Daniel Weary

Prospective Graduate Students / Postdocs

This faculty member is currently not looking for graduate students or Postdoctoral Fellows. Please do not contact the faculty member with any such requests.


Research Classification

Research Interests

Animal welfare
Applied animal behaviour
Dairy cattle
Laboratory animals

Relevant Thesis-Based Degree Programs

Affiliations to Research Centres, Institutes & Clusters

Research Options

I am available and interested in collaborations (e.g. clusters, grants).
I am interested in and conduct interdisciplinary research.
I am interested in working with undergraduate students on research projects.

Great Supervisor Week Mentions

Each year graduate students are encouraged to give kudos to their supervisors through social media and our website as part of #GreatSupervisorWeek. Below are students who mentioned this supervisor since the initiative was started in 2017.


Professor Dan has been such a great supervisor because academically, he challenging my thoughts and encourages me to do things that are slightly outside of my comfort zone. He is very understanding of decisions I make to maintain my mental health and this has made me feel very well supported. I am very lucky to have such a supervisor, thank you!

Maria Chen (2019)


Graduate Student Supervision

Doctoral Student Supervision

Dissertations completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest dissertations.

Environmental enrichment for rats and mice housed in laboratories (2023)

There is mounting evidence that current laboratory housing practices negatively impact rodent welfare. Environmental enrichment is generally recommended to improve housing, but definitions and applications of enrichment vary widely. The aims of this thesis were to explore the concept of environmental enrichment and to test applied strategies to improve housing for rodents in laboratories. In Chapter 2, I conducted a metareview of environmental enrichment for rats and mice. Authors most often supported the provision of social companions, nesting material, shelters, foraging opportunities, and larger environments (for rats). However, authors often described perceived risks or requirements of enrichment, which represent potential barriers to implementing enrichment. In Chapter 3, I investigated how the addition of an upper loft area affects the behaviour of rat dams housed in laboratory cages with their pups. My results suggest that dams use lofts as an area to get away from pups, allowing for more natural weaning and improved emotional states. In Chapter 4, I conducted a similar experiment with mouse dams housed with their pups in shoebox cages. I found that elevated tunnels were not universally effective at altering dam behaviour or welfare, and outcomes differed according to genetic strains. In Chapter 5, I gave shoebox-housed mice access to playpens on a regular basis and tested whether this was a positive experience for them. Mice showed increased anticipatory behaviour and speed of entry, indicating that playpen access was rewarding; they also engaged in a range of natural behaviours while in the playpens. In Chapter 6, I assessed anxiety, aggression, and stereotypic behaviour to determine how regular playpen access impacted mouse welfare. Playpen access improved some welfare measures, but outcomes tended to vary according to genetic strain. Collectively, this work suggests that there are welfare benefits to housing rodents with resources that allow for more diverse or motivated behaviour, but not all strategies will be equally impactful for welfare. More specific and value-neutral terms should be used to describe elements of an environment and how they are believed to affect the welfare of the animals.

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Understanding the social licence to use animals for scientific purposes and the role of institutional transparency (2022)

Meaningful societal dialogue about the use of animals for scientific purposes requires a level of transparency regarding the procedures these animals are likely to experience and the processes institutions engaged in using animals employ to determine what is acceptable. The overall thesis objective was to better understand social licence to use animals for scientific purposes and the role of institutional transparency in this process. Analysis of interviews with research animal facility managers and attending veterinarians at Canadian universities showed the interpretation of institutional transparency varied within and between universities, institutional transparency could be influenced by internal and external pressures, and the main barrier to increased transparency was a lack of motivation to change. Transparency was conceptualized in four ways: 1) true transparency; communication of information for the sake of openness, 2) misguided transparency; attempt to educate people about animal research because then they will support it, 3) manipulative transparency; selective release of positive stories to direct public opinion, and 4) fearful non-transparency; not communicating any information for fear of negative opposition to animal research. Given the diverse understanding of the purpose of transparency, I suggest that active and sustained communication between senior administrators, university veterinarians, animal care staff, and scientists is necessary to build a consensus on how to pursue transparency. While generating consensus at the local institutional level is important, substantial progress would likely benefit from involvement of all stakeholders to work collaboratively and agree to a shared vision for transparency. Analysis of a mix-methods survey that requested public input on proposed animal experiments found that many participants provided substantive and nuanced input that could aid in institutional decision making including social policy alternatives. Analysis of a second mix-methods survey found the public expected oversight for invertebrate animals used for scientific experiments and the absence of this oversight decreased public confidence and trust in scientists. In summary, my results suggest that increased information in the public domain about these practices, incorporation of societal values into decision making, and increased opportunities for participation in research animal governance could help institutions maintain social licence for these practices.

