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Simple Summary: This review seeks to understand how scientific research on trace elements in beef cattle has been developed and how the interaction of this theme with topics related to animal, environmental and human health has been established. Given the duality of many of the trace elements, being known as nutrients in small amounts or toxic when they exceed small concentrations, we brought the One Health perspective to analyse how researchers approach this research theme. In this work, we propose a path through scientific production to promote innovation, sustainability of animal production, food safety and human health. The objective was to investigate the context, approach and research topics present in the papers that analysed trace elements in beef cattle to identify gaps and scientific perspectives for the sustainable management of trace elements in livestock. The main research groups came from the United States, Spain, Japan, Brazil, India and Slovakia, which represented 31% of the papers produced. Only 37% of studies addressed aspects that integrated animal, environmental and human health. The reviewed papers concerned 56 elements and 15 bovine tissues (Cu, Zn, Pb, liver, muscle and kidney highlighted). The main gaps were (1) lack of research in developing countries, (2) the need to understand the impact of different environmental issues and their relationship to the conditions in which animals are raised, and (3) the need to understand the role of many trace elements in animal nutrition and their relationship to environmental and human health. Finally, we highlight possible ways to expand knowledge and provide innovations for broad emerging issues, primarily through expanding collaborative research networks. In this context, we suggest the adoption of the One Health approach for planning further research on trace elements in livestock. Moreover, the One Health approach should also be considered for managers and politicians for a sustainable environmental care and food safety. [ABSTRACT FROM AUTHOR]

Simple Summary: Through the non-destructive recognition and tracking algorithm of multi-objective behaviors of beef cattle, practitioners are able to obtain beef cattle feeding information in an all-round way, which lays the foundation for intelligent farming. This study is based on the deep learning recognition algorithm YOLOv8 and tracking algorithm Deep SORT. Through optimizing the convolution module, introducing the attention mechanism, improving the re-identification network, and the trajectory generation and matching process, a new method for the non-destructive identification and tracking of multi-target behaviors of beef cattle is constructed. The average accuracy of nine behaviors can be up to 96.5%, and the accuracy of multi-target tracking is up to 92.1%, which can provide technical support for beef cattle management. The method proposed in this paper provides theoretical and practical support for the intelligent recognition and management of beef cattle. Accurate identification and tracking of beef cattle behaviors are essential components of beef cattle production management. Traditional beef cattle identification and tracking methods are time-consuming and labor-intensive, which hinders precise cattle farming. This paper utilizes deep learning algorithms to achieve the identification and tracking of multi-object behaviors in beef cattle, as follows: (1) The beef cattle behavior detection module is based on the YOLOv8n algorithm. Initially, a dynamic snake convolution module is introduced to enhance the ability to extract key features of beef cattle behaviors and expand the model's receptive field. Subsequently, the BiFormer attention mechanism is incorporated to integrate high-level and low-level feature information, dynamically and sparsely learning the behavioral features of beef cattle. The improved YOLOv8n_BiF_DSC algorithm achieves an identification accuracy of 93.6% for nine behaviors, including standing, lying, mounting, fighting, licking, eating, drinking, working, and searching, with average 50 and 50:95 precisions of 96.5% and 71.5%, showing an improvement of 5.3%, 5.2%, and 7.1% over the original YOLOv8n. (2) The beef cattle multi-object tracking module is based on the Deep SORT algorithm. Initially, the detector is replaced with YOLOv8n_BiF_DSC to enhance detection accuracy. Subsequently, the re-identification network model is switched to ResNet18 to enhance the tracking algorithm's capability to gather appearance information. Finally, the trajectory generation and matching process of the Deep SORT algorithm is optimized with secondary IOU matching to reduce ID mismatching errors during tracking. Experimentation with five different complexity levels of test video sequences shows improvements in IDF1, IDS, MOTA, and MOTP, among other metrics, with IDS reduced by 65.8% and MOTA increased by 2%. These enhancements address issues of tracking omission and misidentification in sparse and long-range dense environments, thereby facilitating better tracking of group-raised beef cattle and laying a foundation for intelligent detection and tracking in beef cattle farming. [ABSTRACT FROM AUTHOR]

Objective: The aim of the study was to use a meta-analysis to identify the correlation between linear body measurements, including body length (BL), wither height (WH), heart girth (HG), and body volume (BV), and body weight in beef cattle by breed, sex, and age as categories. Materials and Methods: These results can be used as a method for predicting beef cattle body weight. This study used systematic review and meta-analysis guidelines to create a checklist. The first stage was searching for papers relevant to the study objectives. The second stage was searching using the keywords beef cattle, body weight, body measurement, and correlation. The third stage was reviewing the title and abstract. The fourth stage was abstracting information from selected papers, and the last stage was tabulating data. Results: The results from this study were obtained, and 32 papers were eligible for the meta-analysis stage. The correlation between linear body measurement and body weight of beef cattle showed that HG (r = 0.88) and BV (r = 0.97) were significantly (p < 0.05) different compared to BL (r = 0.74) and WH (r = 0.72). The correlation between HG and body weight, and the categorization of cattle breeds showed significantly (p < 0.05) different results. The correlation between BV and body weight of cattle according to breed categories showed results that were not significantly (p > 0.05) different, while age was significantly (p < 0.05). Conclusion: In conclusion, to predict beef cattle body weight, it is necessary to use HG or BV, with breed, sex, and age of cattle as categories. [ABSTRACT FROM AUTHOR]

