bioavailability than is the inorganic selenium supplement. The best chelating process was determined, and the properties of the chelate were determined by characterisation analysis and stability test. The results of this study provide a scientific basis for providing new selenium supplements. [ABSTRACT FROM AUTHOR]

Context: A significant opportunity remains to further increase the supply of premium sheepmeat products to Australia's customers, which requires a more rapid rebuilding of the national sheep flock. To help meet this challenge, developing relevant information for sheep producers to assist them to achieve a profitable flock-rebuilding outcome is viewed as highly desirable. Aims: (1) Develop flock-rebuild scenarios that track inventory, cashflow, profit and loss, and the overall balance sheet over a 5-year projection. (2) Model the impact on flock-rebuilding pathways of exposure to variation in supplementary-feed costs, purchase of stock and price received for sale animals and flock structure. (3) Model variation in benefits and costs for a range of production zones, enterprise types and flock-age profiles. Methods: Fourteen flock-rebuilding pathways were assessed for up to nine flock types, using a spreadsheet model that tracked inventory, cashflow, profit and loss, and the overall balance sheet over 5 years. Key results: The top four pathways for profitability and capacity to rapidly rebuild flock numbers include retention of more older ewes, purchasing young ewes, purchasing older ewes (mostly 5–6-year olds) in Merino and Merino-cross flock types only and joining ewe lambs in Maternal and Cleanskin flock types only. These pathways were not sensitive to variation in the cost of supplementary feed, stock prices or flock structure, although joining Merino ewe lambs became one of the top four pathways when feed costs were lower. Conclusions and implications: The well established practices of retaining ewes for longer and purchasing ewes, especially young ewes, have the most potential to both rapidly and profitably rebuild flock numbers. However, joining ewe lambs, particularly in Maternal and Cleanskin flocks, can also profitably contribute to rapid flock rebuilding. While reducing reproductive wastage or increasing reproductive potential were mostly profitable, they could not rapidly rebuild flock numbers. In contrast, accelerated lambing systems can rapidly rebuild flock numbers, but are only marginally profitable. The outlook for Australia's sheepmeat industry is very positive, with a significant opportunity available to further increase the supply of premium sheepmeat products to customers, by more rapidly rebuilding the national flock. This paper presents the findings of a study focussed on providing the confidence and material to sheep producers to choose optimal pathways to rebuild their flocks. At least 6 of the 14 alternatives investigated were deemed suitable for commercial use and not sensitive to variations in supplementary-feed costs, stock-purchasing and -sale prices. [ABSTRACT FROM AUTHOR]

Numerous non-infectious conditions can affect commercial layer flocks. Some of these, such as conditions related to bodyweight, fatty liver haemorrhagic syndrome and effects of age are common to all production systems, while some are more common in cage systems (cage layer fatigue, feather pecking) or in cage-free systems (grass impaction, smothering, sunlight exposure, cannibalism, predation and injuries). Many of these conditions are covered in other papers and will not be dealt with in here. In the present paper, emphasis will be placed on grass impaction, smothering, effects of age, exposure to high light intensities, predation and conditions related to overweight/obesity issues. All of these are of considerable welfare concern for the industry. Grass impaction is a particular issue when hens are first released to the range areas and are exposed to vegetation or other fibrous materials. Mortality can be high with this problem. Smothering episodes can be generated by sudden flock disturbances, or from overcrowding in nests or related to nest-box design. Other less well understood triggers for smothering are poorly understood but have been linked to temperature variability, retreating shade in range areas on sunny days, dust-bathing opportunities and things that attract birds to certain points in the shed. The incidence of tumours increases with hen age. Most frequently encountered tumours are leiomyomas and adenocarcinomas, both of which are associated with the reproductive tract and are presumably linked to selection for higher and more sustained egg production. The incidence of these neoplastic conditions will need better understanding if increases in flock persistency of lay are desired. Light intensity is understood to be a possible trigger of increased aggressive behaviour and can lead to increased feather pecking and cannibalism. Predation, while frequently reported, is not regarded as a major cause of loss in most farming circumstances, although individual cases can be serious and it is a major cause of concern. Obesity is becoming more recognised as a problem in layer flocks as research begins to focus on its effects. Reduction in average flock weights will be an objective for further improvement in persistency of lay in the future. [ABSTRACT FROM AUTHOR]

Context: Producers' behaviour, attitudes, and ethics towards animal welfare emerge from a complex interplay of factors. Applying insights from behavioural science can therefore enrich our understanding of the myriad factors influencing animal welfare and can provide recommendations for creating a positive shift in producers' behaviour. Aims: The current paper documents a partnership between an organic beef exporter, OBE Organic, and a behavioural science company, Evidn. The partnership aimed to improve beef producers' behaviours towards animal welfare by embedding behavioural science principles into producer feedback sheets that are completed post-slaughter by meat processors and beef exporters. Methods: A five-stage approach was applied. Stage one involved a behavioural science 'hackathon' between OBE Organic and Evidn to refine project scope. Stage two reviewed producer communications at OBE Organic through five semi-structured interviews. Stage three analysed the behavioural science literature and other interventions relevant to animal welfare. Stage four pilot-tested recommendations with 10 stakeholders, followed by the re-design of producer feedback sheets throughout Stage five. Key results: Qualitative results were collected from OBE Organic staff and producers to delineate the potential impacts of the re-designed feedback sheets on animal welfare. Results indicated that re-designed sheets reduced complexity, increased saliency of relevant information, and further motivated behaviour change by providing peer comparisons. Industry partners of OBE Organic responded positively to the company's commitment to improving animal welfare, further enhancing their social licence to operate. Conclusions: Behavioural science is a potentially useful tool for improving animal welfare by further enriching our understanding of the myriad factors influencing producers' behaviour and providing evidence-based recommendations to enhance producers' engagement with animal welfare information contained in producer feedback sheets. Implications: Future work should focus on directly linking the re-designed feedback sheets to improvements in animal welfare (i.e. bruising, meat colour). This could involve a large-scale randomised controlled trial (RCT) to test the impact of re-designed communications on animal welfare outcomes. A large qualitative engagement project could also help understand the system of factors influencing producer behaviour and develop a behaviour change program to further improve animal welfare. Ongoing work is also needed to ensure that engagement with feedback sheets is maintained in the long term. Producers' behaviour towards animal welfare emerges from a complex interplay of factors including personal attitudes, social norms, and the broader societal context. Applying a behavioural science lens can further enrich our understanding of these factors and develop strategies for how animal welfare can be improved. This project represents a potential step-change in agriculture by applying behavioural science to improve producer communications relating to animal welfare. [ABSTRACT FROM AUTHOR]

