Doctoral (PhD) Theses

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https://hdl.handle.net/10182/9

Theses submitted by Lincoln University doctoral students.

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Investigations of soil aluminium and legumes for pastoral farming in the Central Otago high country : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Bell, Lucy
Soil acidity and associated high concentrations of exchangeable aluminium (Al) present significant challenges to the success of legume species and farm sustainability in the high country of Central Otago, Aotearoa New Zealand. Such grasslands rely heavily on legumes for soil nitrogen (N) and quality livestock feed. However, traditional legume species are limited by the district's edaphic and climatic conditions. To address these challenges, this PhD investigated soil chemistry, Al solubility and legumes to support sustainable pastoral farming in the high country. Understanding the mechanisms controlling Al solubility, soil acidity, and buffering capacity is imperative in addressing the challenges of farming on acid soils. The chemistry of acidic grassland soil was investigated to assess Al fractions and associated properties. The low base saturation (< 10%) and very acidic soil pH (pHKCl 2.9–4.1) indicated that the soil had likely shifted beyond the Al-base cation exchange buffering system into hydroxy Al dissolution or organic Al dissolution pH buffering systems. Statistical modelling showed Al solubility in the A horizon soil was controlled by organically bound Al. This finding underscored the importance of the saturation of Al to carbon (C), in addition to soil pH, in predictive models of exchangeable Al. The equation: logAlKCl = 0.74 – 0.49pHKCl + 0.57log(AlCu/C) effectively predicted exchangeable Al in the A horizon of the investigated soil. Moreover, the low pH coefficient indicated that the A horizon was weakly buffered by the exchange of Al3+ and H+ on soil organic matter binding sites. Conversely, no unequivocal explanation of Al solubility was determined in the B and C horizons. Nevertheless, the linear relationship between exchangeable Al and pH indicated pH can be used to predict exchangeable Al in the B and C horizons by the equation: logA Thirteen forage legume species were assessed across three field experiments in Central Otago. Plant survival varied among species, with local climate emerging as the pivotal determinant of legume survival and yields. Lotus (Lotus pedunculatus Cav.) exhibited 100% survival over 18 months at a high altitude, acidic, cool climate site, whereas other perennial legume species showed limited persistence (0–55% survival). At two hotter, drier sites, crimson clover (Trifolium incarnatum L.) had the greatest Year 1 establishment and yields of assessed annual legume species. Moreover, strong Year 1 seed set and subsequent regeneration in Year 2 were observed for crimson clover, striated clover (Trifolium striatum L.), and subterranean clover (Trifolium subterraneum L.) (cv.s Denmark and Narrikup). The differences in survival among these legume species underscore the detrimental effect of climate on many legumes and highlight lotus and crimson clover as key species of interest for farms in high country environments. Following strong survival rates in Year 1 at the high altitude, acidic, cool climate experimental site, lotus and Russell lupin (Lupinus polyphyllus Lindl.) were selected for a glasshouse experiment to investigate potential mechanisms of Al tolerance associated with root growth in acid soil. Shoot and root biomass and root morphology were quantified in response to lime treatments in 0–9 cm and 9–18 cm horizons of 20 cm deep pots. The soil pH was 4.4, 4.9 and 5.4; the exchangeable Al concentrations were 24, 2.5 and 1.5 mg kg-1 for 0, 4.5, and 6.7 g lime L-1 treatments. No response to lime was shown in the mean total shoot and root biomass of lotus (13.2 g DM plant-1) nor Russell lupin (2.9 g DM plant-1). Furthermore, lotus plants did not differ in root length or surface area between the 0–9 and 9–18 cm horizons. However, within 0–9 and 9–18 cm horizons, Russell lupin showed increased root biomass, length, and surface area when lime was not added or was added at a low rate. Greater root biomass in lotus and Russell lupin was associated with a 50% reduction in soil exchangeable Al in the 0–9 cm horizon (16 mg kg-1), compared with the 9–18 cm horizon (32 mg kg-1) and the control soil (27 mg kg-1) in the 0 g lime L-1 treatment, suggesting that this reduction in exchangeable Al concentration is a key mechanism for Al tolerance in these legume species.
Open Access
The impact of InsurTech on the firm performance and financial sustainability of insurance companies and Takaful operators in Malaysia : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Shamsuddin, Jamaltul Nizam Bin
Over the last decade or more, there has been substantial growth in digital innovation, especially in financial technology (FinTech). A subdimension of FinTech, insurance technology (InsurTech), was built to create solutions for the insurance sector based on the technological approach. InsurTech start-ups adopt a user-friendly approach, build a close relationship with insurance customers, and offer a service where the client is protected in all respects. Malaysia’s digital economy grew at an exponential rate to RM66.22 billion in the first half of 2024, accounting for 22.6% of the country’s gross domestic product (GDP). According to a report from the World Economic Forum, Malaysia is at the forefront of adopting industry 4.0 technology, which includes robots. From insurers to advanced technology developers, leading multinational companies have relocated their Asia-Pacific “high-value, high-impact” central operating models to Kuala Lumpur, using Industry 4.0 technologies and the information and communications technology skill pool. This study examines the impact of InsurTech on firm performance and the financial sustainability of insurance companies and takaful operators in Malaysia. Data from 51 registered insurance companies in Malaysia, with the sample spanning from 2008–when the FinTech movement gained popularity following the 2008 global financial crisis–to 2021. The sample period covers major financial issues, economic downturns and the Covid-19 pandemic. This study uses six indicators to measure the firm performance and financial sustainability, i.e. InsurTech, liquidity, financial efficiency, financial stability, solvency, and macroeconomics. This study uses a two-step system GMM analysis to examine the effect of InsurTech on performance indicators (return on assets, return on sales, insurance performance measurement and operating self-sufficiency), insurance characteristics, government interventions and the impact of the Covid-19 pandemic in Malaysia. This study runs the random effect/fixed effect models as a comparison. The two-step system GMM results show that there is no relationship between financial stability and firm performance or between solvency and financial sustainability. In contrast, the results indicate that InsurTech, liquidity, and financial efficiency impact firm performance and the financial sustainability of Malaysia’s insurance companies and takaful operators. The empirical findings indicate that InsurTech companies and insurance characteristics adversely affect the insurance performance measurement and operating self-sufficiency of insurance companies and takaful operators in Malaysia, where takaful operators are more affected than insurance companies. InsurTech and tax incentives have no impact, but InsurTech and the Covid-19 pandemic negatively affect firm performance and the financial sustainability of insurance companies and takaful operators in Malaysia. Through investment in technology, the insurance industry gains a profitable return by having InsurTech in the value chain, reducing manual operations costs and co-integrating with other financial industry players. The financial measurements and their relationships in this study contribute to the insurance industry's growth in Malaysia, with the adoption of advanced technology in insurance services that can improve profitability. Specifically, the study investigates the interactions between financial aspects to provide stakeholders, policymakers, and the insurance industry with a comprehensive understanding of financial and investment decisions.
Embargo
Metabolisable protein supply and diurnal rumen nitrogen management and use in beef steers grazing fodder beet : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Prendergast, Sophie
The winter feeding period in New Zealand presents a significant challenge for beef farmers to provide adequate feed for stock to maintain live weight (LWT) gains. The recent development of the fodder beet (Beta vulgaris subsp vulgaris L.) grazing system has enabled high LWT gains over this period. Commercial beef finishing operations have repeatedly reported ~1kg LWT gain per day, with dietary CP of <13%, and high sucrose and water content. Experiments were developed to investigate rumen and plasma nitrogen use and movement in the fodder beet diet, to better understand the mechanisms enabling high daily LWT gains. Experiment 1 of Chapter 3 quantified the daily and diurnal (1, 3, 6 and 24-hour) dry matter (DM) and nitrogen intake of steers grazing industry standard fodder beet diets (90% fodder beet, 10% supplement), to match intakes with LWT gain of the steers, on a commercial farm. A single group of 69 steers (LWT 352kg) grazed fodder beet in situ for >120 days, with average LWT gain 1.0kg per day. Measured DM intakes and in sacco derived coefficients of rumen nitrogen disappearance were used to estimate metabolisable protein supply, compared with the estimated metabolisable protein demand, and then altered to reduce rumen nitrogen losses and increase bypass nitrogen, to provide new estimates of metabolisable protein supply. These data were used to model rumen nitrogen release across the diurnal period. The diurnal DMI was non-uniform, and with a greater proportional intake of leaf and pasture components in the early grazing period. The diurnal nitrogen intake was then strongly non-uniform, with 47, 66 and 77% of daily nitrogen intake by 1, 3 and 6-hours. The feed nitrogen release was also strongly non-uniform, with 28% released in the first hour, then progressively declining to 24-hours. There was a 2.8kg WSC intake in the first 6-hours, and 0.97kg of WSC intake in the final 18-hours, with reduced nitrogen supply. It was concluded this diet was markedly asynchronous in rumen supply of energy and nitrogen. Despite a dietary CP content of 9.4%, the estimated metabolisable protein supply was adequate to meet the estimated metabolisable protein demand according to the AFRC feeding reference standard, but not for the NRC, for the observed LWT gain. Altering quickly degradable protein losses maximally from 0.8 to 0.95 increased the estimated metabolisable protein supply by 7%, and maximally altering undegraded dietary protein by 12%. It was concluded that the non-uniform pattern of nitrogen intake and asynchronous supply of energy and nitrogen to the rumen did not significantly adversely reduce production in steers grazing this diet, as high LWT