Abstract: Tick-borne diseases are a constraint to livestock production in many developing countries. They are responsible for high morbidity and mortality resulting in decreased production of meat, milk and other livestock by-products. The most important tick-borne diseases of livestock in sub-Saharan Africa are East coast fever (caused by Theileria parva), babesiosis (caused by Babesia bigemina and Ba. bovis), anaplasmosis (caused by Anaplasma marginale) and heartwater (caused by Ehrlichia ruminantium). Despite their economic importance, information on the epidemiology of these diseases in many countries is often lacking or inadequate, resulting in inappropriate disease control strategies being implemented. The availability of specific, sensitive and cost-effective diagnostic methods is important in the design and implementation of effective disease control strategies. In this study PCR assays based on the 18S and 16S rRNA gene sequences, that could identify Theileria / Babesia and Anaplasma / Ehrlichia pathogens of cattle respectively, were developed. In addition, PCR assays based on the β-tubulin gene that could detect T. parva, Ba. bigemina, Ba. bovis and T. taurotragi, and PCR assays based on the cytochrome b gene that could diagnose infection by Ba. bigemina and Ba. bovis were also developed. When the 18S and 16S rRNA gene PCR assays were combined into a multiplex PCR assay, Ba. bigemina and E. ruminantium DNA did not amplify and some non-specific bands were observed following agarose gel electrophoresis. The β-tubulin gene multiplex PCR assay for the diagnosis of T. parva, Ba. bovis and Ba. bigemina worked relatively well when used on laboratory-derived parasite DNA preparations. However, when it was used on field samples collected on FTA cards, multiple non-specific bands were observed after agarose gel electrophoresis of the PCR products. The 18S and 16S rRNA gene PCR assays were used for an epidemiological study of tick-borne diseases of cattle in Central and Eastern Zambia in the wet and dry seasons. All the disease pathogens under study (T. parva, T. mutans, T. taurotragi, Ba. bovis, Ba. bigemina, Anaplasma spp and E. ruminantium) were prevalent in all the regions of the country in both seasons. However, variation was observed in the prevalence of these pathogens between the regions and the seasons. A number of risk factors, associated with the occurrence of tick-borne pathogens in cattle and the tick burdens observed on cattle in the wet season were determined. A negative association was observed between the number of co-infecting pathogens and the erythrocyte packed cell volume (PCV) of carrier cattle. Using recently available genome sequences, mini- and microsatellite markers were developed for population genetic analysis of Ba. bovis and Ba. bigemina parasite populations. Ba. bovis isolates from Zambia and Turkey and Ba. bigemina isolates from Zambia were used in the population genetic analysis. High levels of genetic diversity were observed for both parasites. Population genetic analysis of the Zambian and Turkish Ba. bovis populations, using eight genetic markers showed that the two populations were sub-structured. The Zambian population comprised a single randomly mating population, while the Turkish population comprised two genetically distinct subpopulations. Population genetic analysis of the Ba. bigemina parasites from Zambia showed that this parasite population was in linkage disequilibrium. Further, analysis of the Ba. bigemina population using STRUCTURE showed that it was genetically sub-structured into five distinct subgroups. However, the resulting sample size of each subgroup was too small to definitely determine whether they were panmictic. These results provide an improved understanding of the epidemiology of bovine Babesia parasites in Turkey and Zambia.

The present study was conducted to investigate the phannacokinetics (PK) and phannacodynamics (PD) of some nonsteroidal antiinflammatory drugs (NSAIDs), including phenylbutazone (PBZ, in sheep, goats and donkeys), flunixin meglumine (FM, in sheep and donkeys), carprofen and its enantiomers (CPF, in sheep), paracetamol (PRT, in goats and camels) and NG-nitro-L-arginine methyl ester (L-NAME, in sheep).