Context: Animal production plays a critical role in many global challenges around sustainability, including climate change and resilience, One Health and food security. With this role comes pressures on livestock welfare. Aims: This paper demonstrates key contributions animal welfare makes to global sustainability challenges. Methods: This paper highlights 'win–win' improvements for both animal welfare and other aspects of sustainability by using the following four case studies: tail docking Australian sheep, agroforestry systems in Ethiopia, the Australian dairy-beef industry, and strategic feeding of goats in Pakistan. Key results: These case studies show how animal welfare can be improved alongside livelihoods. However, even in these win–win situations, the adoption of improved practices is not guaranteed. Conclusions: Long-term, sustained change in animal welfare can simultaneously make in roads to other challenges around sustainability. To do this, we must have a broader understanding of the system in which the animals are raised, so that barriers to change can be identified. Implications: Lessons from these case studies can be applied to other production contexts and challenges, highlighting the universal value of understanding and addressing animal welfare. Global challenges around sustainability are putting different pressures on the welfare of livestock. This paper highlights 'win–win' improvements for both animal welfare and other aspects of sustainability, but even in these win–win situations, the adoption of improved practices is not a guarantee for a myriad of external factors. By having a better understanding of the system in which animals are raised, a broader understanding of an animal's welfare, and acknowledging the emotional states that animals experience, progress towards improving welfare and, ultimately, addressing some of these global challenges, can be made. [ABSTRACT FROM AUTHOR]

As the sophistication of genomic technologies increases and their cost continues to decrease, they are becoming routine tools in livestock breeding programs and production systems. The convergence of electronic measurement systems, cloud-based computing and fast internet enable the use of powerful decision support to help automate and manage livestock production, animal welfare and quality control. The complexity of livestock production systems, combined with the challenges of producing top-quality discretionary products for consumers, means that no single organisation has the range of expertise to support coordinated development of innovation in the relevant supply chains. Collaboration between a broad spectrum of scientists and industry partners is essential to ensure well integrated input to the design and implementation of programs to deliver improvements in efficiency, quality and profit. The need for collaboration among researchers, among research organisations and with end-users has never been more important. Collaboration brings together the skills needed to manage complex problems and enables the sharing of facilities and scarce resources within Australia and internationally. However, the most important component of effective collaboration is the early engagement of end-users to contribute to the design of programs of innovation, to ensure that investment is well targeted and that there is ownership of the problem as well as the solutions delivered through research. Although the potential benefits of effective collaboration are clear, it often takes more than logic to get individuals and organisations to work together. There needs to be a significant financial incentive combined with strong industry leadership and agreed common goals. Allocating resources to establish these foundations for effective collaboration should precede any major research and development funding initiative. The present paper argues that the new face of animal science in Australia should be structured around coordinated programs of research and development, on the basis of effective collaboration. Research leading to significant change in agricultural practice almost always involves collaboration between teams of researchers and multiple end-users as well as sharing resources across multiple organisations. Although benefits and efficiencies are easily recognised, effective multi-institutional teamwork is often difficult to achieve. The present paper draws on experience from the Sheep CRC, over a period of nearly 20 years, where collaboration among an increasing number of participants contributed to many significant changes in the Australian sheep industry. [ABSTRACT FROM AUTHOR]

Dr Helen Newton-Turner introduced a powerful model of bringing science into practice by working closely with breeders and the wider industry. This collaboration model has led to considerable achievements in genetic improvement in the Australian animal industries, with efficient genetic evaluation systems being implemented, providing a platform to achieve well defined breeding objectives and the introduction of new technologies such as genomic selection. The same model can be used to foster future development to achieve sustainable further improvements, allowing further technologies such as functional genomics to be used where they add value. This paper was prepared by Professor Julius van der Werf, the 2021 recipient of the Helen Newton-Turner Medal. Julius was awarded the medal for his outstanding contribution to genetic improvement of Australian livestock. [ABSTRACT FROM AUTHOR]

