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1
Alexander, Vincent Rasahd. "The Role of Corticotropin-Releasing Factor in the Behavior and Proinflammatory Activity of Separated Guinea Pig Pups." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1345847290.
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Wenner, Benjamin A. "Effect of Bio-Mos® and outdoor access housing on pig growth, feed efficiency, health, behavior and carcass ultrasound traits." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1345574215.
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Buzzard, Brandi L. "Evaluation of hypobaric hypoxia as a low stress alternative to carbon dioxide euthanasia for use with nursery piglets." Thesis, Kansas State University, 2012. http://hdl.handle.net/2097/14867.
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Master of Science<br>Department of Animal Sciences and Industry<br>Timothy G. Rozell<br>Malnourished piglets that suffer from periweaning failure to thrive syndrome (PFTS) may show no signs of respiratory or enteric diseases but may have decreased feed intake and become debilitated after weaning. Euthanasia is a necessary component of swine production as it is sometimes the only option to alleviate suffering of piglets that are born with congenital defects or suffer from PFTS.
Fifty-eight nursery-aged piglets were utilized in two experiments to evaluate blood parameter differences between healthy and unthrifty piglets and to compare euthanasia methods. Piglets were categorized into two health groups: healthy or unthrifty. During selection, blood was collected for analysis of blood parameters. Piglets were euthanized 24-32 hours after initial blood sampling and a second sample was collected for comparison. After euthanasia, piglets were necropsied for evaluation of euthanasia on pulmonary lesions. No significant difference in number of pulmonary lesions was found between health groups (P = 0.88). Healthy piglets had higher concentrations of glucose, ionized calcium and sodium, and greater pCO₂ than unthrifty piglets (P ≤ 0.05). Unthrifty piglets showed higher concentrations of hemoglobin and hematocrit (P = 0.0002) than healthy piglets.
Piglets were assigned to one of two euthanasia methods to compare electrophysiological and behavioral parameters of hypobaric hypoxia and carbon dioxide gas. Two piglets at a time were euthanized for each method. One animal in the pair was fitted with electrocardiogram and electroencephalogram monitoring devices during euthanasia. Behavioral parameters were also recorded. The average treatment times were 27.4 ± 6.7 minutes for HH and 13.8 ± 5.1 minutes for CO2. Piglets euthanized via CO2 reached an isoelectric state faster than piglets euthanized via HH (P = 0.009). Behavioral observations revealed gasping in 100% of CO2 euthanized piglets during the first five minutes of treatment and only 28.6% of HH euthanized piglets during the same period. During HH, 57.1% of piglets became ataxic in the first five minutes while 76.9% of CO2¬ piglets became ataxic during the same period. Results of this trial indicate that HH may be a lower stress alternative to CO₂ as it causes fewer incidences of aversive behaviors in early stages of treatment.
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Schreibeis, Amanda Danielle. "Cross Sensitization of Depressive-Like Behavior through Two Depression Related Paradigms: Maternal Separation and Its Effect on the Forced Swim Test In the Guinea Pig." Wright State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=wright1484638271891606.
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Dazey, Jennifer. "Influence of Daily Electrical Stimulation of Periaqueductal Grey on Vocalization and Depressive-like Behavior during Separation in Guinea Pigs." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1355011112.
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Andresen, Niels. "The foraging pig : resource utilisation, interaction, performance and behaviour of pigs in cropping systems /." Uppsala : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/91-576-5764-5.pdf.
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Sarubbi, Juliana. "Bem-estar dos animais e uso racional de energia eletrica em sistemas de aquecimento para leitões desmamados." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256978.
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Orientadores: Luiz Antonio Rossi, Daniella Jorge de Moura<br>Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola<br>Made available in DSpace on 2018-08-13T09:10:46Z (GMT). No. of bitstreams: 1
Sarubbi_Juliana_D.pdf: 16417417 bytes, checksum: 878d474575ba837c886a9dcf562c9520 (MD5)
Previous issue date: 2009<br>Resumo: Para que os mecanismos que visam promover condições de bem-estar aos suínos possam ser utilizados, é necessário que se desenvolvam pesquisas para reduzir seus custos e aumentar sua
praticidade, possibilitando a sustentabilidade do processo. O aquecimento de leitões em fase
de creche e maternidade pode ser trabalhado no sentido de viabilizar a eficiência do uso da
energia elétrica sem, no entanto, prejudicar o bem-estar dos suínos. Por meio deste trabalho,
objetivou-se comparar três tecnologias de aquecimento para leitões a partir de três semanas de
idade, em fase de creche, com relação ao uso de energia elétrica, condições de bem-estar e
desempenho dos animais. Estudaram-se três tecnologias de aquecimento: TR - resistências
elétricas suspensas, TP - piso aquecido e TA - aquecimento por convecção. O sistema de
aquecimento por pisos foi melhor sob o aspecto de uso de energia elétrica. O sistema de
aquecimento por resistências elétricas foi o melhor com relação ao atendimento das
necessidades térmicas dos animais e o sistema de aquecimento por convecção foi o melhor
considerando a resposta produtiva, comportamental e fisiológica dos animais. De maneira
geral, atribuindo-se pesos aos aspectos analisados (implantação e operação, uso de energia
elétrica, respostas do ambiente e respostas dos animais), o sistema de aquecimento por
resistências suspensas foi o melhor. Porém, sugerem-se testes para aprimoramento das
tecnologias com a utilização de sistemas híbridos.<br>Abstract: In order to the mechanisms which promote the welfare in pig production can be used, it is necessary to develop research works to lower their costs and increase their practicality,
enabling the sustainability of the process. Heating of piglets in nursery and maternity phases
may be improved to raise energy savings, without undermining the welfare of animals. This
research work aimed to compare three of heating technologies for piglets of three weeks aged,
nursery phase, in relation to electrical energy use, welfare conditions and animal performance.
