Marina von Keyserlingk


Relevant Thesis-Based 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.


Nina is a #GreatSupervisor because of how dedicated she is both to her students and to research. She is one of the most supportive and caring mentors I have worked with and makes sure her students have all the support they need in order to succeed and do well in their studies and in life. Nina is also a leader in her field of research and does a wonderful job guiding and instructing her students in how best to do their own research. It is inspiring to work with Nina and I feel very grateful to have her as my supervisor.

Lara Sirovica (2019)


There are many great things about my supervisors and the program that they have created. Their research program is admirable and it makes me happy and proud to be part of it. Each and every student in my program is up to solving big problems in order to improve the lives of animals and it takes great supervisors to create and then lead such a program. In addition, the program is perfectly organized. There is no competition between the students, there is always help available if needed and more importantly, it feels like a family. Though my supervisors are extremely busy, but, they still make sure that they give enough support and advice to their students in order to succeed. Regardless of it being challenging, I enjoy every day of my life in my program and I feel like I have everything I need to grow and succeed.  

Mohammad Sahar (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.

Behavioural changes associated with early identification of disease in dairy cows (2023)

Lameness and transition cow disease are important welfare issues associated with dairy farming. The aim of this thesis was to develop models and assess their predictive ability for the early identification of cows at increased risk of becoming sick or lame, using behavioural and milk production data. The first aim of my thesis was to investigate whether the association between feeding and agonistic behaviours and postpartum disease using data collected from commercial farms could be used to build predictive models for early identification of cows at risk of becoming sick. Another aim of this thesis was to develop predictive models of cows at risk for lameness based on longitudinal measures of feeding and agonistic behaviour. In Chapter 1, I conducted a literature review on previous research. In Chapter 2, I tested the association of feeding and agonistic behaviours and transition disease on commercial farms; my findings confirm the presence of these associations. In Chapter 3, I used prepartum behaviours to build predictive models for disease postpartum; the resulting models were successful in identifying cows at increased risk of becoming sick. In Chapter 4, I conducted a longitudinal study on lameness and report greater prevalence of lameness compared to a one-time prevalence assessment, suggesting that the dairy industry, which has relied predominantly on prevalence estimates, may in fact be underestimating the extent of this malady. Whilst cows in all parities experience lameness, older cows struggle more than younger cows to recover once lame, and the longer they remain lame, the higher the probability that they will continue to remain lame. In Chapter 5, I combined milk production data with the feeding and agonistic behaviours to build predictive models for lameness; the resulting model successfully identified lame cows at earlier stages of lameness. In conclusion, predictive models developed using behavioural data and milk production can identify cows at higher risk of becoming sick or lame.

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Applying the natural living construct of animal welfare to dairy calf management (2021)

Citizens frequently raise concerns about the lack of naturalness in systems used for farmanimals, including calves reared as part of the dairy production system. The aim of my thesis wasto integrate components of natural living into calf management practices and use differentresearch methods to explore how these practices affect calf behaviour and welfare. In Chapter 2,I reviewed the literature on the behavioural development of calves in pasture and rangelandconditions and identified characteristics of these more natural systems that have been or could beincorporated into modern dairy calf management. The available evidence indicates that calvesreared together with their mothers in a herd on pasture or on rangeland perform a range of socialbehaviours, begin grazing at a young age, and slowly transition from milk to a solid feed diet. InChapter 3, I focused on ways to gradually wean calves from milk, and investigated howpersonality (particularly sociability) could explain variability in feeding behaviours and growth. Ifound that gradually weaning calves by individual intakes provides them with an opportunity towean at a pace that meets the needs of the individual. Additionally, calves that were more‘playful/exploratory’ consumed more milk and concentrate, while calves with more sociabletraits (‘vocal/active’ and ‘interactive in the group test’) consumed less concentrate. In Chapter 4,I explored calf preferences for an outdoor space during summer. Calves increased their timespent outside during their first 6 wk of age, and decreased their time outside after 6 wk of ageand on rainy days. In Chapter 5, I compared the behavioural development (particularly feeding)and problem-solving abilities (evaluated through the completion of a detour task) of calveshoused indoors to calves provided daytime pasture access. Pasture calves appeared more active pre-weaning, and grazed and browsed throughout the experiment. These calves also appeared to engage in fewer non-nutritive oral behaviours, and appeared less reactive during the foodneophobia tests and detour task. Collectively these studies provide evidence that managementpractices can be modified to incorporate the natural living of calves.

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Assessing mood changes and vulnerability to stressors in dairy cattle (2021)

Routine farm management can involve painful and stressful procedures that cause negative affective states and may have long-lasting consequences. Despite a growing interest in animal welfare and affective states, few studies have explored whether housing conditions and routine farm procedures induce long-lasting negative affective states such as negative mood. The first aim of this thesis was to develop methodologies to explore whether dairy cattle show evidence of negative mood in response to common stressful conditions. For this, I first used an adapted judgment bias test to assess changes in mood following hot-iron disbudding. My results suggested that calves experience anhedonia (i.e. the reduced ability to experience pleasure) after hot-iron disbudding. Thus, I designed tests aiming to assess whether calves display anhedonia-like responses after experiencing hot-iron disbudding, regrouping and post-partum stressors including cow-calf separation. My results showed that cattle display signs of negative mood (i.e. negative judgment bias and anhedonia) in response to stressful routine farm procedures. The second aim of this thesis was to explore why individuals show strong variation in how they cope with stressors. For instance, I explored whether individual variation in expectations would predict higher vulnerability to stressors. Negative expectations (i.e. pessimism) may lead to negative perceptions, stronger responses, poor coping strategies (avoidance-based coping strategies), and poor recovery from stressors. My results show that stable differences in pessimism exist in non-weaned dairy calves and that more pessimistic animals perceive and respond more negatively to stressors. I conclude that the study of mood-related changes and individual differences help better understand how living conditions affect farm animal welfare.