Copyright of Feed Research is the property of Editorial Board of Feed Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Consumer perception of beef is heavily influenced by overall meat quality, a critical factor in the cattle industry. Genomics has the potential to improve important beef quality traits and identify genetic markers and causal variants associated with these traits through genomic selection (GS) and genome-wide association studies (GWAS) approaches. Transcriptomics, proteomics, and metabolomics provide insights into underlying genetic mechanisms by identifying differentially expressed genes, proteins, and metabolic pathways linked to quality traits, complementing GWAS data. Leveraging these functional genomics techniques can optimize beef cattle breeding for enhanced quality traits to meet high-quality beef demand. This paper provides a comprehensive overview of the current state of applications of omics technologies in uncovering functional variants underlying beef quality complexities. By highlighting the latest findings from GWAS, GS, transcriptomics, proteomics, and metabolomics studies, this work seeks to serve as a valuable resource for fostering a deeper understanding of the complex relationships between genetics, gene expression, protein dynamics, and metabolic pathways in shaping beef quality. [ABSTRACT FROM AUTHOR]

From a global point of view, the Republic of Serbia has favorable conditions for cattle breeding and beef production, because there are favorable soil and climatic conditions, high production of roughage and fodder, available workforce, installed capacities of meat processing industries (for the production of beef and meat products) etc. However, it is not the only, or exclusive, parameter of the development of cattle production, because there are significant differences in the racial composition and production potential of cattle in certain production districts of the Republic of Serbia. The paper shows the period of the movement of the number of cattle, as one of the potentials for the production of beef, and the heifers that provide new heads for fattening. In the observed time period from 2012 to 2022, it is in permanent decline. According to the obtained data of the calculated value of base and chain indices for the observed time period of ten years, there is no hint of stabilization of breeding and increase in the number of cattle for slaughter. The average number of cattle in the Republic of Serbia was 898 thousand head with a tendency to decrease from 2.5% to 3.0%. At the end of 2022, the estimate of slaughter outside slaughterhouses in December was reduced to 16 thousand heads, however, the number of slaughtered heads increased from May and reached its maximum in October with 20.61 thousand heads and in November when there were 26.45 thousand heads. From this data, it can be seen that the total number of heads has been decreasing since December, which means that there has been stagnation in the number of slaughtered heads. [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]

Copyright of Agricultural Outlook (1673-3908) is the property of Institute of Agricultural Information, Chinese Academy of Agricultural Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Binary outcomes are likely the most common in randomized controlled trials, but ordinal outcomes can also be of interest. For example, rather than simply collecting data on diseased versus healthy study subjects, investigators may collect information on the severity of disease, with no disease, mild, moderate, and severe disease as possible levels of the outcome. While some investigators may be interested in all levels of the ordinal variable, others may combine levels that are not of particular interest. Therefore, when research synthesizers subsequently conduct a network meta-analysis on a network of trials for which an ordinal outcome was measured, they may encounter a network in which outcome categorization varies across trials. Methods: The standard method for network meta-analysis for an ordinal outcome based on a multinomial generalized linear model is not designed to accommodate the multiple outcome categorizations that might occur across trials. In this paper, we propose a network meta-analysis model for an ordinal outcome that allows for multiple categorizations. The proposed model incorporates the partial information provided by trials that combine levels through modification of the multinomial likelihoods of the affected arms, allowing for all available data to be considered in estimation of the comparative effect parameters. A Bayesian fixed effect model is used throughout, where the ordinality of the outcome is accounted for through the use of the adjacent-categories logit link. Results: We illustrate the method by analyzing a real network of trials on the use of antibiotics aimed at preventing liver abscesses in beef cattle and explore properties of the estimates of the comparative effect parameters through simulation. We find that even with the categorization of the levels varying across trials, the magnitudes of the biases are relatively small and that under a large sample size, the root mean square errors become small as well. Conclusions: Our proposed method to conduct a network meta-analysis for an ordinal outcome when the categorization of the outcome varies across trials, which utilizes the adjacent-categories logit link, performs well in estimation. Because the method considers all available data in a single estimation, it will be particularly useful to research synthesizers when the network of interest has only a limited number of trials for each categorization of the outcome. [ABSTRACT FROM AUTHOR]

Cattle beef is an essential animal protein in sub-Saharan Africa. However, pastoralists dominate cattle production in sub-Saharan Africa, and their output is dependent on the availability of fodder from grasslands in rain-fed systems, which makes cattle production more vulnerable to climate change and environmental degradation. However, evidence of climate change impacts on cattle production in the region is scarce. Also, studies on the effects of environmental quality on cattle production using superior proxies (such as ecological and carbon footprints, and grazing land) rather than carbon dioxide emissions are rare. The effects of climatic factors (such as temperature and precipitation) and environmental quality measures (such as ecological and carbon footprints and grazing land) on cattle production in Nigeria, Africa's most populous country, were studied. Other covariates such as cattle share of total livestock population and cattle unit per agricultural land were also considered in the study. Time-series data from 1971 to 2018 were obtained from the Food and Agriculture Organization statistical database, World Bank Climate Change Knowledge Portal, and Global Footprint Network. Using autoregressive distributed lag model to analyze the data, the paper found that carbon footprint, ecological footprint, grazing area, rainfall, cattle share of total livestock population, and cattle unit per agricultural land all have long-term effects on cattle production in Nigeria. Under the current climate change and environmental degradation regime, appropriate policy measures for effective and efficient cattle production were recommended. [ABSTRACT FROM AUTHOR]