The studied heating technologies were: TR - suspended electrical resistors, TP - heated floor
and TA - heating by convection. The heated floor system was better under the aspect of
electrical energy use. The electrical resistance heating system was the best regarding to the
animals environmental needs, and convection heating system was the best considering the
productive, behavior and physiological animal responses. Considering installation and
operation, electrical energy use, environmental and animal welfare aspects, the heating system
by suspended resistors was the best. However, more tests are suggested in order to improve
TA and hybrid systems use.<br>Doutorado<br>Construções Rurais e Ambiencia<br>Doutor em Engenharia Agrícola
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McIntyre, Jayne. "Tail biting in pigs." Thesis, University of Newcastle Upon Tyne, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.275520.
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Durrell, Julie Louise. "Improving the welfare of group housed sows." Thesis, Queen's University Belfast, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343048.
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Appleyard, Stephen John. "The maternal behaviour of the pig in the farrowing crate." Thesis, University of Edinburgh, 2001. http://hdl.handle.net/1842/26132.
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Piglet-weaning mortality is an enduring problem for the pig industry but is likely to be strongly influenced by the maternal behaviour and overall rearing ability, of the sow. Farrowing crates are the most common method of housing lactating sows in this and many other countries. However, farrowing crates pose a welfare dilemma: they are aversive for sows prior to parturition but limit the number of piglet crushing mortalities. One solution to this dilemma would be to breed sows better adapted to the crate system. To this end, a longitudinal breed study was set up that observed the behaviour of individual sows over their first two parities, in farrowing crates both with and without straw. Consistent behavioural traits are identified, most notably sow-piglet interactions and posture changing, and genetic influences are inferred from breed differences. The mean number of still-births and crushing mortalities per litter are modelled for non-behavioural influences. Season and litter size feature strongly for both these models. The behavioural characteristics of crushing and savaging sows are described and discussed in relation to functional explanations and possible causal mechanisms. An argument is developed that identifies piglet-savaging behaviour with being hypersensitive to restriction during pre-farrowing nest-building, resulting in physiological changes influencing the progress of parturition. Sows possess behavioural mechanisms to reduce the risk of crushing, which are modified by the farrowing crate in both positive and negative ways.
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Jarvis, Susan. "Parturition in the pig : relationships between pain, stress and maternal behaviour." Thesis, University of Edinburgh, 1998. http://hdl.handle.net/1842/29820.
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The thesis examines the relationships between pain, stress and behaviour of the pig around parturition. This includes the effects of pregnancy and parturition on maternal nociception, and environmental restriction on stress physiology and behaviour. The main findings are: 1. Late pregnancy and parturition in the pig is associated with an endogenous analgesic system which is, at least in part, mediated via endogenous opioids. 2. Passivity and inactivity are major components of maternal behaviour in the pig and are suggested to be indicative of good maternal care in this species. The thesis provides evidence of an opioid mediation of maternal behaviour which could arise through several potential routes, namely: the action of the analgesic system, general sedation, the inhibition of oxytocin release. 3. A rise in plasma control, ACTH and β-endorphin concentrations were found in pre-parturient gilts housed in both straw bedded pens and conventional farrowing crates. However crates caused further stimulation of the HPA axis reflecting thwarting of nestbuilding behaviour in this restrictive environment. 4. The farrowing crate did not cause further HPA activity during the expulsive phase which may reflect the inactivity of the pig at this time. A rise in plasma cortisol was found as the expulsive phase progressed irrespective of environment however the thesis found that the expulsion of a piglet does not appear to play a major role in this. Overall the thesis has realised a better understanding of parturition in the pig by relating the physiology and behaviour of the pig at this time. The possibility of maternal pain influencing the progress of parturition and maternal behaviour is discussed in relation to possible mechanisms by which this may occur. The thesis has also highlighted welfare implications regarding the use of farrowing crates, and provides information which may be used when considering changes to housing for parturient pigs.
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Jackson, Ciara Jan. "Drinking behavior in nursery aged pigs." [Ames, Iowa : Iowa State University], 2007.
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Dunne, Laura Maria. "The effect of temperament and environment on the behaviour of the pig." Thesis, Queen's University Belfast, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343049.
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Nilsson, Emma. "The effects of an activity ball and ropes on pigs’ behaviours." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-79027.
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Rooting and exploring are two behaviours pigs in the wild spend considerable time doing. When kept in pens with limited access to bedding materials stress can originate and often lead to undesired behaviours. The purpose of this study was to investigate whether environmental enrichment in terms of ropes and an activity ball containing piglet food, can provide an outlet for their natural behaviours and thus reduce undesired behaviours. In total, 141 pigs were used and divided into three groups, control-, activity ball- and rope groups. The observation methods used were 1/0 recording and instantaneous recording with 15 second intervals. In the rope group a significant difference was seen in the interaction with enrichment, as it was higher on day 1. Between the three groups, a decrease in ear-, tail- and equipment biting was seen in the two enriched groups on day 1. On day 3 these difference could only be seen between the control group and the other two groups in equipment biting. However, few data ware collected and so we cannot confirm our hypotheses, concerning whether the environmental enrichments decreased the undesirable behaviours or not. However, most of our findings are in compliance with earlier studies as we among other things found that the rope worked better than the activity ball and that the interest of the enrichments decreased with time.
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Burniston, Stephanie. "Mixed methods analysis of pig associated zoonoses in Lao PDR." Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28811.
