Browsing by Author "Mellor DJ"

Now showing 1 - 8 of 8
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    A Life Worth Living with Dr David Mellor. Interview by Luna Allison, Canadian Federation for Animal Welfare.
    (18/08/2016) Mellor DJ
    Dr. David Mellor is a leading animal welfare thinker and the Foundation Director of the Animal Welfare Science and Bioethics Centre at Massey University’s Institute of Veterinary, Animal and Biomedical Sciences in New Zealand. Dr. Mellor has more than 50 years of teaching and research experience and has developed animal welfare standards, regulations and legislation internationally. He has been widely recognized for making major contributions to animal welfare around the world through consultation, teaching and more than 500 scientific publications. We sat down with Dr. Mellor during his time in Toronto this spring to discuss animal welfare in Canada and advancing our thinking for the betterment of animals.
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    Changes in the welfare of an injured working farm dog assessed using the Five Domains Model
    (21/09/2016) Littlewood KE; Mellor DJ
    © 2016 by the authors; licensee MDPI, Basel, Switzerland.The present structured, systematic and comprehensive welfare evaluation of an injured working farm dog using the Five Domains Model is of interest in its own right. It is also an example for others wanting to apply the Model to welfare evaluations in different species and contexts. Six stages of a fictitious scenario involving the dog are considered: (1) its on-farm circumstances before one hind leg is injured; (2) its entanglement in barbed wire, cutting it free and transporting it to a veterinary clinic; (3) the initial veterinary examination and overnight stay; (4) amputation of the limb and immediate post-operative recovery; (5) its first four weeks after rehoming to a lifestyle block; and (6) its subsequent life as an amputee and pet. Not all features of the scenario represent average-to-good practice; indeed, some have been selected to indicate poor practice. It is shown how the Model can draw attention to areas of animal welfare concern and, importantly, to how welfare enhancement may be impeded or facilitated. Also illustrated is how the welfare implications of a sequence of events can be traced and evaluated, and, in relation to specific situations, how the degrees of welfare compromise and enhancement may be graded. In addition, the choice of a companion animal, contrasting its welfare status as a working dog and pet, and considering its treatment in a veterinary clinical setting, help to highlight various welfare impacts of some practices. By focussing attention on welfare problems, the Model can guide the implementation of remedies, including ways of promoting positive welfare states. Finally, wider applications of the Five Domains Model are noted: by enabling both negative and positive welfare-relevant experiences to be graded, the Model can be applied to quality of life assessments and end-of-life decisions and, with particular regard to negativeexperiences, the Model can also help to strengthen expert witness testimony during prosecutions for serious ill treatment of animals.
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    Characterisation of the Behavioural Effects of a Thoracic Squeeze in Healthy Newborn Piglets
    (MDPI (Basel, Switzerland), 2021-08) Holdsworth SE; Kells NJ; Chidgey KL; Vallée E; Ward N; Mellor DJ; Beausoleil NJ
    A thoracic squeeze has been observed to cause both healthy and low vigour neonatal foals to enter a ‘less-responsive state’, characterised by loss of posture, eye closure and cessation of movement, from which they rapidly recover to express normal healthy behaviours when the squeeze is released. To date, there have been no systematic studies characterising the responses of healthy neonates of other mammalian species to a thoracic squeeze. We describe the responses of healthy newborn piglets (n = 17) to a standardised application of the thoracic squeeze and evaluate the effect of the method of squeeze application on the response. Neonatal piglets were squeezed around the chest with either a soft fabric rope as has been used in foals (n = 8) or a novel purpose-made inflation cuff (n = 9). Both methods were effective at inducing a less-responsive behavioural state in all piglets, with neural reflexes reduced or absent in over half of them. The inflation cuff appeared to induce the less-responsive state faster than the rope, and more piglets squeezed with the cuff remained in this state for the full 10-min squeeze. These findings suggest that the behavioural response of foals to thoracic squeezing can be generalised to neonates of other precocial mammalian species. This initial study provides a foundation for further research using the inflation cuff to explore mechanisms underlying the thoracic squeeze and ways in which it may be applied whilst performing husbandry procedures.