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Dairy cow behaviour and estrous expression: effects of disease and management (2021)

Management of modern dairy farms spend a considerable amount of time ensuring that every cow produces a calf every year, that all cows stay healthy. Despite these laudable goals, fertility and disease continue to be two of the major challenges facing the dairy industry. In this thesis I address both of these areas in an attempt to improve the health and welfare of dairy cattle and to aid farmers in the early identification of sick cows and identifying ways of improving fertility on their farms. My first aim was to assess changes in rumination and feeding behaviour associated with diseases common after calving (Chapter 2). The results indicate that monitoring rumination and feeding behaviour during the time around calving is helpful in the detection of cows with metabolic problems. The second aim focused on understanding how stocking density affects estrous expression and biomarkers of stress (Chapter 3). The results from Chapter 3 showed only mild effects of short-term exposure of lactating dairy cows to housing conditions where there is insufficient lying space for all cows to lie down at the same time, suggesting that many dairy cows are relatively resilient to short-term sub-optimal housing conditions. Lastly, I examined how standing and lying time, in general and around estrus, are affected by stocking density (Chapter 4). This chapter showed that even a short-term increase in stocking density to 133% (cow to stall ratio of 4:3) can have detrimental effects on the standing behaviour of healthy lactating dairy cattle and that individual standing times can be an indicator for the onset of estrus, particularly in understocked cows. In summary, this body of work shows how an improved understanding of behaviour can identify cows at risk for disease, that the choices made by farmers regarding how much lying space cows are given can affect standing and lying behaviour, and that changes in standing behaviour can be used detect estrus in dairy cows.

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Understanding farmer decision-making and the role of advisors to improve dairy cattle welfare (2021)

Canadian dairy farms are becoming increasingly complex businesses with many farms growing in size which requires increased labor. These changes have resulted in new challenges for farmers, including having to balance the human resource management needs of their farm with traditional duties of animal care. To improve animal welfare on farms, it is important to understand the views of the farmers responsible for the day-to-day care of the animals, as well as their advisors such as veterinarians. The overall objective of this thesis was to improve understanding of dairy farmer decision-making on animal care practices and how advisors influence these decisions, focusing on the perspectives of stakeholders in the lower Fraser Valley region of British Columbia, Canada. Chapter 1 introduces the concept of animal welfare and the context for this research. Chapter 2 reviews the available literature on five human resource management concepts on dairy farms: 1) professional accreditation and professional development, 2) extension activities, 3) the role of the advisor, 4) standard operating procedures and, 5) employee training. Chapter 3 describes an interview study with farmers and veterinarians that set out to understand the barriers to improved care of cows around the time of calving, a time period when cows are at increased risk of disease. Chapter 4 describes a participatory study that involved working with farmers to develop standard operating procedures for newborn calf care, including understanding the role of the advisor in this process. Using secondary analysis of the datasets arising from Chapters 3 and 4, Chapter 5 describes a study aimed at understanding who farmers consult across management practices. Lastly, Chapter 6 presents a general discussion, including a description of the contributions arising from this thesis and suggestions for future research including: 1) understanding the extension needs of farmers in Canada, 2) integrating participatory methods in policy, training program and extension curriculum development, and 3) understanding how farmers make animal care decisions with the aid of technology and data on farms. This thesis adds to the growing discussion regarding farmer decision-making and how advisors, including researchers, can work with farmers to improve the lives of the animals under their care.

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Dairy cattle preference for different types of outdoor access and their influence on dairy cattle behaviour (2019)

Worldwide, the public views pasture as important for dairy cattle to have a good life; dairy cows are highly motivated to access pasture. However, the majority of dairy cows in North America are housed indoors year-round and globally, pasture access is declining. Alternative outdoor areas generally require less space than pasture and may thus be easier to implement. In this dissertation, I examined dairy cow preference for various outdoor areas and how these areas influenced cow behaviour. Chapter 1 reviews how tie- and free-stall housing influence cattle behaviour and how this compares when cows are kept on, or given access to, pasture or another type of outdoor area. Chapter 2 investigates the preference of free-stall housed cows for an outdoor sand pack versus a pasture during the night. When provided simultaneous access to both options, cows spent more time on pasture than on the sand pack (90.5±2.6% versus 0.8±0.5% of the night respectively). When only pasture was available, cows spent 90.0±5.9% of their time outside; this declined to 44.4±6.3% of their time when only a sand pack was available. Chapter 3 investigates cow preference for an outdoor wood-chip pack during summer and winter. Cows spent 25.3±4.3% of their time outside in summer and 1.8±0.6% in winter. In summer, cows spent more time on the outdoor pack during the night (50.0±8.4%) than during the day (3.3±1.3%), but this effect was absent in winter (day:1.7± 0.7%; night:2.1±1.0%). Chapter 4 examines the effect of outdoor space allowance on cow behaviour and preference to be outdoors. During the night, cows spent more time outside with increasing outdoor space; outdoor space did not affect the number of agonistic interactions outside. Chapter 5 investigates the effects of an outdoor pack on oestrus behaviours and showed that access to an outdoor pack facilitated the expression of these behaviours. Overall, dairy cows have a partial preference for an alternative outdoor area but preferred pasture over an outdoor sand pack during the night, potentially due to a bigger space allowance on pasture or due to the ability to graze; access to an outdoor pack facilitates oestrus behaviours.

