A survey of calf management practices and farmer perceptions of calf housing in UK dairy herds

When to pair: Effects of different pairing ages on dairy calf health, behavior, and performance

Pair housing presents an alternative to individual or larger group housing systems, though the effects of different pairing ages on calf welfare are not well understood. In this study, we examined the effect of pairing age on the performance, health, and behavior of dairy calves. A total of 140 Holstein female calves (n = 70 pairs) were used, paired at 3 stages: early (6-7 d; 48 calves), intermediate (29-30 d; 48 calves), and late (49-50 d; 44 calves). Calves were housed individually before pairing and weaned at 78 ± 2 d of age. Weight measurements were recorded at birth, 30, 50, and 60 d, and at weaning. Calves' behavior was assessed 5 times per week through scan sampling after milk feedings from d 6 to 7 until weaning, and a food neophobia test was conducted at 50 to 51 d. Health assessments were performed 3 times per week by a veterinarian using Wisconsin clinical scores to diagnose diarrhea and bovine respiratory disease, with pulmonary ultrasonography at 55 d. The results suggest no association between pairing age and the prevalence of diarrhea or bovine respiratory disease, although the statistical power was limited. The number of calves with lung consolidation scores above 2 was also unaffected by pairing age. Early-paired calves exhibited more exploration and play behaviors and less idleness, stereotypies, and nonnutritive oral behaviors than late-paired calves. No differences were observed in cross-suckling likelihood across pairing ages. Early-paired calves also showed a shorter latency to touch a novel feed in the food neophobia test, higher calf starter intake during the first 15 d, and greater ADG up to 50 d. Although overall ADG did not differ among pairing ages, early-paired calves were more homogeneous in weaning weight than late-paired calves. In conclusion, early pairing supports calves' initial development, promoting early feeding behavior and growth and enhancing behaviors associated with positive affective states without adverse effects on health or undesirable behaviors.

Evaluation of changes in calf management from 2012 to 2022 on Austrian dairy farms using an online questionnaire

Calf management is important for the development, health, and welfare of the animals. In this follow-up study, we evaluated calf management practices on dairy farms in Austria using an online questionnaire in 2021 and 2022. We tested the hypothesis that farmers changed calf management on their farm within these 10 years. The total number of analyzable surveys in 2022 was 2,314. All variables changed significantly between years. Therefore, farms were chosen randomly by controlling for confounding changes in herd size (number of dairy cows), farm type (conventional vs. organic), and type of cows' barn (freestall vs. tiestall). From 2012 to 2022, the median number of cows per farm increased from 20 (interquartile range [IQR] 13 to 30) to 22 (IQR 13 to 35), and the percentage of organic-producing farms increased from 23.9% (2012) to 30.6% (2022). The number of farms offering colostrum within 4 h after birth increased from 83.7% to 87.2%. This change was significant when subsampling was performed. The quantity of first colostrum offered to the newborns was mainly 2 to 4 L (69%), with an increased percentage of farms offering less than 2 L (13.3% vs. 18.3%). The percentage of farms testing colostrum quality using an objective method (hydrometer, Brix refractometer, outflow funnel) increased significantly by 4.9-fold and was 9.4% in 2022. On most farms (88.8% and 86.6% in 2012 and 2022, respectively), calves were housed individually after birth. A higher percentage reported grouping calves at an earlier age than in 2012. In both years, mainly whole milk was fed (85.1% vs. 86.3%). The number of farms where nonsalable or waste milk was fed to calves decreased significantly from 84.0% to 74.1%. Milk allowance increased nonsignificantly. Subsampling revealed that the age at weaning increased significantly between years. The most important health problem in calves was diarrhea (in 59.8% of farms, >10% of calves; and in 27.4%, >25%), followed by respiratory tract disease (in 39.8% of farms, >10% of calves; and on 16.4%, >25%). Compared with 2012, in 2022, a significantly higher percentage of farmers stated that they had a calf diarrhea incidence of >10% (39.8% vs. 59.8%). In our study, weak points regarding calf management on farms were not offering enough first colostrum, missing testing for colostrum quality, not housing calves socially in the first weeks postnatum, and feeding restricted amounts of milk. The median mortality rate of 3% (IQR 1 to 5) and increasing diarrhea incidence also show that calf management practices need improvement. Thus, how to get farmers motivated to implement changes in their management in accordance with science-based recommendations remains an open question.

