Redefining dominance calculation: Increased competition flattens the dominance hierarchy in dairy cows

Dominance hierarchies are known for mitigating conflicts and guiding priority of access to limited resources in gregarious animals. The dominance hierarchy of dairy cows is typically investigated using agonistic interactions, often monitored at the feed bunk right after fresh feed delivery when competition is high resulting in frequent interactions. Yet, the outcome of agonistic interactions during times of high competition may be more influenced by cows' high valuation of fresh feed than their intrinsic attributes, such that the dominance hierarchy constructed using agonistic interactions under high versus low competition times might differ. We tested how the structure of the dominance hierarchy changes in relation to different levels of competition in a dynamic group of 48 lactating dairy cows over 10 mo, with 6 cows exchanged every 16 d for a total of 159 cows. Using a validated algorithm we continuously detected the actor and reactor of replacement behaviors in 30 feed bins as cows competed for feed. We also calculated the percentage of occupied feed bins to characterize competition at the moment of each replacement. These data were combined to create hierarchies using Elo ratings, separately for 25 occupancy levels ranging from 13% to 100%. For each 1% rise in feeder occupancy, hierarchy steepness fell by 2.41 × 10-3 ± 9.71 × 10-5 (SE), and the percentage of dyads where both cows replaced each other rose by 0.13% ± 0.01%. At the highest feeder occupancy level in comparison to the lowest one, we observed 7.57% more dyads in which the dominant individual (those won more interactions at the lowest feeder occupancy) started to lose proportionally more. The magnitude of decrease in the winning rate of the dominant individual in those dyads also got amplified by 1.06 × 10-3% ± 1.37 × 10-4% (SE) for each 1% increase in feeder occupancy. These findings illustrate how inferred hierarchies vary with competition, with high competition flattening the hierarchy due to increased success of subordinate animals. We suggest that during heightened competition, increased valuation of resources can affect competitive success more than the individual's intrinsic dominance attributes. We recommend against calculating dominance hierarchies based on agonistic interactions during periods of high competition alone, and more generally urge researchers to differentiate agonistic interactions based on context when constructing dominance hierarchies.

Effects of group size on agonistic interactions in dairy cows: a descriptive study

Group-housed cattle may engage in agonistic interactions over resources such as feed, which can negatively affect aspects of welfare. Little is known about how contextual factors such as group size influence agonistic behaviour. We explored the frequency of agonistic interactions at the feeder when cattle were housed in different-sized groups. We also explored the consistency of the directionality of agonistic interactions in dyads and of the number of agonistic interactions initiated by individuals across the group sizes. Four replicates of 50 cows each were assessed in two group-size phases. In Phase 1, cows were kept in one group of 50. In Phase 2, these same cows were divided into five groups of 10, maintaining stocking density (i.e., ratio of animals to lying stalls and feed bunk spaces). We measured agonistic replacements (i.e., interactions that result in one cow leaving the feed bin and another taking her place) at an electronic feeder using a validated algorithm. We used these data from Phase 1 to calculate individual Elo-ratings (a type of dominance score). Cows were then categorised into five dominance categories based upon these ratings. To ensure a consistent Elo-rating distribution between phases, two cows from each dominance category were randomly assigned to each small group of 10 cows. The mean ± SE number of replacements per cow was similar regardless of whether the cows were housed in groups of 50 (34.1 ± 2.4) or 10 (31.1 ± 4.5), although the groups of 10 were more variable. Further, 81.6 ± 7.7% (mean ± SD) of dyads had the same directionality across group sizes (i.e., the same individual won the majority of interactions in the dyad) and individuals were moderately consistent in the number of replacements they initiated (intraclass correlation coefficient = 0.62 ± 0.11; mean ± SD). These results indicate that the relationship between group size and agonistic behaviour is complex; we discuss these challenges and suggest new avenues for further research.

Swine industry perspectives on the future of pig farming

Understanding the views of those working along the value chain reliant on livestock is an important step in supporting the transition towards more sustainable farming systems. We recruited 31 delegates attending the Pig Welfare Symposium held in the United States to participate in one of six focus group discussions on the future of pig farming. Each of these six group discussions was subjected to a thematic analysis that identified four themes: (1) technical changes on the farm; (2) farm and industry culture; (3) the farm-public interface; and (4) sustainability. The results of this study illustrate the complexity and diversity of views of those working along the associated value chain within the swine industry. Participants spent the majority of their time discussing current challenges, including technical challenges on the farm and public perception of pig farms. Participants were more hesitant to discuss future issues, but did engage on the broader issue of sustainability, focusing upon economic and environmental aspects.