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    Effects of halothane on the electroencephalogram of the chicken
    (John Wiley and Sons, Ltd, 15/05/2018) McIlhone AE; Beausoleil NJ; Kells NJ; Johnson CB; Mellor DJ
    Little is known about the effects of inhalant anaesthetics on the avian electroencephalogram (EEG). The effects of halothane on the avian EEG are of interest, as this agent has been widely used to study nociception and analgesia in mammals. The objective of this study was to characterize the effects of halothane anaesthesia on the EEG of the chicken. Twelve female Hyline Brown chickens aged 8-10 weeks were anaesthetized with halothane in oxygen. For each bird, anaesthesia was progressively increased from 1-1.5 to 2 times the Minimum Anesthetic Concentration (MAC), then progressively decreased again. At each concentration, a sample of EEG was recorded after a 10-min stabilization period. The mean Total Power (PTOT ), Median Frequency (F50) and 95% Spectral Edge Frequency (F95) were calculated at each halothane MAC, along with the Burst Suppression Ratio (BSR). Burst suppression was rare and BSR did not differ between halothane concentrations. Increasing halothane concentration from 1 to 2 MAC resulted in a decrease in F50 and increase in PTOT , while F95 increased when MAC was reduced from 1.5 to 1. The results indicate dose-dependent spectral EEG changes consistent with deepening anaesthesia in response to increasing halothane MAC. As burst suppression was rare, even at 1.5 or 2 times MAC, halothane may be a suitable anaesthetic agent for use in future studies exploring EEG activity in anaesthetized birds.
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    Evaluating the Behavioural Responses of Healthy Newborn Calves to a Thoracic Squeeze
    (MDPI (Basel, Switzerland), 2022-04) Holdsworth SE; Kells NJ; Vallée E; Ward N; Mellor DJ; Beausoleil NJ; Von Keyserlingk M
    A thoracic squeeze has been observed to cause low-vigour neonates of various farmed mammal species, including calves, to enter a state of reduced responsiveness. The removal of the squeeze causes rapid recovery and the expression of normal, healthy behaviours. However, the responses of healthy calves to a thoracic squeeze have not yet been characterized. The responses of 16 healthy newborn calves to a thoracic squeeze are described, along with the effect of the squeeze's application method on the response. Calves aged between 12 and 36 h were subjected to the squeeze using a rope (n = 8) or an inflation cuff (n = 8). In total, 13 of the 16 calves were induced into a state of reduced responsiveness, though neural reflexes persisted in nearly all of them. The squeeze was discontinued for nearly half of those induced before the end of the 10-min period, either due to spontaneous arousal or physiological instability. Both methods of application were equally effective at inducing reduced responsiveness, though responses to the cuff appeared to be more rapid than those to the rope. These findings support previous research on piglets and foals, and suggest that the behavioural responses to a thoracic squeeze are generalised across neonates of precocial farmed mammals; the findings provide a foundation for further research exploring the mechanisms underlying the response and the benefits that its application may bring for the performance of husbandry procedures.