gains were observed. The strongly non-uniform rumen nitrogen release and high LWT gains suggested nitrogen recycling would be required. Finally, it was therefore concluded that there may be additional nitrogen management strategies in operation, as well as the traditional rumen and whole-animal nitrogen use in steers fed this diet, perhaps due to the novel characteristics of the diet, evidenced by the high LWT gains observed. The strongly non-uniform, asynchronous intakes and high LWT gains observed in Experiment 1 led to the development of Experiment 2 in Chapter 4. This compared the DM and nitrogen intakes, LWT gains, rumen and plasma urea and ammonia concentrations, and plasma amino acids of steers on a fodder beet diet or a synchronous total mixed ration (TMR) on a commercial farm. A total of 938 steers in six mobs of ~150 steers, mobs grazed a diet of ad libitum fodder beet in situ or an ad libitum TMR. The diurnal DM and nitrogen intake of steers on the fodder beet and TMR diet treatments were measured at 1, 3, 6 and 24-hours, and rumen and plasma samples were obtained at two times during the grazing period. The LWT gains were similar (0.98kg per day; P>0.05) between treatment groups, despite the different dietary characteristics. The fodder beet diet treatment displayed a greater non-uniform pattern of DM and nitrogen intake than the TMR diet treatment (P<0.05), with 47 and 75% DMI, and 45 and 78% nitrogen intake, at 1 and 6-hours, respectively, and the TMR 20 and 45% DM and nitrogen intake at 1 and 6-hours, respectively. The fodder beet diet treatment had lower mean rumen ammonia concentrations (86mg /L) and higher mean rumen urea concentrations (992mg /L) (P<0.05) than the TMR diet. Plasma ammonia concentrations were 2.13 and 2.46mg /L at the Mid-Winter (P=0.091) and 1.98 and 2.41mg /L at the Late Winter (P=0.022) sampling for the fodder beet and TMR diet treatments, respectively. Plasma urea concentrations were 75.9 and 254.8mg /L at the Mid-Winter (P<0.001) and 180.6 and 318.92mg /L at the Late Winter (P<0.001) sampling for the fodder beet and TMR diet treatments, respectively. Plasma amino acid concentrations were similar (P>0.05) between the two diet treatments, with no apparent differences in glucogenic or ketogenic amino acid groups. While the TMR diet treatment estimated metabolisable protein supply was higher, both diet treatments supplied adequate metabolisable protein to meet demand despite the lower CP content of the fodder beet diet treatment (11.6 vs. 14.1%). It was concluded that there were important differences in rumen and whole-animal nitrogen use between the two diet treatments, despite the observed LWT gains being similar. Experiment 3 in Chapter 5 was designed to investigate rumen nitrogen use and export across the diurnal period in fodder beet diets. A comparison of fodder beet and pasture feeding in treatment groups of eight pen-fed sheep (LWT: 34.1 and 39.3kg) with total urinary collection was used. Rumen nitrogen loss and microbial protein (MCP) outflow via sub-diurnal urinary nitrogen and purine excretion patterns were quantified. Measurements of total DMI and total urine production were undertaken at periods of 1, 3, 6 and 24-hours, to correspond with measurements conducted in Chapters 3 and 4. At 1 and 3-hours, the fodder beet diet treatment had 2-fold higher (P<0.001) nitrogen intakes (5.38 and 5.73g vs 2.28 and 2.92g, respectively). The urinary nitrogen excretion at 1 and 3-hours was not different between the two diet treatments (P>0.05), with 0.36 and 0.71g nitrogen excretion for the fodder beet diet treatment, and 0.23g and 0.47g nitrogen excretion for the pasture diet treatment. The urinary purine excretion was also similar between the two diet treatments at 1, 3 and 6-hours (P>0.05). The low DM content and heterogeneous nature of the fodder beet diet resulted in greater non-uniform diurnal intake of feed water for the fodder beet diet treatment. The feed water intake was ~3-fold and ~2-fold higher for the fodder beet diet treatment at 1 and 3-hours, respectively, and 48% higher for the fodder beet diet treatment at 6-hours (P=0.001, P=0.001, P=0.002). While urine production was higher for the fodder beet diet treatment at 1, 3 and 6-hours (P=0.001, P=0.004, P=0.017), this was not proportionate to the increase in feed water intake compared to the pasture diet treatment. From the comparatively greater water intake against urinary output in the early (1 and 3-hour) feeding period for the fodder beet diet treatment it was concluded that there was a net water retention, most likely an increased GIT volume as rumen digesta volume. It was concluded the proportionately lower rumen export of nitrogen in the fodder beet than the pasture diet treatment in the early (1 and 3-hour) period of the diurnal cycle to urinary nitrogen or to purines was likely due to greater nitrogen retention in the rumen in the early (1 and 3-hour) feeding period, and this may be a mechanism of nitrogen use and movement in the fodder beet diets that may explain the strong production observed with comparatively low CP content. The results of Experiment 3 suggesting reduced rumen nitrogen export in the early feeding period and with this a net water retention were further examined in Chapter 6 in two experiments. Experiment 4a was designed to quantify the proportion of rumen nitrogen exported from the rumen, or recycled to the rumen, in ad libitum fodder beet fed steers, using infusions of isotopically labelled 15N15N urea to either the plasma or the rumen. Experiment 4b quantified the diurnal rumen volume fluctuations in fistulated rising-one-year-old beef steers fed fodder beet or pasture. Four rising-one-year-old steers in metabolism crates (Experiment 4a) had feed intake measured and total faecal and urinary collection, in a 2 x 2 crossover experimental design. In each of two 76-hour periods separated by an 18-day washout, two steers were infused with the stable isotope of 15N15N urea into the rumen, and two steers were infused with 15N15N urea into the jugular and blood and rumen digesta samples were then obtained from steers at 4-hour intervals for 24-hours to determine abundance of 15N in rumen fluid and plasma, and also in daily urine and faeces. Experiment 4b used complete rumen evacuations every 16-hours for 48-hours to determine rumen digesta volume across the diurnal cycle (0, 8, 24-hours after feeding) in steers grazing ad libitum pasture or fodder beet. Diurnal rumen fluid abundance of 15N for the rumen infusion treatment displayed substantial diurnal variation (P<0.001), with the highest abundance observed (488 δ15N ‰) at morning feeding time, but reaching a nadir (223 δ15N ‰) 12-hours after feeding. The jugular infusion treatment did not vary across the diurnal cycle for rumen fluid 15N abundance (P=0.137), with <20 δ15N ‰ difference from the nadir at 12-hours post-feeding. The rumen and jugular infusion treatment abundances were different at 0, 4 and 20-hours after feeding (P<0.05). Plasma 15N abundance for the jugular infusion treatment did not vary across the diurnal cycle (P=0.182), whereas, the rumen infusion treatment did vary (P=0.006). However, the two infusion treatments were not different in plasma 15N abundance (P>0.05) at any measurement period throughout the diurnal cycle. Mean daily urinary excretion of 15N was 3701 for the rumen 15N infusion compared with 9842 for the jugular 15N infusion (P=0.004). The mean abundance of 15N in faeces was higher (P=0.037) for the rumen (238 δ15N ‰) than the jugular infusion (137 δ15N ‰) treatment. These results indicated low transfer of rumen nitrogen to the plasma, with little diurnal variation in this transfer, and that rumen import of nitrogen was more substantial, and greater at diurnal phases associated with higher rumen activity. Experiment 4b demonstrated that rumen volume increases at 8-hours were greater in fodder beet fed steers, compared to pasture fed steers, and the rumen urea pool was significantly greater at 8 and 16-hours after feeding (P<0.05) for the fodder beet diet treatment, and the rumen ammonia pool significantly greater for the pasture diet treatment, across the entire diurnal cycle (P<0.05). From the results of this series of experiments, it was concluded that, in addition to nitrogen recycling strategies previously described, rumen retention of nitrogen in the early post-prandial period, by these several mechanisms identified in this study, was a possible novel rumen nitrogen management approach which may have influenced the high LWT gains observed with this diet by reducing rumen nitrogen losses. The role of rumen adaptation to a diet of low CP and NDF, but high WSC and water content, in any rumen nitrogen management mechanism should be an important consideration in further research.
Embargo
Dimensions of the resilient visitor and visitor system in conservation areas of New Zealand : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Michela, Lydia
New Zealand’s conservation areas are dynamic biophysical environments subject to natural hazards and popular recreation areas for domestic and international visitors and tourists. The human and natural environments form a social-ecological system (SES). Many visitors are unaware of and unprepared for the conditions and natural hazards they encounter which can lead to issues of safety. The main objectives of this research are to investigate what it means for a tourist to be resilient to natural hazards in New Zealand’s conservation areas, what factors, attributes and characteristics influence resilience and what is the relationship between tourist resilience and destination resilience. There is an extensive body of literature investigating the resilience of tourist destinations, communities, and organisations but tourists are less commonly the central focus, even though they represent the demand side of the tourism system. Of the research that does exist for tourists, much of it is focuses on tourists as individuals rather than tourists as part of a SES and it most frequently from a psychological resilience or hazard awareness and preparedness perspective. This study used a mixed methodology to investigate the research questions. The vast majority of survey participants had medium to high levels of experience and skill in conservation-recreation environments. Results showed many visitors were aware of natural hazards and included them in their planning process. Dimensions of visitor resilience were found to be awareness, locus of responsibility for safety, preparedness, and adaptability. The vulnerability and resilience of destinations and tourists are interconnected. Destination stakeholders influence visitors via information provision and risk management decisions. Visitors influence destination resilience by the aforementioned dimensions and by sharing their experiences with others, on the track and back at home. A significant theoretical contribution was the inclusion of a visitor’s social-ecological system of origin as a key influence on recreationists’ dimensions of resilience. A key implication for stakeholders and practitioners is to take a more nuanced perspective on visitors and their origin context in terms of past recreation experience, social circles, and perceptions of responsibility for safety.