Gene editing in animals: What does the public want to know and what information do stakeholder organizations provide?

Organizations involved with gene editing may engage with the public to share information and address concerns about the technology. It is unclear, however, if the information shared aligns with what people want to know. We aimed to understand what members of the public want to know about gene editing in animals by soliciting their questions through an open-ended survey question and comparing them with questions posed in Frequently Asked Question (FAQ) webpages developed by gene editing stakeholder organizations. Participants (338 USA residents) asked the most questions about gene editing in general and animal welfare. In contrast, FAQ webpages focused on regulations. The questions survey participants asked demonstrate a range of knowledge and interests. The discrepancy between survey participant questions and the information provided in the FAQ webpages suggests that gene editing stakeholders might engage in more meaningful public engagement by soliciting actual questions from the public and opening up opportunities for real dialogue.

Training dairy heifers with positive reinforcement: Effects on anticipatory behavior

Dairy cattle are often restrained for veterinary procedures, but restraint can cause fear responses that can make the procedure challenging for both the animal and the human handler. Positive reinforcement training (PRT) is used in other species to reduce fear responses and there is now evidence that this can also facilitate handling in cattle. The objectives of this study were to test the effect of PRT on anticipatory and play behavior in dairy heifers. We predicted that heifers trained with PRT would show more anticipatory and play behaviors than control heifers in the period before gaining access to a chute. We used 20 heifers (5 ± 0.6 mo old) that had been habituated to the chute area and had previous experience with handling. Heifers were randomly assigned to 2 treatments: control (n = 10) and PRT (n = 10). Positive reinforcement training heifers were subjected to a training protocol that included standard farm handling techniques, as well as target training with food reinforcement. Control heifers were moved to the chute using standard farm handling techniques only. As predicted, PRT heifers performed more behavioral transitions (7.6 ± 0.77 vs. 4.4 ± 0.57 transitions for control heifers; F1,9 = 21.99, P < 0.01), and specifically performed more locomotory play such as jumping (2.1 ± 0.30 vs. 0.4 ± 0.19 jumps; F1,9 = 57.18, P < 0.01) and running (2.0 ± 0.40 s vs. 0.5 ± 0.16 s; F1,9 = 20.73, P < 0.01). These results indicate that PRT results in heifers having a more positive emotional state in anticipation of handling, and support the use of training to improve the welfare of dairy cattle.

Attitudes of western Canadian dairy farmers toward technology

Dairy farms have become more reliant on technology. The overall aim of this study was to better understand how dairy farmers view technology and its effects on animal care, including their views on the prospect of integrating gene-editing technology in the future. Virtual-semistructured interviews were conducted with dairy farmers (n = 11) from British Columbia and Alberta. To facilitate discussion, the participants were asked to develop and discuss a timeline describing when and why various technologies were adopted on their farm. Although farmers defined technology broadly and affecting multiple aspects of farm management, this paper focuses on their views regarding how technology can affect animal care. Following thematic analysis of the data, the following 3 themes emerged: (1) the changing role of the farmer (including intergenerational considerations and learning new technology), (2) the effect of technology on the cow and her relationship with the farmer and, (3) technology as the future of the farm. The discussions also highlight the concerns that some farmers have regarding challenges associated with reduced human-animal interactions and effective use of the large amounts of data that are collected through technology. We also specifically asked the participants their views about gene editing as a potential future technology. Most of the participants did not specifically address their views on gene editing, but they spoke about the effect on genetic technologies more generally, often making references to genomic testing. However, some questioned how this technology may affect farmers more generally and spoke about how it could affect human-animal relationships. These results illustrate differences among farmers in the way they view technology and how this can affect the dairy cattle they care for.