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Dairy cattle transition period: disease prevalence and risk factors in grazing and freestall systems (2019)

Many dairy cows become ill in the weeks after calving. The goal of this thesis was to study the epidemiology of these ‘transition cow’ diseases in pasture and confinement systems by undertaking two large observational studies, one in Santa Catarina, Brazil and another in British Columbia, Canada. There is a dearth of research on the prevalence and incidence of transition period diseases in grazing systems. Using a cross sectional approach we measured the prevalence and risk factors for common transition period diseases in 53 small-scale, year-round, grazing dairy herds in Santa Catarina, Brazil. We found that the prevalence of metabolic and infectious diseases in these herds were comparable to those described on high producing indoor systems. Our findings also identified risk factors associated with transition period diseases in these grazing herds. One highly prevalent challenge in indoor systems is lameness, a malady that is often an overlooked in studies of transition period disease. Through a longitudinal study, we followed 455 dairy cows housed indoors on farms located in the lower Fraser Valley region of British Columbia, Canada, to: 1) measure lameness during the prepartum period and 2) assess how lameness contributes to the development of transition diseases. There was a high incidence of lameness during the non-lactating ‘dry’ period, and cows that were lame during the dry period were more likely to develop transition period diseases. One possible mechanism for this association is via reduced feeding time, as lame cows spent less time feeding than sound cows. Reduced body condition score during the dry period was also associated with increased risk of transition period diseases, independently of lameness and feeding time. I conclude that preventing lameness and body condition loss during the dry period may improve transition health.

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Individual variability in the feeding behaviour of dairy calves and goats (2019)

There is individual variability in the development and expression of feeding behaviours in farm animals. This variation cannot be fully explained by differences in genetics, management practices, body size, or growth rate. The aim of my thesis was to describe how personality traits influence feeding behaviour of dairy calves and adult goats during challenging feeding practices, and to investigate alternatives to traditional feeding practices that could help individuals to cope with these challenges by attending to individual needs and promoting natural behaviour. In Chapter 2, I review the evidence that individual variability in feeding behaviour is associated with personality traits of the individual. In Chapters 3 and 4, I focused on the stressful management practice of weaning in dairy calves (i.e. transition from milk onto solid feed diet), and investigated if personality traits could explain variability in feeding behaviours, feed intake, and performance around weaning. I found that calves that were less reactive (exploratory, interactive) performed better during weaning than calves that were more reactive (vocal, inactive) (Chapter 3). When calves were weaned on an individualized weaning plan, I found that individual characteristics (such as fearfulness and learning ability) could explain variability in weaning age (Chapter 4). In Chapters 5 and 6, I focused on feeding practices on dairy goat farms that limit expression of natural feeding behaviours (feeding at floor level) and restricted space at the feeders leading to high amounts of competition to access feed. I provided goats with elevated feeder heights to promote natural browsing behaviours and found that goats ate more from, and competed to access, these feeders more compared to a traditional floor-level feeder (Chapter 5). Goats also differed in their expression of competitive behaviours at different feeder heights: more ‘bold’ goats expressed more aggression and more ‘fearful’ goats avoided competition (Chapter 6). These studies provide evidence that personality traits can explain individual variability in feeding behaviours during challenging feeding practices for dairy calves and goats, and that alternatives to these feeding practices may provide an improved opportunity for individuals to succeed by attending to individual needs and promoting natural behaviour.

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Using behaviour to identify sickness and to evaluate treatment in ill transition dairy cows (2019)

Dairy cows are at high risk of becoming ill with metabolic and inflammatory diseases during the transition period, considered the 3 weeks before and 3 weeks after calving. In many species, behavioural changes induced through the inflammatory process and modulated through neuro-endocrine pathways have been described, including for example, anorexia, decreased activity and decreased social interactions. Such changes in behavior have typically been referred to as ‘sickness behaviours’; an area of study that has seen increased interest in dairy cattle as a way of identifying sick cows and evaluating the effect of treatment. The goal of my thesis was to explore sickness-associated behavioural changes in transition dairy cows, and how these changes are affected by treatment. Chapter 1 summarizes current literature on the factors that contribute to the high disease risk for transition cows, followed by a summary on sickness behaviours in general, and in dairy cows specifically. Data for all research chapters were derived from one study. Chapter 2 examined the effects that treatment with a non-steroidal anti-inflammatory drug (meloxicam) had on the behaviour of dairy cows with metritis; the results did not reveal a clear benefit of meloxicam treatment. Chapter 3 described differences in behaviours at the lying stall between primiparous cows with metritis and healthy cows. The results showed that, in the 3 days before metritis diagnosis, cows with metritis spent more time standing fully in the stall and had more aborted lying events. Chapter 4 identified behavioural differences between cows with fever (but without clinical disease) and healthy cows with normal body temperature. The observed differences in this third study were in line with sickness behaviours previously described in other species; for example, cows with fever consumed less feed, spent less time feeding and engaged in fewer social interactions at the feed bunk. Collectively, the results of my thesis contribute to our knowledge of sickness behaviours in dairy cows and support the idea that these behavioural changes can help to identify sick cows early and to evaluate treatment efficacy. The results may also provide a basis for targeted research on the environmental needs of ill cows.