A meta-analysis approach to evaluate the effects of early group housing on calf performance, health, and behavior during the preweaning period

This study aimed to evaluate the effects of early group housing on the performance, health, and behavior of dairy calves during the preweaning period using systematic and meta-analysis approaches. Peer-reviewed articles written in English that compared dairy calves individually and group-housed with performance, health, or behavior outcomes were collected from Web of Science, PubMed, and CABDirect databases. The resulting articles (n = 850) underwent a 4-step appraisal process following the Preferred Reporting Items for Systematic Review and Meta-Analyses protocols, resulting in a final sample of 51 articles containing 85 studies. The weighted or standardized mean differences between individually housed and group-housed (pair or group with >2 calves) calves were analyzed for each variable using the DerSimonian and Laird methods. Heterogeneity between calf housing systems was evaluated by the χ2 test and I2 statistics. A meta-regression analysis was conducted to identify categorical covariate effects for variables with high heterogeneity. Most of the studies included in this review evaluated female calves (45.8%) weaned at 8 wk old (52.6%). Housing systems were mainly paired housing (55.3%), followed by groups of 3 to 6 calves (30.65) and groups of 7 to 15 calves (4.7%). We did not find studies with comparable outcomes for more robust health parameters (as occurrence of diseases), only blood parameters, that were not influenced by the housing system. However, weight gain and feed intake parameters were higher in group-housed calves. Through the meta-regression, we found that ADG was positively affected by the group housing in studies with calves housed in small pen areas (<1.5 m2 per calf). Group-housed calves presented more active behaviors (feeding and playing) and less stress-related behaviors (self-grooming and interacting with the pen) than individually housed calves. The behavioral tests most used were novel object, human approach, novel environment, and social tests. Individually housed calves presented fewer vocalizations on these tests and spent more time interacting with humans during the human approach test than group-housed calves. Our findings provide consistent evidence that group housing improves the welfare of dairy calves; however, the effects on health parameters are still scarce and unclear.

Survey on colostrum management by German dairy farmers focusing on frozen colostrum storage

Because calves are born with low levels of antibodies, effective colostrum management is one of the most critical factors for successful calf rearing. A timely and adequate supply of sufficiently high-quality colostrum immediately after birth is essential to ensure the passive immunization of calves. Frozen colostrum reserves are recommended to fulfill the immunological and nutrient requirements of newborn calves, even in exceptional situations; however, the implementation rates on German dairy farms and challenges of realization remain unclear. A 33-question online survey, focused on frozen colostrum reserves, was developed to obtain an overview of colostrum management practices on German dairy farms. The questionnaire was divided into 3 sections: (1) personal data; (2) farm characteristics; (3) colostrum management. Of the 155 responses we received, 63.9% were from female farmers, and 35.5% were from male farmers. Conventional farming was practiced on 89.0% of farms, and organic farming was practiced on 7.1% of farms. Of the respondents, 89.0% froze colostrum. The main reasons for freezing colostrum were (1) the dam does not produce enough colostrum; (2) the dam cannot be milked; or (3) the dam died during birth. Farmers primarily froze colostrum from cows during their third to fifth lactation. Before freezing, 33.1% of the respondents measured indicators in the colostrum to estimate Ig concentrations, whereas 2.3% determined the colostrum quality after freezing. Reusable and disposable polyethylene terephthalate deposits (23.1%, 22.3%) and colostrum bags (20.0%) were the primary containers used to freeze colostrum. The main reasons for not freezing colostrum were the high labor intensity and the availability of fresh colostrum from other cows. Thawing methods included buckets (47.7%) and professional water baths (13.8%). The survey identified areas in which improved knowledge transfer could enhance colostrum management. Furthermore, there appeared to be a lack of specific, feasible instructions for employees concerning the practical implementation of colostrum management. Most importantly, the regular determination and documentation of immunoglobulin concentrations should be emphasized. The added value of stored colostrum, relative to a greater workload, should also be promoted, particularly on smaller farms.