Graduate Student Literature Review: Sociability, fearfulness, and coping style-Impacts on individual variation in the social behavior of dairy cattle

Dairy cattle typically live in groups, but individuals within these groups vary in their social behavior. An improved understanding of factors affecting the expression of social behavior may help refine management practices on farms to better accommodate the needs of all individuals within the herd. In this paper, we review (1) some examples of how social behavior is expressed in cattle, (2) commonly assessed personality traits in this species (i.e., sociability and fearfulness) as well as coping style, and (3) how these can affect the expression of social behavior of dairy cattle and in turn their welfare. We also identify understudied social behaviors that personality might influence (social learning, social stress, and social buffering of negative emotions), and that could inform how to improve the welfare of intensively housed dairy cattle.

Mouse isoflurane anesthesia using the drop method

Anesthesia with isoflurane prior to carbon dioxide euthanasia is recommended as a refinement, but vaporizer access can be limited. An alternative to vaporizers is the 'drop' method, introducing a fixed volume of isoflurane into the induction chamber. Previous work suggests that isoflurane administered at a concentration of 5% via the drop method is effective but aversive to mice; lower concentrations have not been tested. We assessed mouse behavior and insensibility with induction using the drop method for isoflurane concentrations below 5%. Male Crl:CD-1 (ICR) mice (n = 27) were randomly allocated to one of three isoflurane concentrations: 1.7%, 2.7%, and 3.7%. During induction, measures of insensibility and stress-related behaviors were recorded. All mice reached a surgical plane of anesthesia, and mice exposed to higher concentrations did so more quickly; as concentrations increased from 1.7 to 2.7 and 3.7%, the time to recumbency (Least squares means ± SE: 120.5 s ± 8.1, 97.9 s ± 8.1, and 82.8 s ± 8.1, respectively), loss of righting reflex (149.1 s ± 8.5, 127.7 s ± 8.5, and 100.7 s ± 8.5, respectively), and loss of pedal withdrawal reflex (214.5 s ± 8.3, 172.2 s ± 8.3, and 146.4 s ± 8.3, respectively) all declined. Rearing was the most frequently performed stress-related behavior, and was most pronounced immediately following isoflurane administration for all treatments. Our results indicate that the drop method can be used to effectively anesthetize mice with isoflurane concentrations as low as 1.7%; future work should assess mouse aversion.

The effects of pain following disbudding on calf memory

Studies have found evidence of pain in the hours following hot-iron disbudding, but little is known about longer-lasting pain following this procedure. Work on humans and rats has shown that lasting pain can have negative effects on the formation and recall of memories. The objective of this study was to assess whether lasting pain following disbudding affects learning and memory in calves. A modified hole-board apparatus was used to assess how quickly calves were able to learn the locations of 4 bottles containing milk dispersed among 11 locations with empty bottles. At 14 d of age and after 6 d of training on this task, calves (n = 30) were randomly assigned to 3 treatments: disbudding with analgesic on the day of the procedure, disbudding with analgesic throughout the study, and sham disbudding. All calves were sedated, given a lidocaine cornual local block and a single injection of an nonsteroidal anti-inflammatory drugs. Starting on the day after their disbudding treatment, calves were tested daily using the modified hole-board apparatus. After 12 d of testing, the locations of the 4 milk-containing bottles were switched, and calves then relearned the locations of the rewarded bottles over the next 6 daily test sessions. We found general working memory (i.e., short-term memory) and reference memory (i.e., long-term memory) increased over the 12 d of testing, declined when locations were switched on d 13, and then again increased over the final 6 d of testing. We did not find an effect of treatment on any measure, perhaps because there was no lasting pain or because effects were too minor to detect using this test of spatial memory.

How might the public contribute to the discussion on cattle welfare? Perspectives of veterinarians and animal scientists

Veterinarians and animal scientists can provide leadership on issues relevant to farm animal welfare, but perceptions of these stakeholders regarding societal expectations for welfare are underexplored. This study involved five focus groups of veterinarians and animal scientists (n = 50 in total), recruited at a European meeting focused on cattle welfare. Participants were invited to discuss topics related to cattle welfare and were prompted with questions to elicit their perspectives of public concerns and how the participants felt public input should be included when developing solutions. Discussions were moderated by trained facilitators, audio-recorded and transcribed, and transcripts analysed using reflexive thematic analysis. Ultimately, four primary themes were developed: (1) The public as concerned; (2) The public as ignorant; (3) The public as needing education; and (4) The public as helper or hindrance. Groups identified specific farming practices viewed as concerning to the public, including lack of pasture access, behavioural restriction, and painful procedures. Discussions about these concerns and the role of the public were often framed around the assumption that the public was ignorant about farming, and that this ignorance needed to be rectified through education. Participants were generally ambivalent in their beliefs regarding public contributions to solutions for farm animal welfare but suggested that consumers should pay more for products to help shoulder any costs of welfare improvements.

