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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

The distribution and breeding performance of the buzzard Buteo buteo in relation to habitat : an application using remote sensing and Geographical Information Systems

Austin, Graham E. January 1992 (has links)
The British uplands support a rich assemblage of a number of predatory and scavenging birds, including golden eagle, merlin, red kite, hen harrier, raven and buzzard, with nationally and internationally important populations of some of these species. A feature all these species have in common is the requirement for large foraging ranges by individuals which means that large tracts of suitable habitat are necessary to support viable populations. Current changes in upland land use such as afforestation and changing agricultural practices give cause for concern. The conservation of these species and others like them requires a greater understanding of how these birds interact with the landscape and how their distribution and breeding performance reflects their habitat. Ecologists are becoming increasingly aware of the potential of Geographical Information Systems (GIS) for exploring these relationships between animal species and their habitat. In this thesis, the buzzard was chosen as a model species to explore ways of predicting bird distributions and breeding performance from readily available data using GIS. This study was carried out in mid-Argyll, Scotland. The distribution and breeding performance of buzzards was determined for a number of study areas, chosen to represent the full spectrum of habitats to be encountered in mid-Argyll, during 1989 and 1990. Parameters of breeding performance used were laying date, clutch size, initial brood size and fledging success. Brood quality was also assessed, based on nestling growth. The breeding performance of buzzards in mid-Argyll was included in a comparison of published data from studies elsewhere in Britain. Laying dates were found to be consistent throughout the country while clutch size, initial brood size and fledging success were seen to differ between studies. No patterns which might relate to latitudinal or climatic trends were apparent and differences were considered to be due to overall habitat differences between the regions considered. While buzzards in mid-Argyll tended to produce low clutch sizes the population as a whole showed high fledging success. While buzzards nestlings in mid-Argyll had good survival rates the high fledging success is probably best explained by absence of human interference, malicious or otherwise in this area. An important consideration when looking at the distribution of a bird size such as the buzzard is whether this might be influenced by nest site availability. Buzzards in mid-Argyll used a number of distinct nest site habitats. While the majority of buzzards nested in trees, a substantial proportion were found nesting on steep banks and crags. Considering the adaptability of buzzards in their choice of nest site and the abundance of acceptable sites it was considered that the availability of potential nest sites was unlikely to influence buzzard distribution in mid-Argyll.
12

Resting behaviour of dairy cows : applications to farm assurance and welfare

Chaplin, Sarah Jane January 2000 (has links)
Lying is a restful, high priority behaviour for dairy cows which can be affected by various factors associated with production but is not directly related to productivity. As such, lying behaviour has potential for use as an indicator of welfare. Information in the literature regarding the effect of stage of lactation on lying behaviour was contradictory and information on optimum lying behaviour and maximum bout lengths was scarce. The aim of this study was to improve knowledge in these areas and find a way of using lying behaviour to assess welfare. Pregnant heifers were observed at pasture in order to describe lying behaviour in conditions that may be considered optimum. Lying behaviour at pasture was characterised as having 10.5 h total lying time per 24h, few (6-7) lying bouts and a long maximum bout length (3.5h). The effect of two very different levels of production on the lying behaviour of heifers during their first lactation and housing period was compared. Although total lying times did not change much over the lactation, early location was associated with disturbed lying behaviour (increased lying frequency and short bout lengths) and indicators of metabolic challenge in low input heifers. High input heifers however, showed more disturbance later in lactation associated with being moved to another feeding group. Two pilot studies were carried out to investigate cows' preferences for cubicles with mats or mattresses and to compare lying behaviour on the two surfaces. Social factors appeared to affect preference and lying behaviour. Consequently total lying times were very low (less than 8h) and preferences were not clear. However, lying times were low even in a group of undisturbed late lactation cows and the pattern of lying (number of bouts and maximum bout length) was similar to that of heifers at grass.
13

