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.

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.

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.

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.

There is considerable interest in the beneficial role of dietary polyunsaturated fatty acids (PUFA) on reproduction in ruminants. Detailed information regarding the mechanisms behind this beneficial effect is limited. The main objective of this thesis was to test the effects of dietary supplementation with omega-3 (n-3) or -6 (n-6) PUFA on gene expression, fatty acid (FA) composition and steroidogenesis in granulosa and theca cells and pre-implantation embryo development. A previous study in our laboratory reported increased follicular-fluid progesterone concentrations in ewes fed an n-3 compared to an n-6 PUFA-enriched diet, but detected no differential effect of n-3 and n-6 PUFA enriched high-density lipoproteins (HDL) on granulosa cell steroidogenesis in vitro. Also, n-6 PUFA enriched HDL reduced early embryo development, but in the absence of a net uptake of FA. In view of these observations it was hypothesised that (i) effects of n-3 PUFA on ovarian steroidogenesis are mediated by theca rather than granulosa cells and (ii) during embryo culture lipids are acquired solely from the albumin fraction of serum, so that albumin delivered n- 3 and n-6 PUFA would exert a greater differential effect on embryo development than either LDL or HDL delivered PUFA. Initial investigations into granulosa cell gene expression profiles using an ovine gonad-targeted cDNA macroarray were unsuccessful, highlighted by subsequent qRTPCR analysis. A thorough investigation confirmed that inconsistencies were due to poor array hybridisation. In vitro data confirmed that n-3 PUFA, via delivery by HDL, increase progesterone production solely in theca cells and that this is associated with an increase in STAR transcript expression. We also demonstrate that albumin is the only serum fraction that leads to a net uptake of FA during embryo culture. PUFA enriched serum and albumin accelerated the development of embryos and increased the yield of morphologically poorer quality blastocysts with increased transcript expression for the antioxidant enzyme SOD1. Important differential effects of n-3 and n-6 PUFA on ovarian steroidogenesis acting solely on theca cells are identified, but differentially effects of PUFA on embryo development are less apparent.

The aim was to assess the impact of milk somatic cell count (SCC) during the first lactation on the lifetime milk production of cows, and therefore estimate potential savings through heifer mastitis control. Cow level SCC over the first lactation was summarised as SCC between 5 and 30 days in milk (SCC1), and the geometric mean and variance of first lactation SCC. The impact of SCC1 on cumulative milk yield over different time periods was assessed for cows in Irish, English, and Welsh dairy herds. The impact of SCC1 and the geometric mean and variance of first lactation SCC on lifetime milk yield, and the association between SCC1 and disposal risk were assessed for cows in Irish dairy herds. Increase in SCC throughout the first lactation was associated with large reductions in the milk yield of cows, and increased disposal risk. Bayesian micro-simulation was used to demonstrate the impact in different herd scenarios. This was extended to synthesise evidence on potential savings using previous research, to estimate the economic impact of specific interventions to reduce the prevalence of cows with high SCC1. There was considerable variation between herds in the apparent impact of SCC1 on SCC throughout the first lactation, indicating the importance of a herd specific approach to control. ‘Cost effectiveness’ of interventions to reduce the prevalence of cows with high SCC1, was found to be highly dependent on the willingness of decision makers to pay for control measures. Increase in herd size was associated with increase in cow SCC, highlighting a need for improved management of mastitis when expansion is planned. An important component of this should be through monitoring and control of mastitis in heifers, especially those in spring-calving Irish dairy herds.

Milk recording consists in the regular, usually monthly, collection of a milk sample from all the lactating cows of a dairy herd. A large sample of milk recording data collected in England and Wales between 2004 and 2006 was used in this thesis. A sample of 8,211,988 recordings in 2,128 herds, representing 16 % of the dairy herds in activity in December 2006, were described and analysed. Calvings followed a seasonal pattern with 80 % more calving in September than in May. Milk production was highest in May (26.5 kg) and lowest in October (24.1 kg). Butterfat was stable, close to 4 % from October to March and reached a minimum at 3.7 % in June and July. Protein stayed between 3.2 and 3.3 % all the year. Geometric mean somatic cell count was between 177 and 180 between October and March and reached 205,000 cells/mL in July and August. At the individual cow level, the mean milk yield, percentage of butterfat, percentage of protein, fat to protein ratio and somatic cell count (geometric mean) were 26.4 kg, 3.96 %, 3.29 %, 1.21 and 90,000 cells/mL, between 5 and 305 days in milk. Changes in individual cow somatic cell counts around a threshold of 200,000 cells/mL between consecutive recording dates were used to predict bulk milk somatic cell count at both the herd-year and test-day levels. The main contributors to bulk milk somatic cell counts were cows staying above the threshold for 2 consecutive test-days. Milk yields and composition at the start of lactation were used to predict the calving to conception interval. Higher milk yield, lower percentage of protein, lower percentage of lactose, higher somatic cell count and higher percentage of butterfat were associated with lower probabilities of conception before 145 days in milk.