Exploring the effect of pain on response to reward loss in calves

Negative emotional states are known to interact, potentially aggravating one another. In this study, we used a well validated paradigm (successive negative contrast, SNC) to determine if pain from a common procedure (disbudding) influences responses to a reward downshift. Holstein calves (n = 30) were trained to approach a 0.5 L milk reward. Latency to approach, number of vocalisations and pressure applied on the bottle were recorded during training. To assess how pain affected responses to reward downshift, calves were randomly assigned to one of three treatments before the downshift. Two groups were disbudded and provided the 'gold standard' of pain mitigation: intraoperative local anesthesia and analgesia. One of these disbudded groups was then provided supplemental analgesic before testing. The third group was sham disbudded. All calves were then subjected to the reward downshift by reducing the milk reward to just 0.1 L. Interactions were detected between test session and daily trials on pressure applied for the Disbudded group (estimate ± SEM: 0.08 ± 0.05), and on vocalisations for the Sham (0.3 ± 0.1) and Disbudding + Analgesia (0.4 ± 0.1) groups. Our results indicate that SNC is a promising paradigm for measuring negative affect in calves and suggests that pain potentially affects the response to a reward downshift.

Social acceptance of genetic engineering technology

Genetic engineering of animals has been proposed to address societal problems, but public acceptance of the use of this technology is unclear. Previous work has shown that the source of information proposing the technology (e.g. companies, universities), the term used to describe the technology (e.g. genome editing, genetic modification), and the genetic engineering application (e.g. different food products) affects technology acceptance. We conducted three mixed-method surveys and used a causal trust-acceptability model to understand social acceptance of genetic engineering (GE) by investigating 1) the source of information proposing the technology, 2) the term used to describe the technology, and 3) the GE application for farm animals proposed. Further, participants expressed their understanding of technology using a range of terms interchangeably, all describing technology used to change an organism's DNA. We used structural equation modelling and confirmed model fit for each survey. In each survey, perceptions of benefit had the greatest effect on acceptance. Following our hypothesized model, social trust had an indirect influence on acceptance through similar effects of perceived benefit and perceived risk. Additional quantitative analysis showed that the source of information and technology term had little to no effect on acceptance. Applications involving animals were perceived as less beneficial than a plant application, and an application for increased cattle muscle growth was perceived as more risky than a plant application. When assessing the acceptability of applications participants considered impacts on plants, animals, and people, trust in actors and technologies, and weighed benefits and drawbacks of GE. Future work should consider how to best measure acceptability of GE for animals, consider contextual factors and consider the use of inductive frameworks.

Review: Using animal welfare to frame discussion on dairy farm technology

The use of technology on dairy farms has increased dramatically over the last half-century. The ways that scientists describe the potential benefits and risk of technology are likely to affect if it is accepted for use on farms. The aim of our study was to identify papers that describe a linkage between technologies used on dairy farms and the welfare of dairy cattle. Our systematic review identified 380 papers, of which 28 met our inclusion criteria and were used to describe the technologies examined, the welfare-relevant measures used, and the ways in which authors framed welfare benefits and risks associated with the technologies. The large majority (27 of 28 papers) used positive frames, considering how the technology could improve welfare. Some authors carefully articulated the logic linking the specific measures to specific welfare-related outcomes (such as the use of accelerometer data to draw inferences about changes in lying times), but others made more general inferences (about health and welfare) that were not (and perhaps could not) be assessed. We conclude that much of the framing focused on animal welfare is biased toward welfare benefits and that future work should strive to address both potential benefits and harms; more balanced coverage may better inform solutions to the problems encountered by the people and animals affected by the technology. Welfare is a complex and multifaced concept, and it is unlikely that any one technology (or perhaps even a combination of technologies) can adequately capture this complexity. Thus, we encourage authors to restrict their claims to specific, welfare-relevant measures that can be assessed independently and thus validated. More general claims about welfare should be treated with skepticism.