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Societal unease with modern agricultural production: the case of animal welfare (2017)

Agricultural intensification has created a great deal of public skepticism. One major area of concern has been the welfare of animals. This thesis explores a diversity of issues centering on perceptions of the welfare of animals. Chapter 1 begins by reviewing the literature on theories of welfare in both humans and animals. After highlighting several challenges for contemporary theorizing about animal welfare, I conclude that philosophical progress on these problems can be enhanced via experimental research. Chapter 2 describes what such an approach might look like by testing the prominent view that animal welfare consists entirely of how an animal feels. Chapter 3 then examines the empirical support for the popular view that there is a negative relationship between farm size and animal welfare. Using a broad conception of welfare, I conclude that farm size and animal welfare exhibit no consistent relationship. Chapter 4 explores how perceived openness and trust affects perceptions of farm animal welfare. I found evidence that attempts to restrict the ability to monitor a farm’s inner-workings (operational transparency) diminished trust, led to more negative perceptions of animal welfare and greater support for legislative and regulatory restrictions governing animal care. Chapter 5 is a case study describing the attitudes of different stakeholders regarding the common practice of dehorning dairy calves. After describing the level of support among different stakeholders in my sample, I explore the barriers to adopting pain mitigation strategies by focusing primarily on the reasons given by participants opposed to providing pain relief.

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Understanding the welfare of dairy animals during the transition between lactations (2015)

The cessation of milking, or dry off, is a regular management practice in dairy animals. This practice initiates a non lactating, or dry, period. Milking begins again after parturition. Provision of a dry period is done largely to improve milk production in the subsequent lactation, but also to address udder health issues (intramammary infections); therefore, the majority of literature focuses on these areas, and little consideration is given to the welfare of the individual animal. The goals of this thesis were to develop a better understanding of how common dry off methods, and the dry period itself, affect three components of animal welfare: biological functioning, affective states and natural behaviour in dairy cows and dairy goats. The first study in this dissertation explored how high producing dairy cows experience abrupt cessation of milking, a commonly utilized procedure. The results suggested that cows remain motivated to leave the pen around milking time, and that these cows leak milk, a risk factor for intramammary infections. Since dry off methodology is not well understood in dairy goats, the second study shifted towards describing dry off management used by goat producers. Although similarities to cow management exist, goat producers show more flexibility in decision making around dry off, sometimes opting to give high producing goats shorter, or even no, dry periods. Within this work, concerns were also identified regarding metabolic issues in goats (pregnancy toxemia and ketosis). Therefore, the final studies combined to explore the early identification of these issues in goats. The third study validated the use of data loggers on goats, allowing for automatic recording of lying behaviour. The fourth study applied these loggers to monitor the lying behaviour of goats during the dry period, and searched for links to pregnancy toxemia and ketosis. The results showed that at-risk goats increase their lying time and decrease their activity, making lying behaviour a promising indicator of metabolic issues. Finally, three key areas are discussed for future research, namely continued work in evaluating affective states in dairy animals, benchmarking of on-farm research results, and exploring the possibilities of deviating from standard annual lactation cycles.

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Understanding the behaviour of transition dairy cows (2013)

Many concerns over the welfare of dairy cattle occur during the time around parturition. As cows transition from a pregnant to a lactating state, they are at high risk of disease and other painful conditions. In most intensive housing systems, these ‘transition’ cows are also kept in environments designed for the ease of management, with little consideration given to the expression of natural behaviours. This thesis addresses two main themes that are currently missing from the transition cow literature: 1) using knowledge of behaviour to improve management and housing practices, and 2) using behaviour as an indicator of poor health. Chapters 3, 4 and 5 address the first theme, and provide evidence that common management practices that disturb cows during parturition may interfere with calving; cows moved from a group pen into an individual pen during a late stage of labour spent more time standing in the hour before calving and experienced prolonged stage II labour compared to those moved earlier. Next, two preference studies were used to determine the type of environments that cows prefer during parturition. Results suggest that cows prefer to be in an undisturbed, secluded environment during labour and calving. To address the second theme, Chapter 2 describes the growing evidence in the human and laboratory animal literature that social behaviour can be useful as both an indicator of illness, as well as an early predictor of disease. Yet, there is little research to date making this link in farm animals. The remaining chapters describe studies that used behaviour to identify cows with three major health problems: infectious disease, dystocia and lameness. Cows with infectious diseases ate less, spent more time lying and secluded themselves from a nearby group pen, all common sickness behaviours in other species. Feeding, social and standing behaviours were also found to predict cows at-risk for dystocia and lameness well before diagnosis. Collectively, these results provide evidence that a better understanding of transition cow behaviour can be useful to both improve housing and management, as well as identify cows at-risk for poor health.

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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.

Agonistic interactions in dairy cattle (2023)

Cattle are gregarious animals that sometimes engage in agonistic interactions and are able to form social relationships, including dominance. The aim of this thesis was to address some of the inconsistencies and gaps in the conceptual understanding of agonistic behaviour and dominance in dairy cattle, methods of data collection, and methods of assessing dominance. I outline that dominance is multidimensional and can be influenced by individual characteristics and other factors, including motivation to access resources. I provide guidelines for a more robust approach to estimating dominance in cattle, including a minimum number of observations required and advantages and challenges associated with different methods. Similarly, while group sizes vary on farms, little is known about how this variation effects agonistic behaviour. I hypothesized that cows would engage in fewer agonistic interactions at the feeder when housed in larger groups. I predicted that the majority of agonistic interactions within dyads would be won by the same individual (i.e., directionality) regardless of group size. I tested these predictions using 4 replicates of 50 cows first housed in groups of 50 which were then divided into 5 groups of 10, maintaining the same stocking density of animals to resources. I used a validated algorithm to determine agonistic interactions, which were used to calculate individual Elo-Ratings (a dominance score) and categorize cows into 5 dominance categories based on these ratings. To ensure a consistent Elo-Rating distribution between group sizes, 2 cows from each dominance category were randomly assigned to each group of 10. Data from the last 3 days in each treatment were used for analysis of agonistic interaction frequency. Although the groups of 10 were more variable, the average number of agonistic interactions per cow in groups of 50 (34.1±2.4, mean±SE; 26.5–41.7, 95% CI) was similar to that in groups of 10 (31.1±5.0, mean±SE; 15.0–47.2, 95% CI). 81.5±5.2% (mean±SD) of dyads had the same directionality across group sizes. My findings indicate that dominance and agonistic behaviour are multidimensional and that group size may not be a major driver of the frequency of physical agonistic interactions at the feeder in dairy cattle.