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Southeast Asia carries a large burden of endemic zoonotic diseases, in livestock and humans, especially in countries where livestock production is increasing among rural households for income generation and poverty reduction. This thesis explores the risk factors for transmission of pig-associated zoonoses – particularly Q fever, brucellosis, hepatitis E, and Japanese encephalitis – in northern Lao PDR, with a view to development of recommendations for “catch-all” control measures to impact on multiple diseases, improving biosecurity and preventing disease transmission to the human population. Research included (i) a qualitative assessment of the knowledge, attitudes, and practices of villagers related to pig-associated zoonoses and their risk factors using focus group methodology; (ii) an assessment of health seeking behaviour at hospital/health centre and village level to examine factors that influence choice of health care provider and determine the impact of health seeking behaviour on illness and treatment costs, and an examination of non-conventional health care sources to understand the complexity of health seeking behaviour and influences on choice of health care provider and, lastly, (iii) health care provider and service delivery assessments to determine healthcare facility routine service delivery procedures and assess capability in diagnosing and treating illness. In terms of disease, the most common illnesses reportedly seen by all those interviewed were respiratory illness, acute febrile illness and diarrhoea, confirming them as the leading causes of morbidity. Knowledge and awareness of the etiological agent of pig-associated zoonoses among villagers, patients, and health care providers was very poor for brucellosis and Q fever, with limited awareness of hepatitis E. Most were aware of Japanese encephalitis. Clinical diagnosis and symptomatic treatment of illness is the normal practice and identification of causative agents in human illness does not often occur. All three empirical assessments identified poor diagnostic capability as a major concern. Focus group discussions revealed that knowledge and awareness of disease risk factors, and of zoonoses in general, was low among villagers. Practices related to food consumption, latrine usage, hand hygiene and sanitation, which are known disease risk factors, were found to be a concern in study villages. Attitudes and practices adopted by villagers in relation to human and animal health and health seeking behaviours were strongly influenced by financial circumstances, access to appropriate healthcare facilities, spiritual beliefs, and a lack of knowledge and resources to maintain the health of both animals and humans. The first point of care when experiencing illness was often the health centre or a local traditional healer or spiritual healer or pharmacist/drug seller, depending on location. This was followed by the district hospital, if nearby. Many villagers described going back and forth between traditional medicine and modern medicine service providers, with 76% (19/25) of participants reportedly seeing more than one type of healthcare provider for a given episode of illness. Self-medication was the most common practice (84% of all participants) irrespective of the care provider consulted. Attendance at a healthcare facility was dependent on available funds and the perceived severity of illness. Overall household costs ranged between no cost, because of the “poor patient” policy that exempts vulnerable groups from paying for care, and $2500 USD for medical treatment, hospital stay, transportation and sometimes food. Healthcare workers at all facility levels (from health centre to provincial hospital) expressed a lack of confidence in making an accurate diagnosis for these pig associated zoonoses due to poor diagnostic capability in their respective facilities. A One Health approach to zoonotic disease surveillance that incorporates transdisciplinary methods and partnerships will lead to improved understanding of the underlining social determinants of health and their impact on health-seeking behaviours, disease transmission and ultimately disease reporting.
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Nygren-Fasth, Veronica. "En jämförelse av beteendeeffekter hos slaktsvin av olika typer av miljöberikning." Thesis, Linköpings universitet, Biologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-103368.
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Hos grisar finner man flera stereotypiska beteenden, som rörbitning och svansbitning. Dessa beteenden är relativt vanliga hos grisar. En miljöberikning definieras som förbättring av ett djurs välfärd, både psykologisk och fysiologiskt, genom förändringar hos djurets omgivning. Denna studie har undersökt om miljöberikningar kan minska stereotypiska beteenden hos grisar. De två olika miljöberikningar som har använts är en jutesäck fylld med halm och en Jolly Ball™. De tre stereotypiska beteendena som studerades var rörbitning, svansbitning och bukmassage. Studien utfördes på 107st grisar uppdelade på 12 boxar, under totalt tre veckor. Alla tre stereotypiska beteenden minskade statistiskt signifikant . Detta visar att båda miljöberikningarna hade en positiv effekt på grisarna då de minskade deras stereotypiska beteenden. De interagerade mer med jutesäcken fylld med halm än vad det gjorde med Jolly Ball™. Grisarna föredrog den miljöberikningen som var omformbar, förstörbar, ätbar, tuggbar, vilket går i linje med liknande studier.<br>Among fattening pigs you find several stereotypical behaviours, such as bar-biting and tail-biting. These behaviours are quite common among domestic pigs. Environmental enrichments are often used to reduce stereotypical behaviours in animals. An environmental enrichment is defined as an improvement of an animal’s welfare, both psychologically and physiologically, through changes in the environment of the animal. With this study, different environmental enrichments were studied to see if they can reduce stereotypical behaviour among fattening pigs. The two different environmental enrichments used were a jute sack filled with straw and a Jolly Ball™. The stereotypical behaviours that were looked at were bar-biting, tail-biting and belly-nosing. The study was carried out on 107 pigs divided into 12 pig boxes, during 3 weeks in total. All three stereotypical behaviours decreased significantly. This shows that the environmental enrichments had a positive effect on the pigs, since they reduced their stereotypical behaviour. The pigs interacted more with the jute sack than they did with the Jolly Ball™. The pigs preferred the environmental enrichment that was destructible, edible, deformable and chewable, which fits well into similar studies that have been executed.
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Crawford, Sara Maria. "Improving the Attitudes and Behavior of Stockpersons Toward Pigs and the Subsequent Influence on Animal Behavior and Production Characteristics of Commercial Finishing Pigs in Ohio." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1325216784.
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Kapell, Dagmar Nicoline Reinhildis Gertrud. "Integration of quantitative and molecular genetic approaches to improve characteristics associated with pig welfare." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5028.
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The aims of this thesis were to investigate whether characteristics associated with animal welfare are genetically and genomically determined by using quantitative and molecular genetic approaches and to develop strategies indicating how these traits could be used in breeding programmes. Two traits that are closely related to animal welfare and associated with high socio-economic values are piglet survival at birth and aggressive behaviour in pigs. Piglet survival traits were analysed based on quantitative Bayesian approaches using phenotypic and pedigree information only, while aggressive behaviour was analysed based on molecular genetic approaches such as genome-wide association studies and genomic selection using additionally a dense panel of single nucleotide polymorphisms (SNP). The latter approach was validated using behavioural traits related to welfare characteristics in a welldocumented mouse data set. Selection for piglet survival at birth is expected to be effective, because all lines and breeds in this thesis showed considerable variation for this trait and relatively high heritabilities, particularly in lines with low average birth weight. Maternal heritabilities of individual birth weight were mostly at moderate magnitude and thus of great interest for selection. The genetic correlations between piglet survival and birth weight indicated that selection for either individual or average birth weight or variation of birth weight within litter would indirectly increase survival. The genetic associations of piglet survival with economically important (re)production traits are of great importance for breeding organisations. Undesirable genetic correlations between piglet survival and (re)production traits were generally of low magnitude, so that simultaneous improvement of all traits could be achieved. A comparison of five breeds and lines showed that differences in genetic parameters between breeds and lines can be substantial and no single selection strategy would be optimal for all. A unique study of a sire and a dam line originating from one breed but selected for more than 25 years with different breeding goals demonstrated how selection pressure can alter the genetic parameters over years. Breeding organisations should therefore consider selection strategies per breed or line individually to achieve maximum overall improvement. This study gives new insight into the use of genomic selection for traits associated with animal welfare. It is one of the first to present estimates for linkage disequilibrium in the pig using a new 60K SNP panel and the first to evaluate the efficiency of genomic selection against aggressive behaviour in pigs. Genomic selection showed a high predictive ability in comparison to traditional polygenic selection. It was especially advantageous for traits with lower heritabilities. In particular in situations where little family information was available, the performance of polygenic selection was low and genomic selection increased the performance considerably. Reducing the number of SNPs did not significantly change the performance of genomic selection. The consistently high performance across models indicates that low-density SNP panels may be sufficient to ensure a high efficiency of genomic selection, thus reducing the high costs associated with genotyping in pig breeding with its short generation interval. To summarize, this thesis has shown how to optimise quantitative and genomic approaches to improve animal welfare related characteristics efficiently in pig breeding programmes.
