Behavioral changes in group-housed dairy calves infected with Mannheimia haemolytica

Producer perceptions of dairy calf management, behavior, and welfare

Approaches for raising calves vary across commercial dairy farms and relate to behavioral opportunities and animal welfare. The objectives of this study were to evaluate how US dairy producers and calf managers perceive (1) the welfare implications of varying management practices (including social housing and milk allowance) and behaviors in dairy calves, and (2) aspects of the human-animal relationship in calf rearing and relationships with on-farm management and personal calf handling habits. Survey questions were primarily quantitative (e.g., Likert scales) and addressed how common calf management practices and observed calf behaviors were related to aspects of welfare, including calf health and comfort. We additionally posed questions addressing respondent habits, management protocols, and perceptions related to human-animal interaction. Responses from 93 dairy producers and calf managers were collected via digital surveys. Social housing was viewed as being generally positive for both calf comfort and health, although this view was stronger with respect to calf comfort. Respondents from farms using social housing (56%) had more positive perceptions of social housing, viewed social play as being associated with better calf comfort and health, and considered access to other calves and "freedom to express natural behavior" as being more important for calves, compared with respondents from farms not providing social housing. Providing greater milk allowances (>7.6 L/d) was viewed as being good for both calf comfort and health, although respondents from farms providing these milk allowances (59%) had more positive perceptions than those who provided lesser allowances. Abnormal oral behaviors were viewed as being associated with both poor calf comfort and health. The welfare importance of various resources which may reduce abnormal oral behaviors (including hay and brushes) was perceived more ambiguously, although respondents from farms providing these resources, compared with those who do not, generally viewed them as more preferred by calves. We observed a positive relationship between how respondents perceived the human-animal bond (i.e., that calves enjoy contact with humans) and stated personal behavior related to calf contact (frequency of contacting calves to scratch or pet them). Respondent demographics were not related to perceptions of the human-animal relationship, but respondents identifying as female described more frequent positive calf interactions. Described aspects of human-animal interactions were not related to implementation of social housing on-farm. Job satisfaction was positively related to perception of the human-animal relationship. Overall, these results suggest that most calf management personnel place a high value on calf welfare, although farms implementing social housing appear to place a greater value on subjective calf well-being, and individual perceptions of animal welfare may depend on practical experience.

Evaluation of candidate data-based welfare indicators for veal calves in Switzerland

Welfare assessment protocols have been developed for dairy cows and veal calves during the past decades. One practical use of such protocols may be conducting welfare assessments by using routinely collected digital data (i.e., data-based assessment). This approach can allow for continuous monitoring of animal welfare in a large number of farms. It recognises changes in the animal welfare status over time and enables comparison between farms. Since no comprehensive data-based assessment for veal calves is currently available, the purposes of this review are (i) to provide an overview of single existing data-based indicators for veal calves and (ii) to work out the necessary requirements for data-based indicators to be used in a comprehensive welfare assessment for veal calves in Switzerland. We used the Welfare Quality Protocol® (WQ) for veal calves and the Terrestrial Animal Health Code from the World Organisation of Animal Health for guidance throughout this process. Subsequently, routinely collected data were evaluated as data sources for welfare assessment in Swiss veal operations. The four WQ principles reflecting animal welfare, i.e., 'good feeding', 'good housing', 'good health' and 'appropriate behaviour' were scarcely reflected in routinely available data. Animal health, as one element of animal welfare, could be partially assessed using data-based indicators through evaluation of mortality, treatments, and carcass traits. No data-based indicators reflecting feeding, housing and animal behaviour were available. Thus, it is not possible to assess welfare in its multidimensionality using routinely collected digital data in Swiss veal calves to date. A major underlying difficulty is to differentiate between veal calves and other youngstock using routine data, since an identifying category for veal calves is missing in official Swiss databases. In order to infer animal welfare from routine data, adaptations of data collection strategies and animal identification are required. Data-based welfare assessment could then be used to complement on-farm assessments efficiently and, e.g., to attribute financial incentives for specifically high welfare standards accordingly.