Context: The accuracy of estimated breeding values (EBVs) is an important metric in genetic evaluation systems in Australia. With reduced costs for DNA genotyping due to advances in molecular technology, more and more animals have been genotyped for EBVs. The rapid increase in genotyped animals has grown beyond the capacity of the current genomic best linear unbiased prediction (GBLUP) method. Aims: This study aimed to implement and evaluate a new single-nucleotide polymorphism (SNP)–BLUP model for the computation of prediction error variances (PEVs) to accommodate the increasing number of genotyped animals in beef and sheep single-step genetic evaluations in Australia. Methods: First, the equivalence of PEV estimates obtained from both GBLUP and SNP-BLUP models was demonstrated. Second, the computing resources required by each model were compared. Third, within the SNP-BLUP model, the PEVs obtained from subsets of SNP were evaluated against those from the complete dataset. Fourth, the new model was tested in the Australian Merino sheep and Angus beef cattle datasets. Key results: The PEVs of genotyped animals calculated from the SNP–BLUP model were equivalent to the PEVs derived from the GBLUP model. The SNP–BLUP model used much less time than did the GBLUP model when the number of genotyped animals was larger than the number of SNPs. Within the SNP–BLUP model, the running time could be further reduced using a subset of SNPs makers, with high correlations (>0.97) observed between the PEVs obtained from the complete dataset and subsets. However, it is important to exercise caution when selecting the size of the subsets in the SNP–BLUP model, as reducing the subset size may result in an increase in the bias of the PEVs. Conclusions: The new SNP-BLUP model for PEV calculation for genotyped animals outperforms the current GBLUP model. A new accuracy program has been developed for the Australian genetic evaluation system which uses much less memory and time to compute accuracies. Implications: The new model has been implemented in routine sheep and beef genetic evaluation systems in Australia. This development ensures that the calculation of accuracies is sustainable, with increasing numbers of animals with genotypes. The accuracy of estimated breeding values is routinely provided to breeders as part of genetic evaluations in Australia. A new method to approximate accuracies using genomic information has been developed and is presented in this paper. The new model has been implemented in Australia's routine sheep and beef genetic evaluation systems. This development ensures that the calculation of accuracies is sustainable with increasing numbers of animals with genotypes. [ABSTRACT FROM AUTHOR]

This paper reviews the small but growing literature on the water footprint (WF) of livestock production and provides an analysis of the strengths, weaknesses, opportunities and threats of this indicator. We identified 42 papers published in peer-reviewed international journals between 2000 and 2017, which covered the WF of dairy, meat and egg production using life-cycle assessment and WF network methodologies. The WF of livestock products decreases with the level of intensification of the farming system. In addition, the WF of meat is higher than that of either milk or eggs. The WF of beef is much larger than the WFs from sheep, goat, pork and chicken. The WF variation among different animal products is explained by the difference of the feed conversion ratio. Ruminants (cattle, sheep and goat) have a poor feed conversion ratio compared with monogastric animals (poultry and swine). Estimating the WF of livestock production and economic analysis of water use at different stages of production will help farmers and other stakeholders to identify the most demanding activities in term of water use, and implement strategies to improve water-use efficiency. Thus, feed production was identified as the largest contributor of the WF of livestock production. Options to reduce the WF of livestock production include the use of low-WF feeds, more efficient irrigation of crops used for livestock feed, and reduced consumption of animal-sourced protein in human diets through substitution with plant proteins. The strengths, weaknesses, opportunities and threats analysis highlighted the importance of combining WF with other environmental-footprint and sustainability indicators to provide more reliable information for decision makers. Water scarcity is one of the main challenges threatening the sustainability of livestock production systems. The present review describes approaches used to quantify water use in livestock production, and the water footprint of the main animal products. The review also highlights possible strategies to reduce water use in livestock sector and reduce the global water shortage. [ABSTRACT FROM AUTHOR]

Context: The performance of commercial beef-breeding herds in northern Australia is highly variable. Identifying and understanding the major factors that influence this is critical in determining which management interventions should be implemented to best manage these factors. Aims: This study aimed to describe the occurrence and magnitude of the risk factors identified as being strongly associated with one or more measures of cow performance in northern Australia. Methods: A prospective epidemiological study was conducted in a cross-section of commercial beef-breeding herds in northern Australia, to determine and quantify the major associations of up to 83 candidate herd management, nutritional and environmental risk factors with cow performance. Descriptive analyses of significant risk factors were conducted. Key results: Unfavourable levels of risk factors were observed for all country types and across three cow-age groups. However, generally, adverse property-level nutritional, environmental and management risk factors had a higher incidence in the Northern Forest, which was associated with significantly lower performance of heifers and cows. This was reflected in generally lower body condition of heifers and cows in this country type. Although the performance of heifers and cows was generally higher in the Southern Forest, the irregular incidence of adverse risk factors contributed to the observed quite variable performance. Conclusions: The factors significantly affecting the performance of cows in the major beef-breeding regions of northern Australia are described. These factors were additively more adverse in the Northern Forest. Implications: In this study, the necessary understanding of the factors most likely to be affecting the performance beef cows in this environment has been described. This is required to make appropriate decisions about management interventions to control these factors. A large epidemiological study known as the Cash Cow project was conducted in commercial beef breeding herds across northern Australia between 2007 and 2011, with the aim of determining and quantifying the effect of management, nutritional and environmental factors on cow performance. This paper describes the occurrence and magnitude of the factors shown to significantly affect cow performance. [ABSTRACT FROM AUTHOR]