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Assessment of the affective component of pain in dairy calves (2021)

Whether they live in our homes, farms or laboratories, many animals are subjected to painful procedures. In humans, pain assessment is mostly done through verbal self report, but the assessment of pain in non-verbal humans and animals remains a challenging task.Pain can be divided in two main components: a reflex response, and an emotional experience. The focus of pain research has largely been centered around reflex responses when animals (and human neonates until recently) are the ones subjected to pain. The aim of this thesis was to address this gap by developing a method to assess the emotional experience (or ‘affective state’) that dairy calves go through during painful procedures. To do so, the focus of our novel approach was on how animals formed memories of procedures they were subjected to. In the first chapter, I reviewed the literature on the assessment of emotion in dairy cattle. I highlighted that many measures reflect how aroused animals are rather than whether they are in a positive or negative state (valence), but that measures based on cognition were promising in evaluating valence. In the second chapter, I studied the pain caused by different injection methods by looking at how much milk calves were willing to give up to avoid injections. Although all methods were more aversive than not receiving an injection, intramuscular injections were more aversive than subcutaneous or intranasal. In the third, fourth and fifth chapter, I studied how calves remembered different methods of disbudding (a procedure that prevents horn growth) by looking at how much they would avoid the place where they experienced the procedure. I found that calves remember disbudding as negative and that learned aversion is reduced if calves are provided pain control both during and after the procedure.In summary, calves showed not to be limited to a ‘knee-jerk’ response to pain. Rather, they formed impactful memories that affected their future behaviour, exhibiting complex emotional processing of pain.

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Understanding individual variation in rat responses to carbon dioxide (2020)

Carbon dioxide (CO₂) is commonly used to kill laboratory rats, but the humanness of this method remains controversial. Cumulative evidence indicates that CO₂ elicits negative emotions in rats. However studies using inescapable exposure (forced exposure) have shown contrasting results. Understanding individual differences could allow for stronger inferences regarding rat experiences when exposed to CO₂. The main aim of this thesis was to determine if CO₂ sensitivity is variable between rats. In Chapter 2, I described rat active and passive behaviours during CO₂ forced exposure and assessed consistency of individual differences in rat response to CO₂. Results from Chapter 2 confirmed that rats do not express passive behaviours when exposed to gradually increasing concentrations of CO₂, showed that the individual rat is an important source of variation in the behavioural responses to CO₂, but this variation was not related to individual differences in coping strategies. In Chapter 3, I investigated consistency and stability of rat individual thresholds of aversion to CO₂ across repeated exposures, and I assessed whether other situational-dependent personality traits could account for the variation in response to CO₂. My results suggest that individual differences in rat thresholds of aversion are not related to other personality traits but to sensitivity to CO₂. In Chapter 4, I assessed the effects of an anxiolytic on the individual thresholds of aversion to CO₂. I found that rats experience anxiety when exposed to lower CO₂ concentrations and variation in rat CO₂ sensitivity is driven by individual differences in the onset of these feelings. Collectively these studies suggest that the emotional experience of rats exposed to CO₂ varies among individuals, likely due to differences in the onset of CO₂-induced anxiety. In these studies using aversion tests, all rats avoided CO₂ before losing consciousness, even less sensitive rats when treated with an anxiolytic. Indicating that CO₂ concentrations required to render rats unconscious elicit negative affective states. Further research is necessary to determine what type of emotions, in addition to feelings of anxiety, are experienced by rats at higher concentrations (e.g. intense air hunger or panic), and whether these experiences also vary between individuals.

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Management practices and cow-level factors related to claw horn disruption lesions in dairy cows (2019)

Prolonged standing has been related to an increased risk of claw horn disruption lesions (CHDL), likely by increasing the mechanical load on the hoof. Standing behaviour can be affected by management practices. For example, prolonged standing has been reported for primiparous animals after mixing with older cows, presumably as a result of increased social competition. The hoof is believed to be more vulnerable to mechanical damage around calving, making this a period of a particular interest. The aims of this thesis were to evaluate the relationship between standing behaviour around calving and CHDL later in lactation, and to investigate if the social environment affects how heifers behaviourally react to regrouping. In Chapter 1, I summarise the current knowledge regarding factors that can affect standing behaviour, with particular focus on the social environment. As there is no consensus for how to interpret longitudinal locomotion data, I evaluate how assessment frequency, and lameness definition affect measures of lameness incidence in Chapter 2. A single observation of compromised locomotion as criterion for lameness was poorly related to more strict lameness definitions, and to the presence of claw lesions at trimming. In Chapter 3, I evaluate if the positive association between prolonged standing and sole lesions found in experimental studies is present also on commercial farms. Standing time and standing bout duration during the first 2 wk after calving were positively related to the odds of developing sole lesions later in lactation, as was an increase in standing bout duration from pre- to postpartum. In Chapter 4, I investigate if the social environment influence the standing behaviour of newly calved heifers after regrouping. I found no difference in standing behaviour between heifers regrouped to a low-stocked pen with familiar animals and heifers mixed with multiparous older cow at 100% stocking density, and under the conditions used in this study regrouping did not cause prolonged standing. These studies provide evidence that standing behaviour during the transition period is temporally related with CHDL on commercial farms, and suggest that the effect of regrouping on standing behaviour is influenced by the conditions under which regrouping occurs.

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Promoting farmer and veterinarian cooperation to improve dairy calf welfare (2018)

