Daniel Weary


Relevant Degree Programs

Affiliations to Research Centres, Institutes & Clusters


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 (Jan 2008 - Nov 2019)
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.

View record

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.

View record

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. 

View record

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.

View record

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.

View record

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.

View record

Understanding humane expectations : public and expert attitudes towards 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.

View record

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.

View record

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.

View record

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.

View record

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

View record

Master's Student Supervision (2010 - 2018)
Assessment of visceral pain associated with metritis in dairy cows (2015)

Metritis is a common disease in dairy cattle but little work has assessed pain associated with this disease. Tissue palpation is commonly used to assess pain in human and veterinary medicine. The objective of this study was to evaluate visceral pain responses during rectal and uterine palpation in healthy cows and in cows diagnosed with clinical signs of metritis. A total of 49 Holstein dairy cows (mean ± SD parity = 2.8 ± 1.8) were subjected to systematic health checks starting 3 d after parturition and continuing every 3 d for 21 d. Cows were scored for vaginal discharge (0 to 4); 13 cows showed a discharge score ≥ 2 during at least one health check and were classified as metritic and 29 cows were classified as ‘healthy’ all showing no sign of any other disease (including mastitis and lameness). Back arch and heart rate variability (HRV) before examination and during palpation were recorded using video and heart rate monitors. Back arch (cm²) on the day of diagnosis was greater in metritic versus healthy cows (1034.3 ± 72.7 cm² vs. 612.8 ± 48.7 cm²), and greater during uterine versus rectal palpation (869.2 ± 45.0 cm² vs. 777.9 ± 45.0 cm²). Heart rate frequency analysis showed that the low frequency portion (LF %) was higher in cows with metritis versus healthy cows (16.5 ± 1.2 vs. 12.9±1.0). The SD between normal to normal inter beat intervals and the root mean square of successive differences both decreased during uterine versus rectal palpation (1.9 ± 0.1 vs. 2.5 ± 0.1 and 1.3 ± 0.1 vs. 1.7 ± 0.1, respectively). Together, these results indicate that the inflammation associated with metritis is painful, and that the pain response can be detected during rectal and uterine palpation. Uterine palpation appears to be more aversive than rectal palpation, suggesting that the former should be avoided when possible.

View record

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.

View record

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.

View record

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.

View record

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.

View record


Membership Status

Member of G+PS
View explanation of statuses

Program Affiliations



If this is your researcher profile you can log in to the Faculty & Staff portal to update your details and provide recruitment preferences.