Dissertations / Theses: 'Fields of Research – 300000 Agricultural, Veterinary and Environmental Sciences'

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Turner, Susan Jane. "Microbiological Indicators of Faecal Contamination in Aquatic Environments." Thesis, University of Auckland, 1996. http://hdl.handle.net/2292/2375.

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1. The aim of this research was to determine appropriate microbial indicator systems for use in monitoring the occurrence and source of faecal contamination in aquatic environments. Particular emphasis has been placed on the identification of indicators which might enable faecal contamination of human origin to be distinguished from that of non-human derivation. Two lines of investigation have been pursued; the use of alternative microbial indicator systems for water quality monitoring, and the development of diagnostic molecular methods for identifying the origin of faecal organisms. 2. Field and treatment plant studies were undertaken to investigate the utility of three indicator systems for monitoring water quality impacts in the coastal area surrounding the discharge from Auckland's North Shore City wastewater treatment plant. F-specific bacteriophage (F-phage) and ratios of F-phage to enterococci and faecal coliforms were examined over a twelve month period in which indicator levels at various stages of the wastewater treatment process were measured. These indicators and levels of Clostridium perfringens spores in sediment were measured in four outfall impact studies. 3. F-phage levels in effluent from the treatment plant (median=2.5 x 102 cfu/l00 ml) were too low to enable their use as source-specific tracers of effluent dispersion. However, higher F-phage levels in raw sewage (median=6.2 x l05 cfu/l00 ml) suggested that phage may be an appropriate indicator of raw sewage contamination in the receiving environment. F-phage was detected in coastal waters remote from the sewage outfall, providing presumptive evidence of sewage contamination entering the sea from sources other than the outfall discharge itself. 4. F-phage/enterococci and F-phage/faecal coliform ratios that were determined for sewage and treated effluent derived from the North Shore plant proved to be highly variable and were therefore unreliable for determining the source faecal contamination. 5. The concentration of Clostridium perfringens spores in sediments did not provide a useful means for tracing the distribution of faecal contaminants in the coastal system because the spore levels were found to be similar throughout the study area. This widespread occurrence of C. perfringens spores prevented identification of defined impact zones for any of the potential sources of faecal contaminants examined. 6. Randomly Amplified Polymorphic DNA (RAPD) analysis was used to investigate whether genetic markers could be identified for Escherichia coli isolates derived from different sources. RAPD profiling was found to be a highly discriminative method able to subtype E. coli strains present in both sewage and in the wastewater stream of a mechanical wood-pulping operation. In the pulp mill effluent, RAPD analysis indicated the presence of a restricted range of E. coli strains compared to the range found in the water intake and sewage effluent discharges. The results obtained provide presumptive evidence for the multiplication of E. coli strains within the wastewater stream. 7. Comparison of RAPD profiles derived from a range of human and environmental E. coli isolates led to the identification of a 1.6-kb marker. present in a subset of human isolates, but found only infrequently in isolates from animal origin. Primers based on sequence information obtained from this region of the genome yielded a direct PCR assay for the 'human' marker. The reliability and utility of the assay was improved when fluorescently-labelled primers and an automated DNA detection system was employed for the analysis of the amplified PCR products. 8. The diagnostic polymorphism was localised to the region immediately downstream of the gene encoding the glycine decarboxylase P-protein (gcvP). Comparison of DNA sequences from this region in 'marker-positive' and 'marker-negative' E. coli isolates revealed an abrupt loss of homology immediately downstream of the transcription termination point of the gcvP gene. The region of non-homology extends for at least 130 base pairs beyond the gcvP transcription terminator. Sequences spanning this region in marker-negative isolates exhibited a high level homology with that determined for E. coli K-12. The origin of the sequence for the same region in marker-positive isolates was unable to be identified. 9. The utility of the marker for environmental monitoring was investigated in a field study of a rural stream receiving bacterial contamination of both human and animal origin. The marker was consistently detected both in isolates derived from sewage effluents and in those found immediately downstream from sewage inputs-despite the presence of a high background of E. coli of animal origin. However the utility of the marker as a sewage-specific tracer was limited by the relatively low numbers of marker-positive d. coli in sewage effluents (approximately 8%). 10. In summary, the work described in this thesis has confirmed the need for multiple indicator systems in water quality monitoring and has identified appropriate areas for further research. The most promising area for future research is in the development of molecular tools which might provide both a better understanding of genetic variation in indicator organisms and enable methods to be developed for the detection of host-specific strains. Location of other polymorphisms likely to be present in the E. coli genome should enable further host-specific markers to be identified which could complement the 'human' marker identified in this study.
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Bates, Andrew John. "Effects of grazing management and pasture composition on the nitrogen dynamics of a dairy farm : a simulation analysis : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Lincoln University /." Diss., Lincoln University, 2009. http://hdl.handle.net/10182/1360.