Current research considering social behavior to improve the welfare of commercially raised dairy calves

Social contact in early life has broad benefits for behavioral development and welfare of the developing dairy calf. The most accessible approach to providing social contact for commercially raised dairy calves is rearing calves in same-age groups, a practice that is growing in popularity. This symposium review highlights developing areas of research relevant for widespread implementation of social housing on commercial farms. I discuss the onset of social behavior in young calves, development of social preferences, implications of calf management and housing for expression of social behavior, individual differences in social behavior, and implications of environmental complexity within the context of social housing. Under both naturalistic and commercial settings, calves interact socially within the first days of life and develop preferences for familiar social companions. Early introduction to social housing appears to benefit the development of social behavior, which may affect integration in later social groups, with potential long-term effects. Housing and management factors affecting socially housed calves have potential to disrupt social synchrony compared with behavior under more natural conditions, which can reduce social lying, cause competition for access to feed, and may have implications for social bond formation and social learning within the social group. Although calves exhibit preferences for familiar individuals and motivation for social synchrony, social behavior is also widely variable between individuals and over time. Individual differences in social behavior may be attributed to personality as well as transient states such as disease or pain, and accommodating individual preferences for social interaction or isolation may be important within groups of larger calves. Throughout this paper, I contrast behavior of commercially raised calves in social housing with behavior of calves under more naturalistic conditions and address both short-term effects for calf development and potential longer-term implications for behavior and welfare. Welfare of commercially raised calves may be improved by refining social housing to better accommodate natural social behavior.

Strategies for Bovine Respiratory Disease (BRD) Diagnosis and Prognosis: A Comprehensive Overview

Despite significant advances in vaccination strategies and antibiotic therapy, bovine respiratory disease (BRD) continues to be the leading disease affecting the global cattle industry. The etiology of BRD is complex, often involving multiple microbial agents, which lead to intricate interactions between the host immune system and pathogens during various beef production stages. These interactions present environmental, social, and geographical challenges. Accurate diagnosis is essential for effective disease management. Nevertheless, correct identification of BRD cases remains a daunting challenge for animal health technicians in feedlots. In response to current regulations, there is a growing interest in refining clinical diagnoses of BRD to curb the overuse of antimicrobials. This shift marks a pivotal first step toward establishing a structured diagnostic framework for this disease. This review article provides an update on recent developments and future perspectives in clinical diagnostics and prognostic techniques for BRD, assessing their benefits and limitations. The methods discussed include the evaluation of clinical signs and animal behavior, biomarker analysis, molecular diagnostics, ultrasound imaging, and prognostic modeling. While some techniques show promise as standalone diagnostics, it is likely that a multifaceted approach-leveraging a combination of these methods-will yield the most accurate diagnosis of BRD.

Comparison and interobserver reliability between a visual analog scale and the Wisconsin Calf Health Scoring Chart for detection of respiratory disease in dairy calves

Respiratory disease is an ongoing challenge for calves in the dairy sector with a relatively high prevalence and impact on welfare and economics. Applying scoring protocols for detecting respiratory disease requires that they are easily implemented, consistent between observers and fast to use in daily management. This study was conducted in one Danish dairy farm from September 2020 through January 2021. The study included 126 heifer calves enrolled in the age of 17 to 24 d. All calves were observed every second day for a period of 46 d. At each visit all calves were scored with a new visual analog scale (VAS) and the Wisconsin Calf Health Scoring Chart (WCHSC). We calculated agreement between the 2 scoring systems based on conditional probability to score higher or lower than a cutoff in the VAS compared with a specified cutoff in WCHSC used as reference test. A generalized mixed effects regression model was developed to estimate the prevalence of respiratory disease and the overall agreement between the 2 scoring systems. The overall agreement between the VAS and WCHSC was 89.6%. The second part of the study assessed interobserver reliability between 2 experienced observers and between an experienced observer and veterinary students. The interobserver reliability was calculated by intraclass correlation coefficient and was 0.58 between experienced observers and was 0.34 between an experienced observer and veterinary students indicating a moderate to poor reliability between the observers. It was possible to use VAS as an alternative clinical scoring method, which primarily focuses on the general condition of the individual calf rather than specific categories of clinical signs. Our study set up lacked a comparison to other diagnostic tools i.e., thoracic ultrasound to confirm the findings which should be considered in future studies when exploring VAS as a screening tool for detection of respiratory disease in dairy calves.

Literature Review on Technological Applications to Monitor and Evaluate Calves' Health and Welfare

Precision livestock farming (PLF) research is rapidly increasing and has improved farmers' quality of life, animal welfare, and production efficiency. PLF research in dairy calves is still relatively recent but has grown in the last few years. Automatic milk feeding systems (AMFS) and 3D accelerometers have been the most extensively used technologies in dairy calves. However, other technologies have been emerging in dairy calves' research, such as infrared thermography (IRT), 3D cameras, ruminal bolus, and sound analysis systems, which have not been properly validated and reviewed in the scientific literature. Thus, with this review, we aimed to analyse the state-of-the-art of technological applications in calves, focusing on dairy calves. Most of the research is focused on technology to detect and predict calves' health problems and monitor pain indicators. Feeding and lying behaviours have sometimes been associated with health and welfare levels. However, a consensus opinion is still unclear since other factors, such as milk allowance, can affect these behaviours differently. Research that employed a multi-technology approach showed better results than research focusing on only a single technique. Integrating and automating different technologies with machine learning algorithms can offer more scientific knowledge and potentially help the farmers improve calves' health, performance, and welfare, if commercial applications are available, which, from the authors' knowledge, are not at the moment.