Restricted
Understanding the bioaccessibility of grape phenolics in association with milk proteins : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2025) Matiwalage, Iresha Nirmalie Wickramanayake
Phenolics are compounds that are widespread in plants and abundant in many fruits. Grapes and their products contain high concentrations of phenolics, particularly anthocyanins, and flavanols such as catechins and epicatechins. phenolics have been reported to have various health benefits, but these may be limited by their low uptake, low bioavailability, and rapid degradation owing to enzymatic and non-enzymatic reactions during digestion. Research has explored several protected delivery options to increase the bioavailability of phenolics in different fruits. Milk proteins have been identified as effective delivery agents for several bioactive compounds including phenolics. Although milk proteins are effective delivery agents for phenolic compounds, the specific interactions of the phenolics with the milk proteins, and factors affecting phenolic-protein interactions require to be understood to facilitate the utilisation of these delivery systems in food, nutraceutical, and pharmaceutical applications. Commercially available extracts of red grape skin from Pinot Noir, grape seed from Sauvignon Blanc, and sodium caseinate 180 were used in this study. Grape extracts and Na-casein protein stock solutions were separately prepared and mixed at different phenolic-to-protein weight ratios, 5:40, 10:40, and 15:40, phenolic-alone controls (5:0, 10:0, and 15:0) and casein-alone control (0:40) in phosphate-buffered saline (PBS). The protein phenolic complex samples were then freeze-dried. In the casein-based grape samples, the total extractable phenolic contents increased from a phenolic-toprotein ratio of 5:40 to 15:40. The percentages were 47.0% in CSK5 to 69.1% in CSK15 and 41.3% in CSE5 to 54.8% in CSE15 in casein-based skin and seed FD samples respectively. Further analysis by HPLC found that catechin, epicatechin, epigallocatechin gallate, gallic acid, and quercetin-3-glucoside were the abundant phenolics in casein-based skin whereas in casein-based seed samples, procyanidin B1, procyanidin B2, catechin, epicatechin and epigallocatechin gallate were the major phenolics. The antioxidant capacity was reflected in the total extractable phenolic content and strong positive linear correlations were found between the total extractable phenolic content and the antioxidant activity and between ABTS and DPPH assays in FD samples. The free phenolic results from the loading efficiency study and total extractable phenolic contents revealed that grape phenolics are more likely to bind with casein when a sample contains a higher protein concentration (e.g. 5:40 phenolic-to-protein ratio containing sample). In the same way, DH% results displayed that protein hydrolysis of casein-based grape skin FD samples was significantly increased during in-vitro digestion, and the increasing order being CSK0 < CSK5 < CSK10 < CSK15 shows that protein hydrolysis is more favourable with the sample having a lower proportion of protein. Significant increases (p<0.05) in phenolic release were noted in three different phenolic-to-protein ratios after one hour of pepsin addition. In contrast, phenolic-alone skin samples showed significant reductions (p<0.05) in phenolic release under acidic pH conditions one hour after adding pepsin indicating rapid phenolic degradation. Even though, both casein-based and phenolic-alone grape skin samples showed a notable increase in phenolic content one hour after pancreatin addition, again it declined during the final two hours in the phenolic-alone skin samples. No differences were found in the phenolic content of three casein-based samples after five hours of digestion resulting in a slower release of phenolics during in-vitro digestion even with the sample having a lower phenolic-to-protein ratio. Reliable with the trends noted in DH% and phenolic release, the antioxidant activity was increased in casein-based grape samples. FT-IR results discovered that grape phenolics interact with casein mainly via non-covalent bonding like hydrogen bonding, hydrophobic, and electrostatic interactions, and no covalent bonds were formed during the formation of casein-grape phenolic complexes. In addition, grape phenolics appear to alter casein's secondary structure by decreasing β-sheet and random coil contents and increasing β-turn and α-helix structures, reflecting increased hydrogen bonding and protein conformational changes, leading to flexible and disordered protein structure and antioxidant activity of casein. The findings of the fluorescence quenching study revealed that adding different concentrations of grape skin and seed phenolics caused to significant decrease in fluorescence intensity of the main emission band of Nacaseinate and the shift of the emission peak slightly toward a higher wavelength. Moreover, both dynamic and static quenching mechanisms were involved with samples at a higher phenolic-to-protein ratio. The highest modified Stern–Volmer quenching constant (K), 4.6 x 10³ M⁻¹ and quenching constant (Kq), 1.5 x 10¹² M⁻¹s⁻¹ at 280 nm excitation wavelengths at room temperature of grape skin phenolics showed stronger quenching interactions and greater binding affinity towards casein protein indicating higher radical scavenging activity in casein. Furthermore, the binding constants (KA) for casein-based skin, 3.49 x 10⁷ M⁻¹ at 290 nm excitation wavelength revealed stronger static quenching interactions between skin phenolics and casein protein. Overall, findings based on protein hydrolysis, phenolic release, antioxidant activity during in-vitro digestion, and the interactions between grape phenolics and casein protein, which together enhance bioaccessibility during digestion, this study confirmed that casein-based grape FD powders are an effective food complex, beneficial for the nutraceutical and food industries.
Embargo
Development of an advanced deep learning and neural network method for automatic early detection of mastitis in dairy cattle : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Fazayeli, Atefeh
Mastitis, a costly and prevalent disease in dairy cows, reduces milk yield, quality, and animal welfare, while increasing treatment costs. Early detection, especially in the subclinical stage, is crucial for controlling the disease and maintaining milk production. This study explores advanced methods for early mastitis detection using data from a robotic milking system. Initially, Self-Organising Map (SOM) was employed to capture the mastitis spectrum. Then, Fuzzy C-Means (FCM) clustering was applied to the SOM map, identifying five health states—healthy, early subclinical, subclinical, late subclinical and clinical—despite the absence of specific labels for the subclinical stages. Building on the insights gained from unsupervised learning with SOM and FCM, we then trained a Bidirectional Long Short-Term Memory (BiLSTM) network to forecast the cow health state for the following day using supervised learning. The BiLSTM model showed high efficacy in forecasting cow health states, with precision, recall, and F1-scores for each state ranging from 0.92 to 1.00. This approach advances mastitis detection by integrating SOM-FCM for spectrum capture and BiLSTM for temporal forecasting, improving early diagnosis and enabling targeted interventions, thus promoting precision dairy farming and better economic outcomes.
Open Access
The Determinants of farmers’ involvement in farm tourism: Insights from Lam Dong Province, Viet Nam : A thesis submitted in fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Huynh, Thuan (Nancy) Thi Phuong
Farm tourism has proven beneficial to agriculture, tourism and the community. However, research in farm tourism has been limited compared with that in general tourism research. Farm tourism is well-developed and has been mainly quantitively studied in European and North American countries. The development of and research on farm tourism in Asian countries is delayed but is getting more attention. This study examines the determinants of farmers’ involvement in farm tourism in Lam Dong province, Viet Nam, a middle income country in South East Asia. The study uses in-depth interviews to gain insights from 52 farmers’ narratives. Thematic analysis is used to analyse the data. The findings suggest that 13 influencing factors impact farmers’ involvement in farm tourism. They are farm location, farming method, family support, farm landscape, farm ownership, crop attractiveness, crop availability, crop value, farmer’s age, education, off-farm experience, social networks and financial ability. Most importantly, a farmer's self-identity plays a significant role in shaping a farmer’s involvement in farm tourism, bringing valuable complements to the explanation of the influencing factors. This study contributes to a better understanding of farm tourism and provides insights for policymakers promoting farm tourism development. The limitations of the study are noted.
Embargo
Reducing nitrogen loss from cow urine patches: Strategies for pasture-based dairy systems : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Kok, Jacobus Christiaan
In dairy grazing systems, intensive farming practices with high nutrient inputs contribute to environmental pollution with nitrogen (N) loss from farmland, a key contributor to water quality degradation. The New Zealand dairy industry aims to reduce N leaching by 40-60% by 2030. Achieving this target may require transitioning from moderate to lower input systems and implementing mitigation strategies focused on managing high N sources, such as cow urine patches, to improve N use efficiency and reduce leaching risk. While cow urine patches present a primary source of N loss from pasture-based dairy farms, there is limited information on how the relationship between urine volume per urination event and urine patch area affect the N leaching risk. The aim of the thesis is to investigate this relationship and how grazing management strategies influence urine N load and plant N uptake following a regrowth period to mitigate N leaching risk. Additionally, it aims to develop a tool for predicting the impact of management strategies on N loss from urine patches. A key finding of the literature review was that successful N mitigation requires tactical and operational knowledge of implementing mitigation strategies, which has slowed adoption due to uncertainty in implementation. Additionally, the review also identified mitigations centred around the transfer of N, specifically relating to the urine patch, urine N load, or plant N uptake, to improve N use efficiency within a farm system. The review identified a lack of decision support tools for farmers to tailor N mitigations to individual circumstances. One finding was the opportunity to provide tactical and operational tools, such as a urine patch model, to understand urine distribution variation and develop management strategies that target urine and urine patch characteristics to reduce leaching risk. Using a modelling approach (Chapter 3), the aim was to determine if reducing N input alone could achieve the required N leaching reduction with minimal impact on farm operating profit, or if additional mitigation practices targeting N transfer from high N sources, such as cow urine patches, are needed to improve N use efficiency and reduce the risk of leaching. A two-year dairy farmlet study was conducted comparing two farm systems: moderate stocking rate (MSR, 3.9 cows/ha); and lower stocking rate (LSR, 2.9 cows/ha); with a benchmark, high-performing commercial demonstration farm (Lincoln University Dairy Farm [LUDF]; 3.4 cows/ha). Milk yield, pasture production, and quality data were collected, and modelled in FARMAX and OverseerFM to estimate the financial and environmental performance of each farm system. The LSR system produced the best environmental outcome across the two years (2018/19 and 2019/20), leaching an estimated 31% less N compared with MSR and LUDF, but at the cost of profitability. The average, annual milk solid production per ha was 28% less for LSR relative to MSR and LUDF. Correspondingly, the average annual operating profit per ha was 35% less for LSR compared with LUDF. A low N input system reduces production and operating profit to the extent that these mitigation strategies may not be adopted. Therefore, the next step was to target sources of high N input, such as cow urine patch areas, and improve N use efficiency from these areas to reduce the risk of leaching. In Chapter 4, we investigated the effects of grazed pasture canopy characteristics (using plant species and height) on urine patch area. The experiment was conducted during autumn in Canterbury, New Zealand. Warm water was used to simulate urine events, ranging in volume from 1 to 8 L, onto either partially (Lenient, 6-15 cm) or fully (Hard, <6 cm) grazed perennial ryegrass and white clover or pure plantain pastures. A thermal digital camera and imaging software were used to calculate the wetted area of each urine event. When a mid-range volume (4 L) was poured onto lenient grazed pastures, plantain had a greater wetted area than perennial ryegrass/white clover pasture (0.30 m2 ± 0.11 m2 and 0.16 m2 ± 0.08 m2, respectively; mean ± standard deviation). However, the wetted area was similar for plantain and perennial ryegrass/white clover pasture under hard grazing (0.36 m2 ± 0.16 m2 and 0.31 m2 ± 0.13 m2, respectively). Irrespective of pasture treatments and grazing intensity, the relationship between water volume and wetted area was curvilinear, with no significant increase in wetted area for simulated urine events greater than 4 L. Our results indicated that both pasture treatments and grazing intensity (i.e., residual pasture canopy) affect urine patch area, which could have potential implications for the urine N load per urine patch. A limitation of this study was that sward surface height was measured at the paddock level rather than for each urine event simulated. The first field experiment (Chapters 5 and 6) was split into two chapters to evaluate two objectives. The first objective was to investigate the effect of pre-graze pasture mass and time of pasture allocation, on total soil N levels from urine patches and subsequent N recovery from pasture following a regrowth period. The experimental design was a 2 x 2 x 2 factorial arrangement of treatments replicated twice within two experimental runs. The first factor corresponded to two levels of pasture mass using moderate to high mass (2226 or 2662 kg DM/ha respectively) to create lower herbage crude protein content in the high mass treatment. The second factor corresponded to time of allocation of pasture using morning or afternoon allocation. The third factor corresponded to time of urine deposition using anticipated peak (dawn) vs nadir (mid-morning) urinary N concentration and urine N load. A two-way interaction indicated larger urine patch areas for moderate mass at peak times (P < 0.05). As well as a three-way interaction which showed that moderate mass allocated in the afternoon resulted in larger urine patch areas (P < 0.05). Total soil N content was 6% higher (P < 0.05) for moderate mass but did not differ (P > 0.05) between peak and nadir times. High mass treatments showed better regrowth in both urine and non-urine patches. For non-urine patches, the herbage N yield was 18% lower for the moderate compared to the high mass pastures (P < 0.05). From this, we concluded that managing pasture mass can influence pasture recovery and nitrogen utilisation, with potential implications for reducing N leaching risk from dairy farms. Chapter 6 aimed to investigate the relationship between volume per urination, urine patch area, and compressed pasture height. The objective of this chapter was to understand if pasture management practices can affect urine patch area and subsequent urine N load. Cows were fitted with acoustic urine sensors (AgResearch, New Zealand) on their hind legs. The sensors captured the timing, duration, volume per urination, and frequency of urination. Thermal digital imaging with an automated algorithm (AgResearch) was used to estimate urine patch area. Our findings revealed that compressed pasture height did not affect the urine volume and patch area relationship. The relationship was also weaker compared to the findings in Chapter 4. The results showed the importance of accurate urine volume measurement and the impact that measurement errors with different methodologies could have on the relationship with urine patch area. Further research with accurate measurements of volume per urination and corresponding patch area is needed to develop tools to model urine and urine patch characteristics and N leaching risk accurately before they can inform management strategies. The second field experiment (Chapter 7) was carried out to collect additional data on the urine volume and patch area relationship. This study investigated the impact of pasture treatments and height on this relationship through simulated urination events. Conducted at Lincoln University Research Dairy Farm, the experiment utilised a 2 x 8 factorial design, comparing perennial ryegrass-white clover pasture with Italian ryegrass-plantain-red and white clover pasture across eight volume treatments (1-8 L). The study found no significant difference in urine patch area between pasture treatments. A curvilinear relationship between urine volume and patch area was identified (similar to that in Chapter 4), with a quadratic model (Urine patch area = 0.129 + 0.056v – 0.003v²) explaining 54.8% of the variance. Additionally, sward surface height significantly influenced urine patch area, with taller pastures reducing urine patch area, especially at higher urine volumes. This interaction was modelled (Urine patch area = 0.1259 + 0.09278v – 0.004742v² – 0.002363vh + 0.0001293v²h), explaining 70% of the variance. In summary, effective strategies must combine reduced N inputs with mitigation practices targeting N transfer from high N sources, such as cow urine patches, to improve N use efficiency and reduce leaching risk. This thesis has shown that altering pasture mass or the timing of pasture allocation does not significantly influence urine patch area; instead, it was primarily affected by the time of urine deposition. Additionally, these grazing management practices do not enhance plant N uptake from urine patches. Management practices aimed at reducing urine N load at peak times might be more effective at reducing N leaching risk than grazing management. However, grazing management can increase N transfer during the regrowth phase from small urine events. By managing sward surface height when smaller urine events fall within the linear part of the volume and patch area relationship, the urine patch area can be increased at the time of deposition, improving urine N load distribution and plant N uptake. Ultimately, the urine patch model indicated that reducing daily N intake and increasing daily urine volume throughout the year can reduce N leaching by up to 14.5%.