Over the last decades, increasing scrutiny by the public related to farm animal welfare has placed pressure on farmers and veterinarians to adopt practices that lead to improvements in farm animal care. Despite these growing demands from the public, and a growing body of knowledge on what farm animals need and want, challenges remain regarding how to motivate farmers and veterinarians to adopt management changes to improve animal welfare. Dairy calves, in particular, face many welfare challenges in the early stages of life. Considering that the farmer is directly responsible for calf care on dairy farms and the veterinarian is a trusted advisor, this thesis explores how farmers and veterinarians cooperate to improve calf welfare. Chapter 1 introduces key concepts such as animal welfare, motivating factors for behavioral change, and the context for the Canadian dairy cattle industry. Chapter 2 reviews current literature on dairy farmer and veterinarian perspectives on cattle welfare and suggests that increased cooperation between these stakeholders could lead to improvements in welfare by identifying shared values for improving welfare, promoting their different perspectives as complementary, and improving communication. To examine this proposition, Chapter 3 reports on a focus group study that explores how veterinarian concerns and actions related to calf welfare correspond to their professional and personal obligations to improve it. Chapters 4 and 5 report on an interview study with dairy farmers that participated in a benchmark study on calf immune system status and growth. Chapter 4 describes how access to information and peer comparison in the form of benchmark reports motivated farmers to improve calf management. Chapter 5 describes how including the veterinarian in the benchmarking process influenced the ways that farmers viewed their veterinarian as an advisor for calf management. Chapter 6 concludes the thesis with a summary of strengths and limitations of this dissertation and recommendations such as creating interventions to improve calf welfare that complement the current management systems and leverage existing relationships between farmers and veterinarians. 

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Understanding the welfare of rats living in standard versus semi-naturalistic laboratory environments (2016)

Rats are one of the most commonly used animals in research. Differences in rat housing lead to differences in brain, behaviour, physiology and health. These differences can also affect rat welfare and the validity of data obtained from these animals. Few studies have assessed the consequences of housing rats in standard laboratory cages compared to more complex, naturalistic environments; fewer still have assessed these consequences in females, or after more than a few weeks of differential housing. The aim of my thesis was to assess the sustained welfare consequences of housing female rats in standard versus semi-naturalistic laboratory conditions. The psychological well-being of animals is central to the concept of animal welfare, so Chapter 2 provides a review of the scientific methods of assessing affective states in animals, how these methods have been applied to rats, and what the results can tell us about rats’ experience of various emotional states. Chapter 3 investigated rats’ propensity to engage in behaviours that are not possible in standard laboratory cages: burrowing, climbing and standing upright. Results indicated that burrowing and standing upright may be especially important to rats. Chapter 4 assessed the sustained affective consequences of standard versus semi-naturalistic housing using an anticipatory behaviour test. Results indicated that standard-housed rats were experiencing poorer welfare than the semi-naturalistic-housed rats. These studies were not designed to test differences in health between the two housing conditions, but given the very limited amount of research on the long-term health effects of differential housing in rats, Chapter 5 documented differences in body weight and development of naturally-occurring tumours. Standard-housed rats were much heavier than semi-naturalistic-housed rats, but there were no differences in the rate of tumour development. Collectively, these results indicate that, compared to the semi-naturalistic housing assessed in this thesis, standard laboratory housing for rats compromises rat welfare by 1) preventing the performance of important natural behaviours; 2) leading to negative affective states; and 3) leading to overweight animals predisposed to developing other health issues. Implications for rat welfare and the quality of the science obtained from standard-housed rats are discussed, and recommendations are provided.

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Food Neophobia, Feeding and Sorting Behaviour in Dairy Calves (2015)

Standard practice within the dairy industry is to separate calves from the dam immediately after birth and raise calves in individual pens during the milk-feeding period with little or no contact with conspecifics. I reviewed empirical work (Chapter 2) on the social development of calves, the effects of social isolation and the practices associated with group housing of dairy calves. From this review I identified literature gaps that were explored in the following chapters. In Chapter 3, I explored how pairing age affects performance and feeding behaviour development in dairy calves. Early pairing (3 d of age) increased solid feed intake and weight gains in comparison to late-pairing (42 d of age) and individual housing. In Chapter 4, I investigated how individual housing of calves affects food neophobia. The results suggested that calves raised in a complex social environment are less reluctant to ingest new feed types. Chapter 5 investigated whether being grouped with experienced dairy cows would affect the development of grazing behaviours in pregnant dairy heifers first introduced to pasture. The results indicated that grouping heifers with pasture-experienced cows improves grazing behaviour in the first hours following introduction to pasture. Chapter 6 assessed whether weaned calves would sort a total mixed ration (TMR) and if sorting was affected by the availability of a separate grain source. I found that calves can sort a total mixed ration and that the provision of a separate source of concentrate reduces sorting. I conclude that calves raised in more complex social environments early in life experience benefits related to feeding behaviour development, performance, ability to cope with novelty, and that experienced companions can be used to mitigate stress associated with novelty.

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Understanding Industry and Lay Perspectives on Dairy Cattle Welfare (2015)

The welfare of dairy cattle is of rising concern in North America. This thesis explores how stakeholders relevant to dairy production—including those working within but also those external to the industry—interpret issues around dairy cattle welfare, with the aim to unearth the root of disagreements and identify common values between diverse groups. Chapter 1 begins by exploring the relevant literature and identifies important gaps. Chapters 2 and 3 describe multi-cohort focus groups of farmers, veterinarians, and other industry stakeholders. Chapter 2 investigates their interpretations of the priority welfare issues facing the dairy industry and demonstrates that these stakeholders hold a broad conception of animal welfare with the potential to link to values in broader society. Chapter 3 explores how these stakeholders perceive challenges to welfare and their desired solutions for change; it shows consensus for education, particularly in the form of peer-led extension strategies, to address low welfare knowledge among farmers and veterinarians. Chapter 4 describes a survey of non-farming citizens before and after touring a dairy farm and demonstrates that, as with industry stakeholders, citizens’ animal welfare values are diverse. Chapter 4 also shows that citizens respond differently to learning more about dairy farming, with some becoming more concerned and others less so. Chapter 5 then describes the use of an online engagement tool to explore in greater depth what appears to be one of the most contentious practices in dairy production—that of early separation of the dairy calf from the cow. It illustrates that support of this practice varies markedly among stakeholder groups, but that people are often concerned with the same issues regardless of their stance, providing paths for compromise on practice and policy. Chapter 6 concludes with a summary of findings and recommendations, including: 1) farmers should engage with veterinarians and researchers to help them adopt practices in better alignment with societal values (such as pain mitigation), 2) industry decision makers should commit to transparency but also be prepared to listen and adapt to informed critiques, and 3) researchers should explore engagement strategies to aid in conflict resolution between industry and lay citizens.