Acquired urinary incontinence in the canine is a distressing and debilitating condition affecting up to 20% of neutered bitches, whilst less than 1% of entire bitches and males suffer from this condition. Although a number of medical and surgical therapies exist for treatment of acquired urinary incontinence, none are able to cure the condition and many animals become refractory to treatment over time. It has long been thought that a decrease in resting tone within the urethra of a bitch following neutering is responsible for the development of acquired urinary incontinence; however, recent studies show that low urethral tone does not always lead to urinary incontinence, suggesting further factors must be involved. Although the exact aetiology and pathophysiology of the condition in the neutered bitch is unknown, it is thought to have many similarities to that of post menopausal urinary incontinence in women. In this condition, urinary incontinence is known to be mediated primarily by changes in the structure and function of the urinary bladder post menopause. The present study looks at the structure and function of the canine urinary bladder in vitro to determine if changes occur post neutering that could lead a bitch to develop acquired urinary incontinence and which may provide novel therapeutic targets for treatment of this disease. Contractility in response to carbachol (muscarinic) and electrical field stimulation was assessed in isolated strips of detrusor muscle from male and female, intact and gonadectomised canines. The potential role of non-adrenergic, non-cholinergic mediated contraction of the detrusor muscle was also examined and this system does not appear to be significantly altered by gonadectomy. Maximal contractile responses were, however, decreased in detrusor strips from neutered compared to entire canines regardless of gender, with detrusor strips from incontinent bitches having some of the weakest responses. Sensitivity to carbachol was also decreased in detrusor strips from neutered compared to entire canines. This suggests a decrease in contractile function of the urinary bladder in neutered canines and is similar to that seen in the bladders of women suffering from urinary incontinence post-menopause due to impaired contractility of the bladder and idiopathic detrusor instability. This suggests that changes in the function of the bladder post neutering may be partly responsible for the development of acquired urinary incontinence in the bitch. Post-menopausal urinary incontinence in women is hypothesised to be a linked to an increase in the collagen to smooth muscle ratio within the wall of the urinary bladder which is thought to impair bladder contractility and lead to the development of detrusor instability. Morphometric analysis of the urinary bladder wall of canines showed that the percentage of collagen within this organ was significantly increased in neutered compared to entire bitches, with incontinent bitches having some of the highest percentage collagen. The percentage of collagen was unchanged in neutered compared to entire males which were similar to entire bitches. These results support the long postulated theory that a decrease in oestrogen following gonadectomy / menopause is involved in the increase of collagen within the bladder. Results describing the pharmacological characterisation of muscarinic receptors (Schild analysis of pKB values) in strips of canine detrusor muscle suggest that the M3 receptor is the primary receptor responsible for bladder contraction in entire canines in vitro but that the M2 receptor predominates in neutered canines. This previously unreported finding could be significant in providing a novel therapeutic target to treat this debilitating disease. Studies that looked at mRNA expression for the muscarinic as well as the LH and GnRH receptors in canine bladder wall showed that there was an increase in expression of all receptors in tissue from neutered compared to entire canines and that tissue from females had higher expression levels than that from their male counterparts. It is known that gonadotrophin levels in the blood increase post neutering, and that decreasing these levels can provide continence in a number of animals. It is therefore possible, that an up-regulation of mRNA expression for these receptors is involved in the changes at the level of the detrusor that could lead to development of acquired urinary incontinence. It is also acknowledged that the muscarinic pathway is the primary pathway responsible for bladder contraction and emptying, therefore, a change in the expression of muscarinic receptors has the potential to alter bladder contractility as demonstrated previously. In conclusion these studies have shown that the structure and function of the urinary bladder of a neutered canine is altered compared to that of an entire canine, and that these changes have the potential to be involved in the development of acquired urinary incontinence in the bitch. Many of these changes mimic those seen in the bladders of post menopausal women suffering from urinary incontinence, thus suggesting that there may be commonality of disease process between the two species which may allow the use of the canine as a model of human urinary incontinence. This data, the first to include male animals in the study of bladder function and structure, suggest that the loss of oestrogen in the female and the concurrent increase in percentage collagen within the urinary bladder are not significant factors in the development of decreased detrusor contractility per se. On the contrary these results suggest that the muscarinic receptor effector pathway may play a crucial role in the development of altered bladder contractility and acquired urinary incontinence, and may provide a therapeutic target for effective treatment of this disease.