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There is an extensive debate on the potential environmental impact of dairy farms and in particular the effect of dairy farms on the nitrogen cycle and the effect that this has on ecosystems. Within New Zealand and in particular in the South Island, the expansion of dairying and the adoption of new dairy systems has led to this becoming an increasingly important issue, locally through its effect on water quality and the environment and nationally and internationally through the production of green house gases. Increases in nitrogen usage at the expense of clover nitrogen fixation, irrigation, stocking rate and the introduction of dairy cows onto light free draining soils previously the preserve of arable or sheep farming has led to concern as to the effect intensive pastoral dairying may have on the nitrogen dynamics of the farm and the environment. This study is designed to assess how changes in grazing management in particular changes in pre-grazing and post-grazing residuals alter the clover/ryegrass balance on the farm and the effect that this has on the farm’s nitrogen dynamics. The effects of qualitative changes in grazing management on pasture composition are well established but little is known of the effect of quantitative changes in pasture management on composition, in particular the effect of grazing residuals. There are a number of detailed models of the physiological processes in the energy and nutrient cycling in plants, animals and the soil. There are a smaller number of whole farm models that through integration and simplification of component models attempt to represent the flux of nutrients though a dairy farm. None of these whole farm models is currently able to model the nitrogen flux through a dairy farm at a sufficient level of resolution to capture differences in pasture composition as these occur spatially, temporally and in response to grazing management. This project sought to better understand the nitrogen dynamics on a dairy farm by constructing and then linking component models – a pasture composition and growth model, a cow model, an excretal return model, a soil model and a water balance model – within a whole farm management schedule. The formal null hypothesis is that the mechanistic, mathematical model constructed for this PhD cannot capture and explain the full range of the changes in soil water content, soil nitrogen status, pasture production and composition and animal production, following the alteration in management of the dairy farm between 2002 and 2004. Individual component models were constructed by the author using the computer software package (Matlab) and validated against data extracted from the literature. The models were then converted into one simulation package using C-sharp as the source code language by Elizabeth Post, Senior Computer Scientist at Lincoln Ventures Ltd, Lincoln, New Zealand and the author. This model was then used to investigate the nitrogen dynamics of a dairy farm: the relationship with pasture composition and whether small changes in pasture residuals make a difference to pasture composition and nitrogen dynamics. Two different simulations were run based on the management practice of Lincoln University Dairy farm (LUDF) over two dairy seasons (2002-03 and 2003-04) and validated against the data recorded on this farm. In 2002-03, 50 cows were over wintered and 580 cows were subsequently milked on 200ha. Post grazing residuals where maintained at 1600-1750KgDM/ha. In 2003-04, 125 cows were overwintered and 635 cows were milked on 200ha with post grazing residuals maintained at 1400KgDm/ha. All models operate on a daily time step. Within the pasture model composition is described by 9 state variables describing different components of the pasture and pasture growth is modelled mechanistically from a calculation of component photosynthesis. A further 9 state variables describe the nitrogen composition of the pasture components. The soil model is a variable two layer, mechanistic representation, parametised for the shallow, stony soils of LUDF. Soil water status is an input for the pasture model while water uptake by the growing plants affects the soil water balance within the soil model. Animal intake and production are modelled mechanistically with model cows described in terms of their age, genetic merit, body weight, breed, pregnancy status, conception date and body condition score. Each cow type produces a different quantity of urinary and faecal excretion which varies with dry matter intake, milk yield and the sodium and potassium status of the pasture. Excretal nitrogen composition is predicted within a separate model which calculates daily nitrogen excretion in faeces, urine and milk. Excretions are deposited randomly over the grazed area and account is taken of overlapping excretions that are created on the same day and overlaps that occur with older excretal patches deposited in previous grazing rounds. Each excretal patch has its own associated pasture, water and soil model reflecting the differences in nitrogen status between patches. Grazing preference is expressed within the model between different classes of excretal patch and between excretal patches and the base pasture and between clover and grass. Supplementary silage is conserved and fed according to the management schedule of LUDF. Cows calve, become pregnant and are dried off within the model according to the relevant records from LUDF. Cows are deemed to arrive on the farm on the day of calving and to leave on the day that drying off is finished (a 5 day procedure within the model), except for those cows that are overwintering which remain on the farm. The soil model has multiple nitrogen/carbon pools and is dynamically linked to all the other models. External nitrogen losses from the system are modelled as volatilisation, leaching and denitrification, with pasture nitrogen uptake from the soil model and fixation by clover from the atmosphere. Both the individual component models and the final assembled composite model were successful in matching the available data in terms of pasture and animal production, pasture composition, soil water balance and nitrogen status and external losses. The model indicates that the low residual, high stocking rate farm returns more excreta to the soil. However, this is countered by a reduction in the amount of dead material returned to the paddock and this reduces the relative size of the pool of nitrogen in the dead organic matter. This produces a relative lack of substrate for the soil microbes which are thus unable to exploit all of the nitrogen in the available pool. Soil ammonium and nitrate pools are also increased from the increase in faecal and urinary return so precipitating an immobilising flux from these larger pools to the smaller pool of nitrogen available to the soil microbes. However, the relative inability of the soil bacteria to fully exploit this means that the production of soil organic live matter and the resulting mineralising flux from the dead organic matter pool through the available pool to the ammonium and nitrate pools is reduced. The larger ammonium and nitrate pools will also be associated with increased external losses from the system as denitrification, leaching and volatilisation are increased. The increase in the clover percentage within the sward in 2003-04 led to greater nitrogen fixation and the model suggests that some of the extra nitrogen is effectively captured by the animals in increased production. However, the reduction in the return of dead matter coupled with an increase in excretal return and the consequent increase in the mineral nitrogen pools within the soil lead to greater losses of nitrogen from the soil.

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Erceg, Vicki Heather. "Detection of behavioural and cognitive dysfunction in mucopolysaccharidosis IIIA affected dogs : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Science at Massey University, Palmerston North, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/1053.

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This study investigated whether behavioural and cognitive dysfunction caused by mucopolysaccharidosis (MPS) IIIA can be detected early in affected dogs’ lives, and to describe the behaviours of these dogs. No other scientific papers have been published on this topic and the population of dogs examined in this study are the only MPS IIIA affected dog colony available worldwide for study. Three main tests were performed on the population of MPS IIIA affected dogs. Physical behavioural assessment tests were performed at six and eight weeks of age and from twenty weeks of age a cognitive function task was taught and then tested to measure the dogs’ performance. A previously validated questionnaire, the canine behavioural assessment and research questionnaire (C-BARQ), was completed at three, six and twelve months of age. The researchers in these studies were blinded to the MPS IIIA status of the dogs examined. The behaviours shown by the MPS IIIA puppies at six and eight weeks of age were not significantly different from the behaviours of the unaffected puppies. This finding supported the research of other MPS IIIA studies and suggests that clinical behavioural changes do not occur at such a young age. The behaviours shown by the MPS IIIA affected puppies appeared to be normal puppy behaviours similar to those described in previous research on puppies. The C-BARQ measured the behaviours shown by the MPS IIIA affected and unaffected dogs. Most of the MPS IIIA affected dogs’ behaviours were not significantly different from the unaffected dogs’ behaviours, but MPS IIIA affected dogs did retrieve significantly more than unaffected dogs at three months of age, and were less distractible at twelve months of age. It would be worth investigating these findings further to decide whether it suggests a subtle alteration in brain functioning. The cognitive function test showed a significant decrease in the success of the MPS IIIA affected dogs in the final maze test. This is the first study on dogs affected with MPS IIIA to find a decline in cognitive function before the occurrence of cerebellar clinical signs and this new knowledge may lead to future developments measuring therapy response and disease progression. The T-shaped maze testing may be valuable in future research on cognitive function in dogs with other diseases such as epilepsy. Thus this thesis provides valuable information on canine MPS IIIA and provides a foundation for future disease investigations.