Technological Tools for the Early Detection of Bovine Respiratory Disease in Farms

Simple Summary

The inclusion of remote automatic systems that use continuous learning technology are of great interest in precision livestock cattle farming, since the average size of farms is increasing while time for individual observation is decreasing. Bovine respiratory disease is a main concern in both fattening and heifer rearing farms due to its impact on antibiotic use, loss of performance, mortality, and animal welfare. Much scientific literature has been published regarding technologies for continuous learning and monitoring of cattle’s behavior and accurate correlation with health status, including early detection of bovine respiratory disease. This review summarizes the up-to-date technologies for early diagnosis of bovine respiratory disease and discusses their advantages and disadvantages under practical conditions.

Abstract

Classically, the diagnosis of respiratory disease in cattle has been based on observation of clinical signs and the behavior of the animals, but this technique can be subjective, time-consuming and labor intensive. It also requires proper training of staff and lacks sensitivity (Se) and specificity (Sp). Furthermore, respiratory disease is diagnosed too late, when the animal already has severe lesions. A total of 104 papers were included in this review. The use of new advanced technologies that allow early diagnosis of diseases using real-time data analysis may be the future of cattle farms. These technologies allow continuous, remote, and objective assessment of animal behavior and diagnosis of bovine respiratory disease with improved Se and Sp. The most commonly used behavioral variables are eating behavior and physical activity. Diagnosis of bovine respiratory disease may experience a significant change with the help of big data combined with machine learning, and may even integrate metabolomics as disease markers. Advanced technologies should not be a substitute for practitioners, farmers or technicians, but could help achieve a much more accurate and earlier diagnosis of respiratory disease and, therefore, reduce the use of antibiotics, increase animal welfare and sustainability of livestock farms. This review aims to familiarize practitioners and farmers with the advantages and disadvantages of the advanced technological diagnostic tools for bovine respiratory disease and introduce recent clinical applications.

Indication of social buffering in disbudded calves

Most dairy calves are housed individually in early ontogeny but social housing has positive effects on calf welfare including an advantage of social buffering, i.e., when negative effects of stress are mitigated through social support of conspecific. The effects of social buffering has not yet been examined in relation to disbudding; a painful husbandry procedure commonly performed on young dairy calves. The objective of this study was to investigate the effect of pair versus individual housing on calves’ behavioral reaction to disbudding. In total 52 female calves were randomly allocated either to individual (n = 16) or pair housing (n = 36, 18 focal). Calves were hot-iron disbudded with a local anesthetic and their spontaneous behavior in home pens was recorded for 24 h pre- and post-disbudding. Eating forage, ruminating, resting, exploration, play, self-grooming, and pain-related behaviors were quantified during eight 20 min intervals during the 24 h periods pre- as well as post-disbudding. In pair-housed (PAIR) calves social resting, active and passive allo-grooming were additionally recorded. The differences between individually housed (INDI, n = 10) and PAIR calves (n = 12) were tested by general linear models. The changes in pre- and post-disbudding behaviors in all calves as well as in social behaviors of PAIR calves were tested by paired t-test. We found that head shaking (t =  − 3.46, P = 0.0024), head rubbing (t = 4.96, P < 0.0001) and self-grooming (t = 2.11, P = 0.04) increased in all calves after disbudding. Eating forage increased only in PAIR calves (t = 2.50, P = 0.030) which also resulted in a difference between treatments with PAIR calves fed more often than INDI calves (F_1,18 = 12.96, P = 0.002). Differences in eating forage may be an indication of improved ability of PAIR calves to recover from disbudding. No other significant differences were detected between treatment groups which might have been caused by our limited sample. Our results provide the first evidence that housing treatment affects calves’ reactions to disbudding, with possible indication of social buffering.

Social networks respond to a disease challenge in calves

Changes in network position and behavioral interactions have been linked with infectious disease in social animals. Here, we investigate the effects of an experimental disease challenge on social network centrality of group-housed Holstein bull dairy calves. Within group-housed pens (6/group) calves were randomly assigned to either a previously developed challenge model, involving inoculation with Mannheimia haemolytia (n = 12 calves; 3 calves/group) or a control involving only saline (n = 12 calves; 3 calves/group). Continuous behavioral data were recorded from video on pre-treatment baseline day and for 24 h following inoculation to describe social lying frequency and duration and all active social contact between calves. Mixed-model analysis revealed that changes in network position were related to the challenge. Compared to controls, challenged calves had reduced centrality and connectedness, baseline to challenge day. On challenge day, challenged calves were less central in the directed social contact networks (lower degree, strength and eigenvector centrality), and initiated contact (higher out-degree) with more penmates, compared to healthy calves. This finding suggests that giving rather than receiving affiliative social contact may be more beneficial for challenged calves. This is the first study demonstrating that changes in social network position coincide with an experimental challenge of a respiratory pathogen in calves.