A cohort study of bovine tuberculosis in cattle in South West England

Ramírez Villaescusa, Ana January 2007 (has links)
Farm, cattle group and individual bovine risk factors for bovine tuberculosis (bTB) in cattle herds in the South West of England were explored. A cohort study using 148 well characterised cattle herds was conducted in SW England 2001-2004. The study was set up in areas affected by foot-and-mouth disease in 2001 and all farms were taking part in the Randomised Badger Culling Trial (RBCT). The use of a standard questionnaire and national data records from the skin intradermal cervical comparative tuberculin test (SICCT) and from the British Cattle Movement Service (BCMS) databases were combined. The two main statistical techniques used were survival analysis and multilevel logistic regression with random effects. Associations with the risk of herd breakdown with bTB were explored using survival analysis. The main factors associated with disclosure of reactor cattle were the purchase of cattle from markets and the storage of slurry and manure in close containment. In the investigation of the risk of an individual bovine animal becoming a reactor using multilevel logistic regression with random effects analysis, explanatory variables at herd, individual cattle and test levels, were explored. The potential exposure to reactor cattle in previous tests was the most significant finding as a risk for a bovine animal reacting at a current test. Only 9/19,027 cattle became reactors if they had not been exposed to a reactor animal previously. When the risk of an animal group having at least one reactor disclosed in the group was investigated using the location of the animal groups within the farm by monthly periods, the risk increased with the number of cattle in the groups when these were housed and with the presence of badgers in the fields when they were grazing. This thesis has provided a deep investigation into the risk factors that can affect the introduction and persistence of infection with M. bovis in cattle herds, and the importance that cattle play in these factors has been highlighted.
14

An epidemiological study of foot, limb and body lesions and lameness in pigs

Kilbride, Amy L. January 2008 (has links)
A cross sectional study of 103 indoor and outdoor British pig farms was carried out in 2003-2004. Over 12,000 pigs aged from 3 days up to multiparious breeding sows were examined. Prevalence of foot, limb and body lesions and lameness was recorded using clear case definitions. Detailed data were also collected on the pen or paddock that the pigs were housed in with particular reference to the floor design, material and condition. Associations between prevalence of disease and the environment the pig was housed in were analysed using multilevel regression models. Post-mortem examination of a small sample of foot and limb lesions was carried out to better understand the pathology. There was a lower prevalence of body and limb lesions in pigs of all ages, and foot lesions in preweaning piglets, housed outdoors compared with indoors. However, there was little difference in the prevalence of foot lesions and lameness in gilts and pregnant sows kept indoors compared with outdoors. In most pigs housed indoors, there was a trend for an increased risk of limb and body lesions and lameness in pigs housed on hard and slatted floors compared with solid concrete floors with bedding. Although, in contrast to this the prevalence of wounds on the limbs in piglets was lower on slatted floors compared with solid concrete floors. The associations between foot lesions and indoor floor type varied with the age of the pig and the type of lesion. In piglets, sole bruising was associated with housing on slatted floors while sole erosion was associated with housing on solid concrete floors without bedding. In gilts and sows, heel flaps were associated with housing on slatted floors while toe erosion was associated with solid floors with deep bedding. In conclusion, this study has provided the most accurate estimates of the prevalence of foot, limb, body lesions and lameness in the English pig herd to date and generated useful hypotheses regarding the aetiology of these lesions. To further understand this topic cohort and intervention studies are now needed.
15

The ethnographic study of the student experience of making meaning and identity through a new Veterinary curriculum