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Muir, Paul David. "Studies on the growth and compositional development of antlers in red deer (Cervus elaphus)." Lincoln College, University of Canterbury, 1985. http://hdl.handle.net/10182/1178.

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The experiments described in this thesis investigated nutritional and physiological aspects of antler growth in red deer stags. The initial experiment (Section 3) examined the effects of winter nutrition on subsequent antler casting date and velvet antler weight. Mature stags on two different farm types (hill country, Farm H and irrigated lowland, Farm L) were offered three levels of winter nutrition, two levels of a concentrate supplement (ad libitum pellets and 1/2 ad libitum pellets) and a basal hay ration. On both properties liveweight gains occurred in supplemented groups and liveweight losses in unsupplemented groups. At antler casting there were significant differences in liveweight of approximately 10 kg between fully supplemented and unsupplemented groups. Realimentation of winter liveweight losses subsequently occurred so that by the following rut the effects of winter undernutrition had been eliminated. On Farm H poor winter nutrition (hay only) resulted in a significant delay in casting date (13 days) and lower velvet antler yields (0.24 kg), than in stags offered the ad libitum concentrate ration. Stags on Farm H were 13 kg lighter at commencement of the trial than at Farm L and the differences in treatment effects obtained between farms may have been due to differences in body condition at commencement of the trial. An association was demonstrated between liveweight and date of antler casting, with heavier stags casting earlier than lighter stags. There was no effect of age of stag on casting date. Of the liveweights recorded, liveweight prior to the rut showed the best relationship with casting date, possibly because the seasonal nature of liveweight change meant that a weight recorded at this time gave the best indicator of the true frame size of a stag. Both age and liveweight significantly affected velvet antler weight, with increases of velvet antler weight of 0.26 kg between 3 and 4-year-old stags and of 0.30 kg between 4 and 5-year-old stags at the same liveweight. Within an age group velvet weight increased by 0.12 kg for each 10 kg increase in pre-rut liveweight. The experiments described in Section 4 comprised studies on antler growth and composition. In order to obtain data on antler growth and composition individual antlers were removed sequentially from mature red deer stags between 28 and 112 days after casting of hard antlers. Contralateral antlers were removed after stripping of velvet. Wide variation occurred in antler casting date (53 days) compared to date of velvet stripping (24 days). The duration of the period of antler growth may therefore be governed more by date of casting than by date of velvet stripping. Mean duration of the antler growth period was 164 days. Growth in length of the antler appeared to follow a sigmoid curve. However, between 28 and 112 days after casting, rates of elongation were close to linear. Mean length of hard stripped antlers was 0.71 m and between 28 to 112 days after casting mean rate of antler elongation was 0.62 cm/day. Over this period indivdual antlers increased in fresh weight at a rate of 13.7 g/d, with heaviest weight recorded 112 days after antler casting, at approximately 130% of final hard antler weight. Between 28 and 91 days of growth, volume of blood in the antler increased linearly at a rate of 194 ml/kg. Three phases of mineralization were demonstrated in developing antlers. Tips of growing antlers were cartilaginous and poorly mineralized. A zone of mineralization occurred 5.0 to 7.5 cm behind the antler tip which corresponded histologically to the transition from mineralized cartilage to trabecular bone. The second phase of mineralization occurred through continued accretion of trabecular bone in the antler shaft. The third phase, described as "terminal mineralization" in this study, appeared to be associated with a rapid increase in density of cortical bone in the periphery of the antler shaft. Terminal mineralization (between 91 and 112 days after casting of hard antlers) coincided with the slowing of growth in length, a decrease in relative blood volume in the antler and an increase in levels of plasma testosterone. These events occurred close to the summer solstice. At velvet stripping individual antlers had a mean weight of 1.12 kg and contained 81.1% dry matter (DM). Fat free organic matter (FFOM) and ash concentration in DM were 36.6 and 60.0%, respectively. Peak daily rates of FFOM and ash deposition occurred between 91 days and 112 days after casting, at rates of 1.4% of hard antler FFOM and 1.6% of hard antler ash. For a stag producing 2.24 kg of hard antler mean rates of FFOM and ash deposition over this period were 9.3 and 18.3 g/d, respectively. On a whole antler basis calcium concentration in antler ash remained constant, at around 35%. Therefore peak rate of antler calcium deposition would be 6.4 g/d. In the final experiment (Section 5) mature stags were offered a maintenance ration of greenfeed oats during the period of peak calcium requirement for antler growth and the kinetics of calcium metabolism were examined using a radio-isotope (⁴⁵Ca). Rates of faecal endogenous loss were low and at approximately 6.4 mg/kg BW per were half the estimated requirements of ARC (1980) for sheep and cattle. Availability of calcium from greenfeed oats was low (mean, 37%) and less than 30% of total calcium requirements were derived from the diet. Poorly mineralized skeletal bones indicated that the shortfall in antler calcium was derived from the skeleton. In spite of a severely negative calcium balance stags were capable of maintaining high and apparently normal rates of antler calcium deposition (mean, 44 mg/kg BW per day). Antlers appear to be acting as a sink with calcium being irreversibly deposited in the antler and lost to the animal's body. On the assumption therefore that antler calcium behaves like calcium lost during lactation a kinetic model of calcium metabolism in the stag was developed.