Purpose: Supply chain governance constitutes the rules, structures and institutions that guide supply chains toward various objectives, including environmental sustainability. Previous studies have provided insight into the relationship between governance and sustainability but have overlooked two crucial dimensions: power dynamics and the influence of outside actors. This paper aims to address these two gaps by measuring differential power (i.e. power asymmetries) among actors across the supply chain, including external actors. Design/methodology/approach: This paper quantifies power dynamics across the entire chain through a structured survey in which supply chain participants rank their peer's ability to affect environmental and social outcomes. This paper tests this approach by surveying 200 industry professionals (e.g. feedlot owners, retailers) and external actors (e.g. NGOs) in the US beef sector. Findings: Respondents ranked the most powerful actors as follows: feedlot owners; processing plant owners; and regulatory agencies. Results also revealed that trade associations, retailers and cow–calf producers and ranchers perceive a sense of powerlessness. This study reveals multiple power nodes and confirms a shift in the power structure depending on which indicator respondents considered (e.g. environmental impacts vs employee safety). This study concludes that the buyer–producer dichotomy often used to assess supply chain governance fails to capture the complex dynamics among actors within supply chains. Originality/value: This study demonstrates a novel approach to measure perceptions of power in supply chains. This method enables researchers to map networks of power across entire supply chains, including internal and external actors, to advance understanding of supply chain governance dynamics. Previous studies have misidentified who governs environmental outcomes in supply chains, and NGOs have overestimated the power of consumers and retailers to influence producers. [ABSTRACT FROM AUTHOR]

Stockmanship is an important determinant for good animal welfare and health. The goal of the FarmMERGE project is to investigate the associations between farmer health and work environment, and the health, productivity and welfare of their livestock. We merged several livestock industry databases with a major total population-based health study in Norway (The Trøndelag Health Study 2017–2019 (HUNT4)). This paper describes the project's collection and merging of data, and the cohort of farmers and farms that were identified as a result of our registry merge. There were 56,042 participants of HUNT4 (Nord-Trøndelag County participants only, participation rate: 54.0%). We merged a list of HUNT4 participants whose self-reported main occupation was "farmer" (n = 2,407) with agricultural databases containing production and health data from sheep, swine, dairy and beef cattle from 2017–2020. The Central Coordinating Register for Legal Entities was used as an intermediary step to achieve a link between the farmer and farming enterprise data. We identified 816 farmers (89.5% male, mean age 51.3 years) who had roles in 771 farming enterprises with documented animal production. The cohort included 675 unique farmer-farm combinations in cattle production, 139 in sheep, and 125 in swine. We linked at least one HUNT4 participant to approximately 63% of the dairy farms, 53% of the beef cattle farms, 30% of the sheep farms, and 38% of the swine farms in Nord-Trøndelag County in the 2017–2019 period. Using existing databases may be an efficient way of collecting large amounts of data for research, and using total population-based human health surveys may decrease response bias. However, the quality of the resulting research data will depend on the quality of the databases used, and thorough knowledge of the databases is required. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to develop a method for predicting the body weight of beef cattle using meta-analysis based on digital image processing. Materials and Methods: The meta-analysis process commenced by collecting studies with the keywords "beef cattle," "correlation," "digital image," and "body weight" from Google Scholar and Science Direct. The obtained studies were reviewed papers based on their titles, abstracts, and content, and then categorized by authors, year, country, sample size, and correlation coefficient. A digital image of body measurements used included wither and hip height, chest depth, heart girth, body length, and top view. The statistical analysis was conducted by calculating effect sizes using the correlation coefficient and sample sizes. Results: The results of the meta-analysis, based on 3,017 cattle from 13 selected studies, showed the highest and lowest correlation coefficients for the top view variable and hip height. Based on cattle breed, significant differences (p < 0.05) were observed in the wither height variable with correlation coefficients of 0.94, 0.79, and 0.66 for Hanwoo, Holstein, and Simmental, respectively. Based on sex, significant differences (p < 0.05) were seen in the wither height variable, with correlation coefficients of 0.73 for males and 0.90 for females, while for hip height, the values were 0.70 and 0.87, respectively. Conclusion: In conclusion, to achieve the best accuracy in predicting the body weight of beef cattle based on a digital image, the top view variable can be used. However, for ease of field experimentation, body length or chest depth can also be used while taking breed and sex categories into the model. [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]

Alfalfa is an important crop for the seven western states in the U.S. However, price reporting is inconsistent across the states and there is no futures market for alfalfa hay. This creates price uncertainty within these hay markets. This paper looks at how closely alfalfa hay prices in one state track with hay prices in another state. Further, the paper seeks to determine what factors have influenced alfalfa hay prices over time. Alfalfa prices for the last 30 years, 1992-2021, for each of the seven western states of Arizona (AZ), California (CA), Idaho (ID), Nevada (NV), Oregon (OR), Utah (UT), and Washington (WA) were analyzed and compared. The hay prices between the states are correlated between 0.85 and 0.96. California and Oregon had the highest prices over time and Idaho and Utah had the lowest prices. A regression model was developed to explain what factors influence western state alfalfa hay prices. The findings indicate that larger May 1 hay stocks for the seven-state total leads to lower alfalfa hay prices. Additionally, increased hay exports increase hay prices. Higher corn, feeder cattle and milk prices all positively impact alfalfa hay prices with corn having the biggest impact and milk prices having the smallest impact. [ABSTRACT FROM AUTHOR]