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Understanding humane expectations: Public and expert attitudes toward human-wildlife interactions (2014)

The field of wildlife management has been on a collision course with societal values regarding animal use for some time. Although wildlife populations are still managed largely under the “North American model of wildlife conservation” to accommodate consumptive uses, many people, often with different concerns, want to be heard in decisions about wildlife. These human dimensions present a challenge to wildlife management, a field in which policy has been generally driven by experts. This research used several public engagement methods to understand broader attitudes towards wildlife management and how to incorporate them into policy. Participants with varying levels of wildlife experience in British Columbia, Canada, were asked in online and telephone surveys for their attitudes towards, and acceptance of, specific wildlife activities and management practices. Findings indicate a gap between public and expert opinions on invasive (e.g., relocation) and lethal management practices (e.g., problem bears, predator control, protection of endangered species). Problems also emerged with the public view of wildlife feeding. This led to a review of its motivations, types and consequences, and an evaluative framework was proposed to assess when feeding is acceptable. When asked to rate the harm to wildlife caused in various ways (hunting, vehicle collisions, pollution, etc.), experts and the public largely agreed on the relative importance of harms, indicating considerable potential for finding common ground between conservation-oriented and welfare-oriented citizens. However, some current management practices, especially those involving killing animals, lacked broad public support and may be improved upon with public participation in policy development, especially with women, urban residents, those with low wildlife engagement and animal-protectionist values. This could take the form of public polling or increased representation on decision-making committees. Societal expectations for managing human-wildlife interactions in BC documented by this research include ensuring that actions have an appropriate conservation purpose, are controllable, use humane methods, and appear fair to both people and wildlife. Including a broader public, educating both experts and the public on issues of humaneness, and strengthening wildlife and animal protection laws and enforcement, may serve to better align wildlife policy with societal values.

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Effects of the early social environment on the responses of dairy calves to novel events (2012)

The pronounced responses of dairy calves to novel events such as weaning and mixing form an obvious welfare concern and represent an important challenge for the dairy industry. I hypothesized that providing calves a more natural social environment would reduce these responses. This thesis consists of 5 chapters, beginning with a general introduction (Chapter 1) and ending with a general discussion and conclusion (Chapter 5). Chapter 2 compares the effects of individual vs. pair housing on calf responses to weaning from milk as well as on the adjustment to a novel pen and novel social partners at mixing. This chapter shows that being housed with a social companion increases starter intake pre-weaning, has a buffering effect on vocal responses at weaning and improves the performance of calves after mixing when compared to calves housed individually. Chapter 3 describes the effects of housing dairy calves with an older companion on the development of feeding behavior before and after weaning from milk. This chapter shows that a weaned companion is an important social model during weaning, stimulating early intake of hay pre-weaning, starter intake post-weaning and improving growth relative to calves housed in groups of similar age. Chapter 4 describes the effects of the early social environment on the behavioral responses of dairy calves to environmental and social novelty. The results from this chapter show that individually housed calves are more reactive to both environmental and social novelty when compared to pair housed calves. Calves housed with an older companion are also more reactive to separation from group members but less reactive to the presence of an unfamiliar calf when compared to calves housed in groups of similar age. Chapter 5 discusses the results of this thesis and suggests that future research on the development of the affective and cognitive abilities of dairy calves in different social contexts can improve the welfare of commercially reared dairy calves. Providing calves access to conspecifics of similar age or an older companion can minimize calf responses to weaning from milk and reduce responsiveness to environmental and social novelty during mixing.

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The Use of Animals in Science: Trends and Public Attitudes (2012)

Given the recent shift towards democratization of science, public engagement (including exploration of public attitudes) on issues related to animal research is important. This thesis explores public attitudes to changing practices in the use of animals in research. Chapter 1 provides a critical review of the existing research related to this topic. Chapter 2 presents a bibliometric analysis of changing patterns in animal use, and documents the increasing use of genetically modified (GM) animals, especially mice and zebrafish. Chapters 3 and 4 describe two online engagement experiments investigating how acceptance of animal-based research is affected by genetic modification, regulation, invasiveness, and the species used. Chapter 3 shows that support for the use of pigs in research decreased when the research involved an invasive procedure or GM animals. Support for invasive research increased when regulation was in place, but regulation had little effect on acceptance of GM animal use. Chapter 4 shows that participants who were willing to support biomedical research on zebrafish were equally willing to support the same research on mice. Participants expressed low levels of support for research involving ethyl-N-nitrosourea (ENU) mutagenesis. Some participants expressed a preference for the use of GM animal models over ENU mutagenesis based on the belief that the former causes less pain, and improves accuracy and efficiency when creating the animal model. Chapter 5 describes an interview study that examined the views of researchers, research technicians, and members of public toward the creation and use of genetically modified animals in biomedical science. The creation and use of GM animals for biomedical research purposes was generally well supported provided that this was associated with tangible human health benefits. However, it was recognized there are obstacles to Three Rs (replacement, reduction, refinement) implementation, and that there should be more effort placed on engaging the public on animal research. Chapter 6 concludes with key policy recommendations: 1) improve scientific reporting, 2) improve data and animal sharing, 3) improve recording of national animal statistics, 4) improve animal welfare assessment, and 5) supplement the Three Rs.