Open Access
The integration of control tools and attractants for optimising ground-based pest control : A thesis submitted in fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Graham, Brittany
The brushtail possum (Trichosurus vulpecula), a marsupial native to Australia, was widely introduced in New Zealand between 1890 and 1930 to support the booming fur industry in Australia. Before the settlement of humans in New Zealand, there were no terrestrial mammals other than bats; therefore, the local species evolved without mammalian predators. This isolation has profoundly affected native species like birds, invertebrates, and reptiles. Forty of the ninety-one land bird species are now extinct, and many others are in severe decline. The government's initiative to eliminate New Zealand's predators (possums, rats, and mustelids) by 2050 has significantly expanded conservation control efforts in recent years. In New Zealand, predator control has been practised for a long time, but simple trapping has since developed into a thriving industry full of expertise, including species-specific attractants. The number of traps and bait stations needed to be set up, and the associated labour and expense would be significantly reduced if animals could be reliably drawn from a distance to a bait station or trap. Research presented in this thesis expands on previous studies with captive and wild animals, identifying the attractiveness of novel multi-sensory lures for possum control. Audio lures are increasingly becoming a popular attractant for pest control in New Zealand as they can draw the animals' attention from further away and potentially become a long-lasting lure. 50% of possums were trapped at traps playing the aggressive possum audio in the winter 2022 trials; however, the attraction towards the aggressive possum audio was not reflected in the autumn 2023 trial replicate, as 57% of possums were trapped at the beep audio traps compared to the aggressive and distressed possum audio and the control. In a subsequent field trial, a newly developed audio-visual lure (AVL) device was evaluated, which emitted the aggressive possum audio. The results demonstrated that it effectively attracted possums to a live-capture cage trap, compared to an existing audio lure. Visual lures are a tried-and-true attractant for possum control in New Zealand, with the flour blaze being a commonly used attractant. However, weather can easily impact flour blaze and may not last long in suboptimal conditions; therefore, identifying a long-lasting visual lure would be an advantage. A trial with captive animals compared a photoluminescent strip, white constant LED light, white flashing LED light and control (no visual lure). Whilst there was no significantly better visual lure overall, the constant LED light treatment had the most encounters (visits within 1 m of the trap). While the lures were under development, Pest Free Banks Peninsula was given assistance for their upcoming control operations, focusing on collecting data on possum home ranges in these habitats. Understanding the size of these home ranges is crucial for optimal device spacing in line with the PFNZ2050 goal of elimination. Possums living in different habitats can have different home range sizes and population densities, especially for individuals living along/in the sea cliffs. Six GPS-collared possums deployed in Le Bons Bay, Banks Peninsula, were retrieved, identifying a significant degree of overlap between the individuals and small home range sizes (average of 2.65 ha) compared to other studies on Banks Peninsula (average of 6.2 ha). The results indicated that possums did not move far from resources or capture locations, and 100x100 m device spacing was sufficient. Complementary research on captive hedgehogs identified the most attractive food-based lures being peanut butter, rabbit meat and salmon, which had significantly more activity than egg, huhu grub, mayonnaise, male hedgehog odour, female hedgehog odour and ferret odour. However, combining the most attractive food-based lures of rabbit meat with a predator (ferret) pheromone (scent) lure worked better when compared to the food-based options on their own (freeze-dried salmon and rabbit meat). Due to the positive results from the hedgehog combination lure trial, this methodology was then applied to free-ranging possums using the best performers from the earlier captive studies being combinations of audio (aggressive possum audio), visual (constant LED light) and scent lures (conspecific bedding material). Overall, there was no significant difference between the treatments; however, the combined audio-visual treatment had the most interactions (animals in traps) and encounters (visits within 1 m of the trap), and possums also spent more time in the encounter zone for audio-visual-scent lure sites. In conclusion, these results indicate that combination lures have the potential to increase possum encounter and interaction rates around traps. The results also highlight the need for pest control managers to be flexible and choose lures that will be the most attractive to individuals at specific times of the year to ensure ongoing success. Adopting a strategic approach to lure selection can significantly enhance the effectiveness of pest control efforts and support the Predator Free 2050 goal.
Open Access
Unlocking the potential of faba bean blanching water: From waste to ingredient - Insights into composition, cholesterol-lowering property, and bakery application : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Feng, Ziqian
The rising demand for sustainable food systems has driven interest in upcycling byproducts from legume processing. This thesis examines the potential of faba bean blanching water (FBBW), a byproduct commonly wasted in faba bean processing, as a source of bioactive compounds and its use in food production. The aims were to investigate the nutritional and bioactive composition of FBBW, evaluate its cholesterol-lowering properties, and assess its efficacy as an ingredient in baked goods. The research involved a compositional analysis of FBBW, including the quantification of carbohydrates, proteins, peptides, amino acids, phytochemicals, and minerals. In vitro assays were performed to test the inhibitory effects of FBBW on HMG-CoA reductase, as well as its impact on cholesterol micellization. Finally, FBBW was incorporated into sponge cakes to evaluate its effects on texture, sensory attributes, and consumer acceptance. The results indicated that bioactive compounds are abundant in FBBW dry matter, including peptides, saponins, and phenolic compounds, all of which contribute to its specific health-promoting attributes. Notably, the peptides in FBBW significantly inhibited HMG-CoA reductase, a key enzyme in cholesterol production, with the inhibitory activity at 64 – 70%. This enzyme inhibition is important for lowering cholesterol levels because it reduces the rate of cholesterol synthesis in the liver. Saponins, which were the predominant component of FBBW, also reduced cholesterol by decreasing cholesterol micellization, a mechanism required for cholesterol absorption in the gut, with the inhibition at 48 – 53%. Saponins significantly reduced cholesterol’s bioavailability, restricting its absorption and contributing to a decrease in overall cholesterol levels. This dual-action mechanism of FBBW shows that it has the potential to effectively manage cholesterol levels while also improving cardiovascular health. Furthermore, FBBW was investigated for its potential as a functional element in food applications, particularly baking products like sponge cakes. When FBBW was added to sponge cake formulations, it improved physicochemical aspects, including texture and adhesiveness. Textural improvements were observed as enhanced softness and cohesion, resulting in a more pleasant mouthfeel. Textural study utilizing instrumental analysis supported these findings, demonstrating that cakes containing FBBW had better adhesiveness (P < 0.05) and moisture retention (P < 0.05). Importantly, consumer sensory evaluations confirmed these instrumental findings, with desirable acceptance ratings for overall satisfaction (P > 0.05) and similar flavour and textural acceptance. Thus FBBW not only has potential for better health outcomes but also provides useful functional qualitites as a food ingredient. These findings highlight the adaptability of FBBW as a sustainable, functional ingredient that may promote health and reduces food waste.
Open Access
Development of functional food with pea cooking water and the effect on human postprandial glycaemic response : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Zhang, Yanyu
High GI carbohydrates are associated with several diseases, including diabetes, obesity, and cardiovascular disease (CVD). The rate of starch digestion and absorption significantly impacts metabolic responses. Slowly digestible carbohydrates are advantageous for managing metabolic disorders such as diabetes and hyperlipidaemia and are found in legumes, pasta, and whole-grain cereals. Peas, a high-quality protein source, are typically consumed after soaking and cooking. Pea cooking water is the by-product of split yellow peas, often regarded as an ideal egg white substitute in bakery products due to its emulsifying properties. Pea cooking water (PCW) was recently reported to be rich in proteins, fibres and micronutrients. However, current research has not specifically investigated the nutritional aspects of pea cooking water, although significant nutrient loss is known to occur during cooking. This study investigated the potential of pea cooking water to manage glycaemic responses in carbohydrate-rich foods by examining its effects on human glycaemic levels as well as the structural and textural properties of these foods. This study examines the structural and nutritional modifications that occour to pasta when PCW or pea flour (PF) are incorporated into the formulation. The inclusion of freeze-dried PCW (PCWFD) in pasta significantly (P<0.05) reduced the optimal cooking time (OCT) and altered water absorption capacity due to its unique structural attributes. Compared to traditional wheat pasta, PCWP exhibited a lower OCT (P<0.05), reduced swelling index (P<0.05), and higher cooking loss when substituting 20% of semolina with PCWFD (P<0.05). Additionally, pasta substituted semlina with 10% and 20% PCWFD showed increased tensile strength and decreased cutting force (P<0.05), maintaining an intact microstructure and consistent particle size distribution. The incorporation of PCWFD modified protein-starch network of the pasta. The modified protein-starch networks in PCWP and PFP resulted in slower glucose release and a lower glycaemic response (P<0.05). The study explored the impact of varying cooking times and PCWFD levels, finding that longer cooking times and higher PCWFD concentrations affect cooking loss and water absorption, influencing glycaemic response. PCWP performs comparably or better than traditional pea flour pasta in in vitro glucose digestion tests. The food matrix does not disrupt the effect of PCW in reducing and slowing glucose release, as demonstrated by comparisons with rice boiled in PCW versus normal water. PCW incorporation significantly reduced postprandial glycaemic responses in human subjects (P<0.05), attributed to the high protein content and fibre effects on gastric emptying. The lower glycaemic index (GI) effect is also due to the higher protein content, lower starch content, and protein-starch interactions. Despite a fully gelatinized structure, PCWP maintain a reduced glycaemic response. These findings highlight the potential of PCW as a functional ingredient to enhance the nutritional profile of pasta, reduce glycaemic responses, and promote sustainable food processing practices. The present work addressed the potential health benefits of PCW to develop of functional food by investigating the effect on human postprandial glycaemic response. It represented a functional and innovative approach to food development while promoting environmentally sustainable practices.