Research was undertaken to investigate whether data maintained within a veterinary hospital database could be exploited such that important medical information could be realised. At the University of Glasgow Veterinary School (GUVS), a computerised hospital database system, which had maintained biochemistry and pathology data for a number of years, was upgraded and expanded to enable recording of signalment, historical and clinical data for referral cases. Following familiarisation with the computerised database, clinical diagnosis and biochemistry data pertaining to 740 equine cases were extracted. Graphical presentation of the results obtained for each of 18 biochemistry parameters investigated indicated that the distributions of the data were variable. This had important implications with respect to the statistical techniques which were subsequently applied, and also to the appropriateness of the reference range method currently used for interpretation of clinical biochemistry data. A percentile analysis was performed for each of the biochemistry parameters; data were grouped into ten appropriate percentile band intervals; and the corresponding diagnoses tabulated and ranked according to frequency. Adoption of a Bayesian method enabled determination of how many times more likely a diagnosis was than before the biochemistry parameter concentration had been ascertained. The likelihood ratio was termed the "Biochemical Factor". Consequently, a measurement on a parameter, such as urea, could be classified on the percentile scale, and a diagnosis, such as hepatopathy, judged to be less or many times more likely, based on the numerical evaluation of the Biochemical Factor. One issue associated with the interrogation of the equine cases was that the diagnoses were clinical in origin, and, because they may have been made with the assistance of biochemistry data, this may have yielded biased results. Although this was considered unlikely to have affected the findings to a large extent, a database containing biochemistry and post mortem diagnosis data for cattle was also assessed.

The work contained in this thesis explores the development of the tibiotarsus shaft and the quality of cortical bone in the modern broiler, in relation to genetic background, growth rate and dietary mineral content. This was achieved through a series of experiments predominantly using a modern selected strain of broiler and an older, unselected control strain, and occasionally utilising current commercial stock. Birds were exposed to a variety of dietary mineral contents, and feeding regimes, and assessments were made of a number of aspects of bone quality, bone turnover, and mineral homeostasis at selected ages .A number of phases in tibiotarsus development were identified from the embryo through to slaughter age at approximately six weeks; these were seen in all strains of broiler chicken investigated. Resorption and replacement of the embryonic cartilage model of the tibiotarsus was found to begin before day 16 of incubation, and a reduction in cortical thickness was observed between this age and hatch as the marrow cavity was enlarged. During this period, the cortex was observed to develop from a maze like scaffold, to display recognisable Haversian canals with the new bone being rapidly mineralised; by day 6, the cortex displayed a distinctive pattern of Haversian canals which remained consistent throughout much of the bird's life-span. From hatch, cortical width began a rapid increase in thickness, which was seen to halt at approximately 18 days of age, cortical thickness remaining approximately constant from this age. The rapid increase in cortical mineral content was also seen to plateau at approximately 11 days.

Haemonchus contortus, a parasitic nematode of sheep, is unsurpassed in its ability to develop resistance to the anthelmintic drugs used as the mainstay of its control. A reduction in drug efficacy leads to prophylactic and therapeutic failure, resulting in loss of productivity and poor animal welfare. This situation has reached crisis point in the sheep industry, with farms forced to close their sheep enterprises due to an inability to control resistant nematodes. The mechanisms of anthelmintic resistance are poorly understood for many commonly used drugs. Altered or increased drug metabolism is a possible mechanism, yet has received little attention despite the clear role of xenobiotic metabolism in pesticide resistance in insects. The cytochrome P450s (CYPs) are a large family of drug-metabolising enzymes present in all species. Their expression is induced on exposure to their substrate and over-expression of a single CYP has been shown to confer multi-drug resistance in insects. The H. contortus genome is currently being sequenced and assembled at the Wellcome Trust Sanger Institute, Cambridge. Despite the lack of a completed genome, the public provision of read, contig and supercontig databases has facilitated the identification of 73 partial gene sequences representing a large family of H. contortus CYPs. Their constitutive expression is highest in larval stages although adult expression was also detected. The majority of CYPs are most highly expressed in the worm intestine, which is thought to be the main organ of detoxification in nematodes and is consistent with a role in xenobiotic metabolism. A small number of CYPs were more highly expressed in anthelmintic resistant isolates than in an anthelmintic-susceptible isolate and may represent candidate genes for further research. The identification of putative H. contortus orthologues of the Caenorhabditis elegans nuclear hormone receptors controlling CYP transcription and the cytochrome P450 reductase gene catalysing electron transfer to CYPs suggests that regulatory and functional pathways may be conserved between the species. Transcriptome analysis using next generation sequencing was undertaken to guide a pilot annotation of 590 Kb genomic sequence. A high degree of conservation was observed between the conceptual translations of H. contortus and C. elegans genes, although at a genomic level, H. contortus consistently had a larger number and size of introns, which may reflect a larger genome than previously predicted. Gene order was not conserved, although regions of microsynteny were present and a bias for intra-chromosomal rearrangements resulted in putative orthologues frequently residing on the corresponding chromosome in both species. Partial conservation of a number of C. elegans operons in H. contortus was identified. These findings have important implications for the H. contortus genome project and the transcriptome databases provide a valuable resource for future global comparisons of gene expression.