Mann, Claire January 2013 (has links)
In 2007 the first brand new Vet School built in over fifty years in the UK, opened at the University of Nottingham. Innovative evidence-based approaches were taken to each aspect of the new Vet School from the ICT infrastructure, staff recruitment through to curriculum design. This is a relatively rare scenario which offers a unique opportunity for research into this set of innovations and their cumulative effect on the student experience. Research into the student experience is timely and relevant. The world knowledge base is rapidly expanding, in part due to digitality, especially in relation to medical and professional learning. This, with the accompanying disappearance of the 'job for life', has led to increased emphasis within education to develop transferable skills and lifelong learning. As the Higher Education (HE) market becomes more competitive, the student role in the market develops towards consumerism. These factors give impetus for studies into new and developing student learning experiences. The author is an educationalist with no veterinary expertise. Due to this outsider perspective, an emergent ethnographic approach was taken to the research. Data sources are wide ranging from participation observation and field notes to recurring interviews with ten key informant students. Analysis was undertaken through thematising data and iterative ethnographic writing, simultaneously with literature review. Data is presented firstly in a series of descriptive vignettes which highlight key findings. Further to this, analysis is presented and underpinned by examples from primary and secondary data. Key issues are described from a majority rule position but also highlighting negative cases. This approach is useful to represent experiences of a community from a combination of participant perspectives. The research is undertaken in the socio-cultural paradigm where learning is not an individual pursuit but one undertaken in a social context. Wenger's (1999) 'Communities of practice' model describes learning as activity through participation in a community during which individuals construct meaning and identity. This model is most often reported in the literature in relation to informal work-based learning as it is argued that distance between context and classroom creates an artificial learning environment. This thesis takes a novel approach to apply the "Communities of Practice" model to a formal learning environment and considers Higher Education to operate at the 'legitimate periphery of participation' of workplace professionalism. By using Wenger's model as a broad framework, the research highlights the importance of both curriculum and relationships to the student learning experience. Evidence-based educational approaches such as integrated curriculum and early reflective learning were shown to be beneficial to student learning, although the student understanding of the benefits of these approaches on their learning developed longitudinally across the early part of the course. Students participate in learning through the important relationships which exist between peers, students and teachers, and those within the experienced veterinary community of practice. Data showed that talk in both formal and informal relationships is a method used by students in constructing conceptual meaning, and is one way that learners understand their construction of a professional identity during the early part of the course. Cognitive, social and experiential congruence between students and others is shown to have impact on the student learning experience. Specific case examples show that the student experience of a wide range of relationships covering each type of congruence has maximum benefit. Peer learning has significant benefits, and talk and discussion are key to developing both meaning and identity. Professional identity is constructed during both formal and informal, planned and emergent contexts. Significant others act as role models or anti-role models in the student learning journey. SVMS learners develop a professional learning identity related to the nature of knowledge and lifelong learning. A brief summary of the most recent British Veterinary Association (BVA) and Association of Veterinary Students (AVS) student satisfaction survey (2008) concludes that Nottingham has the highest levels of satisfaction and perceived readiness for practice amongst its students of any UK Vet School. This research shows the way that students in the new Vet School learn to both 'talk the walk' and 'walk the walk'.
16

Clinical decision making in veterinary practice

Everitt, Sally January 2011 (has links)
Aim The aim of this study is to develop an understanding of the factors which influence veterinary surgeons’ clinical decision making during routine consultations. Methods The research takes a qualitative approach using video-cued interviews, in which one of the veterinary surgeon’s own consultations is used as the basis of a semi-structured interview exploring decision making in real cases. The research focuses primarily on small animal consultations in first opinion practice, however small numbers of consultations from different types of practice are included to highlight contextual influences on decision making. Findings The study reveals differences between the way clinical decision making is taught and the way that it is carried out in practice. In comparison to human medicine, decision making in veterinary practice appears to be more a negotiated activity, relying on social context, which takes account of the animals’ and owners’ circumstances, as well as biomedical information. Conclusions Veterinary practice especially that provided for companion animals has similarities with medical practice, however there are also differences caused by the status of the animal; the contrast between predominately fee for service veterinary care and state funded medical provision; and the acceptability of euthanasia as a “treatment” option. Clinical decision making in veterinary practice is affected by a range of factors including the resources of the owner, the value placed on the individual animal and the circumstances in which the decision making takes place. Veterinary surgeons in practice need teaching and evidence based resources to take account of these factors in order to provide the best care to their animal patients. Further sociologically informed research is required to provide a greater understanding of the contextual factors which influence clinical decision making.
17

