Agriculture and Food Science Theses

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This collection is made up of doctoral and master theses by research, which have been received in accordance with university regulations.

For more information, please visit the UCD Library Theses Information guide.


Recent Submissions

Now showing 1 - 5 of 52
  • Publication
    An assessment of commonage groups and the knowledge transfer needs of upland farmers
    (University College Dublin. School of Agriculture and Food Science, 2022) ;
    Commonages represent ~7% of Agricultural land in Ireland. As predominantly high nature value areas these are of particular interest for preservation and restoration works to encourage biodiversity. However as commonly managed areas this presents a management issue as all parties commonly farming these lands need to work collectively together to make a positive environmental impact. The SUAS project brings together groups of farmers together on these commonages to discuss and address the issues as per each individual commonage. Together proposals are made to address the issues and produce results. In the pursuit of this collective action there is a potential hurdle in achieving harmonised collaboration due to the personal and cultural differences in participants. This study draws on the experiences of SUAS in order to determine key factors and lessons which aid and enhance the collaboration process so that future collaborative projects of a similar nature in Ireland or further afield can share in these lessons. As discovered from the study, key aspects to delivering successful collaboration include: (1) Farmer involvement in all aspects of the project from the beginning. (2) The input of an external facilitator and project manager with distinctly separate roles. (3) Project Manager traits including open and effective communication skills, facilitation and conflict resolution skills, locally knowledgeable, local to the vicinity, an effective and fair leader. Additionally, the study investigated knowledge transfer needs for the scale up of similar projects in Ireland. Lessons include: (1) Farmers require more upland specific research in order to address both production and environmental issues. (2) New information derived from this research is likely to be best received through traditional information sources such as newspapers as opposed to more innovative digital methods. (3) Farmers wish to have the development of future upland agri-environment schemes carried out in a manner that broadly resembles a locally led bottom up approach to their design and implementation.
  • Publication
    Food Emulsions: their role in enhancing the stability and bioavailability of Vitamin D
    (University College Dublin. School of Agriculture and Food Science, 2021)
    This research investigated the formulation, stability and digestion of vitamin D loaded mixed micelles to develop a novel food delivery system for vitamin D. Mixed micelles were prepared with different fatty acids and phospholipid concentrations and their stability to salts was investigated. Mixed micelles formed at NaCl and KCl concentrations from 20–100mM with octanoic acid (C8) or stearic acid (C18). Mixed micelle size increased with increasing phospholipid concentration for C8 and C18, but micelles were inconsistently or not formed outside these concentrations. The hydrodynamic size of mixed micelles increased from 3.8nm for C10 to 4.4nm for C18. Vitamin D incorporation in micelles was not influenced by the fatty acid used. Understanding the stability and formation of mixed micelles and vitamin D loading is a crucial first step to improve vitamin D delivery in foods. Chapter 3 explored the stability of vitamin D loaded mixed micelles subjected to food processing and storage regimes. Shearing (speeds 8,000–20,500rpm) and high-pressure processing (600MPa, 120sec) resulted in no change in mixed micelle size (4.1–4.5nm), reflecting micelle stability to these processes. Mixed micelles improved the retention of vitamin D following exposure to UV-C light, near UV/visible light and heat treatments. Mixed micelles protected vitamin D from degradation over four weeks at 4 or -20°C. Overall, mixed micelles protected vitamin D from degradation in food processing and storage, and may be beneficial to fortify foods with vitamin D. Chapter 4 investigated the ability of mixed micelles to improve vitamin bioaccessibility in vitro compared to oil-in-water emulsions. Vitamin D loaded emulsions were formed with olive or coconut oil alone or with added phospholipid, and two mixed micelle systems. Throughout in vitro digestion, particle size, fatty acid release and vitamin D bioaccessibility were measured. After digestion, particles in the size range 6-10nm were present for the emulsions, but not for the mixed micelle systems. Vitamin bioaccessibility in olive or coconut emulsions was 75% and 78%, respectively, ~90% with added phospholipid and ~90% for the micelles. All systems tested had similar vitamin D concentration in the mixed