Early Detection of Respiratory Diseases in Calves by Use of an Ear-Attached Accelerometer

Simple Summary

Bovine respiratory disease is one of the most important diseases in group-housed calves worldwide, with impacts on calf welfare and farm economics. Early detection of the disease is important for the well-being of the animals and a targeted treatment. Therefore, tools for an automated monitoring of individual calves would be a breakthrough in health management. In this study, we used an ear-attached accelerometer to evaluate its potential for the early detection of behavioral changes related to respiratory disease in calves. Our result showed that accelerometers are able to detect changes in activity and lying times that can be used to predict respiratory disease before clinical diagnosis.

Abstract

Accelerometers (ACL) can identify behavioral and activity changes in calves. In the present study, we examined the association between bovine respiratory disease (BRD) and behavioral changes detected by an ear-tag based ACL system in weaned dairy calves. Accelerometer data were analyzed from 7 d before to 1 d after clinical diagnosis of BRD. All calves in the study (n = 508) were checked daily by an adapted University of Wisconsin Calf Scoring System. Calves with a score ≥ 4 and fever for at least two consecutive days were categorized as diseased (DIS). The day of clinical diagnosis of BRD was defined as d 0. The data analysis showed a significant difference in high active times between DIS and healthy control calves (CON), with CON showing more high active times on every day, except d −3. Diseased calves showed significantly more inactive times on d −4, −2, and 0, as well as longer lying times on d −5, −2, and +1. These results indicate the potential of the ACL to detect BRD prior to a clinical diagnosis in group-housed calves. Furthermore, in this study, we described the ‘normal’ behavior in 428 clinically healthy weaned dairy calves obtained by the ACL system.

Feeding behavior and activity levels are associated with recovery status in dairy calves treated with antimicrobials for Bovine Respiratory Disease

Calves with Bovine Respiratory Disease (BRD) have different feeding behavior and activity levels prior to BRD diagnosis when compared to healthy calves, but it is unknown if calves who relapse from their initial BRD diagnosis are behaviorally different from calves who recover. Using precision technologies, we aimed to identify associations of feeding behavior and activity with recovery status in dairy calves (recovered or relapsed) over the 10 days after first antimicrobial treatment for BRD. Dairy calves were health scored daily for a BRD bout (using a standard respiratory scoring system and lung ultrasonography) and received antimicrobial therapy (enrofloxacin) on day 0 of initial BRD diagnosis; 10–14 days later, recovery status was scored as either recovered or relapsed (n = 19 each). Feeding behaviors and activity were monitored using automated feeders and pedometers. Over the 10 days post-treatment, recovered calves showed improvements in starter intake and were generally more active, while relapsed calves showed sickness behaviors, including depressed feed intake, and longer lying times. These results suggest there is a new potential for precision technology devices on farms in evaluating recovery status of dairy calves that are recently treated for BRD; there is opportunity to automatically identify relapsing calves before re-emergence of clinical disease.

Commercial Dairy Calf Management: Impact on Performance and Health

The transition for the calf from the milk-feeding phase to the grouping and dry feed feeding phase is the second most difficult time for a calf, with the most difficult life phase being parturition and the first day of life. Reducing these stress factors directly relates to reduced health problems and better performance during subsequent life phases. This review will discuss some of the key management factors associated with achieving maximum production potential for the commercial dairy calf.

A Systematic Review of Automatic Health Monitoring in Calves: Glimpsing the Future From Current Practice

Infectious diseases, particularly bovine respiratory disease (BRD) and neonatal calf diarrhea (NCD), are prevalent in calves. Efficient health-monitoring tools to identify such diseases on time are lacking. Common practice (i.e., health checks) often identifies sick calves at a late stage of disease or not at all. Sensor technology enables the automatic and continuous monitoring of calf physiology or behavior, potentially offering timely and precise detection of sick calves. A systematic overview of automated disease detection in calves is still lacking. The objectives of this literature review were hence: to investigate previously applied sensor validation methods used in the context of calf health, to identify sensors used on calves, the parameters these sensors monitor, and the statistical tools applied to identify diseases, to explore potential research gaps and to point to future research opportunities. To achieve these objectives, systematic literature searches were conducted. We defined four stages in the development of health-monitoring systems: (1) sensor technique, (2) data interpretation, (3) information integration, and (4) decision support. Fifty-four articles were included (stage one: 26; stage two: 19; stage three: 9; and stage four: 0). Common parameters that assess the performance of these systems are sensitivity, specificity, accuracy, precision, and negative predictive value. Gold standards that typically assess these parameters include manual measurement and manual health-assessment protocols. At stage one, automatic feeding stations, accelerometers, infrared thermography cameras, microphones, and 3-D cameras are accurate in screening behavior and physiology in calves. At stage two, changes in feeding behaviors, lying, activity, or body temperature corresponded to changes in health status, and point to health issues earlier than manual health checks. At stage three, accelerometers, thermometers, and automatic feeding stations have been integrated into one system that was shown to be able to successfully detect diseases in calves, including BRD and NCD. We discuss these findings, look into potentials at stage four, and touch upon the topic of resilience, whereby health-monitoring system might be used to detect low resilience (i.e., prone to disease but clinically healthy calves), promoting further improvements in calf health and welfare.