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Behavioural and physiological responses of Steller sea lions to invasive marking techniques: evidence of post-operative pain (2010)

Marine mammal research often requires marking and tracking animals to collect long-term ecological data, but these procedures may cause pain. The aim of this thesis was to assess the behavioural and physiological effects of invasive marking and tracking techniques used on marine mammals. This thesis consists of 7 chapters, beginning with a general introduction (Ch. 1) and ending with a general discussion (Ch. 7). Chapter 2 reviews the literature on short- and long-term effects of marking and tagging, concluding that the preponderance of studies focus on injuries and behavioural changes and that no research prior to this thesis has assessed post-operative pain in marine mammals. Chapters 3 to 6 describe experiments designed to fill this gap by focussing on pain responses of endangered Steller sea lions to invasive marking (hot-iron branding) and tracking (implanting a tracking device via intra-abdominal surgery) procedures. Seven behaviours associated with post-operative pain were monitored for 3 d pre- up to 12 d post-surgery with the aim of describing behavioural responses after abdominal surgery (Ch. 3) and comparing the efficacy of two analgesic treatments (Ch. 4). In both studies sea lions spent more time with their back arched and standing, and spent less time lying on the ventral side and in locomotion after surgery, regardless of analgesic treatment. Chapter 5 described the behavioural responses of sea lions after hot-iron branding. In the 3 days after branding sea lions spent more time grooming their branded area, less time with pressure on their branded side, and less time in the pool and in locomotion. Chapter 6 assessed physiological (breathing and heart rate) and behavioural responses of anaesthetised sea lions during hot-iron branding. Sea lions had increased heart and breathing rate during and in the minutes after hot-iron branding. Behavioural responses during branding included trembling and head and shoulder movements. These findings illustrate behavioural and physiological responses that can be applied to assessing pain in sea lions, and suggest that more effective analgesic protocols are required to mitigate pain responses after hot-iron branding and abdominal surgery.

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Illness and milk feeding level effects on calf behaviour (2009)

A consequence of the high rates of morbidity and mortality of calves on North Americandairy farms is the necessity to develop tools for early identification of sickness. As thetrend to group-housing increases, the use of automated feeding systems eases the study offeeding behaviour of individual calves within the group. Little is known about thebehavioural changes associated with the onset of disease in dairy calves, especiallychanges in feeding and resting behaviour. The first study of this dissertation examined theeffect of milk feeding level on the feeding and resting behaviour of group-housed dairycalves fed with an automated feeding system. In two separate experiments, calvesallowed high levels of milk (ad libitum milk replacer and 12 L/d milk) showed reducedfrequency of visits to the milk feeder with visits spread throughout the day and a lowintake of concentrate until weaning. Low-fed calves (4 L/d milk or milk replacer) had ahigh frequency of visits to the milk feeder, however the majority of these visits (~ 90%)were unrewarded (i.e. no milk was served) and resulted in increased milk feederoccupancy times compared to high fed calves. Calves fed low levels of milk also spentless time lying down at 4 to 5 wks of age than high fed calves, probably due to theincreased number of visits to the milk feeder. No differences in the incidence of illnesswere found between treatments. These results provide evidence that milk feeding levelaffects the expression of feeding behaviour, so it must be considered when assessingbehavioural changes related to illness. A second study set out to explore the use of asupplemental heat source by sick calves on preference and lying behaviour. During theirfirst 3 d of life calves fed high (12 L/d) or low (4 L/d) levels of milk did not differ inlying times nor did they show differences in preference for the use of the external sourceof heat. Although no calves were diagnosed with illness during the experiment, calvesshowed a marked preference for heat, spending more than 50% of their time under heatlamps regardless of environmental temperature fluctuations. In the third study, I set out todetermine which behaviours were more susceptible to change in calves afflicted withmild sickness. Calves injected with a mild dose of endotoxin showed a decrease in thetime spent at the hayrack, time spent self-grooming and ruminating. Moreover, whensickness was induced, calves showed an increase in the time spent lying and standinginactive. Lastly, the feeding behaviour of naturally sick calves and healthy counterpartsfed high or low levels of milk from 4 previous studies was investigated. Sick calves fedhigh levels of milk showed a decrease in milk intake, visits to the milk feeder andduration of the visits during the day disease was diagnosed and during the subsequent 3 d.Sick low-fed calves only showed a reduction in the duration of the visits to the milkfeeder. In conclusion, milk feeding level plays an important role in the understanding ofthe behavioural changes occuring at the onset of disease. Providing an external source ofheat may increase the welfare of newborn calves and may also prove to be a useful toolfor identifying sick animals, but further validation studies involving sick calves areneeded. Monitoring reductions in milk intake and visits to the automatic feeder in highmilk fed calves may be a useful measure in identifiying sick calves. In contrast, otherbehavioural indicators of activity level, such as standing or lying down, may be moresensitive when identifying sick calves fed low levels of milk

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Master's Student Supervision

Theses completed in 2010 or later are listed below. Please note that there is a 6-12 month delay to add the latest theses.