micelle phase obtained after digestion. Differences in bioaccessibility were attributed to a higher concentration of vitamin D present in the total digesta for the olive and coconut oil emulsions. The in vitro study showed the potential of mixed micelles to deliver vitamin D and may be as effective as an oil-in-water emulsion at delivering vitamin D. Chapter 5 involved two human studies; Study A) a cross-over post prandial study examined changes in 25(OH)D following consumption of four vitamin D fortified drinks (non-lipid, olive oil, fish oil or mixed micelle based); Study B) a randomised, placebo-controlled trial investigated changes in 25(OH)D concentrations over four weeks following daily consumption of an olive or coconut oil based emulsion fortified with 20µg of vitamin D, a 20µg vitamin D supplement, or a placebo control dairy drink. In Study A, a vitamin D fortified olive oil emulsion increased serum 25(OH)D concentration in insufficient participants (baseline serum 25(OH)D <50nmol/L) but the micelle formulation did not improve vitamin D absorption in this group. There were no significant changes in serum 25(OH)D concentration in vitamin D sufficient participants (baseline serum 25(OH)D =50nmol/L) for any of the vitamin D fortified drinks tested. Study B found that an olive or coconut oil based vitamin D fortified emulsion was as effective at increasing 25(OH)D as a vitamin D supplement in vitamin D insufficient older adults. However, only a coconut oil vitamin D emulsion was as effective as a vitamin D supplement in vitamin D sufficient older adults. In both studies baseline 25(OH)D predicted responses to vitamin D and these responses differed in vitamin D sufficient and insufficient groups.
  • Publication
    Effects of autumn and spring pasture availability and cow production efficiency of intensive pasture-based dairy systems
    (University College Dublin. School of Agriculture and Food Science, 2022) ;
    Maximising both the utilisation of grazed pasture and cow production efficiency on-farm is highly beneficial in order to build a more sustainable and resilient dairy system. The objectives of this thesis were to identify pasture management strategies in autumn and spring to increase the proportion of utilised pasture while also evaluating various efficiency metrics and identifying animal characteristics associated with the efficient conversion of grazed pasture into high value milk output. Over 3 consecutive years, 144 Holstein-Friesian (HF) and Holstein-Friesian × Jersey crossbred (JFX) dairy cows were randomly assigned to 1 of 3 pasture availability (PA) treatments with a target average pasture cover (APC) of 800, 600 and 400 kg DM/ ha for high (HPA), medium (MPA), and low (LPA) on December 1. Grazing rotation length during the 11-wk measurement period in autumn was extended by +13 and +7 days for HPA and MPA, respectively, beyond that required by LPA (37 days) while all animals were housed at similar dates at the end of the grazing season. Besides achieving significant differences in APC and therefore pre-grazing herbage mass, PA had no significant impact on dry matter intake (DMI), milk production, or body condition score (BCS) in late lactation. During the first grazing rotation in spring, daily herbage allowance and total pasture utilised were greatest for HPA (11.7 kg DM/cow and 4,099 kg DM/ ha), intermediate for MPA (10.2 kg DM/cow and 3,319 kg DM/ ha) and lowest for LPA (8. kg DM/cow and 2,794 kg DM/ ha), with the deficit covered by additional grass silage supplementation so that total feed allowance did not differ between PA. There was no effect on daily or cumulative milk yield or milk composition in early lactation. Furthermore, an evaluation of a cost-effective efficiency parameter calculated as the annual fat and protein (milk solids; MS) production per unit of mid-lactation BW demonstrated that highly efficient grazing animals were characterised by a greater and more consistent daily MS yield, an increased DMI earlier in lactation and a greater intake per kg BW. Moreover, the most efficient animals also showed a greater MS yield both per kg of BW and per kg of DMI. An analysis evaluating the production efficiency of HF and JFX on commercial dairy farms identified Jersey crossbred animals to be more efficient in terms of MS yield per unit of mid-lactation BW and total energy requirement per kg of MS produced. However, large variation existed between farms (0.73 to 1.14 kg MS/ kg BW) and between animals within herds (0.42 to 1.47 kg MS/ kg BW). The results from this thesis corroborate the importance of achieving adequate pasture supply at the commencement of calving so that grazing days per ha and the utilisation of grazed pasture can be maximised, irrespective of between year weather and pasture growth variations. Equally important is the identification and breeding of elite animal genetics capable of harvesting additional quantities of fresh pasture as the cheapest feed source particularly in spring and efficiently converting it into a high value milk output.