Scoping review on clinical definition of bovine respiratory disease complex and related clinical signs in dairy cows

Bovine respiratory disease complex (BRD) is a worldwide multifactorial infectious disease. Antimicrobials are commonly used for treating BRD because bacteria are often involved. The clinical diagnosis of BRD is a challenge, especially in adult dairy cows, where information on this syndrome is scant. Having a definition based on consistent and reliable clinical signs would improve the accuracy of BRD diagnosis and could help to develop an optimal treatment approach by an early detection. The aim of this scoping review was to review clinical signs that could be recognized by producers in dairy cattle suffering from naturally occurring infectious respiratory disease, as reported in the literature. A review of the literature was performed for articles published between January 1, 1990 and January 1, 2020. The search of literature in English, French, and Italian languages included 2 different databases (Pubmed, https://pubmed.ncbi.nlm.nih.gov/; CAB abstract, https://www.cabi.org/publishing-products/cab-abstracts/). Clinical signs were categorized as follows: (1) "general manifestations of disease," which included behavioral changes or fever; (2) "alterations in respiratory function," which included clinical signs specifically associated with the respiratory tract examination; and (3) "clinical signs of other body systems," which included clinical signs related to other systems such as diarrhea or subcutaneous emphysema. The focus of the review was on clinical signs that could be monitored by animal handlers and producers. A total of 1,067 titles were screened, and 23 studies were finally included. The most common general clinical signs were increased body temperature (reported in 83% of studies, n = 19), change in feed intake (26%, n = 6), altered mentation (22%, n = 5), and decreased milk production (17%, n = 4). The alterations in respiratory function noted were nasal discharge (74%, n = 17), cough (65%, n = 15), altered respiratory dynamic or dyspnea (61%, n = 14), increased respiratory rate (43%, n = 10), and ocular discharge or lacrimation (30%, n = 7). The clinical signs associated with infectious respiratory disease reported in the 23 studies generally lacked a clear description of what constitutes a deviation from normality (0-50% of studies clearly reported what was considered normal versus abnormal depending on the clinical signs). This limitation prevented any comparison between studies that apparently reported the same "clinical sign," but possibly referred to a different assessment and definition of what was considered normal versus abnormal. Therefore, the definition of clinical signs in a repeatable way with validated interobserver agreement to determine the optimal combination for the diagnosis of BRD in dairy cows is needed. This could lead to a more judicious use of antimicrobials for respiratory disease in adult dairy cows.

Construction of a conceptual framework for assessment of health-related quality of life in calves with respiratory disease

Bovine respiratory disease (BRD) is one of the most prevalent diseases affecting beef and dairy calves worldwide, with implications for lifetime productivity, antimicrobial use and animal welfare. Our objective was to construct a conceptual framework for assessment of health-related quality of life (HRQL) in calves with respiratory disease, based on indicators suitable for direct pen-side visual observation. Health-related quality of life measures aim to evaluate the subjective experience of the animal rather than any related pathology. A conceptual framework graphically represents the concepts to be measured and the potential relationships between them. A multistage, mixed method approach involving diverse data sources, collection methods and stakeholders was applied to promote comprehensiveness, understanding and validity of findings. A scoping review was conducted to identify, characterize and collate evidence of behavioural indicators of BRD. The indicators identified were mapped against the principal attributes of five prominent animal welfare assessment frameworks to appraise their correspondence with different characterizations of the dimensions of welfare. Forty-two semi-structured, individual, qualitative interviews with a purposeful sample of experienced veterinarians and stockpersons from UK, USA and Canada elicited in-depth descriptions of the visual observations of HRQL they make in diagnosing and assessing the response to treatment of calves with BRD. Verbatim interview transcripts were examined using inductive thematic analysis. Respondents provided insights and understanding of indicators of HRQL in BRD such as interaction with feed source, hair coat condition, specific characteristics of eye appearance, eye contact, rumen fill and stretching (pandiculation). In an on-farm pilot study to assess the value of potential HRQL behavioural indicators, there was a moderate positive correlation between behaviour and clinical scores (r_s = 0.59) across the 5 days preceding veterinary treatment for BRD. Interestingly, the behaviours evaluated were observed a median of 1.0 (interquartile range: 1.0-3.5) days before clinical indicators used in the scoring system. The proposed conceptual framework for assessment of HRQL features 23 putative indicators of HRQL distributed across two interrelated domains - clinical signs and behavioural expressions of emotional well-being. It has potential applications to inform the development of new HRQL measures such as structured questionnaires and automated sensor technologies.