Intake-based weaning of dairy calves and the influence of forage type (2022)

The objective of this study was to assess the effects of intake-based weaning methods and forage type on behaviour and growth of dairy calves. Holstein calves (n = 108) were randomly assigned to 1 of 3 weaning treatments: milk reduction by age (wean-by-age), individual dry matter intake (DMI) (wean-by-intake), or combination of individual DMI and age (wean-by-combination). Groups of calves were alternately assigned to 1 of 2 forage treatments: grass hay (Hay), or silage-based total mixed ration (TMR) (n = 6 groups per treatment). Until d 30, all calves received 12 L/d of milk. On d 31, milk was reduced by 25% of the individual’s average milk intake. For wean-by-age calves (n = 31), milk remained stable until d 62 when milk was reduced until weaning at d 70. For wean-by-intake calves (n = 35), milk was further reduced by 25% once calves consumed 200, 600, and 1150 g DM/d of solid feed. For wean-by-combination calves (n = 35), milk remained stable until calves consumed 200 g DM/d; milk was then reduced until weaning at d 70. If calves failed to reach DMI targets by d 62 (failed-to-wean, n = 10), milk was reduced until weaning at d 70. 27 wean-by-intake calves met all 3 DMI targets (successful-intake) and 33 wean-by-combination calves met the 1 DMI target (successful-combination). Successful-intake and successful-combination calves had greater body weight (BW) at 84 d than wean-by-age calves, followed by failed-to-wean calves (123.0 vs 121.6 vs 117.0 vs 100.1 ± 3.1 kg, respectively). During weaning, successful-intake calves ate more starter than successful-combination, wean-by-age, and failed-to-wean calves (1.18 vs 0.85 vs 0.49 vs 0.14 ± 0.08 kg DM/d, respectively). Hay calves had greater BW at 84 d than TMR calves (124.0 vs 119.0 ± 1.6 kg, respectively). During weaning, Hay calves consumed more starter than TMR calves (0.85 vs 0.65 ± 0.09 kg DM/d, respectively). Intake-based weaning can improve performance of calves that successfully wean, and grass hay can improve starter intake and growth around weaning. Some calves consume little solid feed before weaning; further research is needed to understand how these calves should be managed.

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Dairy producer views on calf rearing (2021)

Calf rearing practices vary greatly among farms, including feeding and weaning methods. This variation may relate to differences in how dairy producers view these practices and evaluate their own success, but no previous research has examined these views. The aim of this study was to investigate perspectives of dairy producers on calf rearing, focusing on calf weaning and how they characterized weaning success. We interviewed 18 dairy producers from Western Canada: British Columbia (n = 13), Manitoba (n = 2), and Alberta (n = 3). Participants were asked to describe their calf weaning and rearing practices, and what they viewed as successes and challenges in weaning and rearing calves. Interviews were recorded, transcribed, and subjected to qualitative analysis from which we identified four major themes: (1) reliance on calf-based indicators (e.g., health, growth, and behaviour), (2) management factors and personal experiences (e.g., ease, consistency, and habit), (3) environmental influences (e.g., facilities and equipment), and (4) integration of external support (e.g., advice and educational opportunities). These results provide insight into how dairy producers view calf weaning and rearing and may help inform the design of future research and knowledge transfer projects aimed at improving management practices on dairy farms.

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Employee management and animal care: a comparative ethnography of two large-scale dairy farms in China (2021)

Farm management can directly and indirectly affect animal care. I explored how farm management affected animal care on 2 large dairy farms in China (anonymized as Farm A and Farm B). I used a mini-ethnographic case study design, living for 38 days on Farm A and 23 days on Farm B. I conducted participant observation and ethnographic interviews with farm staff positions within 5 departments in Farm A and 6 departments in Farm B. In addition, I conducted 13 semi-structured interviews (7 on Farm A; 6 on Farm B). I used template analysis to generate key themes. On both farms, workers believed that animal care practices had improved over time, due to 3 key employee management factors: 1) organizational culture, 2) competency of worker and management, and 3) an effective incentive system. These results suggest that animal care may be improved in this context by: 1) promoting a culture in which workers have ‘grit’ and are eager to learn, 2) ensuring basic worker wellbeing, and 3) using animal care outcomes as performance indicators linked to pay.

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The effect of heat stress on the behaviour of dairy cows at the drinker (2020)

Heat-stressed dairy cows on pasture will compete for resources that aid cooling, but it is not known how heat stress affects the competition for water by indoor housed cows, or if competition for water can be recorded automatically with an electronic drinking system. The objectives of my thesis were to 1) validate an electronic drinking system to detect social competition between dairy cows at the drinker by identifying the interval between one cow leaving the drinker and another cow taking her place, and 2) evaluate how heat stress affects the behaviour of indoor-housed cows at the drinker, both at group and cow level. For the first objective, 20 cows were monitored for 4-d by video recording and an electronic drinking system. Replacements (defined as when physical contact initiated by one cow causes the other to remove her head from the drinker with the initiator subsequently placing her head in the same drinker), identified by video, were paired with the interval between drinking events of the 2 cows at the electronic drinker, to identify the interval that best predicted replacements. The optimal interval to identify replacements at the drinker was ≤ 29 s. For the second objective, 69 cows were observed over 59 d. The electronic drinking system recorded time spent at the drinker, frequency of visits, water intake, and competitive replacements. The number of replacements a cow was involved in was used to determine her level of competitive success at the drinker (low, medium, high). The temperature-humidity index (THI) was recorded by the local weather station. With increasing THI, cows drank more water, spent more time at the drinker, made more visits, and engaged in more replacements at the drinker. We also found that cows with low competitive success at the drinker shifted their drinking behaviour to avoid the drinker at the hottest and most competitive time of day. These results indicate that competition between dairy cows at the drinker can be accurately measured with an electronic drinking system, and that drinking behaviour can be used to indicate when cows feel hot.