Oocyte cryopreservation represents one of the most recent developments in the field of reproductive technologies. However, despite of significant progress, the efficiency of oocyte cryopreservation is still very low. Cryopreservation of mature metaphase II (MIl) oocytes has been reported to induce disorganization of the meiotic spindle and chromosome damage. However, cryopreservation of immature oocyte at germinal vesicle (GV) stage may provide an alternative which avoids these problems. Slow freezing protocols have more recently been replaced by vitrification approaches. In this thesis, recovery, viability and subsequent developmental potential following in vitro fertilisation (IVF), parthenogenetic activation or somatic cell nuclear transfer (SCNT) of ovine oocytes vitrified at GV stage and matured in vitro were studied. Solid surface vitrification (SSV) and cryoloop technologies share the advantages of using a containerless system and small volumes of solution (less than t J.ll) which favours rapid cooling. Maturation, fertilisation, cleavage and blastocyst development were significantly decreased in SSV vitrified oocytes as compared to controls. Following cryoloop vitrification, frequencies of in vitro maturation (43.4 vs 63.2%), oocytes with normal spindle and chromosome configuration (50.0 vs 70.4%) and fertilisation (54.0 vs 74. t %) did not differ significantly between vitrified and control oocytes. Numbers of cleaved embryos that developed to the blastocyst stage following IVM/IVF/IVC did not differ significantly between vitrified and control groups (29.4 vs 45.1 %). In vitro matured ovine oocytes vitrified at GV stage using cryoloop were activated by two different protocols (I) a combination of calcium ionophore (A 23187), cycloheximide and cytochalasin 13 (CA+CHX/CI3), (2) strontium and CB (Sr/Cll). No blastocysts developed in vitrified oocytes activated by CA+CHX/CB; however, 3.8% were obtained following Sr/CI3 activation. Developmental competence of ovinc oocytes vitrified at GV stage and used as cytoplast recipients for SCNT was evaluated. Although the frequencies of cleaved embryos were significantly decreased in vitrified oocytes as compared to control, development to morula and blastocyst stage embryos was not significantly different. No significant differences were observed in total cell numbers, number of apoptotic nuclei as detected by Hoechst and TUNEL assay and proportions of diploid embryos in day 7 blastocysts produced following IVF or seNT of vitrified oocytes as compared to control. Pre-treatment of ovine GV-oocytes with cytochalasin 13 (7.5 J.lglml for 60 min) or demecolcine (0.1 flg/ml for 20 min) prior to vitrification improved frequencies of maturation, fertilisation and subsequent development following IVF or parthenogenetic activation. Caffeine treatment during IVM (10 mM for 6 h) increased the frequencies of blastocyst development in vitrified/thawed GV ovine oocytes. Taken together, these studies suggest that, ovine oocytes vitrified at GV stage can be matured, fertilised and develop in vitro to blastocyst stage embryos. Cryoloop vitrification resulted in higher maturation, fertilisation and subsequent development as compared to SSV. Strontium can be used effectively for parthenogenetic activation of vitrified/thawed ovine GV oocytes. Ovine oocytes vitrified at GV stage can be used effectively as cytoplast recipients for SCNT.