Machine Learning Algorithms to Classify and Quantify Multiple Behaviours in Dairy Calves Using a Sensor: Moving beyond Classification in Precision Livestock

Previous research has shown that sensors monitoring lying behaviours and feeding can detect early signs of ill health in calves. There is evidence to suggest that monitoring change in a single behaviour might not be enough for disease prediction. In calves, multiple behaviours such as locomotor play, self-grooming, feeding and activity whilst lying are likely to be informative. However, these behaviours can occur rarely in the real world, which means simply counting behaviours based on the prediction of a classifier can lead to overestimation. Here, we equipped thirteen pre-weaned dairy calves with collar-mounted sensors and monitored their behaviour with video cameras. Behavioural observations were recorded and merged with sensor signals. Features were calculated for 1-10-s windows and an AdaBoost ensemble learning algorithm implemented to classify behaviours. Finally, we developed an adjusted count quantification algorithm to predict the prevalence of locomotor play behaviour on a test dataset with low true prevalence (0.27%). Our algorithm identified locomotor play (99.73% accuracy), self-grooming (98.18% accuracy), ruminating (94.47% accuracy), non-nutritive suckling (94.96% accuracy), nutritive suckling (96.44% accuracy), active lying (90.38% accuracy) and non-active lying (90.38% accuracy). Our results detail recommended sampling frequencies, feature selection and window size. The quantification estimates of locomotor play behaviour were highly correlated with the true prevalence (0.97; p < 0.001) with a total overestimation of 18.97%. This study is the first to implement machine learning approaches for multi-class behaviour identification as well as behaviour quantification in calves. This has potential to contribute towards new insights to evaluate the health and welfare in calves by use of wearable sensors.

Disbudding affects use of a shelter provided to group-housed dairy calves

Disbudding in dairy calves is well established as a painful procedure with broad effects on behavior. The hypothesis of this experiment was that group-housed calves subjected to hot-iron disbudding would exhibit social withdrawal, based on use of a shelter providing physical and visual seclusion from the rest of the pen. We examined effects of hot-iron disbudding on use of this shelter, including individual and shared use, and resting behavior within the shelter. Holstein heifer and bull calves (n = 24) were housed in group pens (4 calves/pen; 3.7 × 8.0 m). Each pen contained a 3-sided open-top shelter (1.2 m square, and 1.2 m high) with an additional half-enclosed wall to allow entry, built out of corrugated plastic. Calves were randomly assigned within pen to be disbudded (n = 12; 10 bulls and 2 heifers; 36.2 ± 3.9 d of age) or receive sham handling only (n = 12; 9 bulls and 3 heifers; 36.3 ± 4.2 d of age). Disbudded calves received a local cornual nerve block and a nonsteroidal antiinflammatory medication before the procedure. Behavior was recorded continuously from video for 3 consecutive days, beginning immediately following the disbudding procedure or handling. Shelter use was highly variable between calves (ranging from 10.8 min/d to 20.7 h/d), but calves showed individual consistency in their use of the shelter over time. Disbudded calves spent more time in the shelter (4.6 vs. 1.6 h/d; disbudded vs. sham). Social use of the shelter as a percentage of shelter use was not affected by disbudding, but disbudded calves spent more time in the shelter together (31 vs. 9% of shelter use; disbudded vs. sham). Disbudded calves entered the shelter more frequently when it was unoccupied (8.1 vs. 5.5 entries; disbudded vs. sham) and similarly left it more frequently when it was occupied. Disbudded calves used the shelter more during daylight hours (0700 to 2000 h; 8.9 vs. 4.1 min/h) on each day, including d 0 when pain mitigation was effective, whereas use did not differ during the night. Disbudded calves spent approximately 40 min less time lying/d and spent a greater percentage of their lying time inside the shelter. These results suggest that disbudded calves make greater use of environmental features that offer seclusion, with use of the shelter possibly reflecting an increased preference for social withdrawal or for some other aspect of this area of visual and physical separation. Further, these results suggest that disbudding even with recommended pain mitigation affects behavior for at least several days.