Crowd sourcing remote comparative lameness assessments for dairy cattle

Lameness assessments are rarely conducted routinely on dairy farms and when completed typically underestimate lameness prevalence, hampering early diagnosis and treatment. A well-known feature of many perceptual tasks is that relative assessments are more accurate than absolute assessments, suggesting that creating methods that allow for the relative scoring of which cow is more lame will allow for reliable lameness assessments. Here we developed and tested a remote comparative lameness assessment method: we recruited nonexperienced crowd workers via an online platform and asked them to watch 2 videos side-by-side, each showing a cow walking, and to identify which cow was more lame and by how much (on a scale of -3 to 3). We created 11 tasks, each with 10 video pairs for comparison, and recruited 50 workers per task. All tasks were also completed by 5 experienced cattle lameness assessors. We evaluated data filtering and clustering methods based on worker responses and determined the agreement among workers, among experienced assessors, and between these groups. A moderate to high interobserver reliability was observed (intraclass correlation coefficient, ICC = 0.46 to 0.77) for crowd workers and agreement was high among the experienced assessors (ICC = 0.87). Average crowd-worker responses showed excellent agreement with the average of experienced assessor responses (ICC = 0.89 to 0.91), regardless of data processing method. To investigate if we could use fewer workers per task while still retaining high agreement with experienced assessors, we randomly subsampled 2 to 43 (1 less than the minimum number of workers retained per task after data cleaning) workers from each task. The agreement with experienced assessors increased substantially as we increased the number of workers from 2 to 10, but little increase was observed after 10 or more workers were used (ICC > 0.80). The proposed method provides a fast and cost-effective way to assess lameness in commercial herds. In addition, this method allows for large-scale data collection useful for training computer vision algorithms that could be used to automate lameness assessments on farm.

Public attitudes toward the use of technology to create new types of animals and animal products

Philosophers have used thought experiments to examine contentious examples of genetic modification. We hypothesised that these examples would prove useful in provoking responses from lay participants concerning technological interventions used to address welfare concerns. We asked 747 US and Canadian citizens to respond to two scenarios based on these thought experiments: genetically modifying chickens to produce blind progeny that are less likely to engage in feather-pecking (BC); and genetically modifying animals to create progeny that do not experience any subjective state (i.e. incapable of experiencing pain or fear; IA). For contrast, we assessed a third scenario that also resulted in the production of animal protein with no risk of suffering but did not involve genetically modifying animals: the development of cultured meat (CM). Participants indicated on a seven-point scale how acceptable they considered the technology (1 = very wrong to do; 7 = very right to do), and provided a text-based, open-ended explanation of their response. The creation of cultured meat was judged more acceptable than the creation of blind chickens and insentient animals. Qualitative responses indicated that some participants accepted the constraints imposed by the thought experiment, for example, by accepting perceived harms of the technology to achieve perceived benefits in reducing animal suffering. Others expressed discomfort with such trade-offs, advocating for other approaches to reducing harm. We conclude that people vary in their acceptance of interventions within existing systems, with some calling for transformational change.

Calves peak-end memory of pain

In humans, the 'peak-end' rule states that recollection of an experience is most often influenced by the peak (the most intense moment) and end of the experience. We investigated whether calves followed the peak-end rule in their memory of a painful procedure: disbudding. As proxies for retrospective and 'real-time' reports of pain, we used conditioned place aversion, and reflex pain behaviours. In two separate trials, calves were subjected to two disbudding conditioning sessions (one horn per treatment), acting as their own control. In the first trial, calves (n = 22) were disbudded and remained in a pen for 4 h, and disbudded and left in another pen for 4 h with an additional 2 h following an analgesic treatment. In the second trial, calves (n = 22) were disbudded and left in pens for 6 h during both treatments, receiving the analgesic at either 2 h or 4 h after disbudding. Calves were then tested for place aversion. For both trials we did not observe a preference for the pens where calves received analgesic treatment towards the end of the session. We did not find an association between aversion and the sum, peak or end of pain behaviours. Results are not consistent with a peak-end effect in calves' memory of pain.