Context: High and variable fetal and calf loss in beef herds occurs across northern Australia. Reasons for the majority of these losses, a major cost to the industry, have remained unknown. Aims: The research question was, which of the 58 region-, property-, management group-, and animal-level risk factors measured are associated with pregnant females failing to wean their calf? Methods: An epidemiological study measured fetal and calf loss (consistently expressed as % points) between confirmed pregnancy and weaning and the major associated risk factors using a selected population from 55 commercial beef breeding herds representing 23 166 pregnancies in the mostly dry tropical environment of northern Australia. Key results: Median fetal and calf loss was 9.5% with large variation. Achievable levels appeared to be <10% for Northern Forest herds, and <5% for Southern Forest, Central Forest and Northern Downs herds. The risk factors most strongly associated with fetal and calf loss were low-fertility country type interacting with phosphorus inadequacy (up to 10% increase), low body condition score interacting with phosphorus inadequacy (up to 8% increase), tall cows (up to 4% increase), and high temperature–humidity index around calving interacting with country type (up to 7% increase). These are nutritional and environmental risk factors and had the combined highest individual effect and frequency. Other risk factors associated with fetal and calf loss included first-lactation cows, which interacted with mustering around calving (up to 9% increase), having not reared a calf in the previous year interacting with cow age (up to 8% increase), low mustering efficiency (up to 9% increase), perceived predation by wild dogs (4–5% increase), high prevalence of Campylobacter fetus sp. venerealis antibodies (7% increase), recent infection with bovine viral diarrhoea virus (9% increase), and inadequate dry-season protein (4% increase). Conclusions: The combined effects of environmental, nutritional and management risk factors on fetal and calf loss in northern Australia were large and additive and were much greater, collectively up to 30–40%, and more consistent than that due to either endemic infectious diseases or animal factors. Implications: Opportunity for remedial action is high and, for the effect of non-infectious risk factors, should target milk delivery to neonatal calves. An observational study was conducted in commercial beef breeding herds in northern Australia to determine and quantify the major associations among herd management, nutritional and environmental factors and individual cow attributes and measures of reproductive performance. This paper presents the findings of the study designed to identify risk factors associated with reproductive losses between confirmed pregnancy and weaning. [ABSTRACT FROM AUTHOR]

Context: There are multiple reports of high annual cow mortality rates in northern Australia, but no reports clearly indicating the overall rates and the impact of primary risk factors. Aims: The research aimed to determine which measured region-, property-, management group- and animal-level risk factors are associated with missing pregnant females. Methods: Risk factors for the annual rate of pregnant-cow mortality were investigated in an epidemiological study using outcomes for 21 554 cows from 52 beef herds in 2009 and 2010 in four primary country types within the mostly-dry tropical north Australian environment. Modelling of 2001–2011 Australian beef-herd statistics was used to corroborate and further quantify findings. Key results: In the epidemiological study, the overall predicted annual mean incidence of missing pregnant cows, a surrogate for mortality, was 10.9%, including lost tags and unrecorded cow movement that were estimated to constitute up to 9% missing cows. Risk factors associated with higher pregnant-cow mortality were as follows: not having follow-up rainfall more than 30 days after the first wet-season storms (4 percentage point increase); <2 t/ha of available pasture biomass in the early dry season (2–6 percentage point increase); pasture dry-season biomass <2 t/ha interacting with less than moderate mid-dry-season body condition score (3–10 percentage point increase); and, calving between April and September (non-significant trend for a 1–2 percentage point increase). Feed-quality measures did not affect mortality rate. Population modelling of Australian beef herd statistics suggested an average annual cow mortality rate in the Northern Forest region of ~7% compared with 2% in more nutritionally endowed regions. Conclusions: The major risk factor for cow mortality is under-nutrition, related either to generally-low soil fertility, seasonally-dry conditions, or management that exposes animals to poor nutrition. Annual mortality of pregnant cows appears 6–9 percentage points higher in the low-fertility Northern Forest region than elsewhere. Implications: Beef cow mortality is a major business cost in northern Australia. The efficacy of targeted management to achieve high cow performance was demonstrated by losses in a third of studied businesses in the Northern Forest being kept to the same or lower levels as median loss in endowed regions. An epidemiological study was conducted in commercial beef-breeding herds in northern Australia to determine and quantify the major associations between measures of performance and risk factors for herd management, nutritional, environmental and individual cow attributes. This paper presents the findings from the study using 21 554 pregnant cows in 52 herds that determined the major risk factors associated with those that went missing. This was supported by an analysis to calculate mortality rates using contemporary statistical data for the Australian beef herd. [ABSTRACT FROM AUTHOR]

Context: Sound reproductive efficiency is a key determinant for the overall productivity of a beef breeding business. For beef breeding herds to obtain high levels of reproductive productivity, breeding females need to efficiently become pregnant while lactating. Aims: This study aimed to determine and quantify the major factors associated with lactating cows becoming pregnant within 4 months of calving (P4M) in commercial beef breeding herds of northern Australia. Methods: A prospective epidemiological study was conducted using 78 commercial northern Australian beef breeding herds and involved 78 000 cattle that were monitored for 3–4 years. A multivariable model-building process was employed to scrutinise the resulting dataset to identify what herd-management practices, and nutritional, environmental and individual cow factors were major determinants of lactating cows becoming pregnant within 4 months of calving (P4M) and to estimate their magnitudes of effect. Key results: Overall, 41.6% of cows per production year were successful for P4M. Country type was strongly associated with 65.4%, 57.5%, 61.8% and 16.4% P4M for the Southern Forest, Central Forest, Northern Downs, and Northern Forest respectively. Between-year variability ranged between 3.3 and 11.7 percentage points. Cows calving in December–January (61%) had a substantially higher occurrence of P4M than did cows calving between July and September (15%). The difference in P4M when comparing availability of wet-season pasture protein and phosphorus was 12.7 and 20.3 percentage points respectively. Modelling of the impact of group seroprevalence and management group prevalence of recent infection with several infectious diseases was estimated, with a large negative association between group bovine viral diarrhoea seroprevalence and P4M suggested. Conclusions: This study further demonstrated the substantial impact that environment, herd management practices, nutrition and disease factors can have on the reproductive performance of females. Implications: To optimise the performance of females (through increasing the occurrence of cows contributing calves in consecutive years) under commercial conditions in northern Australia, herd managers should focus on maximising the proportion of cows within a herd calving at the desired time of the year, ensuring that any nutritional deficiencies and herd health issues are managed, and that cows are managed such that they are of good body condition score at the time of calving. An observational study was conducted in commercial beef breeding herds in northern Australia to determine and quantify the major associations between herd management, and nutritional, environmental and individual cow factors and measures of reproductive performance. This paper presents the findings of the study designed to determine the major predictors of lactating cows becoming pregnant within 4 months of calving. [ABSTRACT FROM AUTHOR]