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Benchmarking passive transfer of immunity and growth in dairy calves (2016)

Poor health and growth of young dairy calves can have lasting effects on development and future production. This study aimed to benchmark calf-rearing outcomes in a cohort of Canadian dairy farms, report these findings back to producers alongside their veterinarians, and document the results. A total of 18 Holstein dairy farms, located in the Fraser Valley region of British Columbia, were recruited and surveyed on current colostrum and feed management practices of pre-weaned calves. Blood samples were collected from 1 to 7 day old calves to estimate serum total protein levels by digital refractometry. Failure of passive transfer (FPT) was determined using a total protein threshold of 5.2 g/dL. Average daily gains (ADG) were estimated from 1 to 70 day old pre-weaned heifers using heart-girth tape measurements with early (≤ 35 days) and late (> 35 days) period growth also analysed separately. At first assessment, the average farm FPT rate was 16%. Overall ADG was 0.68 kg/day, with early and late period growth rates of 0.50 and 0.86 kg/day, respectively. Following delivery of benchmark reports, all participants volunteered to undergo a second assessment. The majority (83%) of participants elected to make at least one colostrum or feed protocol change between data collection periods, including increased colostrum at first feeding, increased initial and maximum daily milk, and reduced time to first colostrum. Farms that made such changes experienced improved outcomes; average FPT rates were reduced by 9% and ADG was increased by 0.06 kg/day for all calves, and by 0.16 kg/day for calves less than 36 days old. These results indicate that benchmarking FPT and ADG can motivate producer engagement on calf care, leading to improved production and welfare outcomes for calves on farms that apply relevant management changes.

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Current methods of mouse euthanasia: Refinements and aversion (2014)

Mice are routinely euthanized by gradual-fill carbon dioxide (CO₂) gas or with isoflurane; the aim of my thesis was to assess refinements to these procedures. The first study assessed the CO₂ method of euthanasia with the aim of minimizing the duration of dyspnea without exposing mice to painful concentrations (>40% CO₂). Various CO₂ flow rates (20, 30, 40, 50% cage vol/min) were used to examine the duration between the onset of dyspnea (identified by laboured breathing) and insensibility (identified by recumbency, loss of the righting reflex or loss of the pedal withdrawal reflex). The interval between the onset of dyspnea and loss of the righting reflex averaged 38.2 ± 2.4 s versus 59.2 ± 2.4 s, using 50% and 20% cage vol/min fill rates, respectively. Thus even at the highest flow rate tested mice experienced more than 30 s of dyspnea, suggesting other methods of euthanasia should be used when possible. The second study examined the same three measures of insensibility during the isoflurane method of euthanasia, with the aim of identifying when it is safe to switch to a high flow rate of CO₂, without subjecting conscious animals to painful concentrations. The results suggested that the onset of recumbency and loss of the righting reflex are not safe indicators of insensibility when using induction with isoflurane; continued induction with 5% isoflurane carried by 17% cage vol/min of oxygen for a minimum of 79 s after the appearance of recumbency is advised before switching to a high flow rate of CO₂. The final study in this thesis used a light-aversion test to examine mouse aversion to: 1) 20% gradual-fill CO₂, 2) 5% isoflurane administered using a vaporizer, and 3) 5% isoflurane administered using the drop-method. Mice chose to remain in the dark chamber longer when exposed to isoflurane administered using a vaporizer compared to both CO₂ and isoflurane drop. Mice were also more likely to become recumbent in the dark side when exposed to the isoflurane vaporizer versus other methods. These results indicate that isoflurane delivered by a vaporizer is a humane refinement for the euthanasia of laboratory mice.

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Cognitive Bias as a Method of Pain Assessment Following Hot-Iron Dehorning of Dairy Calves (2013)

Pain is one of the most highly studied emotions in animals, and the interaction between pain and cognitive processes is well documented in humans. Recent research has attempted to use changes in cognitive processes as a method of assessing emotions of animals. This approach is based on the influence of mood states on attention to and interpretation of information. Studies with humans have shown that depressed or anxious people interpret ambiguous stimuli more negatively, while people in positive states have more optimistic interpretations. These judgement bias tasks have been applied in different animal species, but none have investigated how pain affects emotional states. Here I present the first report of cognitive bias in cattle and the first evidence of a bias in response to pain in any non-human species. I assessed cognitive bias in dairy calves before and after hot-iron dehorning. Previous work has shown that calves experience pain for at least 24 h after this procedure. Calves (n=17) were trained in a go/no-go task to expect positive (milk reward) or negative (time-out with no opportunity to access milk) outcomes following nose contact with a video screen that was either white or red; calves were alternatively assigned white or red as the positive training stimulus, and the opposite colour as the negative training stimulus. Once calves had learned to discriminate between these two training stimuli, they were tested with unreinforced ambiguous probes (screen colours at 25%, 50%, and 75% red) introduced randomly within training sessions. Probes were presented in sessions 1 d before and 1 d after dehorning. Calves approached the ambiguous probe screens less frequently after dehorning (88±5, 55±5, 11±5 % for the near-positive probe, the halfway probe, and the near-negative probe, respectively) compared to before dehorning (92±5, 68±5, 23±5 %), a difference that was numerically most pronounced for the halfway and near-negative probes. These results indicate that calves experiencing pain during the hours after hot-iron dehorning exhibit a negative "pessimistic" bias and support the use of judgement bias tasks in the assessment of animal emotions.