Application of BLUP in prediction of breeding values and estimation of SNP effects in dairy cattle

Ahmad, Sausan January 2011 (has links)
Genetic selection for higher milk production has unavoidably resulted in a decline in fertility of dairy cattle in the UK due to the antagonistic correlation existing between fertility and milk yield. This trend in fertility has necessitated broadening the breeding programme to include fertility traits. However, the heritability of fertility traits currently used in the UK are of low heritability (h2<0.05). Therefore, one approach is to use molecular markers in order to identify animals with the highest genetic merit for fertility. The first aim of this project was therefore to test single nucleotide polymorphisms (SNPs) in candidate genes for their possible associations with fertility PTAs. A group of 408 dairy cows and bulls were genotyped at different loci (GnRH receptor, FSH receptor, LH receptor, activin receptor, and neuropeptide Y receptor Y2 (NPYRY2)). Seven SNPs were identified in the GnRH receptor gene. These were in the promoter and coding regions at positions -331, -108, 206, 260, 341, 383 and 410 relative to the translation start site. Two groups of SNPs were found to be in linkage disequilibrium, the SNPs at positions 206 and 383 being inherited together, as were those at -108, 260, 341 and 410. An association study between these SNPs and fertility PTAs revealed that the -108 SNP group was associated with favourable effects on fertility, reducing PTA for DFS by about 0.4 day. However, when GnRHR gene function was evaluated by measuring circulating LH level after administration of GnRH in pre-pubertal animals, no significant associations of the SNPs with LH levels were detected. Furthermore, five SNPs were identified in the FSHR at residues 502, 669, 596, 658, and 685, four of which (at positions 502, 669, 658, and 685), had deleterious effects on fertility PTAs, increasing CI and DFS, while decreasing NR56. Inaccurate heat detection has been identified as a major contributor to low fertility in dairy cattle, and therefore the second aim of this project was to investigate oestrus expression traits for which BLUP breeding values were estimated. Electronic tags (Fullwood and Lily) were used to measure behavioural activities at oestrus in two separate groups of animals. The first group comprised 103 cows in their first parity. Oestrus behaviour traits were: the number of steps at oestrus (STEPS) and the percentage increase in the number of steps at oestrus (STEPS%) relative to the number of steps over the 10 days preceding oestrus (BASE). Cows in this group were genotyped at 10 genes (GnRHR, LHR, FSHR, oestrogen receptors α and β (ESR), activin receptor, leptin, ghrelin, neuropeptide Y (NPY) and NPYRY2 for SNP identification. Of these SNPs, only those located in the GnRHR, oestrogen receptor α and NPY were found to have statistically significant effects on oestrus traits. The second group consisted of 189 cows with 995 oestrus behaviour records. Oestrus traits were: the number of activity units (AU) at oestrus (ACTIVITY) and the percentage increase in the number of AU at oestrus (ACTIVITY%) over baseline activity (BASE) determined over a 4 day rolling average. In addition to the above mentioned 10 genes, these cows were genotyped at signal transducer and activator of transcription 1 and 5A (STAT1, STAT5A), growth hormone receptor (GHR), prolactin, and prolactin receptor genes. In this study SNPs in the GnRHR, LHR, FSHR, ESRα, GHR, activin receptor, STAT1, and STAT5 were found to have significant effects on oestrus expression. The genetic basis for oestrus behaviour was also investigated applying various animal models in this group. ACTIVITY, ACTIVITY% and BASE had moderate heritabilities of 0.19 to 0.24, 0.16, and 0.25 respectively. The breeding values of the cows were shown to be normally distributed, and ranged between -19 to 27, -18 to 20, and -20 to 28 for ACTIVITY, ACTIVITY%, and BASE respectively. These values are significant in terms of the ability of the stockman to reliably detect cows in heat. There have in the past been few genetic analyses of oestrus behaviour characteristics, and there are few studies of SNP associations with fertility traits of the kind described here. Therefore these studies make a significant contribution to our understanding of the genetics of fertility in dairy cattle, and can be used by breeders as a means to improving fertility in the national dairy herd.
18