Context: Sound reproductive efficiency is a key determinant for the overall productivity and profitability of a beef breeding business. Failure of a cow to conceive results in either culling or the cost of carrying non-pregnant animals. Aims: This study aimed to determine and quantify the major factors associated with non-pregnancy in commercial beef breeding herds of northern Australia. Methods: A prospective population-based epidemiological study of the likelihood of non-pregnancy in cows after an annual mating in northern Australian beef breeding cows used data from 73 herds from four broad country types and 62 323 animal years; approximately 80 property-, management-group- and cow-level risk factors were considered. A multivariable model building process was employed to scrutinise the resulting dataset, so as to identify what herd management practices, nutritional, environmental, and individual cow factors were associated with non-pregnancy and estimate their magnitude of effect. Key results: Non-pregnancy was disproportionately high in the Northern Forest (32.1%), compared with the Northern Downs, Central Forest and Southern Forest where it was 17.1%, 16.0% and 13.2% respectively. Time of expected calving had the largest impact on occurrence of non-pregnancy. Parity also had a significant influence, with first-lactation cows typically having 5–12% higher non-pregnancy than did mature cows. Non-pregnancy decreased with an increasing body condition score at the branding/weaning muster for lactating cows. The difference in non-pregnancy when comparing availability of wet-season pasture phosphorus content and digestibility of pasture during the dry season was 13.2 and 10.2 percentage points respectively. Conclusions: This study demonstrated the substantial impact environment, herd management practices, nutrition and disease factors can have on the reproductive performance of females. Implications: To optimise the efficiency of females (through reducing the occurrence of non-pregnancy) under commercial conditions in northern Australia, production systems should support beef herds calving early in the production year, being in at least moderate body condition and having access to more digestible pastures that address the nutritional requirements for both protein and phosphorus. This indicates focus for management, especially in the Northern Forest where the likelihood of non-pregnancy was highest. A large epidemiological study of annual pregnancy rate was conducted in commercial beef cattle breeding herds in northern Australia. The effect on non-pregnancy of the major herd management, nutritional and environmental risk factors and individual cow factors was determined and quantified. This paper presents the findings of the study designed to determine the major predictors of cows not achieving pregnancy. [ABSTRACT FROM AUTHOR]

Context: Tables of nutrient requirements assist nutritionists to formulate acceptable feeds for broilers but do not consider the objective of a business, namely, to maximise economic returns. Aims: The objective of the present study was to demonstrate that the optimum economic level of balanced protein is not static, but varies according to economic conditions. Methods: Responses of male and female broilers, reported in a companion paper, were used to calculate feed intake and weights of body, carcass, breast, leg and wing at 28, 42 and 56 days of age as functions of dietary balanced protein. Cost of feeding and revenue generated for live, dressed, and further-processed birds were calculated, from which the margin over feeding cost was generated separately for males and females at three ages and three revenue-generating scenarios. Key results: Using baseline values for the cost of protein-containing ingredients and revenue for birds sold live, dressed or further-processed, the dietary protein content that maximised margin over feed cost was always higher for males than for females, and for birds sold further-processed than for those sold dressed or live. Using digestible lysine as the reference amino acid, the optimum in the starter period for males sold live, dressed and further processed was 12.6, 13.3 and 14.2 g lysine/kg respectively. For females, the equivalent values were 11.9, 12.6 and 13.3 g/kg respectively. Where the cost of protein-containing ingredients was increased by 25% or revenue generated from the sale of product was reduced by 25%, the optimum economic level of dietary protein decreased compared with the baseline value. The opposite pertained when ingredient costs decreased, or revenues increased by 25%. Conclusions: These results demonstrated the extent to which economic factors influence the optimum economic level of dietary balanced protein to be fed to broilers. Implications: We have demonstrated that the response of broilers to dietary balanced protein may be used to maximise economic returns of a broiler enterprise under different scenarios. In poultry nutrition, nutritionists usually formulate feed guided by a recommendation table of nutrients, which is generally based on the amount necessary to maximise broiler's response, with no relation to the economic aspects of the poultry production. In the present paper, the authors prepared a sequence of exercises demonstrating an alternative on how the levels of protein might be calculated. Finally, the methodology to estimate the level of protein that maximises the economic return is given. [ABSTRACT FROM AUTHOR]

Dual-purpose cropping (sowing crops with the intention of both grazing them during vegetative growth and harvesting grain thereafter) has become a widespread farming practice in southern Australia. This synopsis paper integrates research from a multi-institutional research project conducted at three nodes located near Hamilton (south-western Victoria), Wagga Wagga (southern NSW) and Canberra (ACT), and sets out 11 principles for the effective utilisation of dual-purpose crops in meat production systems to increase profit and manage risk. Dual-purpose crops can be used to overcome feed quality gaps in late summer–autumn or feed quantity gaps in late autumn/winter. They provide large quantities of high-quality forages for grazing in summer, autumn and winter and can provide a substantial contribution to the annual number of grazing days on a farm. Utilisation of the high-quality dry matter provided by dual-purpose crops is most effective when directed at young growing stock for sale or future reproduction rather than reproducing adult ewes. For example, sale weight of yearlings per ewe was increased by 16% in systems at the Canberra node when dual-purpose crops were prioritised for grazing by weaners. Wool production was also increased in systems that included grazing of dual-purpose crops. Grazing crops in winter does not necessarily reduce supplementary feeding costs for winter or spring lambing. Modelling suggests that inclusion of dual-purpose crops does not substantially change the optimum time of lambing for sheep meat systems. Financial analysis of the experimental data from the Canberra node showed that although cash expenses per hectare were increased in the crop-grazing systems, the overall profitability of those systems over the life of the experiment was greater by AU$207/ha.year than that of the pasture-only system. Factors driving improved profitability included income from grain, higher income from meat and wool, and lower supplementary feeding costs. However, increasing the area sown to crop from 10% to 30% of the farm area in this Southern Tablelands system appeared to increase risk. In south-western Victoria, spring-sown canola carried risk similar to or less than other options assessed to achieve ewe-lamb mating weight. It is likely that at least part of the reduction in risk occurs through the diversification in income from the canola produced as part of the system. It was concluded that the grazing of cereal and canola crops for livestock production can be profitable and assist in managing risk. 'Step changes in meat production systems from dual-purpose crops in the feedbase' was a multi-institutional research program funded by Meat & Livestock Australia. This special issue of Animal Production Science includes key papers from that research program. This synopsis paper integrates research findings across the three nodes of the project and draws out 11 principles for the effective utilisation of dual-purpose crops in meat production systems to increase profit and manage risk. [ABSTRACT FROM AUTHOR]