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Conditioned Place Avoidance of Zebrafish (Danio Rerio) to Three Chemicals Used for Euthanasia (2013)

Zebrafish are increasingly used as a vertebrate model organism for developmental and biomedical research. These fish are commonly euthanized at the end of an experiment with an overdose of tricaine methanesulfonate (TMS), but to date little research has assessed if exposure to this or other agents meets the criteria of a “good death”. Clove oil and metomidate hydrochloride are alternatives to TMS and have been approved for use in several countries. The aim of my thesis was to use a conditioned place avoidance paradigm to compare aversion to TMS, metomidate, and clove oil. Zebrafish showed a natural preference for the light environment (in a 900-s trial, they spend 95% of their time in the light compartment); by exposing them to anaesthetics in the light side of a light-dark box we were able to show a difference in preference after exposure. Conditioned place avoidance was less pronounced for fish exposed to metomidate and clove oil than for TMS; fish exposed to the former reduced the time spent in the preferred light side by 131 ± 68 s and 165 ± 97 s, respectively, versus a reduction of 591 ± 88 s for those exposed to the TMS. Complete rejection, where no attempted entries were made into the light side, were recorded after exposure to anaesthetics. Nine of 17 fish exposed to TMS did not re-enter the previously preferred side, versus 2 of 18 fish and 3 of 16 fish for metomidate and clove oil, respectively. These results suggest that the use of metomidate and clove oil are humane alternatives to TMS and should be considered when euthanizing zebrafish.

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Public attitudes towards housing systems for pregnant pigs (2013)

Public concern for the welfare of farm animals is increasing. Formal methods of gathering public attitudes are important for the development of socially sustainable animal production practices. This study used an online survey to gather public attitudes towards the issue of housing pregnant sows in intensive systems (group housing versus gestation stall housing). Additionally, this research aimed to understand how participant’s stance changed when they were provided additional information on the issue, including two scientific papers, YouTube videos, Google images, and a frequently asked questions page. Initial attitudes (from responses to the first question) and changes in responses before and after accessing additional information were quantitatively analyzed from Likert-scale responses made by 268 participants. One-hundred-and-thirteen comments, written before accessing additional sources of information, were qualitatively analyzed to identify themes and understand reasons behind decisions. Forty-one pairs of comments were analyzed to understand the effect of information on attitudes. Quantitative results reveal that the majority of participants strongly supported group housing before the provision of additional information. Most participants maintained their stance even after accessing additional information; however, an effect of information was found, such that more people strongly supported stalls after the provision of additional information. Regardless of whether participants moderately supported groups or gestation stalls before the provision of additional information, almost half of the people in each of these groups abandoned their position after accessing additional information and shifted to strongly support group housing. Qualitative analysis showed that supporters of gestation stalls tended to focus on physical health, predominantly focusing on spread of disease and the elimination of aggression between animals. Supporters of group housing sows, tended to factor in other requirements for sow welfare, including the importance of social interaction and the ability to perform natural behaviours. With the exception of participants that strongly supported gestation stalls, numerous participants commented on the complexity of choosing one system over the other and described the effect that images had on attitudes.These results point to the importance of providing detailed descriptions, including imagery to the public in efforts aimed at gathering feedback for the development of socially sustainable practices.

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The effects of regrouping and stocking density on social behaviour, lying behaviour and locomotor activity of mid and late lactation dairy cows (2011)

In free-stall systems cows are frequently moved among pens and regrouped. This practice involves individuals being mixed with unfamiliar cows, and stocking density often varies from before to after regrouping. Two separate lines of evidence suggest that regrouping and changing densities have negative impacts on cows welfare; but no study to date has assessed the combined effects. The aim of this study was to test the effect of changes in stocking density at the time of regrouping on the competition, feeding and lying behaviours and locomotor activity of dairy cows. By manipulating group size (6 vs. 12 cows) and pen size (12 vs. 24 stalls) three different stocking densities were created (25 %, 50 % and 100 %). Four groups of Holstein cows were regrouped weekly for 4 weeks and the stocking density changed from before to after each regrouping. The change in density varied from a decrease by a factor of 4 (100% to 25%), a decrease by a factor of 2 (100% to 50% or 50% to 25%), no change (50% to 50%), an increase by a factor of 2 (25% to 50% or 50% to 100%) and an increase by a factor of 4 (25% to 100%). Displacement at the feeding area, feeding time, lying time and the number of steps were scored. The daily means for each group were used to calculate the difference in responses from one day before to one day after each regrouping. Competition at the feed bunk changed after regrouping. The nature of the change was dependent upon the change in stocking density; when density decreased the number of displacements decreased. Changes in lying behavior and locomotor activity after regrouping also varied with changes in stocking density; when stocking density decreased lying time increased and number of steps increased. In conclusion, results of this experiment show that the change in competition behaviour from one day before to one day after regrouping varies with the change in stocking density at regrouping; and this change in competition results in changes in lying time and locomotor activity of cows.

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