Beef quality is characterized by marbling (marbling degree and marbling fineness), physiochemical (shear force, meat color, fat color, texture, and maturity), and sensory (tenderness, flavor, juiciness, taste, odor, and appearance) traits. This paper summarizes and addresses beef-quality characteristics and the beef-grading systems in Korea, Japan, the USA, and Australia. This paper summarizes recent research progresses on the genetic and nutritional factors that affect beef quality. Intramuscular (i.m.) adipose tissue deposition or marbling is a major determinant of beef quality. This paper addresses the mechanisms of i.m. adipose tissue deposition focused on adipogenesis and lipogenesis. We also address selected signaling pathways associated with i.m. adipose tissue deposition. Nutrients contribute to the cellular response and phenotypes through gene expression and metabolism. This paper addresses control of gene expression through several nutrients (carbohydrates, fat/fatty acids, vitamins, etc.) for i.m. adipose tissue deposition. Several transcription factors responsible for gene expression via nutrients are addressed. We introduce the concept of genome-based precision feeding in Korean cattle. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to highlight the difference in the average daily gain recorded in the bulls of the Aubrac breed, exploited in the conditions of our country. The database was made up of data recorded in two fattening bull farms of the Aubrac breed. The average daily gain of the animals recorded at the age of 12 months, as well as the average daily gain at the age of 18 months, were measured. A total of 30 animals (15 animals from farm 1, and 15 animals from farm 2) were studied. The results were statistically interpreted, which showed that there were no significant differences between the animals from the two studied farms, but there were statistically significant differences between the average daily increase recorded at 12 months compared to the average daily increase recorded at 18 months. [ABSTRACT FROM AUTHOR]

The objective of this paper is to evaluate the effects of creep feeding supplementation during the preweaning phase on the growth performance and metabolic characteristics of Nellore heifers. Forty-two female Nellore calves (age = 100 ± 25 d; initial body weight (BW) = 113.4 ± 16.6 kg) were randomly assigned to the following treatments: control, where calves received mineral mix supplementation (n = 21); supplemented in creep feeding, where calves received 6 g/kg BW of a concentrate supplement (n = 21) during a period of 140 d. In the postweaning phase, all heifers received 6 g/kg BW of a concentrate supplement during a period of 210 d. Supplemented heifers had a greater average daily gain (ADG) than control heifers during the preweaning phase and, consequently, were heavier at weaning and at the end of the growing phase (p < 0.05). However, preweaning supplementation did not influence (p > 0.05) the body measurements or BW at the end of the growing period. Greater (p < 0.05) rib fat was observed in supplemented heifers. Concentrations of metabolites were not affected by preweaning supplementation (p > 0.05). Thus, supplementing heifers in the preweaning phase improved growth performance of weaning and body adiposity. [ABSTRACT FROM AUTHOR]

The Internet of Things (IoT) is a development trend in modern industry and life. It can not only reduce the cost of industry and agriculture, but also improve the quality of products and the quality of people's lives. Therefore, IoT breeding is the embodiment of modern intelligent agriculture. For example, in the estrus detection of beef cattle, the quality of video images when tracking beef cattle is reduced due to changes in external climate conditions and the difference between daytime and nighttime illumination. This paper introduces a visual target tracking algorithm based on saliency, so that it has better applicability and robustness. The algorithm realizes the image enhancement of beef cattle in different periods of time and under different weather conditions. It provides high-quality samples for the automatic recognition of beef cattle estrus and realizes the all-day contactless real-time monitoring of beef cattle estrus. Wireless communication, embedded technology, video monitoring, a database, and other technologies are used to combine the fan, water curtain, side window, feeder, camera, various sensors, and other equipment to form a breeding tracking system based on the IoT. The front-end device sent the command to the lower computer through the control key. After receiving the command, the terminal connected to the designated feeding facility and controlled the feeding device cutoff through the relay startup and relay cutoff process. The administrator used a PC or mobile phone for remote control. During estrus, the body temperature of cattle increased significantly, by about 0.26 ℃. The scheme in the article can reflect the environment and estrus in the cowshed in real time and provide more intuitive data for the manager. [ABSTRACT FROM AUTHOR]

Simple Summary: In recent years, the shortage of cow stocks and the reduction of cow breeders in China have caused a shortage of cattle resources and a high price of calves, which has become a bottleneck restricting the further development of China's beef cattle industry. At present, there are few studies on the decision-making behavior of cow breeding in China. In order to explore the factors that affect the decision-making behavior on cow breeding by beef cattle farmers, this paper uses field survey data to make an empirical analysis through the Logit ISM model. The results show that the age of the breeder, the breeding year, the planting area of forage, market expectations, the loan amount, the breeding method policy publicity and policy subsidies are significant factors affecting the decision-making behavior of beef cattle farmers on cow breeding. The beef cattle industry is an important part of herbivorous animal husbandry and an important industry to enrich the dietary structure of residents and promote the income of farmers and herdsmen. The cow is an important foundation to support the healthy development of the beef cattle industry, which is related to the stability of cattle sources and the sustainable development of the industry. However, in recent years, the shortage of cows in our country has led to the shortage of cattle resources and the high price of calves, which has restricted the further development of our beef cattle industry. In order to explore the factors that affect the decision-making behavior behind cow breeding and to find the right policy to mobilize the enthusiasm for cow breeding, based on the field survey of five provinces (cities and regions), including Inner Mongolia Autonomous Region and Ningxia Hui Autonomous Region, this paper conducts an empirical analysis through the Logit ISM model. The results show that market expectation is the surface factor that directly affects the decision-making behavior of cow breeding. The influencing factors of the middle layer are policy propaganda, policy subsidies, breeding years, and feeding methods. The deep root factors are the age of the breeder, the amount of loan, and whether to plant feed crops. Based on this, this paper proposes that we should actively promote the importance of cow breeding, strengthen policy support for cow breeding, formulate scientific and reasonable subsidy policies for cows, innovate financial support methods to solve the problem of fund shortage of farmers, and develop forage resources and reduce the breeding cost of cows. [ABSTRACT FROM AUTHOR]