Open Access
Edible insects, mātauranga, diet, and lifestage to explore the potential of Aotearoa New Zealand insects as food : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2025) O'Connor, Chrystal Te Ohorere
With growing global concerns about food security and environmental sustainability, insects as food could provide a promising alternative protein source. However, research on entomophagy (eating insects) has predominantly focused on Western perspectives, who perceive edible insects as a novel concept, and there is limited exploration of Indigenous knowledge systems. This thesis investigates the potential of native Aotearoa New Zealand insects as sustainable and nutritious food sources, integrating mātauranga Māori (indigenous Māori knowledge) with Western scientific approaches. A survey of Māori participants (n=172) revealed that insects are culturally significant, with 47% of participants having consumed insects or knowing whānau (family) who had. Larvae of the huhu beetle (Prionoplus reticularis White, 1843) was identified as the most consumed insect, with 89% of participants naming it as a traditional food source. The survey also indicated that participants were significantly more likely to consume insects that were native to Aotearoa New Zealand, fed rākau rongoā (medicinal plants), or historically eaten by Māori (P<0.05). Most participants indicated they would eat insects either processed or whole (49%, N=78), with a total of 87% of participants indicating they would be willing to eat insects in some form (processed 37%, N=59, whole 4%, N=7). Through integration of mātauranga Māori, ecological factors, and nutritional considerations, three Lepidoptera species were selected and studied as whole insects; kawakawa looper (Cleora scriptaria (Walker, 1860)), brindled bell moth (Epalxiphora axenana Meyrick, 1881), and brown headed leafroller (Ctenopseustis obliquana (Walker, 1863)), and two culturally significant plant diets; kawakawa (Macropiper excelsum (G.Forst.) Miq.), and mānuka (Leptospermum scoparium Forst.). The selection process considered factors such as sustainability of rearing processes, life cycle length, plant associations, and cultural significance. Amino acid (AA) and mineral analysis, using high-performance liquid chromatography (HPLC) and inductively coupled plasma mass spectrometry (ICP-MS) respectively, showed that all three species met FAO/WHO requirements for essential AAs of 40%, with the essential AA to non-EAA ratios ranging from 41.1% to 44.5%. The brindled bell moth showed significantly higher levels of several minerals, including sodium, magnesium, potassium, and calcium, with iron content (21.4 mg/100g dry weight (DW)) (P<0.05) that exceeded New Zealand recommended daily intake. Diet studies with the brown headed leafroller showed that larvae and pupae reared on either mānuka or kawakawa had significantly higher levels of macrominerals, particularly sodium, magnesium, potassium, and phosphorus, compared to those on laboratory diets. Larvae reared on mānuka demonstrated higher concentrations of several essential AAs, including histidine, isoleucine, threonine, and valine, with total essential AA content (223.2 mg/g DW) significantly higher than those on laboratory diet (166.6 mg/g DW) (P<0.05). The dietary influence was more significant than life stage in determining amino acid composition. Mātauranga Māori recognises that kawakawa leaves eaten by the kawakawa looper have enhanced medicinal properties. Supporting this knowledge, metabolomic analysis using rapid evaporative ionisation MS (REIMS) revealed distinct chemical changes in leaves eaten by the kawakawa looper (444 features, 16.08% differing from non-eaten leaves). These changes were unique and specific to insect herbivory, as artificially damaged leaves showed no significant differences from control leaves. The metabolomic response also varied between species, with the kawakawa looper and brindled bell moth showing the most distinct profiles (20.79% features differing), suggesting species-specific interactions between insects and kawakawa. This research provides the first comprehensive analysis of native Aotearoa New Zealand insects as a sustainable food source, integrating mātauranga Māori and Western scientific approaches. The findings establish a foundation for developing nutritious insect-based foods that align with cultural values and environmental sustainability, demonstrating the potential of native insects in addressing food security challenges in Aotearoa New Zealand and globally.
Open Access
The abundance, activity, and community composition of comammox Nitrospira and canonical ammonia oxidisers in New Zealand soils : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Chisholm, Chris
Nitrification, the microbial oxidation of ammonia (NH3) via nitrite (NO2-) to nitrate (NO3-) is an important process in terrestrial ecosystems, as it contributes to the production of two environmentally significant products, nitrous oxide (N2O), and nitrate. Traditionally, nitrification was thought to be a two-step process, where ammonia is first converted to nitrite by ammonia-oxidising bacteria (AOB) before nitrite oxidising bacteria (NOB) complete the oxidation to nitrate. Later, it was discovered that a group of archaea (ammonia oxidising archaea, AOA) could also undertake ammonia oxidation, typically in oligotrophic/extreme conditions such as low ammonia availability and pH. The separation of nitrification into two steps involving different microorganisms has puzzled scientists as a single organism completing both steps of nitrification was theoretically assumed to be more efficient. The presence of complete ammonia oxidisers (comammox) was later confirmed by cultivating them from an aquaculture system and a core from a deep-sea oil well. It was found that comammox belongs to lineage II of the genus Nitrospira, a group of bacteria traditionally thought to be responsible for nitrite oxidation. Comammox Nitrospira and canonical Nitrospira can be distinguished by the presence of the ammonia monooxygenase gene (AMO). Furthermore, comammox Nitrospira can be separated into clade A and clade B based on the phylogeny of this gene. Clade A can also be further divided into sub-clades A.1, A.2.1, A2.2, and A.3. Since its initial discovery, comammox Nitrospira has been found in a variety of terrestrial ecosystems. Typically, studies have shown that clade B are more abundant in forest and paddy soils, whilst clade A.2 may prefer agricultural soils. Clade A.1 is seen to be the dominant cluster in natural and artificial aquatic ecosystems such as freshwater wells and wastewater treatment plants. However, the presence and distribution of comammox Nitrospira, relative to canonical ammonia oxidisers, in different soils and relationships with soil and environmental conditions are not fully understood. The research described in this Thesis was designed to fill this knowledge gap and improve our understanding of comammox Nitrospira and canonical ammonia oxidisers. Experiment 1 determined the abundance and community composition of comammox Nitrospira throughout New Zealand Dairy farms and quantified the abundance and community composition of comammox Nitrospira in New Zealand under various land uses. It was concluded that comammox Nitrospira are ubiquitous throughout New Zealand soils. Comammox Nitrospira amoA abundance shared a strong positive and strong negative correlation with soil moisture and pH, respectively. Interestingly, the sequencing analysis determined that the comammox Nitrospira community solely consisted of clade B. Two experiments were devised to investigate these correlations, with respect to canonical ammonia oxidisers. Experiment 2 explored the effect of soil pH, with N inputs, on comammox Nitrospira abundance and community composition in New Zealand dairy pasture soils. Comammox Nitrospira preferred the natural (6.1-6.2) soil pH with no nitrogen amendment. Comparatively, the AOB community (dominated by Nitrosospira) responded positively to soil pH and nitrogen input. This may be due to the difference in ammonia availability. Estimated ammonia availability in the synthetic urine treatments (equivalent to 700 kg N ha-1, N700) accurately predicted the AOB amoA gene abundance. Interestingly, the AOA communities (which were predominantly made up of Thaumarchaeota group I.1b clade E) seemed to prefer the natural and high pH soils over the low pH. This may be due to the lineage of AOA present. AOA did not respond to the application of nitrogen. Experiment 3 investigated the effect of soil moisture and temperature on comammox Nitrospira abundance, transcriptional activity, and community composition, relative to canonical ammonia oxidisers. AOB was the dominant nitrifier in the synthetic urine treated soil regardless of temperature or moisture. Peak AOB amoA transcript abundance was positively correlated with estimated soil ammonia availability. While the nitrification rate and changes in AOB amoA gene abundance followed a similar relationship. Ammonia oxidising archaea were strongly influenced by soil temperature. At 20 °C, AOA amoA peak transcript abundance averaged over 1 order of magnitude higher than at 8 °C. A member of the AOA community associated with the Nitrosocosmicus subclade was positively correlated with ammonium and estimated soil ammonia concentrations. The presence and relative increase of Nitrosocosmicus AOA in a high nitrogen environment poses an interesting contrast to the current scientific opinion. Contrary to Experiment 1, the abundance of comammox Nitrospira amoA was not positively correlated with soil moisture. This suggests that the association is more complex than previously thought. Further research is required to determine the drivers of comammox Nitrospira abundance in a high moisture environment. Overall, the results of this thesis indicate that in New Zealand, AOB are the dominant ammonia oxidiser in a nitrogen-rich environment, such as a dairy farm soil. While the majority of the AOA community prefer a high temperature, low nitrogen environment. However, Nitrosocosmicus-like AOA may respond positively to nitrogen amendment, which challenges our current understanding of terrestrial AOA. Comammox Nitrospira may prefer a slightly acidic, oligotrophic soil environment and do not respond to temperature change. However, they may be the main ammonia oxidiser in some high moisture environments, potentially due to biotic interactions with plants or microbes.