Context: Dairy operations have adopted benchmarking as a methodology to rank farms and establish target indexes; however, a connection between benchmarking and farms in the tropics is still warranted. Aims: To evaluate the technical and economic quartiles based on farm return on assets (ROA) of three regions (Centre, South and Triangle) of Minas Gerais state, Brazil, and use them to establish benchmarks for dairy farms. Methods: We collected data from 128 dairy farms (from January to December of 2019). All properties were part of the Educampo® project/Sebrae-MG. Farms were grouped into the Centre, South and Triangle regions, and subdivided into three groups within each region according to their ROA, where 25% of the farms that presented the lowest ROA were classified as the first quartile, 50% of farms were classified as interquartile and the 25% remaining farms were classified as the fourth quartile. Data were analysed as a randomised block design in a split-plot scheme, where the production systems were blocks, the regions were the main plots and the groups were the split plots. Differences were declared when P ≤ 0.10. Key results: Total operating cost ($/L; $ – this currency is in US dollars and it applies throughout the paper); accrual operating cost ($/L); production costs, such as roughage ($/L), hired labour ($/L), percentage of concentrate and hired labour in accrual operating cost (%), were affected by regions and groups. The South and fourth quartile had the greatest total operating cost (0.24 $/L; 0.26 $/L) and accrual operating cost (0.27 $/L; 0.30 $/L), respectively. The majority of economic indexes were higher for Triangle than South and Centre, respectively. The fourth quartile had the greatest net margin (0.09 $/L), profit (0.07 $/L), return on assets (2%) and assets turnover rate (24%). Conclusions: We suggest that benchmarks should be established by region, as there were too many variations among regions. In addition, this study demonstrated the importance of understanding the behaviour of the technical and economic indicators to stratify farms based on their return on assets. Implications: We evaluated technical and economic indexes from three regions and stratified by ROA. Then, we established benchmarks by regions to better guide the producer in decision-making in dairy operations. The evaluation of technical and economic indexes, and the establishment of benchmarking are important for the financial management of dairy operations. We studied a broad spectrum of dairy farms, and analysed which indicators vary the most in high, intermediate and low return on assets' farms. Lastly, we demonstrated the importance of categorising technical and financial indexes to create new benchmarks by region, and that this analysis must be periodically performed, aiming for greater profit. [ABSTRACT FROM AUTHOR]

This is the introductory paper for a Festschrift to honour the contribution that John Langtree Black has made so far to animal science over his 50-year career. The paper outlines the extraordinary wide range of topics, disciplines and animal species covered by his research and intellectual thinking. It describes major contributions made to enhancing knowledge in areas of animal science and to the application of knowledge to rural industries through simulation models, risk-control management systems, methods for measuring ingredient and product quality and communication. An important contribution has been through the management, coordination and integration of findings in large interdisciplinary research programs, particularly with an emphasis on adherence to the scientific method and the role of statistics. The discipline of scientific integrity has been extended to his considerable involvement in community service. [ABSTRACT FROM AUTHOR]

The present paper briefly discusses the impacts of introducing dual-purpose (DP) crops as a grazing resource into what were previously pasture-only grazing systems. The emphasis is on the high-value crops wheat and canola, since these have the greatest potential to increase profits by providing both winter grazing and a high-value grain or seed crop at harvest. A major potential impact of grazing on such crops is that the reduction in grain yield caused by grazing offsets the value of the grazing obtained. The paper shows that this is not the case and that if crop grazing is performed correctly, there will be minimal impact on grain or seed yield; yield may even be increased. 'Correctly' in this context refers mainly to the timely removal of livestock from the crop. Increases in grain yield after grazing arise principally from the conservation of soil water from the winter period through to the grain-ripening stage. The paper emphasises that although the digestibility and crude protein content of DP crops are high, the use of long-season bread wheats as a grazing resource requires that system managers pay greater attention to the sodium and magnesium status of the grazing livestock. This is because of the often high potassium and very low sodium concentrations of wheat forage, which leads to high potassium : sodium ratios in the rumen and reduced absorption of dietary magnesium. Supplementation with sodium and/or magnesium has significantly increased the liveweight gain of stock grazing wheat, but is contra-indicated when grazing canola. The paper also considers the interaction between the amount of grazing provided directly by the crop(s), relative to the possibly increased grazing available from the pasture component of the system, due to 'pasture spelling' while livestock are grazing the crop. Data are presented to show that, overall, the introduction of crop grazing into a previously pasture-based system greatly increases the total amount of grazing obtained. In addition, of the total extra grazing obtained in crop-pasture versus pasture-only systems, up to 40% has been found to come from spelled pasture. This has major implications for the management of the total system. The paper concludes by suggesting that, in the future, research on crop-pasture systems should continue, but should pay greater attention to the grazing of DP crops by cattle and particularly by breeding livestock. In addition, there is a need for much better data on the contribution of crop residues to the total grazing system, plus data on the effects of the introduction of DP crops on the wool production of the total grazing system. [ABSTRACT FROM AUTHOR]