With the development of scale and industrialization of animal husbandry, the era of total prohibition comes. At the same time, the beef cattle industry's demand for natural and safe feed additives is increasing day by day, and the research and development of green, safe and pollution-free substitute products is the inevitable trend of the development of beef cattle industry. Natural Chinese herbal resources are abundant in our country. Chinese herbal are rich in various nutrients and are widely used in beef cattle breeding industry. Chinese herbal feed additives have multiple functions and complex medicinal mechanism. It can cure diseases, reduce inflammation and sterilization, regulate the balance of intestinal flora, promote nutrient absorption and metabolism, improve animal production performance and immune function, feed digestibility and quality of animal products. This paper summarizes the active substances, biological functions and application of Chinese herbal additives in beef cattle breeding, aiming to provide reference for the wide application of Chinese herbal additives and the healthy breeding of beef cattle. [ABSTRACT FROM AUTHOR]

The document titled "Correction to 'Ranking buffel: Comparative risk and mitigation costs of key environmental and socio-cultural threats in central Australia'" addresses a correction that needs to be made to a previous publication. The correction involves a personal communication estimate regarding the benefits of buffel grass to the pastoral industry in Australia. The authors acknowledge that they were unable to obtain reliable estimates and apologize for the error. They clarify that the economic estimate is not the focus of the paper and suggest replacing it with more factual and defendable text. [Extracted from the article]

Environmental regulation can interact with agricultural markets to produce underappreciated competitiveness and leakage effects. This paper measures effective carbon tax stringency by structurally recovering the domestic supply schedule for a trade‐exposed beef cattle industry such that elasticities and carbon tax rates change with product prices (i.e., due to the curvature of the supply function). Two basic propositions from the economics of taxation—that excess burdens increase in elasticities and tax rates—are shown to cause the stringency of uniform carbon policy to vary nonlinearly with output prices. Based on the domestic supply function, the relationship between marginal excess burden, a measure of policy stringency from the industry's perspective, and product prices is estimated. Several policy‐relevant counterfactual scenarios are explored. Results show that with moderately high output prices, supply elasticities are small and the efficiency cost of a $40/tCO2e carbon tax (gross of environmental benefits) is less than $0.01 per dollar tax revenue. As prices decline, supply curves become increasingly elastic and marginal excess burdens grow rapidly. [ABSTRACT FROM AUTHOR]

Copyright of Feed Research is the property of Editorial Board of Feed Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Previous studies on winter supplementation of growing cattle grazing stockpiled native Campos grasslands suggest that forage allowance (FA), herbage mass, and weather conditions before and during the supplementation period could all affect supplement feed efficiency (SFE)—that is, the difference or change in average daily gain (ADG) between supplemented (S) and control (C) animals (ADGchng, kg) per unit (kg) of supplement dry matter (DM) intake. In this study, we analyse data from fifteen collated winter supplementation trials carried out in Uruguay between 2004 and 2018. The working hypotheses of this research paper were: (i) that average substitution rates are positive, and (ii) that ADGchng is not constant throughout the supplementation period and that its variation may be attributed to sward, animal or weather variables. There were two main objectives: (i) to estimate the average supplement substitution rate (sSbR, kg forage, f, dry matter, DM intake reduction: kg supplement DM intake) and potential herbage intake substitution rate (hSbR, kg fDM intake reduction: kg fDM intake of control animals), and its association with SFE, and, (ii) to assess the existence of different phases and supplementation response patterns and its association with other relevant variables. Estimated substitution rates were always positive (sSbR = 0.3–1.1 kg/kg; hSbR = 0.1–0.3 kg/kg) and were negatively and moderately associated with SFE. Supplementation proved to be a dynamic process where three possible supplementation responses over the supplementation period were identified (linear, quadratic and Weibull). While linear patterns did not appear distinctly associated with any particular set of variables, quadratic models were mostly associated with herbage biomass and substitution rates, whereas Weibull models were the clearest in their association with frosts. Regardless of the response pattern, at the beginning of the trials it was the animals' body weight and supplement quality that most influenced supplement response, whereas towards the end, supplementation intake, supplemented animals' ADG and forage quality played a more relevant role. The estimated parameters and response patterns are expected to be used as inputs in decision support systems for livestock farmers in the future. [ABSTRACT FROM AUTHOR]