Open Access
Managing tourist reactions towards gastronomy tourism: An examination of Human-Food-Place (HFP) experiences within a value chain system : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Ayuni, Risca Fitri
Indonesia is a food-obsessed society and has been named a global hub of sustainable gastronomy tourism by UNWTO. Thousands of unique Indonesian gastronomy experiences make food a popular reason why many tourists visit Indonesia. The Indonesian government has identified five main gastronomic destinations: Bandung, Semarang, Solo, Yogyakarta, and Bali. Tourist loyalty is critical for gastronomy tourism as it can be economically and culturally advantageous for a place, even for a broader region. Prior studies have shown that tourist satisfaction is a significant predictor of tourist behavioural intentions, and this includes the intention to revisit a gastronomy destination, visit other gastronomy destinations, and recommend a gastronomy destination to other potential tourists. Studies on gastronomy tourism have also investigated various aspects such as place attachment and place association, local food quality and local food experiences, and the tourist-local interactions between tourists and residents. Two relatively new constructs, tourist self-congruity and destination stereotypes, have appeared in recent research in this topic area. However, no studies to date concerning gastronomy tourism have examined all these constructs in one conceptual model. This study is based on two research objectives: 1) To explore the inter-relationships amongst the constructs in the Indonesian gastronomy tourism industry and 2) To explore the moderating effects of the intensity to travel and to examine whether the conceptual model is supported for both gender sub-groups. The sample used in this study was based on the perception of domestic (Indonesian) tourists. To analyse the collected data, structural equation modelling, and multigroup comparisons using SPSS 28 and SmartPLS 4 was employed. The results showed that when considering tourist behavioural intentions towards gastronomy tourism, the intention to recommend a destination to others was the most significant construct in this study. This was followed closely by the intention to revisit a gastronomy destination and the intention to visit other gastronomy destinations. The findings highlighted the direct relationships amongst constructs. They demonstrated that place association and place attachment affect the intention to revisit a gastronomy destination and the intention to recommend a gastronomy destination to others through the mediating variable of tourists’ satisfaction. This research found that there were no significant associations that supported the role of tourist intensity in travelling as a moderator in the relationship between overall tourist satisfaction and intention to revisit a gastronomy destination. In addition to this, statistically significant differences were found between female and male tourists in terms of the relationship between tourists’ satisfaction and the intention to revisit a gastronomy destination. This research also provides some important theoretical and practical contributions. From a theoretical standpoint, it provides a comprehensive model for a gastronomy tourism value chain. This study also examines distinct types of tourist’s intensity to travel and gender. In terms of practical contributions, this research provides best-practice insights for key place stakeholders. Stakeholders include destination management organizations, managers of Indonesian gastronomy tourism businesses, the Indonesian government, and residents, as they all have roles in the management and success of a gastronomy destination’s branding and sustainability.
Open Access
A transdisciplinary approach to understanding the connections between soil and people, through food production: A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Gillespie, Julie
There is a disconnect between soil, food, and people, that is being exacerbated as our populations become increasingly urban-based. This presents a ‘wicked’ challenge for soil and food security that soil science alone is unable to address. Resolving this issue requires understanding the extent and nature of the current (dis)connections, providing an opportunity to extend beyond the disciplinary boundaries of soil science. This research aims to develop an understanding of the (dis)connections between soil and people through the conduit of food in a place-based context by operating at the interface of mātauraka Māori (Māori knowledge) and soil science. This thesis provides two soil-centred examples of TDR in an Aotearoa New Zealand context, applying the He Awa Whiria (braided rivers) epistemological framework to guide the weaving of knowledges. To develop insight into how soil science and mātauraka Māori can be woven together and gain an understanding of historical connections between soil, food, and people, a case study guided by the questions of Mana Whenua regarding their past horticultural land use at Pōhatu (Flea Bay), Te Pātaka o Rākaihautū (Banks Peninsula), is undertaken. In this study, mātauraka Māori identified likely māra (garden) sites in the bay with oral histories identifying features such as gravel additions to the soil to improve drainage and retain warmth. Analysis of soil horizons modified with rounded beach gravels identified phytoliths with a morphotype consistent with kūmara leaves. Undertaking this study has demonstrated the importance of relationships when weaving knowledges, and the benefits of recognising equal value of the knowledges involved. Building on the results and learnings from the Pōhatu case study, a TDR methodology is applied to develop the place-based Food-Landscape Networks (FLN) framework, placing soil at its centre. The FLN framework applies a holistic approach to understanding the reciprocal connections between soil, food, and people in contemporary local food production systems. To assess the suitability of the FLN framework for understanding connections between soil, food, and people, it has been applied to three food-landscapes in Waitaha (Canterbury). Applying the framework makes visible the (dis)connections between soil, food, and people in three food-landscapes with the primary disconnection being people and soil across all three food-landscapes, as well as identifying where interdisciplinary collaboration is needed. This thesis enhances understanding and demonstrates the importance of engaging with mātauraka Māori as a knowledge of equal value to soil science for addressing complex, soil-centred environmental challenges facing Aotearoa New Zealand. The application of the transdisciplinary FLN framework illustrates the complexity of understanding the reciprocal connections between soil and people, highlighting the limitations of soil science in understanding and addressing this disconnect alone. This signals the need for interdisciplinary approaches, nested within TDR, for consumer disconnects to be addressed. The co-production of knowledge by weaving knowledges together to assess and understand these connections provides an opportunity to connect, and reconnect, people with where food comes from to work towards soil and food security.
Embargo
Improving the performance of fresh value chains for economic development, nutrition and food security: A system dynamics approach : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Seba, Samuel Tigistu
Improving the performance of fresh value chains (FVCs) for economic development and food and nutrition security is vital in the face of emerging local and global challenges. In addition to securing an affordable food supply, well-performing AVCs improve the incomes of actors along the chain. The extant literature indicates that a severe lack of investments throughout FVCs in emerging economies, resulting in high post-harvest losses, erodes actors' margins and leads to a persistent shortfall in the availability of affordable fruit. This research adopts the System Dynamics (SD) modelling approach as it can measure quantifiable ex-ante impacts in the FVCs and offers a system-wide view that accommodates the complexity, dynamic, and multi-objective nature of the problem. Its moderate demand for data, proficiency, and experience in programming languages, and the relatively less obscure nature of models and results to ordinary decision-makers make SD modelling suitable. This research presents findings of modelling the avocadoes value chain (AVC) from the three major producing areas in the developing country. The primary aim was to identify, analyse, and explain the causes of the poor performance of the AVC and simulate the impacts of selected interventions. The theoretical and empirical literature on AVCs in emerging economies suggests a severe lack of investments by all stakeholders, resulting in high reported post-harvest losses (25% - 40%) that reduce incomes and affordability, causing a persistent shortfall in fruit availability. Various theories indicate factors influencing investment decisions, including profitability, availability of skills and input, availability and cost of finance, and uncertainties created by actors' opportunistic behaviours. An extensive literature review, observations of the AVC activities, in-depth semi- structured interviews, and Group Model Building (GMB) workshops were used to collect data, collaboratively build qualitative and quantitative SD models, and validate the outputs. To build the model, secondary data from several sources was combined with primary data from the interviewees and GMB workshop participants. Quantitative SD modelling identified several feedback loops in play, determining the performance of the AVC. Currently, dominant loops arise from interactions of market realities and efforts of actors to protect and increase their margins. When faced with faced with decreasing margins due to high post-harvest losses, retailers pass parts of these costs to consumers and producers by increasing consumer prices and reducing producer prices. Two dominant loops revealed how producers and consumers push back by decreasing quantity demanded and quantity supplied, swaying prices in their favour. Given the resulting decrease in quantity of demand, bumper fruit supplies reduce producer prices, decrease revenue and margins, and discourage investment in subsequent seasons to cut back on production. Essentially, these loops represent a vicious cycle in which a severe lack of investments leads to remarkably high post-harvest loss and reduced margins that decrease affordability and producer prices, impacting quantity demanded and discouraging investment which ultimately decreases availability. In this vicious cycle, the high post-harvest loss also reduces income to agribusinesses, leading to low economic development and discouraging investment. Comprising all these feedback loops, simulation of the quantitative SD model for the past and future twenty years also revealed persistent low levels of income to actors, affordability and availability, given the high post-harvest loss as a result of the prevailing level of incentives and drivers of the lack of investments. The salient cost of high post-harvest loss, mostly realised at the retailer stage, continues to erode their margins, particularly in distant urban centres, even after continually pushing consumer prices up, reducing affordability. The resulting decrease in quantity demand pushes producer prices down, forcing them to continue cultivating a small number of avocado trees under a low-input production system, limiting the growth in the availability of avocadoes in the whole chain. A coherent set of interventions spearheaded by modernising and organising retail was identified collaboratively. Modernised and organised retailers can assume chain leadership and deploy bestowed customer value and market information to incentivise and sanction other transformed actors to invest, access, and fulfil supply contracts, enforcing implemented quality and fruit handling standards and facilitating the flourishment of agribusiness credit services and efficient payment systems. Scenario analysis suggests that the current trajectory would lead to a worsening of performance even in a plausible best case, while interventions bring about robust positive ex-ante impacts on actors’ incomes, affordability, and availability from improved levels of investments. The research identified several institutional changes needed to effectively implement these interventions, including legislating mandatory fruit quality and safety standards, independent quality-assuring services, and forming hybrid producer organisations and organised retail. The research results contribute a strategic planning input and a platform for dialogue in efforts to build effective AVCs. Results also extend the literature in improving and measuring the performance of AVCs.