  • Publication
    Investigating farmer’s attitudes, beliefs, and practices in relation to lime and nutrient management planning; Implications for advisory services
    (University College Dublin. School of Agriculture and Food Science, 2022)
    Applying lime to agricultural soils can provide a range of economic, production and environmental benefits for the farmer and the wider agriculture sector. ‘Ag Climatise’, the national climate and air roadmap for the agriculture sector in Ireland, published in 2020 highlights the need for Ireland to apply two million tonnes of lime per annum if we are to reach our environmental targets. Over the past number of decades Ireland has failed to continually surpass one million tonnes of lime applied annually. Therefore, despite the obvious benefits, Irish farmers are not applying the appropriate amounts of lime to their farms. This study applied mental models as the conceptual framework to analyse this problem. The insights and opinions of influential stakeholders including suppliers, researchers, policy makers and extension specialists on issues with lime application were collected and analysed. Their views were combined into a singular ‘expert’ mental model that would represent the perspective of the wider AKIS. The expert model was then compared and contrasted against that of actual farmers to determine whether they aligned and whether the ’experts’ were fully aware of the drivers and barriers affecting farmers every day practices. The analysis of the mental models revealed similar perspectives held by the experts and farmers around issues with extension services, lime marketing and farmer attitudes and motivation. However the experts focused more on areas such as soil testing and research whereas farmers had keen interest in the practical implications of lime application as well as the significance of farmer’s habits and values. The study points to the need to address the issues preventing greater adoption of lime by farmers with particular attention to issues identified from the farmer mental model, including those factors likely to have a significant influence on farmers’ attitudes, beliefs and practices. Recommendations to strengthen current advisory approaches include the development of localised strategies that will address the key needs and realities a specific region may be encountering. A localised participatory model could empower advisors together with local supplier and other vested stakeholders to provide targeted bespoke information to farmers in ways that would improve engagement and encourage increases in lime application.
  • Publication
    Best practices and competencies of agricultural advisors supporting Interactive Innovation
    (University College Dublin. School of Agriculture and Food Science, 2022) ;
    Irish and European agriculture face significant challenges in terms of sustainability and food and nutrition security, which has been further challenged due to crises such as the Covid-19 pandemic and the escalating war in Ukraine. Making our food supply more sustainable brings about new challenges for actors in the food value chain. Innovation plays a key role in assisting actors in local systems to respond effectively to rapid changing environments. The EIP-AGRI recognises the key role agricultural advisors have in facilitating change through interactive innovation and therefore this new role requires an evolving set of competencies. This study examines the best practices and competencies of agricultural advisors assisting in interactive innovation. This research was conducted through the analysis of nine interactive innovation case studies from across Europe, and a survey of 56 respondents from agricultural extension managers across Europe. To add an Irish perspective a comparative analysis was conducted with the use of the current competency profile of Agricultural Development Officers (ADO) within Teagasc. Additionally, responses within the European survey of Teagasc managers were individually analysed to understand their current perspectives on what is required for interactive innovation. This was reinforced with the use of two semi-structured interviews of senior agricultural extension managers within Teagasc. On analysis of the data from the case studies and survey, an inventory of best practices and competencies contributing to successful interactive innovation was established. The study found that an extension organisation has a positive influence on the enabling environment of interactive innovation. The output of this research is a ‘Success Profile for Interactive Innovation’ which identifies the best practices, competencies and enabling environment for interactive innovation . As this is a relatively new and under researched area, these results offer a key foundation for the requirements of agricultural advisors in fostering interactive innovation. Through a comparative analysis of the success profile and the current competency profile of Teagasc ADO, similarities and differences were documented. Findings of these were reinforced by the key informant interviews, which show that despite some recent actions undertaken by the organisation, the awareness of the need for interactive innovation has not fully permeated the organisation. This is evidenced by the outdated competency profile for hiring, evaluation and promotion activities within the organisation. Organisational influences may affect the advancement of interactive innovation by agricultural advisors, and without actively encouraging these best practices and competencies they will continue to be undervalued within the organisation.