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    Mental Experiences in Wild Animals: Scientifically Validating Measurable Welfare Indicators in Free-Roaming Horses
    (MDPI (Basel, Switzerland), 2023-04-28) Harvey AM; Beausoleil NJ; Ramp D; Mellor DJ; Padalino B
    The mental experiences of animals are what characterises their welfare status. The Five Domains Model for assessing welfare aligns with the understanding that physical and mental states are linked. Following measurement of indicators within each of the four physical/functional Domains (1. Nutrition; 2. Physical environment; 3. Health; and 4. Behavioural interactions), the anticipated negative or positive affective consequences (mental experiences) are cautiously inferred and assigned to Domain 5. Those inferences derive credibility from validated knowledge of the underlying systems of physiology, neurophysiology, neuroethology and affective neuroscience. Any indicators used for assessing welfare need to be scientifically validated. This requires, firstly, evidence of the links between a measurable/observable indicator and the physical/functional impact (in Domains 1 to 4), and secondly, a demonstrable relationship between the physical/functional impact and the mental experience it is inferred the indicators reflect (in Domain five). This review refers to indicators of physical/functional states in Domains 1 to 4, which have been shown to be measurable in free-roaming wild horses, and then evaluates the scientific evidence linking them to inferred mental experiences in Domain 5. This is the first time that the scientific evidence validating a comprehensive range of welfare indicators has been synthesised in this way. Inserting these indicators into the Five Domains Model enables transparently justifiable assessment and grading of welfare status in free-roaming horses.
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    Updating Animal Welfare Thinking: Moving beyond the "Five Freedoms" towards "A Life Worth Living".
    (14/03/2016) Mellor DJ
    The Five Freedoms have had major impact on animal welfare thinking internationally. However, despite clear initial statements that the words 'freedom from' should indicate 'as free as possible from', the Freedoms have come to be represented as absolute or fundamental freedoms, even rights, by some animal advocate and other groups. Moreover, a marked increase in scientific understanding over the last two decades shows that the Freedoms do not capture the more nuanced knowledge of the biological processes that is germane to understanding animal welfare and which is now available to guide its management. For example, the named negative experiences of thirst, hunger, discomfort and pain, and others identified subsequently, including breathlessness, nausea, dizziness, debility, weakness and sickness, can never be eliminated, merely temporarily neutralised. Each one is a genetically embedded element that motivates animals to behave in particular ways to obtain specific life-sustaining resources, avoid or reduce physical harm or facilitate recovery from infection or injury. Their undoubted negativity creates a necessary sense of urgency to respond, without which animals would not survive. Also, the temporary neutralisation of these survival-critical affects does not in and of itself generate positive experience. This questions the commonly held assumption that good animal welfare will result when these internally generated negative affects are minimised. Animals may also experience other negative affects that include anxiety, fear, panic, frustration, anger, helplessness, loneliness, boredom and depression. These situation-related affects reflect animals' perceptions of their external circumstances. Although they are elicited by threatening, cramped, barren and/or isolated conditions, they can often be replaced by positive affects when animals are kept with congenial others in spacious, stimulus-rich and safe environments which provide opportunities for them to engage in behaviours they find rewarding. These behaviours may include environment-focused exploration and food acquisition activities as well as animal-to-animal interactive activities, all of which can generate various forms of comfort, pleasure, interest, confidence and a sense of control. Animal welfare management should aim to reduce the intensity of survival-critical negative affects to tolerable levels that nevertheless still elicit the required behaviours, and should also provide opportunities for animals to behave in ways they find rewarding, noting that poor management of survival-critical affects reduces animals' motivation to utilize such rewarding opportunities. This biologically more accurate understanding provides support for reviewing the adequacy of provisions in current codes of welfare or practice in order to ensure that animals are given greater opportunities to experience positive welfare states. The purpose is to help animals to have lives worth living, which is not possible when the predominant focus of such codes is on survival-critical measures. Finally, an updated characterisation of animal welfare that incorporates this more accurate understanding is presented.
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    Updating Animal Welfare Thinking: Moving beyond the 'Five Freedoms' towards 'A Life Worth Living'
    (14/03/2016) Mellor DJ
    Gaining knowledge of animal welfare and applying it in ways that improve our care of animals can be understood as a journey. Different countries, regions of countries and people within those countries have reached different stages in this journey. However, even for those who have travelled far on this journey, it will never end because new or modified approaches to animal care will be needed as we continue to learn more about how animals perceive and respond to the circumstances in which they find themselves.