A Living Lab approach to understanding dairy farmers' technology and data needs to improve herd health: Focus groups from 6 European countries

For successful development and adoption of technology on dairy farms, farmers need to be included in the innovation process. However, the design of agricultural technologies usually takes a top-down approach with little involvement of end-users at the early stages. Living Labs offer a methodology that involve end-users throughout the development process and emphasize the importance of understanding users' needs. Currently, exploration of dairy farmers' technology needs has been limited to specific types of technology (e.g., smartphone apps) and adult cattle. The aim of this study was to use a Living Lab approach to identify dairy farmers' data and technology needs to improve herd health and inform innovation development. We conducted 18 focus groups with a total of 80 dairy farmers from Belgium, Ireland, the Netherlands, Norway, Sweden, and the United Kingdom. Data were analyzed using Template Analysis, and 6 themes were generated representing the fundamental needs of autonomy, comfort, competence, community and relatedness, purpose, and security. Farmers favored technologies that provided them with convenience, facilitated their knowledge and understanding of problems on farm, and allowed them to be self-reliant. Issues with data sharing and accessibility and usability of software were barriers to technology use. Furthermore, farmers were facing problems around recruitment and management of labor and needed ways to reduce stress. Controlling aspects of the barn environment, such as air quality, hygiene, and stocking density, were particular concerns in relation to youngstock management. Overall, the findings suggest that developers of farm technologies may want to include farmers in the design process to ensure a positive user experience and improve accessibility. The needs identified in this study can be used as a framework when designing farm technologies to strengthen need satisfaction and reduce any potential harm toward needs.

Invited review: The effect of weaning practices on dairy calf performance, behavior, and health-A systematic review

The aim of this systematic review was to summarize the literature assessing the effects of weaning practices on performance, behavior, and health of dairy calves. Only published, peer-reviewed articles written in English and specifically assessing the effects of weaning treatments on dairy calves were eligible for inclusion. Studies had to include 2 or more treatment groups that addressed at least one of 4 interventions: weaning age (i.e., when milk was fully removed), weaning duration (i.e., number of days from start of milk reduction to when milk was fully removed), weaning criteria (e.g., age vs. intake), or alternative weaning methods (e.g., water dilution). Outcome measures could include starter intake, growth (BW or ADG), behaviors (5 specific sucking behaviors; play behavior; lying behavior; vocalizations; unrewarded visits to an automated milk feeder), and health (mortality rate, diarrhea, and respiratory illness). We conducted 3 targeted searches using Web of Science and PubMed. The articles underwent a 2-step screening process, resulting in a final sample of 44 studies. The majority of studies investigated weaning age (n = 22), followed by weaning duration (n = 13), weaning criteria (n = 9), and other weaning methods such as dilution, linear versus step-down milk reduction, or meal-based approaches (n = 6). There was consensus for positive effects (or at least no negative effects) on overall growth of calves weaned at later ages, over longer durations, based on starter intake, or weaned using step-down or meal-based milk removal approaches. This is despite reduced starter intake in calves weaned at later ages; most studies found improved starter intake in calves weaned over longer durations. Weaning based on starter intake had superior growth and feed intakes compared with calves weaned at a fixed earlier age. Few studies assessed interactive effects of weaning method and milk allowance. However, weaning after 8 wk appears to support superior weight gain, provided preweaning milk allowances are adequate (above 6 L/d). Weaning can lead to hunger-related behaviors and reduced welfare, yet only half of the studies assessed the effects of weaning method on calf behavior. Weaning at later ages can reduce signs of hunger (based on unrewarded visits to the milk feeder), but it is unclear if weaning over longer durations or weaning by starter intake reduces or prolongs hunger. There was little consensus among the few studies that measured oral behaviors of calves. Positive welfare indicators, such as play behavior, were rarely measured, yet are crucial to understanding the emotional states of calves during this potentially stressful diet transition. Health was rarely the primary objective of the study, with low sample sizes to conduct statistical comparisons. Overall, there remains significant knowledge gaps in our understanding of how best to wean calves. A successful weaning program must minimize signs of hunger while promoting high growth and feed intakes, so we encourage future work to include behavioral indicators of hunger and positive welfare to evaluate how weaning methods are experienced by the calf.