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Kongara, Kavitha. "Studies on renal safety and preventive analgesic efficacy of tramadol and parecoxib in dogs : thesis in fulfilment of the degree of Doctor of Philosophy in Veterinary Clinical Science, Institute of Veterinary Animal and Biomedical Sciences, College of Sciences, Massey University, Palmerston North, New Zealand." Massey University, 2008. http://hdl.handle.net/10179/864.

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Ovariohysterectomy and castration are common surgical procedures in small animal practice that can result in clinically significant postoperative pain. One way of controlling postoperative pain is administration of a single analgesic or a combination of different classes of analgesics prior to the onset of noxious stimuli. A constraint to the perioperative use of traditional opioids and non-steroidal anti-inflammatory drugs (NSAIDs) is their undesirable side effects. In this series of experiments, the preventive (pre-emptive) analgesic efficacy of two popular human analgesics, tramadol (an ?atypical? opioid) and parecoxib (a NSAID with selective COX-2 inhibition) was evaluated in dogs. Initially, the efficacy and renal safety of parecoxib, tramadol and a combination of parecoxib, tramadol and pindolol (a -adrenoceptor blocker and 5-HT1A/1B antagonist) were screened in anaesthetised healthy dogs. These analgesics increased the dogs? nociceptive threshold to mechanical stimuli, without causing significant alterations in the dogs? glomerular filtration rate (GFR) estimated by plasma iohexol clearance. Subsequently, the efficacy of tramadol was compared with morphine, in dogs undergoing ovariohysterectomy or castration. The Glasgow composite measure pain scale-short form score (CMPS-SF) and changes in intraoperative electroencephalogram (EEG) responses were used to assess the efficacy of analgesics. Of the three treatment groups (preoperative morphine, 0.5 mg kg-1; preoperative tramadol, 3 mg kg-1; a ?combination? of preoperative low-dose morphine, 0.1 mg kg-1, and postoperative tramadol 3 mg kg-1), dogs given the ?combination? had significantly lower pain scores after ovariohysterectomy. In castrated dogs, preoperative tramadol (3 mg kg-1) and morphine (0.5 mg kg-1) were tested and no significant difference in the CMPS-SF score were observed between them. Changes in EEG variables were not specific between the treatment groups in ovariohysterectomised dogs. Finally, the efficacy of test drugs was evaluated against acute noxious electrical stimulation in anaesthetised dogs, using EEG. Median frequency of the EEG, a reliable indicator of nociception, increased significantly in tramadol and parecoxib groups, compared to morphine, after electrical stimulation. These studies demonstrated that tramadol and parecoxib can produce analgesia in dogs with insignificant side effects. The efficacy of tramadol appears to vary with the type of noxious stimulus. A complete prevention of noxious input by administration of analgesics pre- and post-operatively could have important clinical applications.

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Dittmer, Keren Elizabeth. "Inherited rickets in Corriedale sheep : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University, Palmerston North, New Zealand." Massey University, 2008. http://hdl.handle.net/10179/882.

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Inherited rickets of Corriedale sheep is a newly discovered skeletal disease of sheep with simple autosomal recessive inheritance. The clinical signs resemble rickets in other species and include decreased growth rate, thoracic lordosis and angular limb deformities. Radiographic features include physeal thickening, blurred metaphyseal trabeculae and thickened porous cortices. Computed tomography scanning of long bones reveals increased bone mineral content and cortical area, but decreased bone mineral density. Gross lesions include segmental thickening of physes, growth arrest lines, collapse of subchondral bone of the humeral head, thickened cortices and enthesophytes around distal limb joints. Microscopically there is persistence of hypertrophic chondrocytes at sites of endochondral ossification, inappropriate and excessive osteoclastic resorption, microfractures and wide, unmineralised osteoid seams lining trabeculae and filling secondary osteons. Affected sheep are persistently hypophosphataemic and hypocalcaemic. Normal serum 25-hydroxyvitamin D3 concentration accompanied by a two-fold elevation in 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) suggested a defect in endorgan responsiveness to vitamin D as a likely mechanism, but this was not supported by in vitro studies using cultured skin fibroblasts. These studies revealed normal vitamin D receptor function and the presence of 24- hydroxylase mRNA in cells from affected sheep, even without induction by 1,25(OH)2D3. Inappropriate overexpression of 25-hydroxyvitamin D3-24- hydroxylase, the enzyme that breaks down active vitamin D, is therefore considered the probable cause of inherited rickets in Corriedale sheep. Such a mechanism has not previously been described as a cause of inherited rickets in humans or other animal species. Treatment of affected sheep with high oral doses of vitamin D3 weekly for 3 months showed a trend towards increased bone mineral density, thus supporting an intact vitamin D receptor. Preliminary studies on immune function revealed reduced numbers of CD4+ and CD8+ lymphocytes and reduced interferon-? production by lymphocytes stimulated with parasite antigen. This new form of inherited rickets may be widespread in

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Ford, Colleen D. "The fate of nitrogen in lactose-depleted dairy factory effluent irrigated onto land." Lincoln University, 2008. http://hdl.handle.net/10182/837.