Thoroughbred horse jump racing is popular in Great Britain (GB). Unfortunately it is associated with inherent risk of injury to the horses involved and it has been shown that the risk is significantly higher in jump than in flat racing. As a result, jump racing has been made a priority in racehorse injury investigation by the racing authorities in GB and is the focus of this thesis. Data about injuries and fatalities collected by veterinary surgeons, from all official race meetings between 2000 and 2009 was made available by the British Horseracing Authority (BHA). Following initial examination of the data, review of the literature and discussion with the BHA, a list of outcomes (injuries and fatality) was defined for further investigation. Multivariable logistic regression modelling was employed to investigate associations between potential risk factors and the outcomes. Model validation techniques were then used for outcomes with the greatest frequencies. In addition, post-mortem (PM) findings from a subset of the available data provided the opportunity to evaluate the accuracy of the information provided. Outcomes selected for further investigation were: fatality, tendon strain, epistaxis, hind limb fracture, pelvic fracture, and proximal forelimb fracture. Multiple risk factors were identified as being significantly associated with each outcome which can be used to guide legislation or further investigation. Risk factors common to many of the outcomes were: season, surface firmness (going), race distance and previous racing history (especially previous flat start history). Notably in some instances the relationships between these common risk factors and the outcomes varied, such that a risk factor might be associated with increased likelihood of one outcome but a decreased likelihood of another. Attempts to validate the models with the most frequent outcomes (fatality, superficial digital flexor tendinopathy and epistaxis) against a novel data set (from the year 2010), demonstrated variable calibration and discrimination and relatively poor predictive ability for all of the models. This was thought to be related to the low outcome frequencies and potentially related to risk factors unaccounted for in the models. Evaluation of the accuracy of the recording system for fatal distal limb fractures using PM findings demonstrated good identification of fracture presence, but relatively poor definition of all affected bones. Frustratingly it was concluded that making policy decisions based on the risk factor models will not be straightforward. Few risk factors had strong associations with all outcomes, not all risk factors are readily modifiable and many potential modifications (such as stopping horses from racing) would have major long term deleterious implications for horses. However, new risk factors for injury were identified providing some additional information about injury aetiology; previously recognised associations (such as firm ground and injury) are supported by the work; and sensible recommendations can be made to the industry, such as: closer monitoring of horses based on their previous racing careers or previous injuries. In addition, further training of racecourse veterinarians and/or provision of diagnostic aids (such as radiography) can be recommended to help with diagnoses made at the racecourses.