Predicting Body Weight in Pre-Weaned Holstein-Friesian Calves Using Morphometric Measurements

Regularly weighing calves helps to assess the efficiency of the rearing period and contributes to animal welfare by allowing more precise feeding and medication application in dairy farming, but many farmers do not weigh their calves regularly. Improving the feasibility of this process is, therefore, important. The use of morphometric measurements has been used to estimate the weight of cattle. However, many studies have focused on adult animals or used a wide age range. As calves experience allometric tissue growth, specific models for certain ranges might be more accurate. Therefore, the aim of this work was to develop a weight estimation model specific for pre-weaned Holstein-Friesian calves using morphometric measurements and to compare the model with another equation previously validated for the same breed with young and adult animals. From four dairy farms, 237 measurements of body weight, heart girth, abdominal girth, hip height, withers height, and body length were taken from Holstein-Friesian male and female calves. Linear and non-linear regression analysis was used to test the relationship between body weight and morphometric measurements, with age, sex, and farm as possible explanatory variables. Selected models were compared with goodness of fit and agreement tests. The final model was able to accurately predict body weight (R2 = 0.96) with a mean difference of -1.4 ± 3.24 kg. Differences in the relationship between body weight and morphometric traits were observed between farms, but not between males and females. The genetics of the animal population at farm level may be responsible for this variability and further studies are needed to understand this variability and improve weight prediction models. The developed model was able to perform better in the agreement tests than the previously validated model for Holstein-Friesian animals, suggesting that different equations should be used depending on the growth phase the animal is in. In addition, a web application has been developed to facilitate the use of the developed model by farmers. This avoids the use of calibrated weight bands, which are usually calibrated for a broader age range or for beef cattle.

Calf Management: Individual or Paired Housing Affects Dairy Calf Health and Welfare

Previous research has indicated that preweaned dairy calves reared in pairs compared with individually have improved performance and indicators of animal welfare. One hundred and thirty Holstein female calves completed the trial, with eighty-five being allocated to paired housing and forty-five calves being allocated to individual housing. Daily live weight gain (DLWG), treatments and mortality were recorded throughout the preweaning period. Salivary cortisol, latency to feed and latency to approach a novel object were assessed at batching. There were no significant differences in DLWG, mortality and disease treatments between the average of the pair and the individually housed calves, although the pair-reared calves were quicker to approach the milk feed after batching and interacted more quickly with a novel object. The heaviest born calves within the pair had the highest DLWG from birth to weaning, with a higher percentage of calves approaching the novel object, compared with the lightest born calf within the pair. This study shows that calves within a pair may have significantly different performance and welfare during the preweaning period, with the heavier calf outperforming and displaying less fear and more exploratory behaviour than the lighter calf within a pair.