Perceptions of laboratory animal veterinarians regarding institutional transparency

Institutions using animals for research typically have a veterinarian who is responsible for the veterinary care programme and compliance with regulatory obligations. These veterinarians operate at the interface between the institution's animal research programme and senior management. Veterinarians have strong public trust and are well positioned to share information about animals used for scientific purposes, but their perspectives on sharing information with the public are not well documented and their perceptions of transparency may influence how institutional policies are developed and applied. The objective of our study was to analyse the perceptions of institutional transparency among laboratory animal veterinarians working at different universities. Semi-structured, open-ended interviews were used to describe perceptions of 16 attending veterinarians relating to animal research transparency. Three themes were drawn from the interviews: (i) reflections on transparency; (ii) reflections on culture; and (iii) reflections on self. Veterinarians reflected on their personal priorities regarding transparency and when combined with barriers to change within the institutions, sometimes resulted in reported inaction. For example, sometimes veterinarians chose not to pursue available opportunities for change at seemingly willing universities, while others had their initiatives for change blocked by more senior administrators. The sharing of information regarding the animals used for scientific purposes varied in how it was conceptualised by attending veterinarians: (i) true transparency; communication of information for the sake of openness; (ii) strategic transparency; attempt to educate people about animal research because then they will support it; (iii) agenda-driven transparency; selective release of positive stories to direct public opinion; and (iv) fearful non-transparency; not communicating any information for fear of negative opposition to animal research. Transparency was not perceived as an institutional priority by many of the veterinarians and a cohesive action plan to increase transparency that involves multiple universities was identified as a promising avenue to overcome existing barriers.

Invited review: Social dominance in dairy cattle: A critical review with guidelines for future research

Cattle are gregarious animals able to form social relationships. Dominance is one of the most widely studied social behaviors of dairy cattle, especially cows confined indoors. However, much of the past dairy cattle research has used an unstandardized approach, differing in definitions and conceptual understanding of dominance, as well as their methods of data collection and dominance calculation. The first of the 3 aims of this review is to evaluate how dominance relates to the social behavior of housed dairy cows. Cows engage in agonistic interactions to establish and reinforce dominance relationships. An individual's dominance is influenced by intrinsic characteristics, such as personality, and extrinsic factors, including group composition. When competing for resources, agonistic interactions can also be influenced by individual motivational differences, such as hunger, which may diminish the role of dominance in regulating competition. Our second aim is to critically review methods used to assess dominance in cows. This includes discussions on the effect of time and location of data collection on measured values as well as the viability and limitations of some dominance calculation methods. We propose that different methodologies lend themselves to different types of research questions. For example, the use of data stream-based methods that consider the sequence of interactions are useful for estimating how dominance fluctuates with changing conditions and can be used in a dynamically changing group. In contrast, matrix-based methods that aggregate social interactions may be best for identifying the social position of individuals and understanding how social characteristics influence the attributes of a stable hierarchy. Our third aim is to discuss the future of dominance research. We use a flowchart to illustrate guidelines for a more standardized approach to measuring dominance in cattle. We also identify areas in need of further conceptual clarification, suggest practical applications of dominance when managing dairy cattle, and discuss some limitations of dominance research.

Rats move nesting materials to create different functional areas: Short report

Here we document how rats separate their living space into different functional regions. Five groups of four female Sprague Dawley rats were housed in caging systems that consisted of two standard cages connected by a tube. Both cages were provided with the same amount of bedding and nesting materials, but only one contained food and water. Nesting cover and weight of each cage were measured once a week for five weeks during cage cleaning. We found that the cages with food and water had 9% less nesting material coverage but had gained 90% more weight when compared with cages where food and water were absent. These results indicate that, when provided with separate spaces, rats move nesting materials away from the cage containing food and water sources, but preferentially excrete in the cage with water and food.

Hunger affects cognitive performance of dairy calves

Hunger remains a significant animal welfare concern as restricted feeding practices are common on farms. Studies to date have focused on negative effects on health and productivity but little research has addressed the feeling of hunger, mostly due to methodological difficulties in assessing animals' subjective experiences. Here, we explored the use of a cognitive approach to disentangle motivational hunger (a normal state that is of limited welfare concern) from distressful hunger (a state associated with intense negative emotions). Cognitive performance in a foraging task is expected to follow an inverted U relationship with hunger levels, providing an opportunity to make inferences about different hunger states. We assessed the effect of milk restriction on calf cognition in two experiments using a modified hole-board test. Experiment 1 showed that reducing milk allowance from 12 to 6 l d^-1 impaired all measures of cognitive performance. Experiment 2 showed that the same type of feed restriction also disrupted calves' capacity to re-learn. We conclude that hunger associated with reduced milk allowance can disrupt cognitive performance of dairy calves, a result consistent with the experience of distressful hunger.