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A two-year lysimeter study was undertaken to compare the environmental effects (e.g. nitrate leaching and nitrous oxide emissions) of soil applied lactose-depleted dairy factory effluent (LD-DFE) with lactose-rich DFE. The aim of this experiment was to determine the fate of nitrogen from LD-DFE and dairy cow urine applied to a Templeton fine sandy loam soil (Udic Ustrochrept), supporting a herbage cover of ryegrass (Lolium perenne) and white clover (Trifolium repens). Measurements were carried out on the amount of nitrogen lost from the soil via leaching, lost by denitrification, removed by the pasture plants, and immobilized within the soil organic fraction. Further, a comparison between the fate of nitrogen in LD-DFE irrigated onto land under a "cut and carry" system, as opposed to a "grazed" pasture system was undertaken. Lactose-depleted dairy factory effluent was applied at three-weekly intervals during the summer months at rates of 25 and 50 mm, until nitrogen loading targets of 300 and 600 kg N ha⁻¹ yr⁻¹ had been achieved. Measured leaching losses of nitrogen averaged 2 and 7 kg N ha⁻¹ yr⁻¹ for Control 25 and Control 50 treatments; 21, 20 and 58 kg N ha⁻¹ yr⁻¹ for 25 and 50 mm "cut and carry" treatments respectively; and 96 kg N ha⁻¹ yr⁻¹ for the 25 mm "grazed" treatment. The range of nitrate-N leaching loss from LD-DFE plus urine is no different from the lactose-rich DFE nitrate leaching loss. Uptake of nitrogen by the growing pasture averaged 153, 184,340,352,483, and 415 kg N ha⁻¹ yr⁻¹ for Control 25, Control 50, LD-DFE 25 and LD-DFE 50 mm "cut and carry" treatments, and the LD-DFE 25 mm "grazed" treatment, respectively. Denitrification losses were 0.06, 4.4, 1.69, 19.70, and 7.4 kg N ha⁻¹ yr⁻¹ for Control 25, the LD-DFE 25 "cut and carry" treatments, the LD-DFE 25 mm "grazed" treatment, and calculated "paddock losses", respectively. Isotopic nitrogen studies found that 29.4 and 25.8% of applied LD-DFE nitrogen was immobilised in the LD-DFE 25 and LD-DFE 50 "cut and carry" treatments. The results of this experiment confirm the findings of the previous lactose-rich DFE study, in that the effects of grazing stock are of greater environmental concern than the removal of lactose from the effluent waste stream.

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Thomas, Craig W. "Current practices and future possibilities of performance recording extensively-grazed commercial beef herds in New Zealand." Diss., Lincoln University, 2008. http://hdl.handle.net/10182/844.

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There is little evidence that the productivity of New Zealand beef herds has improved over time. Data from the NZ Meat and Wool Board’s Economic Service (2006) suggest that the average national calving percentage has declined over the last two decades. During the same period cattle carcass weights have increased but so too has the average cow live-weight which has resulted in increased maintenance costs of the cow herds. It is unclear whether production efficiency in the industry has improved or declined over time. The aim of this research was to develop means of improving productivity in commercial beef herds through practical methods of performance recording. The objectives were firstly to establish current management practices in commercial herds and secondly to develop an objective system for cow selection and culling which would have practical application in commercial herds. Beef management survey Ninety two commercial beef producers with more than 100 breeding cows from the greater Canterbury region of New Zealand were surveyed. Pasture control was the main reason given for owning a beef herd. Size and conformation were the main selection criteria for choosing replacement heifers and bulls. Over 80% of herds retained their own heifers as replacements and >60% mated yearling heifers to first calve at two years of age. Fertility was poor in the surveyed herds. In-calf rates at pregnancy testing averaged 88% for maiden heifers, 92% for rising second calvers and 93% for mixed age (m.a.) cows. There was no significant difference between in-calf rates of maiden heifers mated to first calve at two or three years of age; nor was there any significant difference between the re-breeding success of the two groups. Heifers mated at least one week earlier than m.a. cows, achieved a re-breeding success 4.7% greater (P<.01) than those mated at the same time. Reasons for cows not weaning a calf included wet dry (9.3% of pregnant cows wintered), pregnancy tested not-in-calf (7.4%) and dam death (2.6%). Only 87.9% of pregnant females wintered weaned a calf (89.4% of m.a. cows and 84.9% of heifers). Reasons why cows exited the herds included diagnosed empty (37.2% of all exits), involuntary culls (25.4%), sold wet dry (16.2%), deaths (13.1%) and poor calf production (5.1%). Vaccination was infrequent with clostridial vaccines the most common in m.a. cows (15.2%) and in calves (40.7%); vaccination against Leptospirosis was much less common. Very few of the surveyed farms used any system of performance recording; as a result there was very little performance-based selection or culling practiced. Evaluation of alternative measures of cow productivity Data from four performance recording beef herds were used to compare alternative measures of cow productivity with the industry standard which is calf weaning weight adjusted for sex (SOC) and age of calf and age of dam (AOD), i.e. the “200 day weight.” None of the alternative measures evaluated required knowledge of calving date and all were relatively easily obtainable in extensively managed beef herds. The assessment of cows was based not on their estimated breeding values but instead on their most probable producing ability which, as the sum of all of the permanent, repeatable aspects of the calf-rearing ability of the cow, explains considerably more of the variance of weaning weight than does breeding value alone. SOC and AOD-adjusted marking weight, weaning weight and average daily gain (ADG) between marking and weaning were the traits mostly highly correlated with the 200d wt of calves (r = 0.68, 0.90 and 0.74. respectively). An Extensively- Grazed-Cow-Weaning-Index of these three indicator traits was found to be more highly correlated than any of the individual traits on their own (r = 0.94). Index weights for the three indicator traits were calculated within each herd and then those within-herd index weights were regressed on readily obtainable herd descriptive variables to obtain a regression equation that could predict index weights for any herd. When the model was applied to data from two additional herd years not included in the original model, the EGCW Index was highly correlated with the 200d weights (r>0.90). Performance-based culling of previously unselected commercial beef herds based on the EGCW Index will result in improved productivity due to the moderately high repeatability of calf weaning weight. Objective data from extensively grazed commercial herds will also make possible the use of commercial herd data in genetic evaluations of herd sires.

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Black, Amanda. "Bioavailability of cadmium, copper, nickel and zinc in soils treated with biosolids and metal salts." Lincoln University, 2010. http://hdl.handle.net/10182/1561.