Diagnosis and mechanisms of bovine ovarian cysts

Wills, Jennifer Rose January 2012 (has links)
Ovarian cysts are a cause of reproductive failure and economic loss in postpartum dairy cows. Using a unique combination of research to approach this problem, this thesis aimed to better understand mechanisms of ovarian cyst formation. The use of progesterone as a tool in cyst diagnosis was initially examined. Results demonstrated that 13/30 (43%) cows had progesterone profiles that disagreed with veterinarian diagnosis. Furthermore treatment in 21/30 (70%) cows was ineffective within 4 weeks of administration, and no pregnancy was established earlier than 8 weeks post treatment in all cows. When veterinarian and hormonal diagnosis agreed pregnancy was achieved, on average, two weeks earlier than when they disagreed. Effects of cow management, specifically the NEB experienced during late gestation and early lactation were investigated to determine whether these increased requirements resulted in the development of ovarian cysts. Results demonstrated that from early lactation all 85 cows were in a state of NEB. Ovarian cysts were confirmed in 31/79 cows, and these cows had significantly higher or lower peripheral concentrations of some metabolites, vs. no-cyst cows. Long term down-regulation with a GnRH agonist, followed by a period of observation to monitor the recovery of reproductive function, was conducted for evaluation as a potential model for ovarian cyst formation. Results indicated that 6/12 cows exhibited an LH surge within 104 hours of luteal regression while 6 animals did not (P<0.001). FSH concentrations in 6/12 cows showed divergence comparable with LH surges. 8/12 had at least 1 follicle >8mm and 5/12 had at least 1 follicle >20 mm. Follicle appearance was heterogeneous, with 63% of follicles showing some degree of luteinisation. Positive immunostaining for steroidogenic enzymes was detected in 12.5% of follicles. In conclusion, these results have important clinical significance in improving the diagnosis and management of ovarian cysts in dairy cows.
19

Novel approaches to expression and detection of oestrus in dairy cows

Homer, Elizabeth January 2013 (has links)
Detection of oestrus is a key determinant of profitability of dairy herds, but is increasingly difficult to observe in the modern dairy cow, with shorter duration and less intense oestrus. Current trends in the dairy industry also exacerbate the problem of poor oestrous detection as herd sizes are increasing, yet there is less labour on the farm. As a consequence fewer cows are seen standing to be mounted, the definite sign that a cow is in oestrus. Concurrent with the unfavourable correlation between milk yield and fertility, oestrous detection rates have declined to less than 50%. Although visual detection of oestrus is accurate, it can be time consuming and inefficient. In response to these constraints and poor oestrous detection rates automated methods of detection are currently employed although they are lacking in accuracy and efficiency. The current work investigated possible risk factors among the herd for decreased oestrous expression, measured by activity monitors (Lely-HR Tags), with emphasis on individual cow factors affecting the activity increase at oestrus (n=205 cows). A novel approach was also tested, Ultra-wide band (UWB) technology (Thales Research Technology, UK) for proof of concept that oestrus, mounting and standing to be mounted, could be detected in dairy cows (initial validation studies plus 2 week long trials, n=16 cows; 8 in each). Several parameters were investigated for their association with maximum activity increase at oestrus using generalised linear mixed models. Activity increases at oestrus between 2 and 4 fold. Various influential factors that affect the activity increase were reported in this study: parity, successive oestrous number post partum and milk yield are inversely related to the activity increase at oestrus and activity increases were affected by time of year for each oestrus event (P<0.05). In addition, larger activity increases at oestrus were not related to an increased probability of conception. The three dimensional position of 12 cows, with their oestrous cycles synchronized, and 4 pregnant control cows were monitored continuously, using UWB mobile units (MU) operating within a base unit (BU) network for a period of 7 days. Cow position was reported twice per second in real-time with this system. In the complete study 10 cows came into oestrus as confirmed by simultaneous visual observation & CCTV recording, activity monitoring (Lely-HR Tags) and by analysis of milk progesterone concentration. Raw data taken from the UWB system were then analysed post trial to determine whether oestrus could be detected; including elevations in cow height and cow interactions. Furthermore, automated software was developed and script analysis (MatLab R2012b, The MathWorks, Inc., US) was carried out to detect cows in oestrus, reporting the time of oestrus onset in real-time. UWB accurately confirmed oestrus in 9 out of 10 cows in oestrus as confirmed by real-time video recording and continuous visual observation of activity. Although due to the constraints of the script 1 cow could not be detected in oestrus by UWB as she was the only cow in oestrus at the time equipped with a MU. Further confirmation of oestrus was carried out by physiological measurements; increases in activity on the day of oestrus and low progesterone concentrations <1ng/ml. In addition, UWB accurately confirmed 6 out of 6 cows as not being in oestrus. In conclusion UWB accurately detected cows in oestrus. Furthermore, automated detection by UWB enables the identification of the onset of oestrus, mounting, and when cows are in oestrus and first stood to be mounted, in real-time. Therefore UWB is advantageous because knowledge of onset of oestrus allows for accurately timed artificial insemination (AI) coinciding with ovulation, in order to increase conception rates. In summary, variables that affect expression of oestrus have been identified by this work. This would allow for identification of cows prone to decreased oestrous expression. In addition UWB accurately detected oestrus when cows displayed mounting and standing to be mounted behaviour. This work has shown ‘proof of concept’ that with further development UWB could be used as a novel automated method of oestrous detection. Therefore the current work has provided knowledge on factors that influence oestrous expression and possible solutions to the permanent improvement of detection. The work also provides evidence of a novel technology that can be developed in order to increase oestrous detection rates.
20