The rise of sequencing technology brought about a surge of new methodologies that offered a new and deeper level of understanding of the role of the microbiome in the health and performance of livestock. This started a chain reaction in technology evolution, and a decade later, we have developed a new appreciation of a healthy gut and the role of early colonisation and nutrition in developing the microbiome, and its subsequent impact on animal productivity. An abundance of new products flooded the livestock supplement market with the promise of improving the health of intestinal microbiota. However, the impact of these products and any potential gains they might provide have not always been quantified or validated. Further to this, the potential interactions with the microbial community naturally occurring in the feed-base have not commonly been considered. We have recently shown that animal feed carries a complex microbial community that can have various impacts, including negating farm biosecurity measures. The ruminant animal provides an even greater level of complexity where physiological drivers act to maintain ruminal homeostasis. Despite many advances, numerous knowledge gaps remain, and the methodologies are not without their challenges with almost constant evolution in analysing and interpreting data. In this paper, we will discuss the benefits, challenges and shortfalls of microbiome science, its interfaces with multi-omics research and the strategies of its contribution to animal production science. With advances in sequencing technology, research of microbial communities has become more accessible and affordable. In livestock research, the roles of microbiota are associated with animal performance and welfare. Although universally accepted, amplicon-sequencing methodology has several issues that need to be considered in data interpretation. Here we review the main shortfalls, benefits and uses of the methodology in livestock research. [ABSTRACT FROM AUTHOR]

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. High prices for goats in Australia due to high international demand has 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 goats within these managed production systems. The present paper demonstrates that the highest rates of liveweight gain of young male Rangeland goats is when they are offered a high energy supplement. [ABSTRACT FROM AUTHOR]

Artificial intelligence (AI) is beginning to live up to its promise of delivering real value, driven by recent advances in the availability of relevant data, computation and algorithms. In the present paper, I discuss the value to agriculture from AI over the next decade. The more immediate applications will be to improve precision information about what is happening on the farm by improving what is being detected and measured. A consequence of this are more accurate alerts to farmers. Another is an increased ability to understand why phenomena occur in farm systems, so as to improve their management. From improved data and understanding come improved predictions, enabling more optimal decisions about how to manage farm systems and stimulating the development of decision support and recommender systems. In many cases, robotics and automated systems will remove much of the need for human decision-making and improve farm efficiencies and farm health. Artificial intelligence will also be needed to enable organisations to harness the value of information distributed throughout supply chains, including farm data. Digital twins will also emerge as an important paradigm to improve how information about farm entities is organised to support decision-making. There are also likely to be negative impacts from AI, such as disruption to the roles and skills needed from farm workers, indicating the need to consider the social and ethical impacts of AI each time a new capability is introduced. I conclude that understanding these challenges more deeply tends to highlight new opportunities for positive change. Every aspect of society and industry seems to be examining the potential benefits from applying artificial intelligence (AI). In the present paper, I examine the likely benefits to agriculture from applying AI and discuss some of the challenges. I identify 21 different areas, with the highest-value capabilities being those where multiple different areas of AI developments are brought together to form new capabilities such as farm robots, digital twins and supply-chain traceability. [ABSTRACT FROM AUTHOR]

Increased market pressure to improve meat yield and quality require improved methods of predicting body composition in growing animals. Current systems of animal nutrition based on nutrient supply and animal characteristics predict animal growth from nutrient inputs, but, as of yet, do not accurately predict body composition. The present paper explores the evidence and data required to support an existing model of the effects of energy intake on visceral and muscle protein mass and energy expenditure to predict heat production, growth and body composition of sheep. While parameters of the model related to energetic costs of protein in muscle and viscera can be supported by independent studies, parameters associated with energetic costs of protein gain, particularly in viscera, are harder to reconcile with independent measurements. The range of available data on systematic changes in visceral organ mass over time in response to feed intake is limited, which may constrain generalisation of the parameters of the model with regard to the wide range of production situations faced by the sheep and cattle industries. However, sufficient data exist in the literature to test, and if required, revise the current framework. Current animal nutrition systems based on nutrient supply and animal characteristics may predict performance but are inadequate to predict retail yield and composition. The relationship between oxygen uptake, visceral and muscle protein mass, and energy expenditure can be used to explain variation in animal growth and composition with regard to nutritional changes over time. This paper explores independent evidence supporting an existing model linking protein metabolism to animal performance and body composition, and identifies data gaps for future research. [ABSTRACT FROM AUTHOR]

An introduction to the special issue for the 2020 Australasian Dairy Science Symposium. [ABSTRACT FROM AUTHOR]

Professor Valerius Geist was a world-renowned deer biologist who made important contributions to deer science, especially in the areas of animal behaviour, the evolution of cervids in the Pleistocene, and deer conservation. One of his greatest accomplishments was to define the core principles that have made wildlife management unique in North America. The deer science community deeply regrets his passing in 2021. Eulogy for the life and achievements of Professor Valerius Geist. [ABSTRACT FROM AUTHOR]