Simple Summary: Developing new, ecologically healthy feed has always been the focus of sustainable animal husbandry development and has been a research hotspot in academic circles. Currently, the bio-feed industry is developing rapidly and efficiently. The resources of feed raw materials are constantly being enriched and expanded, strain screening research is gradually deepening, production technologies such as enzyme preparations and bacterial preparations are continuously being optimized and upgraded, and the number of professional livestock personnel is constantly increasing. The development of bio-feed has broad application prospects. However, there are increasing problems facing biological feed. Therefore, this paper summarizes the classification, function, application, and existing issues of biological feed in livestock and poultry production to provide a reference for subsequent related research and applications. Biological feed is a feed product developed through bioengineering technologies such as fermentation engineering, enzyme engineering, protein engineering, and genetic engineering. It possesses functional characteristics of high nutritional value and good palatability that can improve feed utilization, replace antibiotics, enhance the health level of livestock and poultry, improve the quality of livestock products, and promote a better breeding environment. A comprehensive review is provided on the types of biological feed, their mechanism of action, fermenting strains, fermenting raw material resources, and their current status in animal production to facilitate in-depth research and development of applications. [ABSTRACT FROM AUTHOR]

Copyright of Feed Research is the property of Editorial Board of Feed Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Feed Research is the property of Editorial Board of Feed Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Beef is known to be an important ingredient in the cuisine of European countries, and globally it ranks third in consumer preferences. In this context, the paper describes aspects related to cattle herds as well as slaughtered cattle and beef production in the European Union and in the main countries where the breeding of these animals is a tradition. Thus, France, Germany and Ireland were in the first positions. At the same time, EU beef imports and exports are presented, in terms of value for the categories: live animals, fresh and chilled beef and frozen beef. Against the background of the current geopolitical instability, it is worth noting that Romania does not occupy an important position on the beef market, especially since the number of animals and slaughtered meat production decreased during the analyzed period, 2015-2021. Instead, for our country we can see an increase in imports. [ABSTRACT FROM AUTHOR]

The purpouse of this paper was to highlight the morpho-productive indicators of Aubrac and Aberdeen Angus cattle breeds exploited in Romania. Data were collected from a number of 40 cattle, following the weaning weight (age of 7 months) and the average daily gain increase of the animals, which benefited from similar exploitation conditions. Also, based on the results obtained, a statistical interpretation was performed. At the age of 7 months, an average body weight of 216.6 kg was observed in Aubrac cattle, with an average daily gain increase of 912 g/day, while in Aberdeen Angus cattle an average body weight of 184.3 kg was observed, the animals recorded an average daily gain increase of 799 g/day. In conclusion, in the case of both breeds of cattle, the satisfactory parameters specific to the breeds of meat were highlighted, but making a comparison we can appreciate that the results observed in the Aubrac breed are superior. [ABSTRACT FROM AUTHOR]

The study assessed the relationship between rib fat thickness and carcass price among different carcass weight groups in Korean native cattle (Hanwoo), taking into account changes in the beef grading system. Data from 8 926 Hanwoo steers, with an average age of 30.6 ± 1.88 months and slaughtered between 2017 and 2019, were analysed. The variables considered included rib fat thickness, carcass weight, eye muscle area, marbling score, and carcass price. Steers were categorised into eight carcass weight groups ranging from 250 kg to 650 kg in the original system, rib fat thickness consistently had a negative impact on carcass price, with partial coefficients of rib fat thickness on carcass price ranging from -1.96 to -46.5 depending on the carcass weight groups. Conversely, in the revised system, the impact of rib fat thickness varied from negative to positive, turning positive at the 450 kg carcass weight group. These findings may guide decision-making in beef cattle production and feeding strategies under the revised grading system. [ABSTRACT FROM AUTHOR]

By definition, ill and injured animals are on the negative valence of animal welfare. For beef cattle kept in feedlot settings, advances in cattle health management have resulted in a greater understanding and prevention of illness and injury. However, the management of cattle once they become ill and injured is an understudied area, and there are gaps in knowledge that could inform evidence-based decision-making and strengthen welfare for this population. The aim of this review is to provide a comprehensive overview of the acquired knowledge regarding ill and injured feedlot cattle welfare, focusing on existing knowledge gaps and implications for hospital and chronic pen management and welfare assurance. Ill and injured feedlot cattle consist of acutely impaired animals with short-term health conditions that resolve with treatment and chronically impaired animals with long-term health conditions that may be difficult to treat. A literature search identified 110 articles that mentioned welfare and ill and injured feedlot cattle, but the population of interest in most of these articles was healthy cattle, not ill and injured cattle. Articles about managing ill and injured cattle in specialized hospital (n = 12) or chronic (n = 2) pens were even more sparse. Results from this literature search will be used to outline the understanding of acutely and chronically ill and injured feedlot cattle, including common dispositions and welfare considerations, behavior during convalescence, and strategies for identifying and managing ill and injured cattle. Finally, by working through specific ailments common in commercial feedlot environments, we illustrate how the Five Domains Model can be used to explore feelings and experiences and subsequent welfare state of individual ill or injured feedlot cattle. Using this approach and our knowledge of current industry practices, we identify relevant animal-based outcomes and critical research questions to strengthen knowledge in this area. A better understanding of this overlooked topic will inform future research and the development of evidencebased guidelines to help producers care for this vulnerable population. [ABSTRACT FROM AUTHOR]