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Public perceptions of dairy cow-calf management systems differing in type of social and maternal contact (2021)

Early cow-calf separation followed by individual housing is standard practice for calf rearing on dairy farms. However, a growing body of evidence suggests that as awareness grows the public will oppose these practices, which could compromise the dairy industry’s social license. Despite disagreement amongst different stakeholders over weighting and evaluations of effects of early separation (e.g. distress response, disease risk), recent reviews suggest there is little biological evidence supporting this practice. The acceptability of alternative cow-calf management systems differing in type of social and maternal contact is unknown. This thesis used a mixed methods online survey with a convenience sample of 307 Canadians to investigate perceptions of these systems, examining the effects of providing social or foster cow contact following early separation or not separating cow-calf pairs. Attitudes and perceptions of animal welfare were less negative (assessed on a 7-point scale where 1 is most negative, 7 is most positive, and 4 is a neutral midpoint) towards the system where calves were not separated from the cow (4.3 ± 0.30; 4.2 ± 0.28), compared to systems in which the calf was separated and individually housed (2.0 ± 0.29; 2.0 ± 0.27 ), separated and group housed (2.4 ± 0.31; 2.1 ± 0.29), or separated and kept with a foster cow (2.2 ± 0.29; 2.0 ± 0.27) (F₃,₂₉₃ = 43.97, P
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The effect of free-choice pasture access on lameness recovery and behaviour of lame dairy cattle (2021)

Free-choice access to pasture allows cows to exert their own preference and may benefit lame cows by providing a softer and more comfortable lying and standing surface. However, the effect of this system on lameness has not yet been explored. The objective of this thesis was to investigate whether a 7-wk period of free-choice pasture access would improve lameness recovery and to document effects on lying behaviour, relative to control cows housed in the same group but not allowed outside. Lactating Holstein cows, all lame upon enrollment and housed inside a free-stall barn, were pseudo-randomly allocated to one of two treatments (balancing for gait score, parity, and previous lesion history, using rolling enrollment): free-choice access to pasture (n = 27; Pasture) or indoor housing only (n = 27; Indoor). Cows were gait scored weekly, by an observer blind to treatment, using a 5-point numerical rating system (NRS) from 1 = sound and NRS 5 = severely lame, and hoof inspections were performed by professional hoof trimmers at the start and end of the 7-wk period. Cows were categorized as sound (NRS ≤ 2 over 2 consecutive weeks) or lame, and lying behaviour was assessed using accelerometers. Cows with pasture access spent, on average, 15% of their time outdoors, with the majority of time spent outside between 1630 to 0700h (23% on pasture). Over the 7-wks, 42% of cows became sound; cows with pasture access were more likely to become sound and spent more time sound compared to cows kept only indoors (2.0 ± 0.34 vs. 0.81 ± 0.35 wk). Cows spent more time standing while on pasture versus when indoors (74% vs. 47%, respectively) and overall, cows with pasture access lay down for less time and tended to have fewer lying bouts than cows kept indoors. These results suggest that free-choice pasture access aids in lameness recovery. Future research is required to investigate longer-term effects of free-choice pasture access on the recovery of hoof lesions and re-occurrence of lameness cases in dairy cows.

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Introducing heifers to freestalls using a social model (2018)

Older conspecifics can model important behaviours in group-living species, potentially reducing reliance on trial and error learning. On many farms animals are segregated by age, preventing this social modelling from occurring. The modern dairy farm is an ideal model for studying how young cattle adapt to new environments, and how these adaptations may improve through the use of social models. Freestalls, a common housing system for dairy cattle, contain individual cubicles designed to provide a clean and easy to maintain lying surfaces for cattle. However, learning to use these stalls can be a challenge for naïve animals. When introduced to freestalls for the first time, some animals refuse to lie in these stalls, choosing instead to lie in the wet manure alleys. The aim of this study was to compare the behavioural responses of naïve dairy heifers when introduced to freestalls with and without a social model that was familiar with freestall housing. Naïve Holstein heifers were randomly assigned into pairs; half were assigned a social model, and the remaining pairs were left as control groups, using 11 groups per treatment. When first introduced to freestall housing, all heifers showed a mean (± SE) 2.5-3 ± 0.6 h/d decrease in lying time and around a 1 ± 0.4 h/d decrease in average feeding time, while average time spent standing in the alley increased by 2 ± 0.4 h/d with these behaviours returning to baseline within two days. Heifers moved without a social model were more likely to lie in the alley versus heifers moved with an experienced social companion, but otherwise lying behaviour was not affected by treatment. These results indicate that the transition to freestall housing is difficult for all heifers, and providing naïve heifers with an experienced social model can reduce occurrences of undesirable stall refusal behaviour.