Symposium review: Precision technologies for dairy calves and management applications

There is an increasing interest in using precision dairy technologies (PDT) to monitor real-time animal behavior and physiology in livestock systems around the world. Although PDT in adult cattle is extensively reviewed, PDT use for the management of preweaned dairy calves has not been reviewed. We systematically reviewed research on the use and application of precision technologies in calves. Accelerometers have the potential to be used to monitor lying behavior, step activity, and rumination, which are useful to detect changes in behavior that may be indicative of disease, responses to painful procedures, or positive welfare behaviors such as play. Automated calf feeding systems can control delivery of nutritional plans to individualize feeding and weaning of calves; changes in feeding behaviors (such as milk intake, drinking speed, and unrewarded visits) may also be used to identify early onset of disease. The PDT devices also measure physiological and physical attributes in dairy calves. For instance, temperature monitoring devices such as infrared thermography, ruminal boluses, and implanted microchips have been assessed in calves, but no herd management-based commercial system is available. Many other PDT are in development with potential to be used in dairy calf management, such as image and acoustic-based monitoring, real-time location, and use of enrichment items for monitoring positive emotional states. We conclude that PDT have great potential for application in dairy calf management, enabling precise behavioral and physiological monitoring, targeted feeding programs, and identification of calves with poor health or behavioral impairments. We strongly encourage further development and validation of commercially available technologies for on-farm application of the monitoring of dairy calf welfare, performance, and health.

Bovine Respiratory Disease Diagnosis: What Progress Has Been Made in Clinical Diagnosis?

Bovine respiratory disease (BRD) complex is a worldwide health problem in cattle and is a major reason for antimicrobial use in young cattle. Several challenges may explain why it is difficult to make progress in the management of this disease. This article defines the limitation of BRD complex nomenclature, which may not easily distinguish upper versus lower respiratory tract infection and infectious bronchopneumonia versus other types of respiratory diseases. It then discusses the obstacles to clinical diagnosis and reviews the current knowledge of readily available diagnostic test to reach a diagnosis of infectious bronchopneumonia.

Impact of Maternal High Stocking Density during the Dry Period on Dairy Calf Health, Behaviour, and Welfare

Simple Summary

Negative impacts of stressful maternal experience during pregnancy on offspring health and behaviour have been reported in various mammalian species including humans, laboratory animals, and farm animals. This study investigated the effect of limited space allowance for dairy cows during late gestation on the growth and behaviour of their offspring during the pre-weaning period. Our results indicated associations between maternal high stocking density and a higher frequency of social behaviours and increased behavioural reactivity to weaning in offspring. Maternal high stocking density also reduced behavioural reactions of healthy offspring to a painful procedure. However, there was no association between maternal high stocking density and offspring growth or behaviour in the first week of life. To our knowledge, this study is the first to attempt to demonstrate associations between maternal stocking density during late pregnancy and offspring behaviour in dairy cattle.

Abstract

This study aimed to investigate the effect of maternal stocking density during late pregnancy (approximately 60 ± 4 days before calving) on offspring performance during the pre-weaning period. Forty-five dairy calves were born to cows that went through either industry minimum standards (H: n = 24, high stocking density) or more extensive space allowances (L: n = 21, low stocking density) during the dry period. Body weight and average daily gain during the pre-weaning period (day 1–49) were measured. Observations were made of: (i) activity levels (day 2–6); ii) the level of training required to use an automatic feeder, and behavioural reactions to the group environment (d7); (iii) feeding and social behaviour in the group pen (day 7–21); and (iv) responses to weaning (day 40–49) and disbudding (day 28+). Compared to L calves, H calves made more frequent social contacts with pen mates in the group pen (p = 0.003) and decreased their lying time around weaning (p = 0.045). Among the healthy calves, L calves displayed more severe behavioural reactions to the disbudding procedure (p < 0.001), a significant increase in salivary cortisol concentrations (p = 0.013), and more frequent pain-related behaviour (p = 0.036). This study indicated associations between maternal stocking density during late pregnancy and some welfare-relevant offspring outcomes during the pre-weaning period; these effects were found to be modulated by offspring health status.