Using the conditioned place preference paradigm to assess hunger in dairy calves: Preliminary results and methodological issues

Dairy calves are typically fed restricted amounts of milk. Although feed restrictions are predicted to result in negative affective states, the relative aversiveness of 'hunger' remains largely unexplored in this species. Here, we investigated whether the conditioned place preference paradigm can be used to explore how calves feel when experiencing different levels of satiation. This paradigm provides insight into what animals remember from past experiences, the assumption being that individuals will prefer places associated with more pleasant or less unpleasant experiences. Sixteen Holstein calves were either fed a restricted (3 L per meal totalling 6 L per day) or 'enhanced' milk allowance (ad libitum up to 6 L per meal totalling up to 12 L per day) in their home-pen. Calves were then placed in a conditioning pen for 4 h immediately after being fed their morning meal to allow them to develop an association between the pen and their state of post-prandial satiation. Calves were conditioned across four days with their satiation state alternating between days to allow them to develop an association between pen and satiation levels. On the 5th day, calves were individually allowed to roam freely between the two pens for 30 min. We expected that calves would prefer the pen where they previously experienced higher levels of satiation, but our results show no to limited effects of treatment. However, some methodological issues (colour and side bias) prevent us from drawing strong conclusions. We discuss reasons for these issues and potential solutions to avoid these in future studies.

A qualitative survey approach to investigating beef and dairy veterinarians' needs in relation to technologies on farms

Globally, farmers are being increasingly encouraged to use technologies. Consequently, veterinarians often use farm data and technologies to provide farmers with advice. Yet very few studies have sought to understand veterinarians' perceptions of data and technologies on farms. The aim of this study was to understand veterinarians' experiences and opinions on data and technology on beef and dairy farms. An online qualitative survey was conducted with a convenience sample of 36 and 24 veterinarians from the United Kingdom and Ireland, respectively. The data were analysed using reflexive thematic analysis to generate four themes: (1) Improving veterinary advice through data; (2) Ensuring stock person skills are retained; (3) Longevity of technology; and (4) Solving social problems on farms. We show that technologies and data can make veterinarians feel more confident in the advice they give to farmers. However, the quality and quantity of data collected on cattle farms were highly variable. Furthermore, veterinarians were concerned that farmers can become over-reliant on technologies by not using their stockperson skills. As herd sizes increase, technologies can help to improve working conditions on farms with multiple employees of various skillsets. Veterinarians would like innovations that can help them to demonstrate their competence, influence farmers' behaviour, and ensure sustainability of the beef and dairy industries.

Factors that influence dairy farmers' decisions to implement Johne's Disease control practices: A systematic review

Johne's Disease (JD) is an infectious ruminant disease that can cause economic loss for famers through reduced milk yields and infertility and has negative implications for animal welfare. JD is endemic in the dairy populations of many countries and there has been significant effort by governments and industry to try and control it. However, these efforts have had limited success. Many studies look at individual control programmes or the adoption of Johne's control measures; however a wider perspective on what drives farmer participation Johne's control does not currently exist. This study seeks to fill this gap by conducting a systematic review informed by the PRISMA statement. The results suggest that psychological factors such as participation fatigue, cognitive dissidence over animal welfare and not having first-hand experience of the disease act as barriers to Johne's control. To better promote Johne's control, this review emphasises that control programmes need to engage farmers, advisers, and supply chain actors in their design and delivery of control programmes to account for differing attitudes and levels of knowledge.

Evidence of personality-dependent plasticity in dairy calf movement behaviours derived from automated data collection

Individual consistency in behaviour, known as animal personality, and behavioural plasticity in response to environmental changes are important factors shaping individual behaviour. Correlations between them, called personality-dependent plasticity, indicate that personality can affect individual reactions to the environment. In farm animals this could impact the response to management changes or stressors but has not yet been investigated. Here we use ultra-wideband location sensors to measure personality and plasticity in the movement of 90 dairy calves for up to 56 days starting in small pair-housing enclosures, and subsequently moved to larger social housings. For the first time calves were shown to differ in personality and plasticity of movement when changing housing. There were significant correlations between personality and plasticity for distance travelled (0.57), meaning that individuals that travelled the furthest in the pair housing increased their movement more in the social groups, and for residence time (- 0.65) as those that stayed in the same area more decreased more with the change in housing, demonstrating personality-dependent plasticity. Additionally, calves conformed to their pen-mate's behaviour in pairs, but this did not continue in the groups. Therefore, personality, plasticity and social effects impact how farm animals respond to changes and can inform management decisions.