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Lameness and lying behaviour in grazing dairy cows (2018)

Lameness is a serious welfare issue for dairy cows. To date, the majority of studies have focused on its effect on health and behaviour at the herd-level. The objectives of this study were to identify firstly, between-cow and secondly, within-cow changes in lying behaviour associated with consistent and changing lameness status in grazing dairy cows. Previous studies of lying behaviour in grazing dairy cows have not considered the effect of precipitation, thus a third aim was to determine the effect of precipitation on lying behaviour. A total of 252 dairy cows from 6 pasture-based farms in southern Brazil were gait scored weekly to assess lameness using a 5-point scale (1 – 5, numerical rating score [NRS]) for 4 consecutive wk. Cows were considered to have consistent lameness if they were scored as lame (NRS ≥ 3) on each of the 4 visits and considered to have a changing lameness status if scored as being non-lame (NRS
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Exploratory behaviour in laboratory zebrafish: potential benefits of exploring the unknown (2017)

Zebrafish are one of the most used animals in scientific research. They are typically housed in barren conditions that greatly differ from their vegetated and fluctuating wild habitats. This disconnect has received increasing attention in recent years, particularly concerning the physical environment and the necessity of environmental enrichment. However, research investigating the psychological needs of zebrafish—a highly cognizant animal—is in its infancy. One method of addressing this gap is to investigate the use of cognitive enrichment—that is, providing a captive animal with appropriate cognitive challenge in effort to improve welfare. Therefore, the aim of this thesis was to assess the role of allowing laboratory zebrafish to engage in exploration on their behavioural responses. I provided zebrafish with an opportunity to explore novel tank space by offering them access to a previously inaccessible portion of their semi-natural home tanks, within which they had been housed for nine months. I examined their exploratory behaviour (latency and number of inspections of the novel space), anxiety behaviour (bottom-dwelling) and social behaviour (agonistic behaviour, cohesion and coordination) on the day before (baseline), the day of, the day after and two weeks after providing access to the novel area. Zebrafish were found to quickly move into the new space (on average within 9.7±7.6 seconds; mean±SD) and sustained their interest on each of the observation days (P0.73), indicating that the exploration opportunity was likely not anxiety-provoking. Further, the opportunity to explore increased positive affiliative social behaviour: reducing agonistic behaviour (P=0.02), and increasing both cohesion (P=0.04) and coordination (P=0.04) relative to baseline. Considering their natural habitats would normally include such information-gain opportunities, I suggest the use of barren and stagnant laboratory conditions compromises the behavioural and psychological needs of zebrafish and reduces welfare. This thesis adds to the growing body of literature focusing on the role cognitive stimulation may play in welfare and indicates that zebrafish are good candidates for further cognitive enrichment research.

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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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Colour Matters: Coho Salmon (oncorhynchus kisutch) Prefer and are Less Aggressive in Darker Coloured Tanks (2015)

Fish are capable of colour vision and certain colours have been shown to affect growth and survival, skin colour, stress response, and reproduction. Beyond these physiological consequences, colour has also been shown to affect aggression levels, which is a widespread problem in aquaculture. The compatibility of fish with tank colour has been largely neglected within the aquaculture industry. Common practice is to use light blue tanks but there is no scientific basis for this choice. Closed containment aquaculture systems provide a good model to investigate the effects of tank colour on fish. Though closed containment aquaculture systems provide the opportunity for full control of environmental conditions, little research to date has investigated which parameters within these systems promote fish welfare. The aim of this study was to assess preferences of coho salmon for tank colour and determine the effects of colour on aggression. Coho salmon (n=100) were randomly assigned to 10 tanks, each bisected to allow fish to choose between two colours. Using a Latin-square design, each tank was tested with each of the following colour choices: blue vs. white, light grey, dark grey, and black, as well as black vs. white, light grey, dark grey, and a mixed dark grey/black pattern. Fish showed a strong preference for black over all other tank background options (p
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Clincal ketosis and standing behaviour in transition dairy cows (2014)

Ketosis is a common disease in dairy cattle, especially in the days after calving, and is often undiagnosed. The objective of this study was to compare the standing behaviour of dairy cows with and without ketosis during the days around calving to determine if changes in this behaviour could be useful in the early identification of sick cows. Serum beta-hydroxybutyrate (BHBA) was measured in 370 cows on three commercial dairy farms, twice weekly from 2 to 21 d after calving. Standing behaviour was measured from 7 d before calving to 21 d after calving using data loggers. Retrospectively, 19 cows with subclinical ketosis (BHBA ≥1.2 and ≤ 2.9 mmol/L) and 20 cows with clinical ketosis (BHBA >2.9 mmol/L) were matched by farm with 39 non-ketotic cows (BHBA
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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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Effect of regrouping on social behaviour and milk production of mid-lactation dairy cows, and individual variation in aggression (2013)

Dairy cows are often mixed into new social groups for management reasons, but this is recognized as a cause of social stress. The objectives of this study were to investigate the effect of regrouping on social behaviour, self-licking and milk production of mid-lactation cows introduced in pairs, and to see whether individual variation in aggression is consistent before and after regrouping. In 7 replications (n=7), 14 mid-lactation cows were introduced in pairs into an established group of filler (resident) cows. After regrouping, agonistic contacts and displacement of the introduced cows increased during the first 3 and 2 days, respectively. Compared to baseline (the day before regrouping), the number of social licking events between the introduced cows and the resident cows in the pen did not change after regrouping, but the proportion of social licking between the two introduced cows increased sharply after regrouping (38 ± 9 %) compared to baseline (10 ± 9 %). Duration of social licking decreased declined after regrouping; whereas, self-licking increased on the day of regrouping. Compared to the resident cows, milk production of the introduced cows significantly decreased on the first 2 days after regrouping, and showed a negative linear association with agonistic contacts received and with displacements lost. Two measures of aggressive behaviour (proportion of agonistic contact initiated and proportion of displacements won) were relatively consistent before and after regrouping (R² = 0.75 and 0.68 respectively), suggesting that the differences reflected individual differences in aggressiveness, rather than social status within a given group. In the present experiment, low-and high-aggressive individuals were not different in milk production, social licking and age at first calving, but low-aggressive cows had higher 305-day projected milk production (12,928.0 ± 580 kg) than high-aggressive cows (10,530.0 ± 530 kg). Individual variation in aggression was not associated with body weight, although the heaviest cow in the group won all encounters before and after regrouping. The findings of this study provide the first insights that introducing cows in pairs may mitigate the effects of social stress during mixing.