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It is widely accepted that bioavailability, rather than total soil concentration, is preferred when assessing the risk associated with metal contamination. Despite this, debate continues on what constitutes a bioavailable pool and how to best predict bioavailability, especially in relation to crop plants. The overall aim of this thesis was to assess and validate measures of cadmium (Cd), copper (Cu), nickel (Ni) and zinc (Zn) bioavailability in a range of soils amended with metal salts and biosolids. Six potential measures of bioavailability were investigated and compared: total metal; 0.04 M EDTA extraction; 0.05 M Ca(NO₃)₂ extraction; soil solution extracted using rhizon probes; effective solution concentration (CE) determined using diffusive gradients in thin films (DGT); and modelled free ion activities (WHAM 6.0). These were compared to shoot metal concentrations obtained from plants grown in three soils with contrasting properties treated with biosolids and metal salts. The first study involved a wheat seedling (Triticum aestivum) assay carried out under controlled environmental conditions on incubated soils treated with metal salts and biosolids. Results showed that the presence of biosolids resulted in increases of DOC, salinity, Ca and Mg in soil solution as well as total concentrations of Cu and Zn, dry matter was also adversely affected by increased levels of salinity. The addition of biosolids did not significantly alter the extractability or solubility of Cd, Cu, Ni and Zn although concentrations of Cd in shoots were significantly lower in plants grown in biosolids amended soils compared with unamended soils. The second study involved a field experiment that used 20 cm diameter by 30 cm deep soil monoliths of the same three soils treated with metals and biosolids, and perennial ryegrass (Lolium perenne) was grown for 24 months. Results revealed the addition of biosolids significantly increased the amount of DOC, salinity, Ca and Mg in solution. The presence of biosolids also significantly altered the bioavailability of Cd, Cu, Ni and Zn, as measured by soil solution, CE and free ion activity. However, this change had little effect on plant metal uptake. The length of time following treatment application had the greatest effect on soil chemistry and metal availability, resulting in pH decreases and increases in DOC, soil solution salinity, Ca and Mg. The free ion activities of each metal increased with time, as did soil solution Cd and Zn and CE-Cu, with results for Zn indicative of migration through the soil profile with time. Plant uptake of Ni and Zn also changed with time. Nickel concentrations in shoots decreased, while concentrations of Zn in shoots increased. The findings from the two studies demonstrated that biosolids increased the amount of DOC, salinity, Ca and Mg present in soil solution. In the lysimeter study measures of metal availability were affected in soils amended with biosolids, but this did not effect shoot concentrations. The overall predictive strengths of the six potential measures of bioavailability was investigated using results from the previously described experiments and related studies carried out by ESR and Lincoln University using nine different soils amended with combinations of biosolids and metal salts. Of the four metals Ni provided the strongest correlations between metal bioavailability and shoot concentrations, with 0.05 M Ca(NO₃)₂ extraction giving the strongest relationship for Ni concentrations in shoots (r² = 0.73). This suggests that the solubility of Ni is highly indicative of shoot concentrations and that Ca(NO₃)₂ is a robust measure of Ni bioavailability. In addition Ca(NO₃)₂ provided the best estimate of Zn bioavailability (r² = 0.65), and CE-Cd provided the best measure of Cd bioavailability, although it could only describe 47 % of shoot Cd concentration. Results for Cu were typical of previously described studies as assays of Cu availability are almost always poorly correlated with shoot concentrations, with total Cu having the strongest relationship (r² = 0.34). Methods based on the extractability and solubility of Cu in soils were poor indicators of Cu concentration in shoots. Overall, the addition of biosolids did not alter the outcome of these bioavailability assays, and results indicated that total metal concentrations present in the soils and biosolids matrix, plus length of time since soil treatment, had a greater affect on metal bioavailability.

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Sheldon-Sayer, Lynne. "The vegetation of Maud Island, Marlborough, New Zealand." Lincoln University, 2006. http://hdl.handle.net/10182/1707.

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Maud Island (Te Hoiere - "a long paddle or mighty pull") is a moderately sized island of 309 hectares, located in the Pelorus Sound (41°, 02 'S, 173° 54 'E) Marlborough, at the north-east end of the South Island of New Zealand. It has a long history of human modification and impacts since its colonisation by Maori and early Europeans. The vegetation of Maud Island has been studied in the 1980's and again in the early 1990's. The objectives of this study were to (1) describe how the vascular plant communities vary in species composition across Maud Island, (2) determine which environmental factors are important predictors of the variation in species composition of Maud Island plant communities, and (3) describe the pattern of succession of the plant communities on Maud Island over the last twenty years. In this 2001 study, I comprehensively sampled the vegetation on Maud Island using a Reconnaissance Description Procedure in a total of 158 plots across the island and compared these results to previous descriptions. I also retook photos at permanent photo points to provide a visual comparison of vegetation change. In total, 219 plant species were identified; 177 species occurred within the plots and 42 additional species were observed while walking around the coastline and walking tracks. Six dominant plant species occurred in over 70% of the plots. They were Pteridium esculentum, Pseudopanax arboreus, Hebe stricta var. stricta, Melicytus ramiflorus, Ozothamnus leptophylla and Coprosma robusta. Two-Way Indicator Species Analysis resulted in the description of eight different plant communities on the island. Detrended correspondence analysis showed a high degree of turnover in species composition among these communities. Canonical correspondence analysis showed that slope and moisture were particularly important predictors of variation in plant species composition. The environmental factors that best predicted to variation communities were slope, moisture, and a gradient in historical disturbance. Comparisons of present and past vegetation maps and photos (ground and aerial) showed, in terms of the successional pathways of the vegetation on Maud Island, that over time, the vegetation is reverting from short stature grassland and scrub to predominantly forest scrub and young secondary forest.

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Hill, Andrew Gordon. "An investigation of Leucocytozoon in the endangered yellow-eyed penguin (Megadyptes antipodes) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Science at Massey University, Turitea, Palmerston North, New Zealand." Massey University, 2008. http://hdl.handle.net/10179/1063.