This paper proposed a supplemental feeding pusher based on beef cattle's auxiliary feeding needs to solve the traditional feeding mode of manual work, labor intensity, and inconsistent manual work standards. Firstly, the conveyed feed particles movement process was established as a motion model and the basis of the design parameters of the screw conveyor was explained. ANSYS static analysis module was used to ensure that the structural parameters of the discharging device were reasonable, ANSYS vibration modal analysis module was used to verify the frame strength and stability. According to the theoretical design of the trial prototype, the control system with STM32F103RE microcontroller as the core was carried out. Finally, the orthogonal test was conducted with the screw shaft speed, sweeping roller brush height, and traveling speed as test factors; different parameters were set to verify the effect of supplemental feeding and pushing, and parameter optimization of the test results was carried out using Design-Expert software. The optional combination of working parameters was determined to be the feeding screw shaft speed 188 r/min, the sweeping roller brush speed 160 r/min, and the work speed 0.26 m/s. The test demonstrated that the residual feed width was 0.73 m, and the transverse coefficient of variation was 14.9%, which could satisfy the needs of auxiliary feeding for beef cattle. This study reduced feed waste and met the cattle feeding needs to the greatest extent, and it could provide a reference for auxiliary feeding machinery. [ABSTRACT FROM AUTHOR]

In the past few decades, genomic selection and other refined strategies have been used to increase the growth rate and lean meat production of beef cattle. Nevertheless, the fast growth rates of cattle breeds are often accompanied by a reduction in intramuscular fat (IMF) deposition, impairing meat quality. Transcription factors play vital roles in regulating adipogenesis and lipogenesis in beef cattle. Meanwhile, understanding the role of transcription factors in regulating adipogenesis and lipogenesis in beef cattle has gained significant attention to increase IMF deposition and meat quality. Therefore, the aim of this paper was to provide a comprehensive summary and valuable insight into the complex role of transcription factors in adipogenesis and lipogenesis in beef cattle. This review summarizes the contemporary studies in transcription factors in adipogenesis and lipogenesis, genome‐wide analysis of transcription factors, epigenetic regulation of transcription factors, nutritional regulation of transcription factors, metabolic signalling pathways, functional genomics methods, transcriptomic profiling of adipose tissues, transcription factors and meat quality and comparative genomics with other livestock species. In conclusion, transcription factors play a crucial role in promoting adipocyte development and fatty acid biosynthesis in beef cattle. They control adipose tissue formation and metabolism, thereby improving meat quality and maintaining metabolic balance. Understanding the processes by which these transcription factors regulate adipose tissue deposition and lipid metabolism will simplify the development of marbling or IMF composition in beef cattle. [ABSTRACT FROM AUTHOR]

Copyright of Feed Research is the property of Editorial Board of Feed Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Bovine respiratory disease (BRD) has been identified as the most significant infectious disease of feedlot cattle in eastern Australia.1 Bovine respiratory disease causes economic loss due to medication costs, mortalities, excessive feed inputs associated with increased time on feed, reduced sale prices and associated labour costs. Bovine respiratory disease is a complex multifactorial condition with multiple animal, environmental and management risk factors predisposing cattle to illness. A range of microorganisms are implicated in BRD with at least four viral and five bacterial species commonly involved individually or in combination. The viruses most commonly associated with BRD in Australia are bovine herpesvirus 1 (BHV1), bovine viral diarrhoea virus (BVDV or bovine pestivirus), bovine parainfluenza 3 virus (PI3) and bovine respiratory syncytial virus (BRSV). More recently, bovine coronavirus has been identified as a potential viral contributor to BRD in Australia.2 A number of bacterial species have also been recognised as important to the BRD complex; these include Mannheimia haemolytica, Pasteurella multocida, Histophilus somni, Trueperella pyogenes and Mycoplasma bovis. Although one or more of the pathogens listed above can be isolated from clinical cases of BRD, there is no evidence that infection alone causes serious illness. This indicates that, in addition to specific infectious agents, other factors are crucial for the development of BRD under field conditions. These can be categorised as environmental, animal and management risk factors. These risk factors are likely to exert their effects through multiple pathways including reductions in systemic and possibly local immunity. For example, stressors such as weaning, handling at saleyards, transport, dehydration, weather conditions, dietary changes, comingling and pen competition might reduce the effectiveness of the immune system. Reduced immunocompetence can allow opportunistic infection of the lower airways with potential pathogens leading to the development of BRD. The objective of this paper is to critically review the evidence for management practices aimed at reducing the incidence of BRD in Australian feedlot cattle. Predisposing factors (Table 1) largely beyond the control of most feedlots, such as weather and exposure to respiratory viruses, are discussed separately, but these factors can generate indirect prevention responses that are discussed under the preventative practices categories. The current practices are classified as either animal preparation practices (Table 2) or feedlot management practices (Table 3). [ABSTRACT FROM AUTHOR]

Rumen is an important digestive organ of ruminants, the health of rumen function directly affects the digestion and absorption of feed by ruminants. Maintaining the stability of its microflora is of great research value for maintaining animal health, exerting its production performance and improving economic benefits. In the paper, the composition of rumen microflora, the mechanism of nutrient absorption and metabolism in rumen digestion and the measures to improve rumen health of beef cattle are reviewed, in order to provide reference for promoting efficient utilization of diets and improving production performance of beef cattle. [ABSTRACT FROM AUTHOR]