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Feeroz, Mohammed Mostafa. "The ecology and behaviour of the pig-tailed macaque (Macaca nemestrina leonina) in Bangladesh." Thesis, University of Cambridge, 1999. https://www.repository.cam.ac.uk/handle/1810/251687.
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Söderquist, Astrid. "Familiarity and personality affect social support in juvenile pigs in a foam stunning situation." Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-172276.
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Animals in distress can experience an attenuation of their stress response if provided companionship. This thesis studied the social support phenomenon in 72 nine-week old juvenile pigs (Sus scrofa domesticus) of the crossbreed Yorkshire/Hampshire. Pigs were placed either alone or with a familiar or an unfamiliar age-matched conspecific of the opposite sex in a stunning box. Half of the groups were exposed to an air-filled foam inside of the box and the other half was exposed to an empty box. All pigs underwent an individual behaviour assessment at eight-weeks of age for a personality evaluation. The results of this thesis indicate that pigs were startled by the foam exposure as suggested by changes in activity, escape attempts and vocalisations. Indications of social buffering were found with regards to performance of escape attempts, altered activity patterns and engagement in affiliative social behaviours. Differences were observed in the social behaviour of familiar and unfamiliar pig pairs, suggesting that familiarity between pigs should be preferred from a welfare perspective. Correlations between possible personality traits and the pigs’ behaviour in the foam box study can be understood within the coping style framework. The results suggest that pigs show variation in their need for social support and that personality could have been a bias in interpreting the pigs’ behavioural response to the foam stunning situation. This thesis provide support that the welfare of pigs during foam stunning may be improved if pigs are stunned in groups of familiar individuals.
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Waran, Natalie Kay. "The behaviour and welfare of early-weaned pigs." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239165.
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Turner, Simon Phillip. "Social organisation and resource requirements of pigs housed in large groups." Thesis, University of Aberdeen, 2000. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=158508.
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The resource requirements and social behaviour of pigs housed in large groups were examined in a series of experiments. (i) The nipple drinker requirement was addressed by using four treatments (60 pigs, 3 drinkers; 20 pigs, 1 drinker; 60 pigs, 6 drinkers and 20 pigs, 2 drinkers). Drinker provision had no effect on water use, but in a larger group more water was used in less time (p<0.001). The diurnal pattern of drinking, overt aggression and lesion score indicated no difference between treatments. (ii) Pigs, housed on deep straw in groups of 20 or 80, were provided with a low (50<I> </I>kg/m<sup>2</sup>) or high (32 kg/m<sup>2</sup>) floor space allowance. Large groups had a lower growth rate. Skin lesions were elevated and immune response was lowered by a low space allowance. (iii) Two feeder space allowances (32.5<I> </I>and 42.5<I> </I>mm/pig) for pigs housed in groups of 20 or 80 were investigated. Food intake was lower in the low feeder allowance treatments and pigs in large groups tended to have a reduced growth rate. (iv) Pigs from the same pen in an unfamiliar arena maintained a similar degree of proximity regardless of origin group size. (v) Pigs from groups of 80 demonstrated reduced aggressiveness (increased latency to fight, decreased rate of aggression) towards unacquainted pigs in an arena, but showed even less aggression towards pen mates. (vi) No evidence of spatial sub-division of the large group into smaller units capable of maintaining a dominance hierarchy was found. Resource provision and group size largely did not interact, but may independently compromise productivity and behaviour. A large group was associated with a reduction in performance. The dominance hierarchy was of less importance in large groups, despite recognition being intact, and sub-grouping behaviour did not provide an alternative strategy for group social organisation.
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Liu, Dongqing. "Market-making behavior in futures markets /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2002. http://uclibs.org/PID/11984.
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Kardegar, Nadia. "Electrical Brain Stimulation and Depressive-like Behavior in Guinea Pigs." Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1342408797.
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Day, Jon Edward Lewis. "The causation of foraging behaviour in the growing pig : the role of internal and external factors." Thesis, University of Edinburgh, 1995. http://hdl.handle.net/1842/14752.
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This thesis examines in detail some of the internal and external factors which are implicated in the causation of foraging behaviour in growing pigs. Special reference is given to the interface between exploratory and feeding motivations, and the role of gastro-intestinal distension in determining the tendency to perform foraging behaviour. Four experiments were performed which found: 1. Extrinsic exploration equates to the appetitive component of the dominant motivation (e.g. extrinsic exploration for food and foraging), and therefore can be directly affected by the level of feeding motivation, whereas intrinsic exploration is not directly affected by the level of feeding motivation. 2. Chewing behaviour, such as tail-biting, is initiated through extrinsic exploratory behaviour, but then sustained by feeding motivation. In addition, feeding motivated chewing is moderately reinforced by taste, but is strongly reinforced and perpetuated by taste paired with a relevant source of feedback. 3. Growing pigs are able to respond for the repeated presentation of a feeding related conditioned stimulus in a manner which is indicative of their level of feeding motivation. This methodology allows feeding motivation to be measured in the absence of food ingestion. 4. The level of feeding motivation resulting from the ingestion of a bulky food is inversely proportional to the degree of gastro-intestinal distension. However, this effect is only temporary because feeding motivation responds primarily to the nutrient content of a meal.