Defining and teaching veterinary professionalism

Mossop, Liz January 2012 (has links)
Despite extensive research and discussion around the notion of medical professionalism, veterinary professionalism is an understudied area. The aim of this study was to define the concept of veterinary professionalism and analyse the hidden curriculum of a new veterinary school, in order to produce a new curriculum of professionalism. This study used a constructivist grounded theory method to develop the definition. An iterative approach, using interviews and focus groups, collected information from a range of stakeholders including veterinary surgeons, professional bodies, veterinary nurses and clients. Sampling was theoretical and concluded when theoretical saturation had been reached. An analysis of the hidden curriculum of a new veterinary school was also undertaken using a cultural web model to perform a thematic analysis of focus group narratives from staff and students. The outcomes from both studies were combined to develop a curriculum of veterinary professionalism. The normative definition of veterinary professionalism produced places the attribute of balance as the central component. Veterinary surgeons are constantly managing the requirements and expectations of their clients, the animals under their care, society and the veterinary practice that provides their employment. The ability to balance these demands and therefore demonstrate professionalism is helped by attributes which are: efficiency, technical competence, honesty, altruism, communication skills, personal values, autonomy, decision making, manners, empathy, confidence and acknowledgement of limitations. The components of the veterinary school’s hidden curriculum emerged within the framework of the cultural web and the development of professional identity was a consistent theme. The school’s central paradigm was found to be a community that is hard working and friendly. Routines and rituals were readily identified, as were both positive and negative role models. The curriculum of veterinary professionalism produced is an integrated, spiral curriculum involving strategies such as early clinical experience and critical event analysis to guide student reflections and shape their development as professionals. Four core professional skills of communication, ethical reasoning, reflective practice and learning skills are central to the curriculum. These are used to reinforce the values and behaviours included in the definition of professionalism. The definition of veterinary professionalism should also contribute to discussions around the position of the profession in society. The central behaviour of balancing responsibilities between clients, animals, the practice and society appears to be uniquely positioned, and may have application in other professionalism contexts. The presented curriculum is a good starting point for any veterinary school wishing to teach veterinary professionalism, alongside consideration of their hidden curriculum.

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