Open Access
Behavioural traits to identify subclinical diseases of grazing ruminants : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Fan, Bowen
Animal welfare and wellbeing can be improved through the early detection and diagnosis of disease. Subclinical infections in particular can be difficult to determine, however, animals may demonstrate subtle changes in behaviour. These changes related to eating, ruminating, inactive behaviour and active behaviour can potentially be identified and measured through sensor technologies. This thesis composes of a series of studies designed to explore changes in behavioural patterns of grazing ruminants experimentally challenged with subclinical infections using commercially available accelerometers. The objective of the first trial (Chapter 3) was to investigate the changes in grazing, ruminating and activities of grazing dairy calves infected with the internal gastrointestinal nematodes Ostertagia ostertagi and Cooperia oncophora and determine the behavioural patterns after receiving an anthelmintic treatment, using neck mounted sensor collars. At Day -12 relative to an experimental infection, animals were dewormed and fitted with Allflex EveryCow collars which can identify mutually exclusive behaviours such as eating, ruminating, resting, walking, medium activity, high activity and behaviour related to heavy breathing. On Day 0, they were allocated into one of two treatments, viz, Infected, in which animals were orally dosed weekly for three weeks with a 1:1 mixture of 20,000 O. ostertagi and C. oncophora L3 larvae, or Control in which animals remained uninfected, and grazed a new pasture that had not previously been grazed. Animals were rotationally grazed as a mob with weekly shifts and each break back-fenced to reduce the risk of self-infection. On Day 49, to assess the behavioural response following anthelmintic treatment, half of calves in each treatment were orally administered with the Matrix Oral triple combination anthelmintic and continued to be monitored, using a 2 × 2 factorial experimental design, viz, Control without Drench (COD), Control with Drench (CD), Infected without Drench (IOD), Infected with Drench (ID). Results showed nematode challenge increased daily eating time (+14.8 minutes per day, mins/d, P = 0.007) and reduced daily ruminating time (-9.8 mins/d, P = 0.001) and daily mid-activity duration (-5.3 mins/d, P = 0.023) in grazing calves. After 49-day challenge of gastrointestinal nematode (GIN) infection, the mean faecal egg counts (FEC) of Infected and Control groups were 700 ± 181 and 33 ± 18 eggs/gram, respectively. Furthermore, there was a lack of a consistently high level of parasitism in the calves. To help determine if there was any potential for subtle changes in behaviour to be detected, three animals at the extremes of each of the initial intended treated groups, viz, animals in IOD and 3 animals in ID with the highest FEC and three calves in COD and four calves in CD with highest body weight gain were selected. Parasitism increased FEC and decreased daily live weight gain (643.7 g/day vs 790.6 g/day for parasitized animals and control animals respectively, P = 0.029) from Day 20 to Day 49. There were non-significant negative correlations between log10 (FEC+1) and behavioural measurements for daily eating duration (r = -0.085, P = 0.501), daily walking duration (r = -0.16, P = 0.191), daily mid-activity duration (r = -0.18, P = 0.155), daily high activity duration (r = -0.060, P = 0.636), and daily heavy breathing duration (r = -0.17, P = 0.174) with non-significant positive correlations for daily ruminating duration (r = 0.018, P = 0.889) and daily rest duration (r = 0.16, P = 0.197). In the parasitized animals with the high-level output of FEC, nematode infection significantly increased their mean daily eating duration (+34.6 mins/d, P = 0.020), compared with their uninfected counterparts, and had no effect on mean daily ruminating duration (-18.2 mins/d, P = 0.737), mean daily walking duration (-14.4 mins/d, P = 0.598), mean daily mid-activity duration (-10.3 mins/d, P = 0.498), mean daily high activity duration (-7.2 mins/d, P = 0.744). Moreover, nematode infection increased eating time during cooler periods of the day (+1.7 mins/h from 0400 to 0800 hours, +1.5 mins/h from 2000 to 2300 hours) and decreased in the early morning (-0.7 mins/h from 0000 to 0300 hours) and in the afternoon (-1.5 mins/h from 1300 to 1700 hours) (P < 0.001), and reduced the duration of mid-activity during most times of the day (-0.5 mins/h from 0000 to 0700 hours, -0.2 mins/h from 1100 to 1300 hours, -0.2 mins/h from 1500 to 2300 hours, and +0.2 mins/h from 0800 to 1000 hours, P = 0.007). In parasitized animals post anthelmintic drenching, heavy breathing duration was decreased (-0.1 mins/h) from 0200 to 0500 hours and then increased (P = 0.010) during most time of the day (from 0600 to 0900 hours, from 1100 to 1600 hours and from 2200 to 0100 hours) with fluctuations from 1700 to 2100 hours. In control animals post anthelmintic drenching, walking duration was reduced (P = 0.010) during early morning from 0100 to 0700 hours (-0.4 mins/h) and at dusk from 1700 to 1800 hours (-0.6 mins/h), and increased from 0800 to 1600 hours (+0.3 mins/h) and in the late evening from 1900 to 0000 hours (-0.2 mins/h), while heavy breathing duration was increased (P = 0.018) during most times of the day (+0.1 mins/h from 0500 to 0900 hours, +0.2 mins/h from 1100 to 0000 hours). Unfortunately due to an outbreak on Mycoplasma bovis on the research farm the first study was required to be terminated after only a short-time post-drenching. Due to biosecurity requirements continuing investigations in cattle was not an option and it was decided to instead use sheep as the species of choice for the remainder of the studies. A paucity of commercially available sensors for sheep meant that alternatives must be found and validated. Of these, the Cowmanager sensor tags were chosen due to their relative size and weight and possible suitability for a sheep ear. However, these tags had not previously been evaluated in sheep. The second trial (Chapter 4) was aimed to determine if the Cowmanager tags could provide an accurate and meaningful representation of the behaviour of sheep. In order to do this, a lipopolysaccharide (LPS) challenge model was used which provides a predictable and consistent short-term change in animal behaviour such as lethargy, and inappetence without long-term negative consequences. At recruitment (Day -10), twenty female Coopworth lambs of 8-10 months (mean live weight = 38.63 ± 2.04 kg) were weighed and fitted with CowManager SensOor ear tags which can identify mutually exclusive activities of five categories: eating, ruminating, inactive behaviour, active behaviour and highly active behaviour, and allocated within live weight strata to one of two treatments, respectively receiving 0 or 0.5 μg/kg body weight of endotoxin LPS with an experimental design of 2 × 2 Latin square. On Day 0, the lambs in the LPS group were intravenously injected with LPS contained in sterile saline, while the control lambs were intravenously injected with sterile saline solution. Seven lambs (four lambs in the LPS group and three control lambs) were randomly selected and individually marked for visual identification for verification of the behavioural changes. To validate the data between visual observation and sensor recordings, the behaviours of the seven lambs were visually observed and recorded every minute for 60 consecutive minutes for two hours between 0900 hours and 1600 hours within three days around the period of LPS infusion. A week after the first intravenous infusion of LPS, the two groups were swapped and intravenously administered with 0.5 or 0 μg/kg body weight of LPS, and the experimental procedure was repeated for the second period. The behaviours of the same seven lambs previously marked for visual identification was recorded via visual observation based on the same procedure to compare with sensor recordings. LPS infusion elevated rectal temperatures after 4 hours from 39.31℃ to 39.95℃, indicating successful establishment of an acute fever response for comparison between groups (P < 0.001). Results showed there was good agreement between visual observations and sensors for active and not active behaviour, but poor agreement with eating and ruminating time. For each of the five recorded behaviours, time spent eating, ruminating, not active, active and highly active, the accelerometers were able to detect an effect of LPS challenge. Compared with the control, LPS infusion decreased eating time (-6.7 mins/h, P < 0.001), active behaviour (-8.4 mins/h, P < 0.001) and highly active (-2.9 mins/h, P < 0.001) and rumination time (-1.4 mins/h, P = 0.075) and increased inactive behaviour (+16.0 mins/h, P < 0.001) in challenged lambs. This provided validation of the Cowmanager tags for use in sheep. Alkaloids produced by ryegrass endoyphytes are known to cause changes in animal behaviour, inducing heat stress and ryegrass staggers in severe cases. In Chapter 5, the potential for CowManager SensOor ear tags to categorize changes in eating, ruminating and other behavioural activities of grazing lambs exposed to endophyte-infected perennial ryegrass was evaluated. Thirty Coopworth lambs with a mean live weight (± SE) of 33.6 ± 0.46 kg were allocated randomly within live weight strata to either endophyte-free cultivars of ryegrass (Control) or wild type endophyte-infected cultivars of ryegrass pasture (Endophyte). Live weight change, behaviour and incidence of ryegrass staggers were monitored over a 2-month grazing period. Moderately severe staggers (score 4/5) occurred in 40% of lambs in the endophyte treatment with a mean staggers score of 2.33 ± 0.41 (P < 0.001) for the endophyte group at the end of trial. During the period of ryegrass staggers, compared with those grazing the control pasture, lambs in the endophyte group had had no significant difference in eating time (-36.0 mins/d, P = 0.516), time spent being active (+29.9 mins/day, P = 0.556) and being inactive duration (-43.7 mins/day, P = 0.114), but increased time spent ruminating (+40.2 mins/d, P = 0.051). When comparing lambs in the same group with stagger score 4 and those with staggers score 1 or 0 during staggers period, these behavioural differences were even more pronounced though non-significance was presented (-82.2 mins/d for eating, P = 0.073; -62.9 mins/d for being inactive, P = 0.221; +124.0 mins/d for being active, P < 0.001; +48.9 mins/d for ruminating, P = 0.015), indicating that it was not a reflection of the different swards or the physical characteristics. Changes in the pattern of behaviours during staggers period were also evident as reflected in a diurnal alteration of each activity over time of the day. The challenge of toxic alkaloids produced in endophyte-infected ryegrass led to more time eating during cooler period of the day (P < 0.001) and more time being active for compensation during day-time (P < 0.001) as well as more ruminating time during night-time (P < 0.001) and less time being inactive (P < 0.001) and highly active (P < 0.001), especially in the lambs with severe ryegrass staggers. The final trial then compared the effect of a chronic subclinical infection with gastrointestinal nematode parasites on sheep behaviours (Chapter 6). At start of this trial on Day 0, thirty-six Coopworth ram lambs at 8-10 months of age were weighed, fitted with CowManager SensOor ear tags, and randomly allocated within live weight to one of four experimental groups, non-parasite exposure groups (NP), NP1 (n = 9, 34.89 ± 3.93 kg,) and NP2 (n = 9, 34.56 ± 2.82 kg), oral administration of parasites (OP), OP1 (n = 9, 34.89 ± 3.00 kg) and OP2 (n = 9, 34.44 ± 2.94 kg) with a three-times weekly trickle infection for four weeks with the equivalent of 130 Teladorsagia (Ostertagia) circumcincta L3 larvae per kg live weight (LW) and 80 Trichostrongylus colubriformis L3 larvae per kg LW per day. After 4 weeks of infection, the NP1 group and OP1 group were orally administered once with an anthelmintic. Two weeks later, the NP2 group and OP2 group were orally treated once with the same anthelmintic. GIN infection resulted in a reduction in mean daily eating time (-91.7 mins/d, P = 0.001) and an increase in mean time spent being inactive (+88.4 mins/d, P = 0.001) and active (+7.4 mins/d, P = 0.017) with no differences in mean daily ruminating time (-15.5 mins/d, P = 0.395) and mean daily highly active duration (+12.7 mins/d, P = 0.400). Compared with the control, the animals challenged with nematode infection increased eating time during cooler period of the day (+1.5 mins/h from 2000 to 0200 hours) with less time spent eating during sunrise (-4.7 mins/h) and sunset (-1.7 mins/h) (P < 0.001). Further, compared with the control, the animals infected with nematode reduced daytime ruminating (-0.5 mins/h from 0600 to 1600 hours) and increased ruminating time at dusk (+0.5 mins/h from 1700 to 1900 hours) and in the evening (+0.8 mins/h from 2100 to 0000 hours) (P < 0.001). In addition, compared with the control, nematode infection increased inactive time of parasitized animals in the early morning/after sunset with a reduction during the late afternoon (-0.6 mins/h from 1400 to 1800 hours) and late evening (-1.1 mins/h from 2200 to 0100 hours) (P < 0.001), increased active duration in the early morning (+1.2 mins/h from 0400 to 0700 hours) with reductions in the late morning (-0.2 mins/h from 1000 to 1200 hours) and from late afternoon to evening (-0.3 mins/h from 1500 to 2200 hours) (P < 0.001), and increased highly active duration during most times of the day (+0.6 mins/h from 0300 to 1800 hours) with a decrease in the evening (-1.1 mins/h from 1900 to 0200 hours) (P < 0.001). Compared with the control animals, for the infected animals, anthelmintic drenching increased eating time during most of the daytime +1.6 mins/h with a decrease during cooler times of the day (-2.4 mins/h from 2000 to 0300 hours) (P < 0.001), increased night-time ruminating (+1.3 min/h from 2000 to 0200 hours) with an increase in the early morning (-1.1 mins/h from 0300 to 0800 hours) and in the afternoon (-1.0 mins/h from 1300 to 1800 hours) (P < 0.001), increased inactive duration in the morning (+0.9 mins/h from 0200 to 1000 hours) and in the afternoon (+1.3 mins/h from 1200 to 1700 hours) with a decrease in the early evening (P < 0.001), reduced active duration from 0300 to 0500 hours (-0.6 mins/h) and from 0700 to 1400 hours (-1.1 mins/h) with an increase from 1500 to 1800 hours (+0.9 mins/h) and from 2000 to 0200 hours (+0.9 mins/h) (P < 0.001), decreased highly active duration during most of the daytime (-1.1 mins/h from 1000 to 1800 hours) with an increase in the evening (+2.2 mins/h from 1900 to 0100 hours) (P < 0.001). In summary, the results from these trials demonstrate that altered behavioural patterns of grazing animals due to health challenges of diseases or toxins can be detected through commercially available sensor technologies. Acute health challenge in lambs can increase inactive duration and compensate to reduce eating duration, rumination duration, active duration and highly active duration in a short period, whereas chronic endophyte staggers challenge in lambs results in increased daily active duration and daily ruminating duration with a decrease in daily eating duration, daily inactive duration and daily highly active duration. Chronic subclinical parasitic challenge in dairy calves can induce an increase in daily eating duration and daily rest duration, and decrease daily durations of ruminating, walking, mid-activity, high-activity and heavy breathing. However, chronic subclinical nematode challenge in lambs can result in a decrease in daily durations of eating, ruminating and an increase in the daily durations of being inactive, active and highly active. The magnitude and duration of total daily behavioural changes varied under these health challenges. Moreover, both chronic subclinical GIN challenge and chronic challenge of toxic alkaloids in endophyte-infected ryegrass can increase eating time during cool periods of the day, decrease time spent being active during nighttime with an increase in the daytime in grazing lambs at pasture. However, chronic subclinical GIN challenge can increase inactive duration at sunrise and sunset and decrease daytime ruminating and increase ruminating duration in the evening, while chronic challenge of toxic alkaloids can increase ruminating duration with a reduction in inactive duration during most of the day. Consequently, behavioural changes detected by commercially available sensor technologies evaluated in these studies could be applied as a useful and potential tool to identify changes in behavioural patterns of each category under infection challenges of diseases or toxins, indicating animal health status and determining the need of treatments for individuals or a whole mob.