Technical note: validation of a system for monitoring individual behavior in beef heifers

The objectives of the 2 studies conducted were to validate the accuracy of an automated monitoring device (AMD; HR-LDn tags, SCR Engineers Ltd., Netanya, Israel) for different types of behaviors or cow-states (side lying, resting, medium activity, high activity, rumination, grazing, walking, and panting) in beef heifers and to determine if the total time per cow-state recorded by the AMD corresponds to the total time per cow-state recorded by instantaneous observations. Cow-state is recorded every second and, within 1 min, the most prevalent cow-state is considered to be the behavior presented by the animal during that interval. Study personnel (n = 2) observed heifers (n = 10) for 20 min from 0800 to 1140 h and 10 min from 1500 to 1640 h during 4 consecutive days and recorded continuously each cow-state at started and ended. Thus, study personnel were able to determine within a 1-min interval, which cow-state was most prevalent and represented the heifer's behavior. Because the proprietary machine learning algorithm prioritizes certain behaviors over others based on their contribution to the understanding of generalized bovine behavior patterns, we also determined the most prevalent behavior observed in 5-min intervals. Test characteristics (sensitivity, specificity, accuracy, and negative and positive predicted values) were calculated using the observer as the gold standard. In study 2, heifer behavior was scanned by observers (n = 2) every 5 min from 0800 to 1100 h and 1500 to 1800 h for 3 consecutive days. Total minutes per cow-state according to the observer were compared with the total minutes per cow-state according to the AMD during the same period to determine the correlation coefficient. In study 1, test characteristics were high (low ≤ 40%, moderate = 41 to 74%, high ≥ 75%) for rumination (≥ 89.7%), grazing (≥ 76.5%), and side lying (≥ 81.8%), and moderate for resting (≥ 48.8%). In study 2, the correlation coefficient for rumination (R2 = 0.92) and grazing (R2 = 0.90) were high and the correlation coefficient for resting (R2 = 0.66) and walking (R2 = 0.33) were moderate. We conclude that the AMD used in this study showed high accuracy when measuring rumination and grazing, but it was subpar when measuring resting and walking. The algorithms employed by the AMD used need to be improved for determination of walking and resting behaviors of beef cattle.

From Science to Practice: A Review of Laterality Research on Ungulate Livestock

In functional laterality research, most ungulate livestock species have until recently been mainly overlooked. However, there are many scientific and practical benefits of studying laterality in ungulate livestock. As social, precocial and domestic species, they may offer insight into the mechanisms involved in the ontogeny and phylogeny of functional laterality and help to better understand the role of laterality in animal welfare. Until now, most studies on ungulate livestock have focused on motor laterality, but interest in other lateralized functions, e.g., cognition and emotions, is growing. Increasingly more studies are also focused on associations with age, sex, personality, health, stress, production and performance. Although the full potential of research on laterality in ungulate livestock is not yet exploited, findings have already shed new light on central issues in cognitive and emotional processing and laid the basis for potentially useful applications in future practice, e.g., stress reduction during human-animal interactions and improved assessments of health, production and welfare. Future research would benefit from further integration of basic laterality methodology (e.g., testing for individual preferences) and applied ethological approaches (e.g., established emotionality tests), which would not only improve our understanding of functional laterality but also benefit the assessment of animal welfare.

Evaluating effects of providing hay on behavioral development and performance of group-housed dairy calves

Providing access to forage has been shown to influence feeding behavior and non-nutritive oral behavior in individually housed calves, and these effects may be enhanced or altered in calves reared in social housing. We evaluated the effect of hay provision on the behavioral development and performance of group-housed dairy calves. Holstein calves (n = 32) were group-housed (4 calves per group) at 17 ± 3 (mean ± SD) d of age. All calves were provided milk replacer (8 L/d) via an automated milk feeder and pelleted starter and water ad libitum. Pens were randomly assigned to receive either chopped coastal Bermuda grass in buckets adjacent to the starter trough (starter and hay, STH; n = 4 pens), or no additional feed (starter only, ST; n = 4 pens). Calves were weaned through a 10-d stepdown program beginning at 46 d of age. Intake of solid feed and hay were recorded daily, and body weights were measured weekly. The behavior of 2 focal calves per pen was recorded continuously from video for 12 h on 2 consecutive days during each of wk 4, 6, and 7 of life, to measure solid feed intake time, grooming, and pen-directed sucking. Hay provision influenced total feed intake, with calves provided hay having greater total solid feed intake in the week before weaning (0.79 vs. 0.55 kg/d, STH vs. ST, respectively; SE = 0.19). Average daily gain (ADG) was similar during the pre-weaning period but tended to be greater for STH calves during weaning. Calves in pens provided hay also had fewer unrewarded visits to the milk feeder during weaning (12.5 vs. 21.1 visits per 12 h, STH vs. ST, respectively; SE = 3.59) and performed less pen-directed sucking (9.11 vs. 19.3 min per 12 h, STH vs. ST, respectively; SE = 2.86). Self-grooming time and bout characteristics evolved differently between treatments over time, with pens of calves provided hay having a greater increase in frequency and duration of self-grooming bouts during weaning. Overall, we found that providing hay to pre-weaned calves resulted in behavioral and performance benefits, including greater total feed intake and reductions in pen-directed sucking, suggesting that access to hay may improve calf welfare.