The Use of an Activity Monitoring System for the Early Detection of Health Disorders in Young Bulls

Comparison of physiological markers, behavior monitoring, and clinical illness scoring as indicators of an inflammatory response in beef cattle

Clinical illness (CI) scoring using visual observation is the most widely applied method of detecting respiratory disease in cattle but has limited effectiveness in practice. In contrast, body-mounted sensor technology effectively facilitates disease detection. To evaluate whether a combination of movement behavior and CI scoring is effective for disease detection, cattle were vaccinated to induce a temporary inflammatory immune response. Cattle were evaluated before and after vaccination to identify the CI variables that are most indicative of sick cattle. Respiratory rate (H2 = 43.08, P < 0.0001), nasal discharge (H2 = 8.35, P = 0.015), and ocular discharge (H2 = 16.38, P = 0.0003) increased after vaccination, and rumen fill decreased (H2 = 20.10, P < 0.0001). Locomotor activity was measured via leg-mounted sensors for the four days preceding and seven days following vaccination. A statistical model that included temperature, steps, lying time, respiratory rate, rumen fill, head position, and excess saliva was developed to distinguish between scores from before and after vaccination with a sensitivity of 0.898 and specificity of 0.915. Several clinical illness signs were difficult to measure in practice. Binoculars were required for scoring respiratory rate and eye-related metrics, and cattle had to be fitted with colored collars for individual identification. Scoring each animal took up to three minutes in a small research pen; therefore, technologies that can automate both behavior monitoring and identification of clinical illness signs are key to improving capacity for BRD detection and treatment.

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.

Monitoring the Effect of Weed Encroachment on Cattle Behavior in Grazing Systems Using GPS Tracking Collars

Weed encroachment on grasslands can negatively affect herbage allowance and animal behavior, impacting livestock production. We used low-cost GPS collars fitted to twenty-four Angus crossbred steers to evaluate the effects of different levels of weed encroachment on animal activities and spatial distribution. The experiment was established with a randomized complete block design, with three treatments and four blocks. The treatments were paddocks free of weeds (weed-free), paddocks with weeds established in alternated strips (weed-strips), and paddocks with weeds spread throughout the entire area (weed-infested). Animals in weed-infested paddocks had reduced resting time and increased grazing time, distance traveled, and rate of travel (p < 0.05) compared to animals in weed-free paddocks. The spatial distribution of the animals was consistently greater in weed-free paddocks than in weed-strips or weed-infested areas. The effects of weed encroachment on animal activities were minimized after weed senescence at the end of the growing season. Pasture weed encroachment affected cattle behavior and their spatial distribution across the pasture, potentially impacting animal welfare. Further long-term studies are encouraged to evaluate the impacts of weed encroachment on animal performance and to quantify the effects of behavioral changes on animal energy balance.

Using Canine Olfaction to Detect Bovine Respiratory Disease: A Pilot Study

Bovine respiratory disease (BRD) is the leading cause of morbidity and mortality in feedlot cattle and is a major welfare and economic concern. Identification of BRD-affected cattle using clinical illness scores is problematic, and speed and cost constraints limit the feasibility of many diagnostic approaches. Dogs can rapidly identify humans and animals affected by a variety of diseases based on scent. Canines' olfactory systems can distinguish between patterns of volatile organic compounds produced by diseased and healthy tissue. In this pilot study, two dogs (“Runnels” and “Cheaps”) were trained for 7 months to discriminate between nasal swabs from cattle that developed signs of BRD within 20 days of feedlot arrival and swabs from cattle that did not develop BRD signs within 3 months at the feedlot. Nasal swabs were collected during cattle processing upon arrival to the feedlot and were stored at −80°C. Dogs were presented with sets of one positive and two negative samples and were trained using positive reinforcement to hold their noses over the positive sample. The dogs performed moderately well in the final stage of training, with accuracy for Runnels of 0.817 and Cheaps of 0.647, both greater than the 0.333 expected by chance. During a double-blind detection test, dogs evaluated 123 unique and unfamiliar samples that were presented as 41 sets (3 samples per set), with both the dog handler and data recorder blinded to the positive sample location. Each dog was tested twice on each set of samples. Detection test accuracy was slightly better than chance for Cheaps at 0.451 (95% CI: 0.344–0.559) and was no better than chance for Runnels at 0.390 (95% CI: 0.285–0.496. Overall accuracy was 0.421 (95% CI: 0.345–0.496). When dogs' consensus response on each sample set was considered, accuracy was 0.537 (95% CI: 0.384–0.689). Detection accuracy also varied by sample lot. While dogs showed some ability to discriminate between BRD-affected and healthy cattle using nasal swabs, the complexity of this task suggests that more testing is needed before determining whether dogs could be effective as a screening method for BRD.