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Hock injuries in freestall housed dairy cows (2013)

The objective of this thesis was to investigate housing and management risk factors associated with the prevalence of hock injuries in freestall herds (n = 76) in two areas of intensive dairy production, Northeastern US (NE-US) and California (CA). One group of high-production multiparous cows (n = 38) was monitored for hock injuries on each farm and data on management, facility and stall design were collected. Risk factors associated with the overall proportion of cows having injuries or severe injuries at the univariable level were submitted to multivariable general linear models. In NE-US, overall hock injuries increased with the percentage of stalls with fecal contamination (OR = 1.26; CI = 1.02 to 1.54, for a 10% increase), and with the use of sawdust bedding (OR = 3.47; CI = 1.14 to 10.62), and decreased with deep bedding (OR = 0.05; CI = 0.02 to 0.14), sand bedding (OR = 0.06; CI = 0.02 to 0.15), bedding DM ≥ 83.9% (OR = 0.08; CI = 0.03 to 0.20), and access to pasture during the dry period (OR = 0.17; CI = 0.05 to 0.53). In the multivariable model, only the presence of deep bedding remained significant. Severe hock injuries increased with the use of automatic scrapers (OR = 2.29; CI = 1.11 to 4.71) and the percentage of stalls with fecal contamination (OR = 1.14; CI = 1.00 to 1.31, for a 10% increase), and decreased with sand bedding (OR = 0.22; CI = 0.10 to 0.49), deep bedding (OR = 0.24; CI = 0.11 to 0.52), bedding DM ≥ 83.9% (OR = 0.28; CI = 0.14 to 0.58), and access to pasture during the dry period (OR = 0.42; CI = 0.18 to 0.97). The multivariable model included the use of automatic scrapers and deep bedding. In CA, stall stocking density (OR = 1.41; CI = 1.00 to 2.01, for a 10% increase) and bedding concavity (OR = 1.08; CI = 1.01 to 1.16, for a 2.5-cm decrease) were associated with an increase of hock injuries. In general, deep-bedded and well-maintained stalls significantly reduced the risk of hock injuries.

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The Rehabilitation of Black Bears (Ursus americanus) in North America: A Survey of Current Practices (2013)

Throughout the year, black bear (Ursus americanus) cubs are orphaned, abandoned, or permanently separated from their mothers due to natural or human causes. Although cubs have been the focus of limited rehabilitation efforts in North America for more than 30 years, information on bear rehabilitation remains sparse. Furthermore, a lack of agreement exists regarding the suitability of bears as rehabilitation candidates. There is concern that exposure to humans during the rehabilitation process may increase the likelihood of bears becoming nuisances upon release. Yet previous research suggests that their genetic predisposition to emigrate and lead relatively solitary lives may limit the ef-fects of any habituation to humans that takes place during care. Clearly, given the lack of research as well as the controversy, there is a need to determine whether rehabilitation is a viable option for black bears in North America. Accordingly, a survey was sent out to 39 wildlife rehabilitation centres (9 in Canada and 30 in the United States) to obtain detailed information on how cubs are raised and released. Findings from the multi-institution, multi-year study suggest that black bears are suitable rehabilitation candidates, as they can be raised and released using a variety of methods, while achieving high survival rates and weights compared to bears at a similar age in the wild. The results of this study provide vital information for wildlife rehabilitators and government, and may be useful for the development of future policies and standards for the rehabilitation of black bear cubs in North America. Furthermore, with a better understanding of the rehabilitation process, government wildlife agencies may be more open to supporting black bear rehabilitation in the future.

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Controlling energy intake in the prepartum period to improve transition cow health (2011)

A common feeding practice during the dry period is to switch dairy cows to a low forage, energy dense diet 3 weeks prepartum, but this practice has been criticized as it may lead to the overconsumption of energy and increase the risk of metabolic disease postpartum. The aim of this trial was to compare the metabolic status of transition Holstein dairy cows fed a 77% forage diet (77F) (NEL = 1.46 Mcal/kg; NDF = 41%) versus those fed a 87% forage diet (87F) (NEL = 1.41 Mcal/kg; 48% NDF). Approximately 60 days before calving cows were dried off and fed the 87F diet. Three weeks before expected calving cows were randomly assigned to either remain on the 87F diet (n=42) or switched to the 77F diet (n=45). After calving, all cows were fed a common lactation diet (NEL=1.59 Mcal/kg). Dry matter intake (DMI) was measured daily from 2 weeks before to 2 weeks after calving. Blood was sampled twice-weekly prepartum and daily for 10 days postpartum. Subclinical ketosis (SCK) was diagnosed using a threshold of BHBA ≥ 1.0 mmol/L after calving. Metritis was determined by examining vaginal discharge. Cows on the 87F diet had lower DMI prepartum than those on the 77F diet (12.7 kg/d ± 0.3 vs. 15.4 ± 0.3, P
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Temporal feed restriction and overstocking increase competition for feed in group-housed dairy cattle (2011)