The principal aims of the work presented in this thesis were to further investigate the pathophysiology of the acute phase proteins in bovine mastitis and to document the changes in the protein composition of milk during mastitis using modem proteomic methods. Mastitis is one of the most important diseases affecting cattle worldwide. It has adverse effects on the economics of milk production through reducing the quality and quantity of milk. Acute phase proteins (APPs) are valuable markers of inflammatory lesions and are widely used in the veterinary field for disease diagnosis. This study further investigated the presence of APPs, haptoglobin (Hp) 1 I and mammary- associated serum amyloid A3 (M-SAA3) in the milk of cows with mastitis and evaluated the possibility of using these proteins to detect mastitis. An Enzyme linked immunosorbent assay (ELISA) was developed and validated for the measurement of milk Hp. A commercially available ELISA was used for the detection ofM-SAA3 in milk. Both Hp and M-SAA3 showed similar kinetics to somatic cell counts and can be considered as sensitive and reliable markers of mastitis. Advanced proteomic methods were developed and used to further characterise the changes taking place in the proteins expressed in normal and mastitic milk. The methodology for analysis of the bovine milk proteome was successfully established. This part of the work concluded that the patterns of protein expression of clinically mastitic milk showed clear differences from that of normal milk. Further analysis of milk samples from a mild subclinical model of Staphylococcus aureus mastitis showed that alterations to the milk p:oteome were only minimal. However this study was useful in identifying areas worthy of future research. Recent publications on APP research speculate upon the local production ofM-SAA3 in the bovine mammary gland. The final objective of this study was therefore to investigate the expression of MSAA3 in bovine mammary tissue. Our studies confirm the local production of M-SAA3 in the bovine mammary gland and its up-regulation during bovine mastitis. This finding may provide further information on a possible role for this protein. Overall the findings detailed in this thesis indicate that APPs in milk are valuable markers of mastitis and additionally that the ease of collection of milk by non-invasive methods suggest that milk has potential for the discovery of disease biomarkers.

This thesis examines some aspects of milk yield manipulation utilizing some factors that can effect the function of the mammary gland. In the first part of study, the effect of photoperiod on lactation performance in the goats was studied, and particularly to investigate if this response can be potentiated by prior exposure to short periods of short days elicited by melatonin treatment. Long light did not produce clear stimulatory effect on milk yield, but a small response was seen in autumn and only in goats that were not treated by melatonin. Repeated short cycles of melatonin did not sensitize lactating goats to subsequent long light effect to milk yield regardless of stage of lactation or commencement time of year. Indeed, this treatment might produce a detrimental effect on milk yield when applied in early lactation. The second part of the study was to determine the maximum metabolic capacity of cows from different genetic merit. We adopted a multiple galactopoietic stimuli, increasing milking frequency, bovine somatotropin and thyroxine, applied in additive stepwise fashion at peak yield to cows from high and low genetic merit. This approach was successfully drove the cows into what we believe their maximum metabolic capacity. Milk yield was increased in an additive fashion at each stimulus. The increase in milk yield capacity was associated with mammary growth which was detected during the maximum stimuli. There was no significant difference in the response to the galactopoietic stimuli between cows from different genetic merit which did not suggest that high genetic merit cows are milking closer to their maximum capacity and, therefore, at greater risk of collapse of metabolic control than low genetic merit cows.

A longitudinal epidemiological study of trypanosome infections in domestic livestock was carried out over thirteen months in Busia District, an endemic area of Rhodesian sleeping sickness. It was demonstrated that chemoprophylaxis of domestic livestock with Samorin ® (Rhône Poulenc, France) could virtually eliminate the reservoir of potentially human infective T. brucei spp. infections in domestic animals. In addition to being a potentially useful control measure during outbreaks of sleeping sickness, chemoprophylaxis showed a net economic benefit in the productivity of local cattle. The duration of chemoprophylaxis of domestic livestock with Ethidium ® (Laprovet, France) was much less, as was the economic benefit to livestock production, however the level of challenge was much less in this trial. From the relative preference of tsetse flies for each species of domestic animal and the prevalence and incidence of trypanosome infections, it was concluded that cattle and to a lesser extent pigs were the most important species of domestic livestock in the animal reservoir of Rhodesian sleeping sickness in Busia District. Of the risk factors investigated for cattle acquiring trypanosome infections, the most important was an existing trypanosome infection. The effect on the epidemiology of sleeping sickness of a greater than expected interaction between species of trypanosome infecting cattle offers a possible mechanism for the natural control of the animal reservoir of Rhodesian sleeping sickness. Various parasitological diagnostic techniques for the detection of trypanosome infections in cattle in the field were assessed. Maximum sensitivity of diagnosis and minimum bias in the relative importance of each species of trypanosome was achieved by selecting a suitable combination of diagnostic techniques.