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Feldman, Todd. "Portfolio manager behavior and global financial crises /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2009. http://uclibs.org/PID/11984.
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Rabin, Lawrence Aaron. "The effects of wind turbines on California ground squirrel (Spermophilus beecheyi) behavior : successfully integrating conservation and animal behavior research /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2005. http://uclibs.org/PID/11984.
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Grigoriadis, Dimitris F. "Reproductive behaviour of pigs in a dynamic service system." Thesis, University of Aberdeen, 2000. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=191661.
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The behaviour, welfare and reproductive efficiency of sexually mature pigs kept in groups rather than singly has recently become important because of new EU legislation to ban sow stalls and tethers. Four studies were undertaken to examine the behavioural, welfare and economic implications of a Dynamic Service System (DSS) for gilts. The DSS is a semiintensive variant of 'group mating'. In DSS, the female population is changed on a regular basis while the boars, forming a team, are resident. In total, 1402 gilts and 38 boar teams were used to establish behavioural parameters and reproductive output (i.e. conception rate and litter size) in such a system. The behaviour of the sexual partners was continuously recorded for 6,288 hours (i.e. 262 days). The results indicated that male sexual behaviour differed significantly between and within boar teams. Social dominance failed to significantly affect male sexual behaviour and a comparison of the male social and sexual hierarchies showed that they were poorly correlated. Gilt reproductive behaviour and performance were not affected by the number of heat periods experienced prior to service, at a controlled age. There were no detrimental influences on gilt productivity of halving the size of the boar teams from 4 to 2 individuals. Overall, the reproductive performance of gilts in a DSS was at least as good as in other conventional mating systems. The Dynamic Service System was shown to be compatible with good welfare and acceptable behavioural patterns, and is clearly a valuable alternative in future pig production.
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Liljenstolpe, Carolina. "Consumer valuation studies and structural modelling of the pig industry : a focus on animal welfare /." Uppsala : Dept. of Economics, Swedish University of Agricultural Sciences, 2008. http://epsilon.slu.se/200835.pdf.
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Bjorland, Clayton M. "On the long time behavior of fluid equations /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2008. http://uclibs.org/PID/11984.
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Leidy, Chad. "Thermotropic behavior of lipid domains in model membranes /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2002. http://uclibs.org/PID/11984.
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Johansson, Gustav. "PCG in game bits and its effect on player behaviour." Thesis, Högskolan i Skövde, Institutionen för informationsteknologi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-18695.
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This dissertation presents a study that explores the idea of implementing PCG in game bits. Procedural Content Generation (PCG) refers to content in games that is created by an algorithm rather than a human. Game bits is the part of game content that relates to graphics, audio and other elements that don’t directly affect gameplay. The goal was to find out what a PCG implementation in game bits needs to affect player behaviour. Qualitative play sessions with interviews were performed to examine potential ways this could occur. Results show that no noticeable behavioural differences appeared due to PCG in game bits, but three properties are set up detailing how implementations would increase the odds of affecting player behaviour. These properties are: PCG implementation changing visuals drastically, different visual elements matching and game space generation matching game bits repeatedly.
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Lee, Lik Wee. "Critical behaviour of spin glass models /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2006. http://uclibs.org/PID/11984.
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Ismayilova, G. "THE USE OF IMAGE LABELLING TO IDENTIFY PIG BEHAVIOURS FOR THE DEVELOPMENT OF A REAL-TIME MONITORING AND CONTROL TOOL." Doctoral thesis, Università degli Studi di Milano, 2014. http://hdl.handle.net/2434/229554.
Full textAbstract:
The behaviour of animals is the most informative indicator of the farm status, reflecting animal responses to the change of their welfare, health or surrounding environment. Complex and continuously changing animal responses could be monitored through automated and real time measurements offered by PLF. The most crucial component of an effective PLF system is a precise real-time algorithm able to detect, quantify or even predict the target behaviour, considering that animals are individually different in their responses. During the process of the development of such an algorithm the input of the expertise in animal ethology and biology is indispensable. Understanding of biological mechanisms is a key element in comprehension of the message given by animal behaviour.
One of the most important contributions of the specialist with biological background in algorithm development is labelling.This thesis was particularly dedicated to the labelling and its importance in the process of the development of successful PLF system.
The objective of this thesis was application of image labelling technique to contribute to the development of an automatic PLF systems to monitor behaviours of pigs.
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Lee, Tim. "The behavior of endangered populations in a randomly fluctuating environment /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2002. http://uclibs.org/PID/11984.
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Chu, Ling-Ru. "The behavior and social preferences of New Zealand white rabbits /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
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Nelson, Erik Healy. "Population consequences of predator avoidance behavior in the pea aphid /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
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Jasiniauskaitė, Lina. "Paršingų paršavedžių elgsenos tyrimai." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2009. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2009~D_20090313_131751-78251.
Full textAbstract:
Kiaulių elgsena sąlygojama įgimtų instinktų, pasireiškiančių pastoviais steriotipais budėjimo, poilsio miego, maitinimosi, dauginimosi, gimimo ir kitose būsenose. Atskiros elgsenos reakcijos kaip atsakas į vidinius ir išorinius dirgiklius reiškiamos aktyvumu, agresyvumu, hierarchinių pasiskirstymu grupėse, pirmenybe mitybos ir kitiems veiksmams, į kuriuos reikia atsižvelgti organizuojant gyvulių laikymą ir priežiūrą. Skirtingai nuo laukinių gentainių, didžiausiais kiaulių aktyvumas pasireiškia dieną. Dėl to visas technines gyvulių priežiūros operacijas reikia atlikti šviesiu paros metu ir sudaryti būtinas sąlygas jų poilsiui nakties metu. Tenka paminėti, kad fermų sąlygomis kiaulės guli apie 80% paros laiko, 10% laiko sugaišta maitinimuisi, o likusį 10% laiko – kitoms aktyvumo formoms (judėjimui, peštynėms, žaidimams ir kt.).