Pain in the hours following surgical and rubber ring castration in dairy calves: Evidence from conditioned place avoidance

Male cattle reared for beef are typically castrated. Male calves born on dairy farms are increasingly reared for beef, so a better understanding of how to humanely perform this procedure in dairy systems is now required. We studied the short-term affective responses of dairy calves to castration using a conditioned place aversion paradigm. Young Holstein bulls (16 d old, n = 30) were castrated by either rubber ring (n = 15) or surgery (n = 15), and then kept in a visually distinctive recovery pen for 6 h after the procedure. Calves acted as their own control and were sham castrated and allowed to recover for 6 h in another visually distinctive pen. During both castration and sham procedures, calves received a sedative (xylazine, 0.2 mg/kg), local anesthetic (lidocaine, 5 mL), and a nonsteroidal anti-inflammatory (meloxicam, 0.5 mg/kg). After exposure to both treatments (castration and sham), calves were tested for place aversion by providing free access to the 2 pens where they experienced the different treatments. Calves were tested for aversion 48, 72, and 96 h after their last treatment. We recorded how much time they spent in each pen and where they chose to rest. We did not find differences in time spent resting or resting location, suggesting that calves did not form a more negative memory of castration in comparison to the sham procedure. The lack of treatment effects may be due to features of our testing paradigm, including effective multimodal pain control during the 6-h conditioning period and limiting testing to the first days after the procedure.

Effects of intake-based weaning and forage type on feeding behavior and growth of dairy calves fed by automated feeders

The objective of this study was to assess the effects of intake-based weaning methods and forage type on feeding behavior and growth of dairy calves. Holstein dairy calves (n = 108), housed in 12 groups of 9, were randomly assigned to 1 of 3 weaning treatments: milk reduction based on age (wean-by-age), individual dry matter intake (DMI; wean-by-intake), or a combination of individual DMI and age (wean-by-combination). Groups of calves were alternately assigned to 1 of 2 forage treatments: grass hay or a silage-based total mix ration (TMR; n = 6 groups per treatment). Until 30 d of age, all calves were offered 12 L/d of whole milk. Starting on d 31, milk was gradually reduced by 25% of the individual's average milk intake. For wean-by-age calves (n = 31), the milk allowance remained stable until d 62 when milk was again reduced gradually until weaning at d 70. For wean-by-intake calves (n = 35), milk allowance was reduced by a further 25% once calves consumed on average 200, 600, and (finally) 1,150 g of dry matter (DM) per day of calf starter and forage. For wean-by-combination calves (n = 35), milk intake remained stable until calves consumed on average 200 g of DM/d, at which point milk was reduced linearly until weaning at d 70. If calves failed to reach DMI targets by d 62 (n = 10), milk was then reduced gradually until weaning at d 70. Of the 35 wean-by-intake calves, 27 met all 3 DMI targets (successful-intake), and 33 of the 35 calves in the wean-by-combination treatment met the 200 g of DM/d target (successful-combination). Successful-intake and successful-combination calves had greater final body weight (BW) at 12 wk of age than wean-by-age calves (123.7 vs. 122.3 vs. 117.7 ± 3.1 kg, respectively). During weaning, successful-intake calves ate more starter and consumed less milk than successful-combination and wean-by-age calves (starter: 1.19 vs. 0.89 vs. 0.49 ± 0.07 kg of DM/d, respectively; milk: 2.7 vs. 4.2 vs. 5.9 ± 0.17 L/d, respectively). After weaning, successful-combination and successful-intake calves consumed similar amounts of starter; however, wean-by-age calves continued to consume less starter (2.85 vs. 2.78 vs. 2.44 ± 0.10 kg of DM/d, respectively). During weaning, hay and TMR calves ate similar amounts of forage, but hay calves consumed more starter (0.96 vs. 0.75 ± 0.07 kg of DM/d, respectively). After weaning, hay calves continued to consume more starter (2.88 vs. 2.50 ± 0.10 kg of DM/d, respectively), whereas TMR calves consumed more forage (0.33 vs. 0.15 ± 0.02 kg of DM/d, respectively). Hay calves had greater final BW at 84 d compared with TMR calves (124.0 vs. 119.0 ± 1.6 kg, respectively). These results show that the inclusion of a DMI target can improve starter intake and BW for calves that successfully wean, and that forage type can influence the transition onto solid feed. We also found that approximately 10% of calves failed to consume even 200 g of DM/d by 9 wk of age; more research is needed to better understand why some calves struggle to transition onto solid feed.