Assessment of pain associated with bovine respiratory disease and its mitigation with flunixin meglumine in cattle with induced bacterial pneumonia

Pleuritic chest pain from bacterial pneumonia is often reported in human medicine. However, studies investigating pain associated with bovine respiratory disease (BRD) are lacking. The objectives of this study were to assess if bacterial pneumonia elicits a pain response in calves with experimentally induced BRD and to determine the analgesic effects of transdermally administered flunixin. Twenty-six calves, 6-7 months of age, with no history of BRD were enrolled into 1 of 3 treatment groups: (1) experimentally induced BRD + transdermal flunixin at 3.3 mg/kg twice, 24 h apart (BRD + FTD); (2) experimentally induced BRD + placebo (BRD + PLBO); and (3) sham induction + placebo (CNTL + PLBO). Calves induced with BRD were inoculated with Mannheimia haemolytica via bronchoalveolar lavage. Outcomes were collected from -48 to 192 hours post-treatment and included serum cortisol; infrared thermography; mechanical nociceptive threshold; substance P; kinematic gait analysis; visual analog scale (VAS); clinical illness score; computerized lung score; average activity and rumination level; prostaglandin E2 metabolite; plasma serum amyloid A and rectal temperature. Outcomes were evaluated using either a generalized logistic mixed model for categorical variables or a generalized linear mixed model for continuous variables. Right front force differed by treatment (P = 0.01). The BRD + PLBO had lower mean force applied to the right front limb (85.5 kg) compared to BRD + FTD (96.5 kg) (P < 0.01). Average VAS differed by a treatment by time interaction (P = 0.01). The VAS scores differed for BRD + PLBO at -48 (3.49 mm) compared to 168 and 192 h (13.49 and 13.64 mm, respectively) (P < 0.01). Activity for BRD + PLBO was higher at -48 h (27 min/h) compared to 48, 72, 120 and 168 h (≤ 22.24 min/h) (P < 0.01). Activity differed by a treatment by time interaction (P = 0.01). Activity for BRD + FTD was higher at -48 and 0 h (28.2 and 28.2 min/h, respectively) compared to 48, 72, 96 and 168 h (≤ 23.7 min/h) (P < 0.01). Results show a combination of reduced activity levels, decreased force on the right front limb, and increased visual analog scale pain scores all support that bacterial pneumonia in cattle is painful. Differences in right front force indicate that flunixin transdermal may attenuate certain pain biomarkers in cattle with BRD. These findings suggest that BRD is painful and analgesic drugs may improve the humane aspects of care for cattle with BRD.

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.

Large Group Housing Systems in Fattening Bulls-Comparison of Behavior and Performance

According to international housing recommendations, fattening bulls should not be housed in groups of more than 12-20 animals. However, there are no scientific studies supporting these recommendations as most studies on fattening cattle refer to smaller groups. Therefore, the aim of this study was to analyze and compare behavior and performance of 187 fattening bulls housed in different group sizes of 16, 22, and 33 animals. Behavioral observations were performed during three observation periods at an average age of 8.5, 13, and 17 months. Furthermore, body condition, health status and carcass weights were analyzed. Effects of increasing group size were observed regarding more synchronized lying behavior, longer lying durations and more undisturbed feeding and lying behavior. Interindividual variations in lying and feeding as well as mean and maximum percentages of animals participating simultaneously in interactions did not increase with group size. Health and growth performance were satisfactory in all group sizes. Therefore, the results of this study do not provide scientific evidence for the common argument that increasing group size leads to increased aggression. Furthermore, these findings indicate large group systems to be suitable for the housing of fattening cattle and to contribute to increasing animal welfare. Consequently, current recommendations should be revised.