Tarpusavio bendravimo tikslais kiaulės naudoja garsinius signalus bei uoslę, lytėjimą, klausą. Kiaulių uoslė yra daug kartų stipresnė nei žmogaus. Kiaulės dažnai atpažįsta žmones ar gyvūnus pasikliaudamos vien uosle. Jos taip pat gali užuosti baimės kvapą kurį išskiria žmonės. Taip paaiškinama kodėl kiaulės kriuksi pamatę žmogų. Priklausomai nuo kiaulių amžiaus, fiziologinės būklės kinta ir kiaulių elgsena.
Tyrimo tikslas: įvertinti paršavedžių elgesenos ypatumus paršingumo metu, jas laikant vasaros stovykloje.
Tyrimo uždaviniai: 1. Nustatyti paršavedžių įvairių elgsenos formų trukmę šviesiu paros metu; 2. Palyginti jaunų ir senų paršavedžių elgseną... [toliau žr. visą tekstą]<br>The aim of work was to assess the behavioral features of sows.
Objectives of work were: to determine the sows of different forms of behavior during the duration of daylight hours. Relatively calm and temperamental behavior of sows. Assess the flow behavior of the sows, depending on weather conditions.The study was carried out in vilage of Utenėlė, in pig farm. The study was concluded 15 pregnant Duroc breed sows group. The observation period was 15 days, 70–85 time the day. Fixed behavior of sows during the daylight hours, from 8 am. am to 18 pm. evening. Fixed basic behavior of the form: the activity, rest, aggression. Pregnant sows during the observation was considered as the summer camps, with moveable type of light, which was straw. Sows during the observation time was 1 moved into a new, grass grew enclosure. Data biometrics processed using the Windows operating system Excel spreadsheet Juozaitienė, V. Kerzienė. Calculated the arithmetic average of the error, the reliability (p). Observations were recorded for the three main types (Table 1) behavior, rest, the overall activity and aggression. Rest belonged to the behavior of sleeping, lying, sitting, activity - eating, drinking, walking, aggressive – all the conflict situations encountered among sows, at the time of observation. Sows of 68 percent. Total observation time spent lying and sleep compared the behavior of 1 to 7 were the result of a reliable (p <0,05). In most cases, the sow lying opted hangar, which was... [to full text]
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Pajor, Edmond A. "The correlates of individual variation in the ontogeny of solid food consumption in pigs /." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=60111.
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In order to describe the ontogeny of solid food consumption by pigs and determine its influence on weight gain, before and after an abrupt weaning at 4 weeks of age, individual feed consumption was measured using a technique that combined load cells and video images. Feed consumption varied greatly both between and within litters. Within litters, consumption was positively correlated with birth weight, and with early weight gains. This suggests that greater feed intake was typical of larger and more mature pigs rather than reflecting compensation for poor milk intake by smaller litter-mates. Within-litter differences in weight gain during the two weeks after weaning were positively correlated with birth weight but not correlated with pre-weaning creep feed intake. Creep feed intake appeared to contribute to pre-weaning gains and these were correlated with post-weaning gains; however a more direct affect on post-weaning gain could not be detected.
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Petkov, Christopher Iliev. "The perceptual organization of sound : behavior and neural contributions in macaques /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.
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Kuhn, Carey Elizabeth. "Measuring at sea feeding to understand the foraging behavior of pinnipeds /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2006. http://uclibs.org/PID/11984.
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Fowler, Ada Christine. "Population genetic structure and breeding philopatric behavior of Cackling Canada Geese /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
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Bornett, Hannah. "The effects of social organisation on feeding behaviour in growing pigs." Thesis, University of Edinburgh, 2001. http://hdl.handle.net/1842/28543.
Full textAbstract:
Group housed pigs make less frequent feeder visits of a longer duration, and eat at faster rate than pigs housed individually. They also have lower growth rates which may be due to elevated stress associated with aggression and social stress. The aim of this thesis is to investigate the stability of feeding patterns in individual pigs, the effect of grouping and group composition on feeding patterns and to assess the consequences of this shift in feeding behaviour for the welfare and performance of grouped pigs. The flexibility of feeding behaviour was assessed by restricting the time of access to food of previously <i>ad libitum</i> fed pigs to 2 hours per day and then returning them to 24 hr access. When pigs had restricted access to food they made fewer daily feeder visits, of a longer duration, with a higher food intake per visit than the control pigs that had 24 hour access to food throughout. Flexibility was assessed by comparing feeding behaviour before and after restriction. The pigs that experienced a period of restricted feeding either resumed their previous behaviour or showed the same trend as the controls. It was concluded that feeding behaviour was flexible. A second experiment investigated the effect of grouping on feeding behaviour. Pigs were housed individually for 3 weeks after which they were combined into groups of 4 for 3 weeks, before being returned to individual housing for a further 3 weeks. When grouped, pigs made fewer visits to the feeder of a longer duration than when they were housed individually. Possible explanations for the changes in feeding behaviour are competition, group cohesion, or that the high frequency of feeder visits when the pigs are housed individually is a consequence of a lack of social stimulation. The results suggest that group cohesion is most likely to have been causal in the observed changes in feeding behaviour.
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Claassen, Ryan L. Gingerich. "An activist mediated model of presidential elections : campaigns to structure voting behavior /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2005. http://uclibs.org/PID/11984.
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Hollis-Brown, Lisa Anne. "Individual variation in the antipredator behavior of captive rhesus monkeys (Macaca mulatta) /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2005. http://uclibs.org/PID/11984.
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Stevens, Daniel J. "Metal binding behavior of the prion protein and relevance to disease progression /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2008. http://uclibs.org/PID/11984.
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Bakker, Victoria Josina. "Behavior and habitat relations of forest-associated sciurids in a fragmented landscape /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
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Bauman, Melissa Dawn. "The role of the amygdala in the development of primate social behavior /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
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Seydack, Armin H. W. "Ecology of the bushpig Potamochoerus porcus Linn. 1758 in the Cape Province, South Africa." Thesis, Stellenbosch : Stellenbosch University, 1990. http://hdl.handle.net/10019.1/19406.