Using animal history to inform current debates in gene editing farm animals: A systematic review

There is growing interest in gene editing farm animals. Some alterations could benefit animal welfare (e.g., improved heat tolerance in cattle with the “slick” gene), the environment (e.g., reducing methane emissions from cattle with induced pluripotent stem cells), and productivity (e.g., higher weight gains in cattle with the “double muscling” gene). Existing scholarship on the acceptability of such modifications has used myriad approaches to identify societal factors that shape the ethics and governance of this technology. We argue that integrating historical approaches—particularly from the relatively new and burgeoning field of animal history—offers a form of “anticipatory knowledge” that can help guide discussions on this topic. We conducted a systematic review of the animal history literature in English, German, and Spanish to identify the influence of political, scientific, economic, social, and cultural factors on the development and acceptance of such technologies. We identified analogous structures and fault lines in past debates about farm animals that provide insights for contemporary discussions about gene editing. Those analogous structures include the market power of meatpackers or the racialized precepts in livestock breeding, and fault lines, like the disconnect between states and citizens over the direction of food systems. Highlighting these similarities demonstrates how external forces have shaped—and will continue to shape—the acceptance or rejection of emerging biotechnologies as applied to farm animals.

Measuring lameness prevalence: Effects of case definition and assessment frequency

Lameness assessments are commonly conducted at a single point in time, but such assessments are subject to multiple sources of error. We conducted a longitudinal study, assessing the gait of 282 lactating dairy cows weekly during the first 12 wk of lactation, with the aim of assessing how lameness prevalence changed in relation to case definition and assessment frequency. Gait was scored using a 5-point scale where scores of 1 and 2 were considered sound, 3 was clinically lame, and 4 and 5 were severely lame. We created 5 lameness definitions using increasingly stringent thresholds based upon the number of consecutive events of locomotion score ≥3. In LAME1, a cow was considered lame when locomotion score was ≥3 at any scoring event, in LAME2, LAME3, LAME4, and LAME5, a cow was considered lame when locomotion score was 3 or higher during 2, 3, 4, and 5 consecutive scoring events, respectively. We also assessed the effect of assessment frequency on measures of prevalence and incidence using weekly assessment (ASSM1), 1 assessment every 2 wk (ASSM2), 1 assessment every 3 wk (ASSM3), and 1 assessment every 4 wk (ASSM4). Using LAME1, 69.2% of cows were considered lame at some point during the trial, with an average point prevalence of 31.8% (SD: 2.8) and average incidence rate of 10.9 cases/100 cow weeks (SD: 3.7). Lameness prevalence decreased to 28.0% when using LAME5. Survival analysis was used to assess the effects of parity, using these different case definitions. Parity is a known risk for lameness, such that case definitions and prevalence estimates should be stratified by parity to inform management decisions. Using the LAME3 criterion, primiparous cows had the highest chance of reaching 12 wk without a lameness event, and fourth and higher parities had the lowest. Weighted linear and quadratic kappa values were used to assess agreement between different assessment frequencies and lameness definitions; we found substantial to excellent agreement between ASSM1 and ASSM2 using LAME1, LAME2, and LAME3 definitions. Agreement was fair to substantial between ASSM1 and ASSM3 and low to fair between ASSM1 and ASSM4. Likewise, the agreement between LAME1 and LAME2 was fair in primiparous cows, substantial in second and third parity cows, and poor to fair in fourth and greater parity cows. We conclude that lameness prevalence estimates are dependent upon case definition and that the use of more stringent case definitions results in fewer cows classified as lame. These results suggest that routine locomotion assessments be conducted at least every 2 wk, and that cows should be defined as lame on the basis of 2 consecutive assessments.