Dairy cows are often overstocked. Some managers are now also using ‘slick bunk’ management to save on feed costs, but this reduces the time cows have access to feed. Both practices may increase competition and affect feeding behaviour in cows. The aim of this study was to determine the effects of temporal and spatial restrictions on the feeding and competitive behavior of group-housed cows. Using a replicated Latin square design 48 Holstein cows were randomly assigned to groups of 6 cows. Groups were tested as overstocked at the feeder (2:1 cows:feed bin) or not (1:1 cow:bin) and provided feed access for either 14 or 24 h/d. DMI, feeding time and rate were measured for 24 h and 2 h following fresh feed delivery for the last 4 d of the 7 d periods. Displacements were recorded for 2 h after delivery of morning feed (peak feeding period) and 2 h following afternoon milking. DMI tended to decline when temporal access was restricted (27.0 vs. 25.7 ± 0.5 kg/d), but was not affected by overstocking (26.4 ± 1.9, mean ± SD). Temporally restricted cows spent less time feeding (190.9 vs. 207.9 ± 6.1 min). Overstocked cows that were also temporally restricted had greater feeding rates during the day (156 vs. 137 ± 4 g/min) and especially during the peak feeding period (175 vs. 146 ± 4 g/min) compared to cows that were not restricted. In the peak period, overstocked cows had reduced DMI (3.0 vs. 3.4 ± 0.1 kg/h) and feeding times (20.8 vs. 25.8 ± 1.0 min/h) and increased feeding rates (161 vs. 138 ± 4 g/min). Cows with restricted temporal access had greater DMI (3.9 vs. 2.6 ± 0.2 kg/h) and time spent feeding (27.3 vs. 19.2 ± 1.3 min/h) during the peak period, compared with cows that were not restricted. Restricting temporal access in conjunction with overstocking resulted in the greatest increase in daily displacements (15.0 vs. 3.8 ± 1.4 displacements/d); the majority of these occurred during the peak period. Adequate space and time to access feed is essential to minimize feed bunk competition in indoor group-housing systems.

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Assessing Cow Comfort Using Lying Behaviour and Lameness (2010)

Over the past decade, there has been growth in scientific research on welfare in modern dairy production systems. The issue of cow comfort and how it relates to the risk of lameness has received considerable interest. The objectives of this thesis were to establish reliable methods of using lying behaviour as a measure of cow comfort, to describe the variation in lying behaviour of individual cows within farm and between farms, and to evaluate the relationship between stall comfort, lying behaviour, and lameness. A cross-farm assessment was conducted on 43 commercial dairy farms in the Fraser Valley region of British Columbia. Electronic data loggers recorded lying behaviour of 2033 cows at 1-min intervals for 5 days. The first study established that monitoring at least 30 cows per farm for 3 days provides an accurate estimate of the lying behaviour of the lactating cows at that time. Cows averaged 11 h/d lying down, separated into 9 bouts/d with an average duration of 88 min/bout. Cows were scored for lameness using a 5-point Numerical Rating System (NRS) in which 1 = sound and 5 = severely lame. A subsample of 1319 cows from 28 farms using either deep-bedded stalls (n = 11) or mattress stalls (n = 17) were used for the second study. Overall, 21% of the cows were scored as NRS = 3 and 7% as NRS = 4; no cow was scoared as NRS = 5. Mattress farms had higher prevalence of NRS = 4 compared to deep-bedded farms (9 vs. 4%, respectively). Cows with NRS = 4 housed on deep-bedded stalls spent 1.6 h/d more lying, and had longer bouts compared to cows with NRS ≤ 3, but there were no behavioural differences among cows with different degrees of lameness housed on mattress stalls. Extreme lying behaviour, particularly the high lying times (≥ 14 h/d) and long lying bouts (≥ 99 min/bout) were associated with increased odds of lameness, regardless of stall surface. Stall comfort, lying behaviour, and lameness are interlinked, and should all be integrated as measures of cow comfort.

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Effects of sawdust bedding dry matter on lying behaviour of dairy cows: a dose dependent response (2010)

The objective of this thesis was to determine the effects of bedding dry matter on lying behaviour of Holstein cows. Over time bedding becomes wet with urine, feces and milk, but no research is available to guide recommendations for farmers regarding how often bedding should be replaced. I carried out two replicates of an experiment testing the effects of varying dry matter content of sawdust bedding systematically over five treatment levels. One replicate was conducted during the summer and one in the winter to test if the effects of damp bedding varied with season. The five bedding treatments averaged (± SD) 89.8 ± 3.7, 74.2 ± 6.4, 62.2 ± 6.3, and 43.9 ± 4.0, and 34.7 ± 3.8% dry matter. Over the course of the trial, minimum and maximum temperatures in the barn were 2.6 ± 2.0 and 6.8 ± 2.2º C in the winter and 13.3 ± 2.5 and 22.6 ± 4.1º C in the summer. In both seasons, five groups of three non-lactating cows were housed in free stalls bedded with sawdust. Following a five day acclimation period on dry bedding, groups were exposed to the five bedding treatments in a five by five Latin square. Each treatment lasted four days, followed by one day when the cows were provided with dry bedding. Stall usage was assessed by 24 hour video scanned at five minute intervals averaged over two days. Responses were analyzed in a mixed model with group as the observational unit. Bedding dry matter affected lying time, averaging 10.4 ± 0.4 hours per day on the wettest treatment and increasing to 11.5 ± 0.4 hours per day on the driest bedding. Lying time varied with season, averaging 12.1 ± 0.4 hours per day across treatments during the winter and 9.9 ± 0.6 hours per day during the summer, but season and bedding dry matter did not interact. These results show that wet bedding reduces lying time in a dose dependent manner during both winter and summer seasons.

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