Invited review: The effect of milk feeding practices on dairy calf behavior, health, and performance-A systematic review

The aim of this systematic review was to summarize the literature assessing the effects of milk feeding practices on behavior, health, and performance on dairy calves. Peer-reviewed, published articles, written in English, directly comparing the effects of milk allowance, milk feeding methods, or milk feeding frequency on dairy calves were eligible for inclusion. Outcome measures could include sucking behavior, sucking on a teat (nutritive sucking, non-nutritive sucking on a teat), abnormal sucking behavior (non-nutritive sucking on pen fixtures, other oral behaviors, or cross-sucking), signs of hunger (vocalizations or unrewarded visits at the milk feeder), activity (lying time or locomotor play), feeding behavior (milk intake, starter intake, milk meal duration, or starter meal duration), growth (body weight or average daily gain), and health (occurrence of diarrhea, respiratory disease, or mortality). We conducted 2 targeted searches using Web of Science and PubMed to identify key literature. The resulting articles underwent a 2-step screening process. This process resulted in a final sample of 94 studies. The majority of studies investigated milk allowance (n = 69). Feeding higher milk allowances had a positive or desirable effect on growth, reduced signs of hunger, and increased locomotor play behavior during the preweaning period, whereas starter intake was reduced. Studies addressing health pointed to no effect of milk allowance, with no consistent evidence indicating that higher milk allowances result in diarrhea. Studies addressing milk feeding methods (n = 14) found that feeding milk by teat reduced cross-sucking and other abnormal oral behaviors. However, results on the effect of access to a dry teat were few and mixed. Milk feeding frequency (n = 14 studies) appeared to have little effect on feed intakes and growth; however, there is some evidence that calves with lower feeding frequency experience hunger. Overall, findings strongly suggest feeding higher volumes of milk using a teat; however, further work is needed to determine the optimal feeding frequency for dairy calves.

Welfare of calves

This Scientific Opinion addresses a European Commission request on the welfare of calves as part of the Farm to Fork strategy. EFSA was asked to provide a description of common husbandry systems and related welfare consequences, as well as measures to prevent or mitigate the hazards leading to them. In addition, recommendations on three specific issues were requested: welfare of calves reared for white veal (space, group housing, requirements of iron and fibre); risk of limited cow–calf contact; and animal‐based measures (ABMs) to monitor on‐farm welfare in slaughterhouses. The methodology developed by EFSA to address similar requests was followed. Fifteen highly relevant welfare consequences were identified, with respiratory disorders, inability to perform exploratory or foraging behaviour, gastroenteric disorders and group stress being the most frequent across husbandry systems. Recommendations to improve the welfare of calves include increasing space allowance, keeping calves in stable groups from an early age, ensuring good colostrum management and increasing the amounts of milk fed to dairy calves. In addition, calves should be provided with deformable lying surfaces, water via an open surface and long‐cut roughage in racks. Regarding specific recommendations for veal systems, calves should be kept in small groups (2–7 animals) within the first week of life, provided with ~ 20 m²/calf and fed on average 1 kg neutral detergent fibre (NDF) per day, preferably using long‐cut hay. Recommendations on cow–calf contact include keeping the calf with the dam for a minimum of 1 day post‐partum. Longer contact should progressively be implemented, but research is needed to guide this implementation in practice. The ABMs body condition, carcass condemnations, abomasal lesions, lung lesions, carcass colour and bursa swelling may be collected in slaughterhouses to monitor on‐farm welfare but should be complemented with behavioural ABMs collected on farm.