Open Access
The lived experience of adults with Dyspraxia/DCD : A thesis submitted in partial fulfilment of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) McAllum, Leanne Maria
Dyspraxia is an emergent social phenomenon that has generally been associated with childhood and motor coordination difficulties. The experience of Dyspraxia in adulthood is, conversely, not well understood with only a small number of studies examining Dyspraxia across the life course. Dyspraxia is predominantly conceptualised in both the research literature and practice using the biomedical model. Dyspraxia is one of several neurodivergent experiences and possibly the least well known, having only been recognised in the past two decades, in comparison to a longer social awareness of experiences such as Dyslexia and Autism. Known as Developmental Coordination Disorder (DCD) in the medical literature, the phenomenon has been etiologically defined as a physical functional deficit. By contrast, Dyspraxia can also be understood as having cognitive functional aspects, such as in the Aotearoa New Zealand context. The objectives of this research were firstly to examine the lived experiences of participants with Dyspraxia/ DCD in relation to predominant social biomedical conceptualisations. A second objective was to identify the repercussions of contemporary social framings of Dyspraxia/ DCD in Aotearoa New Zealand and how Dyspraxia is understood and addressed, particularly in adulthood. The approach taken to answer the research objectives was that of the thematic analysis of semi-structured interviews undertaken with both people with Dyspraxia and professional participants. In this work, a qualitative approach was employed in the form of semi-structured interviews with twenty-three people with Dyspraxia to better understand the lived experience. Further, twenty-six professionals in medical and education fields were also interviewed to investigate the role of institutions on the Dyspraxia lived experience. Participants were located through two gatekeeper organisations, cold-calling and snowball sampling techniques. This research, undertaken by an insider researcher with Dyspraxia, highlighted that an examination of Dyspraxia is unable to be considered independently of social contexts. Further, it was found that biomedical framings affected the lived experience of participants with Dyspraxia/DCD in Aotearoa New Zealand and the subsequent social response to the phenomenon. The lived experience of Dyspraxia in adulthood was found to have implications for how people with Dyspraxia construct their identity with Dyspraxic participants describing the need to adapt in normative social settings to achieve inclusion. This thesis adds to current conceptualisations by utilising the capabilities approach (CA) to examine the lived experience of Dyspraxia in relation to the medical and social models. Throughout are a range of accounts from Dyspraxic participants, describing their attempts to access the capabilities necessary to ensure the life outcomes they value. The CA can account for the significant changes between childhood and adulthood described by study participants within their social worlds. In contrast to the biomedical perception that DCD is a physical deficit, this thesis shows that the attainment of capabilities is complex and evolves across the lifespan in response to personal heterogeneities but also the social environments that Dyspraxic participants inhabit. The CA was found in the discussion to improve upon, and complement, current conceptualisations of Dyspraxia. Conceptualising Dyspraxia in alternate ways to better explain study findings, such as using the CA, suggests a range of areas for future research and practice.
Embargo
Essays on the role of rural finance, green finance and digital financial inclusion on agricultural carbon emissions reduction : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Hu, Die
Green agricultural development is significant for China against the background of carbon peak and carbon neutrality, and at the same time, it is crucial to secure China's food security. This thesis examines the influence of finance on agricultural carbon emissions, specifically focusing on the significant role of rural finance, green finance and digital financial inclusion. This thesis comprises three essays investigating whether rural finance, green finance and digital financial inclusion help to reduce agricultural carbon emissions in China. The first essay estimates China's agricultural carbon emissions from 2001 to 2020 and analyzes the temporal and spatial characteristics of agricultural carbon emissions, providing a research base for the thesis. Next, the essay examines the impacts of rural finance on agricultural carbon emissions by introducing the rural finance development indicator into the environmental Kuznets Curve Theory. This not only extends the theory but also helps validate the rural environmental Kuznets Curve in China. The findings reveal that the environmental Kuznets Curve hypothesis is invalid in rural China and that rural finance is not conducive to reducing agricultural carbon emissions. The second essay uses a bidirectional-fixed effects regression model, a quantile regression mode, and a difference-in-differences model to investigate the impacts of green finance on agricultural carbon emissions (ACEs). The results reveal that green finance significantly negatively correlates with ACEs in the eastern and central regions but is insignificant for the whole of China. Secondly, there is significant regional heterogeneity in the impact of green finance on ACEs. The impacts of green finance on agricultural carbon emissions also vary across different quantities, showing an asymmetric impact of green finance on ACEs. Thirdly, the Green Finance Reform and Innovation Pilot Zones do not show a direct policy effect on ACEs. The third essay investigates the combined effect of green finance and digital financial inclusion on ACEs using bidirectional fixed-effects regression, moderation mechanism analysis, and Two-Stage Least Squares instrumental methods. The finding reveals that green finance positively impacts ACEs reduction but digital financial inclusion negatively impacts ACEs’ reduction. Moderation mechanism analysis shows that digital financial inclusion has a negative role in moderating the impact of green finance on ACEs, indicating uncoordinated development between green finance and digital financial inclusion in rural China. The results are robust to different methods that address the endogeneity issues. This thesis extends the ACEs theory into the agricultural sector, not only enhancing the scope of the Environmental Kuznets Curve Theory into the agricultural sector but also addressing the omitted variables criticized by scholars by considering financial development's impact on the environment. This thesis also examines the role of green finance in reducing carbon emissions in the agricultural sector, which was overlooked in previous research. Using quantile regression to examine the asymmetric effects of green finance across different quantiles and a difference-in-differences model to examine green policy impacts provides more robust results and critical information for formulating policies. More importantly, this thesis provides a unique perspective to examine the combined effects of green finance and digital financial inclusion, offering pivotal conclusions and policy recommendations.
Embargo
An examination of the quality of sustainability reports in the GCC : A thesis submitted in partial fulfilment of the requirements for the Degree of Doctor of Philosophy at Lincoln University
(Lincoln University, 2024) Kashif, Sameerah
The growing global sustainability challenges and rising stakeholder demand for companies to be accountable for their actions have led to an increase in sustainability reporting. Given this increase, it is important to examine the quality of sustainability reports to determine whether they provide incremental information which facilitates informed decision making by stakeholders. However, studies examining the quality of sustainability reports have typically focused on content quality, with few studies investigating textual quality, visual quality and/or balanced reporting. The quality of sustainability reports published by the Gulf Cooperation Council (GCC) listed companies is examined in this research. This research focuses on readability, graphs, and negative information to examine textual quality, visual quality and balanced reporting, respectively. In Phase 1, a quantitative analysis is conducted to investigate textual quality by measuring the level of language difficulty (readability) of sustainability reports. In Phase 2, visual quality is examined by conducting a quantitative analysis of graphs used in sustainability reports. In Phase 3, quantitative and qualitative analyses are used to investigate balanced reporting in sustainability reports. The research findings are examined and interpreted through the lens of impression management and legitimacy theory. This research finds that overall, sustainability reports published by the GCC listed companies include complex language that makes the reports difficult to read. Report readers would require at least a post-graduate level of education to efficiently read and understand the sustainability reports. Considerable evidence of impression management elements is found in the graphs included in the sustainability reports. The findings of the balanced reporting analysis reveal that generally companies are reluctant to report on the challenges and setbacks faced during business operations. When companies report negative information, they mostly adopt legitimation strategies that reinforce corporate commitment towards sustainable business practices. Companies are also found to symbolically portray commitment towards sustainability when reporting negative information. The findings indicate various impression management elements that lower the textual quality, visual quality and impede balanced reporting in sustainability reports. By being the first research that examines textual quality, visual quality and balanced reporting in a single study, this research provides insights into the role of impression management and its potential to affect the quality of sustainability reports and corporate legitimacy. In doing so, this research adds to the limited literature on impression management in sustainability reports and contributes to the debate in academic literature of whether sustainability reports are used to communicate incremental information or as tools for impression management. This research provides guidance to companies on the use of language, graphs and negative information to enable them to communicate information in an accurate, balanced, and clear manner. This research will benefit companies, standard-setters and legislators by highlighting the textual and visual features of best practice and the significance of balanced reporting for publishing good quality sustainability reports.

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