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Yellow-eyed penguins have suffered major population declines and periodic mass mortality without an established cause. On Stewart Island a high incidence of regional chick mortality was associated with infection by a novel Leucocytozoon sp. The prevalence, structure and molecular characteristics of this leucocytozoon sp. were examined in the 2006-07 breeding season. In 2006-07, 100% of chicks (n=32) on the Anglem coast of Stewart Island died prior to fledging. Neonates showed poor growth and died acutely at approximately 10 days old. Clinical signs in older chicks up to 108 days included anaemia, loss of body condition, subcutaneous ecchymotic haemorrhages and sudden death. Infected adults on Stewart Island showed no clinical signs and were in good body condition, suggesting adequate food availability and a potential reservoir source of ongoing infections. A polymerase chain reaction (PCR) survey of blood samples from the South Island, Stewart and Codfish Island found Leucocytozoon infection exclusively on Stewart Island. The prevalence of Leucocytozoon infection in yellow-eyed penguin populations from each island ranged from 0-2.8% (South Island), to 0-21.25% (Codfish Island) and 51.6-97.9% (Stewart Island). The high prevalence on Stewart Island represented the infection of 100% of chicks and 83% of adult yellow-eyed penguins when tested by PCR. Sequencing of Leucocytozoon sp. DNA found similarities between infections in yellow-eyed penguin adults and chicks, but differences to Leucocytozoon sp. DNA obtained from Fiordland crested penguins. These findings support the suggestion of cross infection between adults and chicks, and indicate that endemic infection in yellow-eyed penguins is unrelated to that in Fiordland crested penguins. Examination by histology and electron microscopy showed tissue megaloschizonts and circulating round gametocytes. Megaloschizonts up to 440µm diameter showed an affinity for hepatic and splenic tissue and were observed releasing occasional intact cytomeres. Round gametocytes were observed within leucocytes in visceral sections, but not peripheral blood smears. The morphology of Leucocytozoon sp. in yellow-eyed penguins showed similarities to the pathogenic species L. simondi and L. sakharoffi but not L. tawaki. A successful treatment protocol for leucocytozoonosis has not been established, although treatment in a Fiordland crested penguin was able to suppress parasitaemia. The role of Leucocytozoon in yellow-eyed penguins as a cause of morbidity and mortality remains unclear. Further investigation into direct pathogenicity, and the interaction of concurrent disease and environmental influences is required. The findings of this thesis provide potential management recommendations and highlight areas requiring further investigation.

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Patterson, R. G. "A study of the soils and agronomy of a high country catchment." Lincoln University, 1993. http://hdl.handle.net/10182/1315.

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This study was undertaken to research the principles and practices behind increased pasture productivity on Longslip Station, Omarama. A range of landscape - soil - climate - plant systems were identified, then analysed and the legume responses measured. By isolating cause and effect and appreciating the driving variables of each system, lessons learnt could be reliably and objectively transferred to the rest of the farm. Extrapolation to the balance of the property (15,150 ha) permitted immediate large-scale development and engendered confidence to lending institutions, Lands Department, catchment authorities and ourselves. Soil (land) cannot be well managed and conserved unless it is mapped reliably and its characteristics measured and interpreted by skilled observers (Cutler, 1977). Soil resource surveys, and their interpretation, are an essential ingredient of rational resource evaluation and planning. This thesis is a figurative and comparative survey and study of the soil catenary bodies, resident vegetation, legume establishment and pasture production characteristics of a 400 hectare catchment, in relation to, and as influenced by soil landscape unit, slope component, altitude, aspect and time. The inherent diversity in landform, soil properties and vegetation communities in a single catchment in the high country has not previously been fully studied or appreciated. This has lead to blanket recommendations for fertilizer, seed and management regimes both within and between properties and even regions. This study reports on the diversity of, yet predictable change in soil properties with slope position (upper, middle and lower) aspect and altitude in terms of both soil physical properties e.g. soil depth and water holding capacity and soil chemical properties such as pH, BS%, %P, %S, %N and %C. The composition of the resident vegetation and its differential response to oversowing and topdressing and subsequent change through time is reported and discussed. Finally an epilogue gives an insight into the problems and frustrations of farming practices in the high country from a motivation and personal perspective and political point of view that it is essential to come to terms with.

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Jimenez-Castro, Claudia. "Management of a marine protected area by a local NGO in Honduras: its implications for local communities." Lincoln University, 2008. http://hdl.handle.net/10182/1237.

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This study explores the factors that influence the management of a protected area situated on private land as well as the implications of these factors in the interaction between the NGO and the communities associated with this area. The protected area, Marine National Monument Cayos Cochinos, is an archipelago surrounded by reefs in the Honduran Caribbean. This area is home to a highly heterogeneous population of fisherfolk communities –most are members of the Garifuna ethnic group– and wealthy Honduran and foreign landowners. This case study also comprises three fisherfolk communities outside the protected area who fish in Cayos Cochinos. Local fishermen in Cayos Cochinos are settled in community-owned areas; however, these settlements started by the occupation of private lands. Wealthy landowners have either individual land titles or shares of a firm owning four of the islands. The protected area was established through the initiative of this firm to protect the natural resources. This area is nominally co-managed by a local nongovernmental organisation (NGO) and two government agencies; however in practice it is managed solely by the NGO. This study discusses the influence of the nature of the Honduran legislation regarding protected areas and of the co-management agreement on the management of Cayos Cochinos. This research also shows that the management priorities of this protected area are only partially based on the Honduran government’s laws and regulations and the guidelines specific for this area. Lack of government participation in the co-management of the area, financial constraints, influences on the NGO of stakeholders in higher positions of power with respect to it, personal preferences of the NGO managers and issues regarding the communities’ leadership, have all had an influence on the management priorities of the protected area since its constitution. The combined effect of these factors has influenced the management of the NGO towards prioritising the natural resource conservation. This area is managed under a ‘people-out’ conservation paradigm. The adoption of this paradigm has disadvantaged the fisherfolk communities inside and outside the protected area by restricting their access to the natural resources on which their livelihoods are highly dependent. However, the same situation has favoured the private landowners by limiting the access of the fisherfolk communities to the land owned by the former. The privileging of one community sector over another has created conflicts between the NGO and the fisherfolk communities. However, these conflicts have been fuelled by other factors such as the steady contesting of the land titles over the territories occupied by the latter, and by the support that external organisations have given to the latter at the expense of the original owners of the land. This research suggests that local NGOs in charge of the management of natural protected areas might have limited capacity to abide by national conservation and sustainable development priorities due to the likelihood to be influenced by external forces with different priorities.