Sheep stocking rate influences farm profit significantly; however determining the optimal stocking rate is a difficult task. In this paper, we address this challenge through three main steps. First, we review the definition of stocking rate; second, we examine prior research relevant to the review topic and highlight the factors that need to be considered when determining the optimal stocking rate; and third, we make recommendations for improvements in research on establishing the optimal sheep stocking rate. Inconsistency in the definition of stocking rate can lead to miscommunication among researchers, advisers and farmers. If 10 dry sheep equivalents (DSE)/ha is optimal for one flock, it may not be optimal for another flock because the DSE measure does not fully capture the nuances of different patterns of nutritional requirements among sheep classes and feed availabilities and their respective prices and costs. The optimal stocking rate occurs when the marginal economic benefit of an additional animal equals its marginal cost. Determining this point requires an understanding of the quantity and quality of feed available throughout the year, the optimal liveweight profile throughout the year, the impact of seasonal variation, the impact of labour availability, the cost of alternative feeds, prices of livestock and livestock products, the risk preferences of the farmer, and any emission policies relating to greenhouse gases. Farmers tend to use their own judgement to set their stocking rates, with the aim of maximising utility. However, the complexities listed make it a challenging task. Thus, researchers have used various simulation and programming models to aid decision-making over optimal stocking rates, but most farmers continue to rely on their own personal judgement. Moreover, often a focus of this modelling is for sheep systems in eastern Australia. Generalising this research across Australia is difficult due to differences in climatic conditions and markets across Australia. Often farmers are unaware of the profits they are foregoing when choosing either an overly conservative or excessive stocking rate. Our research has shown that foregone income of up to AUD50 per hectare can occur when a stocking rate 30% below or above the optimum is selected. Thus, despite the complexities that underpin the stocking rate decision, we believe that there are potential rewards from further research on the optimisation of stocking rates. [ABSTRACT FROM AUTHOR]

Dairy cows in Australia and New Zealand are generally kept outdoors, making them susceptible to weather variability and in particular heat stress. In this paper, we review (1) exploiting genetic variability to improve heat tolerance, (2) genotype by environment interactions, i.e. suitability of high merit cows to weather variability and (3) how novel phenotyping and genomics can help improve heat tolerance. Selection for heat tolerance is a permanent and cumulative strategy and especially useful in grazing situations where management practices, such as cooling mechanisms, are sometimes impractical. Australia was the first country in the world to release breeding values for heat tolerance in dairy cattle nationally in 2017. The breeding value captures genetic variation in the reduction of milk production traits with rising temperature and humidity. The breeding values have been validated in independent studies (in Victoria, Australia, and California, USA), showing that thermotolerant cows maintain a lower core body temperature under hot and humid conditions. Genotype by environment interactions for traits sensitive to heat is only a concern for farms in very extreme conditions and therefore affect only a small proportion of individuals (those in the extreme 5th percentile). Heat tolerance is a complex trait in that in addition to milk traits, health and fertility may also be affected. Next-generation heat tolerance breeding values may include sensor device information in addition to changes in milk composition, or other measurable biomarkers. This is especially useful when measured in genotyped female populations. Research into novel ways of measuring heat tolerance could transform the way we select for this trait and capture more of the complexity of this trait. To be successful in this area, multi-disciplinary collaboration among animal scientists is likely to facilitate this goal. Combining genomics, traditional and novel measures of heat tolerance with intermediate metabolic biomarkers and prioritised genetic variants could be a way to capture the complexity of thermotolerance in future heat tolerance breeding values. Finally, selecting cows that are resilient to variability in weather is feasible and heat tolerance is a good example of this. Dairy cows are susceptible to weather variability and in particular heat stress because of the metabolic load associated with lactation. Australian genomic breeding values for heat tolerance have been available for breeding decisions since 2017 and have been validated in independent studies. Technological advances, such as sensor devices and novel biomarkers that are measurable in female genomic reference populations will pave the way for the next-generation heat tolerance breeding values. [ABSTRACT FROM AUTHOR]

Litter management is important when rearing meat chickens because litter conditions can affect production as well as chicken health and wellbeing. An industry survey was conducted to gather information from Australian meat chicken growers and integrators about their litter management practices, providing an opportunity to share their knowledge, experiences and perceptions about litter re-use and litter turning. This information was essential for researchers investigating litter management practices because it provided a better understanding about litter preparation and shed configuration to ensure that representative and timely data could be collected. Eighty-four survey responses were received from all major growing regions across Australia. The survey closely reflected the proportions of conventional and free-range production systems of Australian chicken meat industry, with approximately 21% of survey responses representing free range and 80% representing conventional barn housing. Concerning litter management practices, the survey showed that litter re-use is limited (32% of responses), but litter turning is a widespread practice (89% of responses). Litter turning is used to reduce the occurrence of caked litter and to keep litter 'working'. Maintaining 'dry and friable' litter has been shown to reduce the risk of health issues and allows chickens to display behaviours, such as dustbathing, which are believed to be associated with improved welfare. Comments from the survey indicated that litter turning alone does not achieve dry and friable litter, and that proactive ventilation, heater and drinker management are essential. Growers also explained that litter turning is not without its challenges, and can potentially contribute to spikes of dust, ammonia and/or odour. They also expressed concerns relating to operating machinery in poultry houses, particularly when there is high liveweight density. When growers were asked about litter re-use, several reported that it has benefits in reducing production costs and improving moisture holding capacity, but concerns were also expressed about risks relating to ammonia, litter beetle control and disease transmission. Researchers will be able to use these survey results to gain an insight into practices, perceptions, constraints, and challenges relating to the Australian chicken meat industry and ensure that future research relating to litter management reflects local conditions and practices. Litter management is important in meat chicken production because good litter contributes to good productivity, health and wellbeing. Many different practices are used to manage litter, and they can lead to different outcomes. This paper summarises the responses of a survey that allowed growers and integrators in the Australian chicken meat industry to share their litter management practices and experiences. This survey will provide researchers with a deeper understanding of industry practices and conditions and will enable them to tailor their studies to reflect these. [ABSTRACT FROM AUTHOR]