Full textAbstract:
Thesis (PhD) -- Stellenbosch University, 1990.<br>ENGLISH ABSTRACT:Bushpig sociology, energetics, reproduction and population dynamics were
studied over an 8-year period in the Cape Province, South Africa. The
social organization was found to be strikingly different from that known
from other suid species. The basic social unit is a unimaternal family
group, occupying a resource-based territority, with a monogamous mating
system. This form of social organisation is related to the dispersed
nature of food resources, to which it provides exclusive access. It is
reminiscent of canid social systems. Agonistic behaviour, communication
and maternal behaviour were studied as the opportunity arose. The
average home range size was 7,2 kmª, ranging from 3,8 to 10.1 kmª. Home
ranges were often traversed within 1-4 days, as part of territory
patrolling. The average diel ranging distance was 3 km. Bushpig were
active during both night and day and exhibited a basic bimodal rhythm.
The main phase of intensive foraging occurred from before dusk to
midnight, with a secondary activity peak after dawn. Activity schedules
were geared to avoid extreme ambient temperatures. Temperature
regulation and water use were investigated, with particular reference to
thermoregulatory behaviour (nest building). pelage characteristics, body
core temperature dynamics, thermoneutral zones and resting metabolic
rates. The thermoneutral zone for 10 kg bushpig juveniles was estimated
to lie between 13° and 30°C and that for adults between 8° and 25°C.
Foraging behaviour, diet and its nutritient content were investigated.
Regional differences in the nutritional quality of bushpig diets in the
Eastern and Southern Cape were associated with the predominance of
nutrient-rich and nutrient-poor substrates respectively. These in turn
were reflected by divergent life history features in the populations
from the two regions. Patterns of growth and energy storage were
described and the value of various parameters (e.g. mass to size ratio,
fat depositions, blood composition) to evaluate condition was
investigated. In studying reproductive biology, sexual maturation,
female reproductive cycles, prenatal litter statistics, foetal
development, 1actation, breeding seasonality and reproductive turnover
were the main aspects addressed. The role of food quality, body
condition and social status in determining reproductive success was
discussed. Bushpig population density estimates in the Southern Cape
ranged between 0,3 and 0,5 animals/kmª• The dynamics of Southern and
Eastern Cape populations were found to differ. The differences are
consistent with the hypothesis that social organisation is determined by
the distribution and availability of food while diet quality shapes
life history tactics. A life history model was developed which links
edaphoclimatic environmental conditions with diet quality, metabolic
turnover rate and, ultimately, life history features. In the concluding
chapter some of the managerial implications of the research findings are
discussed.<br>AFRIKAANSE OPSOMMING:Die sosiologie, fasette van die energiebalans (temperatuurregulasie,
voeding). voortplanting en bevolkingsdinamika van bosvarke is in die
Kaapprovinsie (Suid-Afrika) oor 'n tydperk van 8 jaar bestudeer. Dit
kon bewys word dat die sosiale organisasie van die bosvark van die van
ander varksoorte verskil. Die basiese sosiale eenheid bestaan uit 'n
familiegroep wat slegs 'n enkele telende moederdier bevat. Ruimtelike
organisasie is gebaseer op 'n stelstel van voedingsterritoriums. 'n
Monogamiese paringstelsel kom voor. Die yl verspreiding van voedsel
word as die onderliggende rede vir die sosiale organisasie beskou.
Gedragspatrone (kommunikasie, aggressie, grootmaak van kleintjies) is
bestudeer soos die geleentheid voorgekom het. Heelwat ooreenkomste is
gevind tussen die sosiale organisasie van die bosvark en lede van die
hondefamilie. Die gemiddelde woongebiedgrootte is 7,2 kmª (tussen 3,8
en 10,1 kmª). Woongebiede word gewoonlik binne 1-4 dae deurkruis en dus
soos territoria gepatroleer. Die gemiddelde daaglike bewegingsafstand
was 3 km. Bosvarke was beide gedurende die nag en die dag aktief en het
'n bimodale aktiwiteitsritme gevolg. Die hoofaktiwiteitsfase van
intensiewe voeding het tussen sononder en middernag plaasgevind, met 'n
sekondere fase na sonop. Soedoende is temperatuuruiterstes vermy.
Temperatuurregulasie en watergebruikpatrone is bestudeer, insluitend
temperatuurreguleringsgedrag, haarkleedeienskappe, liggaamskerntemperature,
termoneutraliteit en metabolise omset. Voedingsgedrag, voedsel en
die voedingswaarde daarvan is ondersoek. Verskille tussen die Oos- en
Suid-Kaap in die kwaliteit van voedsel hang saam met die laer vlak van
voedingsstowwe in die gronde van die Suid-Kaap. Bosvarkbevolkings in
die twee streke toon verskille in populasiedinamika wat hieraan
toegeskryf kan word. Groei- en energiestoorpatrone is beskryf. Die
moontlikhede is ondersoek om kondisie te evalueer met behulp van
parameters soos massa tot grootte-verhoudings, vetneerleggings en
bloedwaardes. Aspekte van voortplantingsbiologie, soos geslagsrypheid,
vroulike voortplantingssiklusse, voorgeboortelike werpselgroottes,
foetale ontwikkeling, laktasie, seisoenaliteit en voortplantingsomset is
behandel. Die rol van voedselkwaliteit, kondisie en sosiale status by
die bepaling van voortplantingsukses word bespreek. Skattings van die
bevolkingsdigtheid van bosvarke in die Suid-Kaap het gewissel tussen 0,3
en 0,5 diere per kmª• Op grond van die verskille in bevolkingsdinamika
tussen bosvarke in die Suid- en Oos-Kaap is 'n model ontwikkel om die
verband tussen bevolkingsregulering en lewensstrategieeë (life history
tactics) te verklaar. Hiervolgens het voedselbeskikbaarheid die tipe
sosiale organisasie bepaal terwyl die lewensstrategieë van bevolkings
die gevolg is van voedselkwaliteit. Die model stel vaar 'n verband
tussen groeipleksomstandighede, voedselkwaliteit, metaboliese omset en
bevolkingsdinamika. In die laaste hoofstuk word sommige van die
bestuursimplikasies van die navorsingsbevindinge bespreek.
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Lima, R. "Analysis of the blood flow behavior through microchannels by a confocal micro-PIV/PTV system." Doctoral thesis, Tohoku University, 2007. http://hdl.handle.net/10198/1263.