Beef production drives a significant proportion of Australia's agricultural economy, representing AUD11 billion in agricultural production value annually. The profitability of cattle farms across seasons varies greatly and is particularly influenced by weather and associated uncertainty through pasture growth. Furthermore, producers must be careful in managing stocking rates to avoid overgrazing which has a significant environmental and economic impact. Predictive modelling of pasture and cattle liveweight can help producers to better manage this difficult balancing act. In this paper, we integrate a model for pasture growth and cattle weight gain to formulate predictions of liveweight production volume and pasture biomass. Monte‐Carlo simulation was used to understand the impact of uncertainty in model inputs relating to weather. Through such an approach, a distribution of possible pasture outcomes and beef production is formed which can be inspected to determine, for example expected production volume and risk of overgrazing. The methodology is demonstrated and validated through application to case study data sourced from Australian beef producers. Results demonstrate that it is possible to obtain reasonable predictions of liveweight gain and highlight the importance of considering the associated uncertainty. The accuracy of the proposed models has been examined by calculating statistical parameters MSE, MAE and R2. This approach can provide insight into the distribution of possible production outcomes given the long‐term rainfall outlook. The use of such predictive models and simulations by producers will lead to better‐informed planning of stocking rates, with benefits to productivity and sustainable utilisation of pasture. [ABSTRACT FROM AUTHOR]

In recent years, eco-efficiency assessment has proven to be an effective tool to reduce the environmental damages of agricultural activities while preserving their economic sustainability. Hence, this paper aims to assess the eco-efficiency of a sample of 148 beef cattle farms operating in the extensive livestock system of Central Italy. The analysis is based on Farm Accountancy Data Network (FADN) economic data in the year 2020 and includes, as environmental pressures, farm expenditure for the use of fuels, electricity and heating, and fertilizers. A two-stage approach was implemented: in the first stage, an input-oriented DEA model including slack variables was used to quantify farm eco-efficiency scores and determine the polluting inputs' abatement potentials. In the second stage, the influence of possible influencing factors on eco-efficiency scores was tested using a regression model for truncated data. The analyzed farms were found to be highly eco-inefficient, as they could abate their environmental pressures, on average, in a range from 56% to 60% while keeping the value of their global production constant. Fertilizers and fuel consumption were identified as the least efficiently operating inputs, with potential reductions in terms of the related expenditures fluctuating between 9% and 42%. Farms showing a high-intensity livestock system, a low labor intensity, and a larger farm area were recognized as the most eco-efficient. Environmental and animal welfare subsidies were found to not affect eco-efficiency, while a negative influence was estimated for a single farm payment, which does not seem to be an incentive mechanism for farms to operate efficiently. [ABSTRACT FROM AUTHOR]

Copyright of Feed Research is the property of Editorial Board of Feed Research and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper aims to investigate the influence of increasing chitosan doses on the relative proportion and abundance of cellulotytic, amylolytic bacteria, and Archaea transcripts for grazing cattle. Five rumen cannulated crossbread steers [3.6 months and 300 ± 25 kg body LW (live weight), mean ± standard deviation] were used in a 5 × 5 latin square design, randomly assigned to treatment sequence containing chitosan added to 0, 400, 800, 1200, or 1600 mg/kg concentrate. There was the effect of chitosan on the population of Fibrobacter succinogenes, Ruminococcus albus, and Archaea. The lowest population of these bacteria of 576.60 mg/kg DM (dry matter), 1010.40 mg/kg DM, and 634.80 mg/kg DM were noted when chitosan was added at levels of 3.87, 4.16, and 3.52. Except for Ruminococcus albus, which was not affected by increasing chitosan doses, supplementation of this additive in the concentrate quadratically increased the relative abundance of Fibrobacter succinogenes and Archaea Supplemental 740 mg CHI/kg concentrate for grazing steers receiving concentrate at 150 grams/100 kg LW is recommended to promote minimal effect on the relative population and abundance of cellulolytics and amylomatics and to restrict Archaea growth. [ABSTRACT FROM AUTHOR]

Simple Summary: Subcutaneous fat deposition in cattle has become the focus of breeders' attention because excessive deposition is not conducive to efficient feed conversion. In the present study, based on the results of blood transcriptome sequencing and the detection of metabolites, bioinformatic analysis was used to explore the differential genes and metabolites associated with the subcutaneous fat depot phenotype of beef cattle. In conclusion, the functional genes SMPD3 and CERS1, as well as the metabolite sphingosine 1-phosphate, were identified as an important metabolite and candidate genes to account for the differences in phenotype. These differential genes and the metabolite are thought to have an important reference value for effective breeding to improve beef performance. A crucial goal of reducing backfat thickness (BFT) is to indirectly improve feed conversion efficiency. This phenotype has been reported in certain papers; however, the molecular mechanism has yet to be fully revealed. Two extreme BFT groups, consisting of four Qinchuan cattle, were chosen for this study. We performed metabolite and transcriptome analyses of blood from cattle with a high BFT (H-BFT with average = 1.19) and from those with a low BFT (L-BFT with average = 0.39). In total, 1106 differentially expressed genes (DEGs) and 86 differentially expressed metabolites (DEMs) were identified in the extreme trait. In addition, serum ceramide was strongly correlated with BFT and could be used as a potential biomarker. Moreover, the most notable finding was that the functional genes (SMPD3 and CERS1) and metabolite (sphingosine 1-phosphate (S1P)) were filtered out and significantly enriched in the processes related to the sphingolipid metabolism. This investigation contributed to a better understanding of the subcutaneous fat depots in cattle. In general, our results indicated that the sphingolipid metabolism, involving major metabolites (serum ceramide and S1P) and key genes (SMPD3 and CERS1), could regulate BFT through blood circulation. [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 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]