Salmonella enterica subspecies enterica (S. enterica) infection remains a global problem in a wide range of animals and in man. Poultry-derived food is a common source of human infection with the non-host-adapted Salmonella strains while fowl typhoid and pullorum disease are serious diseases in poultry. Development of novel immune-based control strategies against Salmonella infection necessitates a better understanding of the host-pathogen interactions at the cellular level. This study characterizes, in vitro and in vivo, the immune responses that develop following infection of avian species with typhoid and non-typhoid Salmonella serotypes. Salmonella serovars Typhimurium, Enteritidis, Hadar and Infantis showed a greater level of invasion and/or uptake characters to both chicken macrophages (HD11) and chicken kidney epithelial cells (CKC), when compared with S. Pullorum or S. Gallinarum. Nitrate and reactive oxygen species were greater in Salmonella-infected HD11 cells compared with the non-infected controls. HD11 cells revealed higher mRNA gene expression for CXCLi2 (IL-8), IL-6 and iNOS genes in response to S. Enteritidis infection when compared to S. Pullorum-infected cells. S. Typhimurium- and S. Hadar-infected HD11 showed higher gene expression for CXCLi2 versus S. Pullorum-infected cells. Higher mRNA gene expression levels of pro-inflammatory cytokine IL-6, chemokines CXCLi1 (K60) and CXCLi2 and iNOS genes were detected in S. Typhimurium- and S. Enteritidis-infected CKC followed by S. Hadar and S. Infantis while no significant changes were observed in S. Pullorum or S. Gallinarum-infected CKC. Epithelial cell response and production of pro-inflammatory cytokines and chemokines were greatly influenced by Salmonella virulence markers, including Salmonella pathogenicity island type-1 (SPI-1), SPI-2 and bacterial flagella. In chicken infections, S. Enteritidis and S. Infantis colonized the caeca more efficiently than S. Gallinarum and S. Pullorum. High numbers of B-lymphocytes and macrophages were observed in the caecal tonsils of infected birds. S. Enteritidis infection in newly hatched birds elicited the expression of CXCLi1 and CXCLi2 chemokines in the caecal tonsils, while S. Gallinarum up-regulated the expression of LITAF. In older chickens, S. Enteritidis infection resulted in a significantly higher expression of CXCLi2, iNOS, LITAF and IL-10 while S. Pullorum appeared to down-regulate CXCLi1 expression in the caecal tonsils. Data from spleens showed either no expression or down-regulation of the tested genes. In conclusion, data from the present study provide further insights on the interaction of Salmonella with poultry, and while both S. Typhimurium and S. Enteritidis are strong inflammatory serotypes, S. Pullorum and S. Gallinarum are not.

Chicken meat is an important source of high quality protein in the diet of most people in the world. Consequently, the increasing demand for this meat has made chicken meat production the most important growth sector among other meat species. This has been achieved by a half century of intensive genetic selection for growth traits; however, this was coupled with poor reproductive performance of broiler breeders. Ross 708 represents a broiler breeder strain that has been developed for breast-meat yield, and has been reported to exhibit poor reproductive performance in comparison to Ross 308, a typical broiler breeder strain. Accordingly, the current study investigated key points involved in the reproductive process that might influence variation in reproductive performance. Ovarian follicles number was the first point to investigate, as they are the main material of the egg. Liver fatty acid profiles were also investigated in order to identify lipid metabolism and the efficiency of dietary fat utilisation, as the liver is the main site that supplies different body tissues with fatty acids. Carcass fat content was also examined as its negative relationship with reproduction is well documented. Finally, the content of calcium in the tibia bone was examined to identify whether variation in egg production was associated with differences in the metabolism of this element. Accordingly, broiler breeder females from Ross 308 and 708 strains, reared under the standard production system on two different commercial farms of PD Hook, were collected throughout the reproductive cycle; starting at 25-week-old and in five weeks interval until 55-weeks of age. Findings showed no difference in the number of both the large yellow follicles (P=0.332), and the small yellow follicles (P=0.134); whereas the number of large white follicles was higher in the 708 ovaries (P=0.005). Differences in lipid metabolism were identified with a strong tendency for the 708s towards having lower content of linoleic acid (P=0.056) in addition to significantly lower a-linolenic acid (P=0.005). Of particular importance is the latter fatty acid as it is the precursor to (n-3) fatty acids, some of which were found to be less (P<0.001) in the 708s including docosapentaenoic (DPA) and docosahexaenoic (DHA). The importance of these fatty acids in follicular maturation is well documented in addition to the importance of the linoleic acid; these findings indicate that the 708s were not receiving adequate levels of the essential fatty acids which might have contributed to their poor reproductive performance. The 708s also laid down significantly more fat (P<0.001) in comparison to the 308s which could be another factor that has impaired their reproduction performance. This could indicate different levels of metabolic hormones which, in turn, have been found to act in concert with the reproductive hormones. 708s also exhibited a trend towards lower content of calcium in their tibiae, with an age by strain interaction and thus suggesting a difference in the metabolism of this element at some ages. The current study has addressed changes of the investigated parameters with age, but the effect of genetic selection on reproductive performance was difficult to address. Rather, some physiological differences have been identified; 708s were found to be receiving inadequate amounts of essential fatty acids, calcium content was found to be less at some ages and they exhibited a higher content of carcass fat. All these factors have the potential to contribute to poor reproductive performance, and once they are taken into consideration better assessment for the effect of the continued genetic selection for more growth traits can investigated.