Full textAbstract:
Over the years, various experimental methods have been applied in an effort to understand the blood flow behavior in microcirculation. Most of our current knowledge in microcirculation is based on macroscopic flow phenomena such as Fahraeus effect and Fahraeus-Linqvist effect. The development of optical experimental techniques has contributed to obtain explanations on the way the blood flows through microvessels. Although the past results have been encouraging, detailed studies on the flow properties of blood in the microcirculation has been limited by several technical factors such as poor spatial resolution and difficulty to obtain quantitative detailed measurements at such small scales. Therefore, there is still a lack of knowledge on the microscale flow behavior of blood cells through microvessels.
In recent years, due to advances in computers, optics, and digital image processing techniques, it has become possible to combine a particle image velocimetry (PIV) system with a conventional microscope. As a result, this combination, known as a micro-PIV, has greatly increased the resolution of the conventional PIV. Although the conventional micro-PIV technique has proven to be useful in measuring the flow behavior in microfluidics devices, the entire flow field is illuminated and consequently the out-of-focus emitted light can result in high levels of background noise, which degrades the measured velocity fields. More recently, considerable progress in the development of confocal microscopy and the advantages of this technique over conventional microscopy have led to a new technique known as confocal micro-PIV. This technique combines the conventional PIV system with a spinning disk confocal microscope (SDCM), which has the ability to obtain in-focus images with an optical thickness less than 1 m (optical sectioning effect) and also to improve the particle image contrast, definition, and spatial resolution. This emerging technique has been successfully applied to measure homogenous fluids, however the question whether a confocal micro-PIV system is a suitable technique to study the blood flow behavior through microchannels remains.
In our work, a confocal micro-PIV system and also a confocal micro-particle tracking velocimetry (PTV) system are used, for the first time, to investigate in vitro blood flow through microchannels. By using these systems we have aimed to obtain further insights into the complex flow properties of blood in the microcirculation with the expectation that a better understanding on the blood flow phenomena will make a contribution to the prevention, diagnosis, and treatment of vascular diseases.
The validity of our confocal micro-PIV system is performed by comparing the experimental results of pure water seeded with tracer particles with an established analytical solution for a steady flow in a long straight microchannel. Good agreement was obtained, especially around the centre of the microchannel, with errors on the order of 5% or less. Furthermore, we have also demonstrated, for the first time, the ability of the confocal micro-PIV to generate 3D velocity profiles of a blood cell suspension fluid ( 4% haematocrit (Hct)).
The confocal system is used to determine both ensemble and instantaneous velocity profiles for in vitro blood (haematocrit up to 17%), flowing through a 100-m square glass microchannel at a constant flow rate and low Reynolds number (Re = 0.025). It was observed small fluctuations in the instantaneous velocity profiles which were found to be closely related to the increase with the Hct. Although the micro-PIV community tend to ignore these fluctuations, this study shows that the root mean square (RMS) values increase with the haematocrit implying that the presence of RBCs within the plasma flow strongly influences the measurements of the instantaneous velocity fields. Consequently, information provided by instantaneous velocities should be taken into account. Furthermore, by measuring the velocity profiles in vitro blood (20% Hct) in a rectangular (300 m wide, 45 m deep) polydimethysiloxane (PDMS) microchannel, small fluctuations were also found in the velocity profiles. Therefore, our results clearly show evidence that the encountered fluctuations are closely related to the motion and interaction of RBCs when flowing in a crowded environment.
We show that the confocal micro-PIV system is able to measure with good accuracy the blood plasma flow with Hct up to 9%, in a 100 m square microchannel. However, for Hct bigger than 9%, the light absorbed and scattered by the RBCs contributes to diminish the concentration of tracer particles in the acquired confocal images. Hence, a novel approach was implemented to the confocal system in order to obtain more reliable quantitative measurements on the motion of blood cells at high suspensions of RBCs. By using labeled RBCs and Dextran-40, a confocal micro-PTV system was employed, for the first time, in an effort to track individual tracer cells at high concentration suspensions of RBCs. The ability of the confocal system to generate thin in-focus planes has allowed both qualitative and quantitative measurements in flowing blood at concentrated suspensions (up to 35% Hct) of cell-cell hydrodynamic interaction, RBC orientation and RBC radial dispersion at different depths. Such data is thought to be extremely relevant to elucidate the blood transport mechanisms and associated diseases such as thrombosis and atherosclerosis.
By using the confocal micro-PTV system, the RBCs radial dispersion coefficient (Dyy) was measured in the middle plane of a 50m and 100 m glass capillaries in both diluted and concentrated suspensions (Hcts up to 35%) at low Reynolds numbers (Re from 0.003 to 0.005). There is evidence that the RBCs Dyy tends to increase with the Hct but, at Hct of about 25%, it tends to level off. This finding suggests that, at moderate Hcts, the development of the plasma layer and the consequent decrease of the local cell density, surrounding the RBCs, may enhance the radial dispersion of RBCs. In addition, we have also found that Dyy is greatest at radial positions between 0.4R to 0.8R, whereas at locations adjacent to wall (0.8R to 1R) and around the middle of the capillary (0R to 0.2R) the paths of the tracer RBCs tend to exhibit lower radial displacements. Furthermore, our results also provide evidence that RBCs Dyy tends to decrease with the diameter. This phenomenon is believed to be due to Hct reduction with the diameter (Faharaeus effect) and also to geometry constrictions which limit the amplitude of the RBCs radial displacements. Hence, this finding seems to indicate that the reduction of RBC radial dispersion may be linked to the decrease in apparent viscosity with decreasing diameter (Faharaeus-Lindqvist effect).
The work reported in this thesis represents the first application of a confocal micro-PIV/PTV system to study the blood flow behavior through microchannels. The confocal system proves to be able to eliminate the problems and concerns of the experimental techniques used in the past and provide additional detailed description on the RBC motion not obtainable by other conventional methods. Finally, the research carried out throughout this thesis provides the basis not only to obtain further insights on the blood mass transport mechanisms under both physiological and pathological conditions but also to improve the existing theories, models, and computer simulations on the blood flow at both micro and macroscale levels.<br>The Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT); The Science and Technology Foundation (FCT)