Effects of different milk feeding levels and frequencies on performance of Holstein heifers during weaning and first lactation

In the present study, the effects of milk feeding amount and feeding frequency (FF) on performance, blood metabolites, rumen fermentation, and performance of dairy heifers during the first artificial insemination (AI) and first lactation were investigated. The treatment group consisted of 48 female Holstein heifer calves (12/treatment) distributed in a 2 × 2 factorial arrangement with milk feeding [high = 8 L/d, HL or medium = 6 L/d, ML] and feeding frequency [2 × or 3 ×]. All calves were fed on a step-up/step-down method, weaned from milk at 56 d of age, and observed until 70 d of age. Heifer calves were kept uniform from 70 d of age until the first lactation to evaluate the long-term effects of the treatments. We observed no FF effect and no interaction between the level and FF on feed intake, average daily gain (ADG), feed efficiency (FE), body weight (BW), structural growth, blood metabolites, and rumen fermentation parameters. Calves fed HL milk had higher total dry matter intake (DMI), BW, and ADG during the pre- and post-weaning periods. During the preweaning period, HL-fed calves had higher serum insulin (trend) and glucose concentrations compared to ML-fed calves. Lower age at first AI was observed in calves fed HL rather than ML regardless of FF. Weight at first AI, milk yield (305 d), and energy-corrected milk (ECM-305 d) in the first lactation showed a trend toward higher values in HL-fed calves compared to ML-fed calves. Preweaning performance and calf maturity can be positively affected by feeding high amounts of milk at both FF.

Using Machine Learning and Behavioral Patterns Observed by Automated Feeders and Accelerometers for the Early Indication of Clinical Bovine Respiratory Disease Status in Preweaned Dairy Calves

The objective of this retrospective cohort study was to evaluate a K-nearest neighbor (KNN) algorithm to classify and indicate bovine respiratory disease (clinical BRD) status using behavioral patterns in preweaned dairy calves. Calves (N=106) were enrolled in this study, which occurred at one facility for the preweaning period. Precision dairy technologies were used to record feeding behavior with an automated feeder and activity behavior with a pedometer (automated features). Daily, calves were manually health-scored for bovine respiratory disease (clinical BRD; Wisconsin scoring system, WI, USA), and weights were taken twice weekly (manual features). All calves were also scored for ultrasonographic lung consolidation twice weekly. A clinical BRD bout (day 0) was defined as 2 scores classified as abnormal on the Wisconsin scoring system and an area of consolidated lung ≥3.0 cm2. There were 54 calves dignosed with a clinical BRD bout. Two scenarios were considered for KNN inference. In the first scenario (diagnosis scenario), the KNN algorithm classified calves as clinical BRD positive or as negative for respiratory infection. For the second scenario (preclinical BRD bout scenario), the 14 days before a clinical BRD bout was evaluated to determine if behavioral changes were indicative of calves destined for disease. Both scenarios investigated the use of automated features or manual features or both. For the diagnosis scenario, manual features had negligible improvements compared to automated features, with an accuracy of 0.95 ± 0.02 and 0.94 ± 0.02, respectively, for classifying calves as negative for respiratory infection. There was an equal accuracy of 0.98 ± 0.01 for classifying calves as sick using automated and manual features. For the preclinical BRD bout scenario, automated features were highly accurate at -6 days prior to diagnosis (0.90 ± 0.02), while manual features had low accuracy at -6 days (0.52 ± 0.03). Automated features were near perfectly accurate at -1 day before clinical BRD diagnosis compared to the high accuracy of manual features (0.86 ± 0.03). This research indicates that machine-learning algorithms accurately predict clinical BRD status at up to -6 days using a myriad of feeding behaviors and activity levels in calves. Precision dairy technologies hold the potential to indicate the BRD status in preweaned calves.