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Willems, Nancy. "Forest structure and regeneration dynamics of podocarp/hardwood forest fragments, Banks Peninsula, New Zealand." Lincoln University, 1999. http://hdl.handle.net/10182/1301.

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Although species maintenance in small forest fragments relies on successful regeneration and recruitment, few studies have examined the effects of fragmentation on regeneration processes. New Zealand's podocarp species rely on large disturbance openings operating across a vegetated landscape to stimulate regeneration. Clearance of vegetation that results in small fragments of forest removes regeneration opportunities for podocarps by destroying the intact vegetation mosaic, and as a result may exclude disturbances of the scale necessary for podocarp regeneration. Fragmentation alters the disturbance regime of the landscape, with important implications for the regeneration of podocarps on Banks Peninsula. The four remaining lowland podocarp-hardwood fragments on Banks Peninsula were sampled to determine the structure and regeneration patterns of podocarps and to assess their long term viability. Density, basal area, and size and age class distributions were used to examine current composition, and in conjunction with spatial analysis, to identify past regeneration patterns and infer likely future changes in composition and population structure. Podocarp size and age class structures for three of the four fragments were characteristically even-sized and relatively even-aged (eg; Prumnopitys taxifolia c. 350 to 600 years), with little or no regeneration for approximately the last 200 years (old-growth fragments). Regeneration of the current podocarp canopy in the old-growth fragments may have been stimulated by flooding. The fourth younger fragment showed much more recent regeneration with Prumnopitys taxifolia, Podocarpus totara and Dacrycarpus dacrydioides mostly 80-160 years old, and substantial populations of seedlings and saplings, probably as a result of anthropogenic fire. In the absence of major disturbance the podocarp component in forest fragments on Banks Peninsula is likely to decline with composition shifting towards dominance by hardwood species. There is some evidence to suggest that canopy collapse will stimulate some podocarp regeneration within the fragments, however it appears to be unlikely that podocarps will persist on Banks Peninsula indefinitely within the fragments studied. There is an urgent need for more quantitative research in New Zealand fragmentation literature, and a need for more emphasis on processes. Banks Peninsula offers potential for a more landscape scale approach in forest management, and the maintenance of regenerating scrub in pockets about the Peninsula may offer the regeneration opportunities for podocarps that are lacking within protected fragments. My study took a quantitative approach in examining the effects of forest fragmentation on the demographics of podocarps and compositional change in forest fragments on Banks Peninsula.

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Lin, Xiaoxiao. "Evaluation of Kahne rumen sensors in fistulated sheep and cattle under contrasting feeding conditions : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Agriculture at Massey University, Palmerston North, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/1313.

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The Kahne rumen sensor (bolus) is a device developed to measure temperature, pressure and pH in non-fistulated animals. This bolus allows real-time monitoring of the rumen environment, which could help preventing health problems such as rumen acidosis in cows. It is less invasive to use boluses compared to other technologies that measure the ruminal pH (e.g. rumenocentesis). Kahne boluses and transceivers are commercially available in the market. Several studies on the relationships between data recorded by the bolus and actual data recorded by independent devices were conducted. The bolus temperature and pressure were compared with actual temperature and pressure under controlled conditions. The pH drift was studied by comparing the difference between bolus and direct measurement over time. The capture of the data was calculated for each bolus in various experiments to examine the factors affecting the data capture rate of the boluses. Animal to animal variation was studied using boluses in a group of cows fed and managed under uniform conditions. An animal experiment involving fistulated cows eating two different diets was performed using boluses to monitor the changes of ruminal pH. There was no apparent interruption to normal animal behaviour as a result of using boluses. Regression relationships between bolus measurements and actual data for both temperature and pressure were developed and used for calibration of bolus data. The pH drift was a problem, as the regression relation between the pH difference and the time for one bolus from one experiment could not represent this bolus on other experiment. The data capture rate on the hourly basis ranged from 0 to 100%, but was usually between 30 to 70%. The data capture rate was affected by many factors and further studies to identify these factors are needed. A study of animal to animal variation suggests that in a comparison of 2 treatments, a minimum 3 cows per group would be required to detect the standard deviation of 0.11 for a pH difference of 5% of the mean (approximately 0.35 pH units). Seventeen cows per group would be required to detect the standard deviation of 0.33 for the same difference. The boluses effectively monitored the ruminal pH change in cows easting two different diets and the profile of change of pH was successfully analysed. Feeding 7.6 kg baleage twice a day cause pH to decrease at 0.009 pH units per minute during feeding, while offering a similar quantity of grass and hay once a day resulted in a decrease of 0.0009 pH units per minute during feeding. The beginning of pH increase was about 1 hour following feeding and continuous during resting and rumination. The level of pH increase did not differ significantly for two diets.. The Kahne devices appear to have advantages compared to other technologies for the measurement of parameters of the rumen environment on a real-time basis. Boluses are especially good at intensively monitoring the temperature, pressure, and pH in the rumen. The major limitations of this technology to be used are the data capture rate and the pH drift. By improving the limitations found in the experiment, the Kahne rumen sensor could become very useful for both scientific research and under commercial conditions for monitoring animal health.

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Puig, Virginia Moreno. "Conservation issues for Hochstetter's frog (Leiopelma hochstetteri): monitoring techniques and chytridiomycosis prevalence in the Auckland region, New Zealand : a thesis presented in partial fulfillment of the requirements for the degree of Master of Science in Conservation Biology at Massey University, Auckland, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/1132.

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Amphibians are suffering extinctions and range contractions globally. This is caused by numerous factors and most of them are related to human activities. The overall aim of this thesis was to make a significant contribution to the conservation of the endemic amphibian Leiopelma hochstetteri through research. This was achieved by focusing in two of the main conservation issues for this species, the need for standardised and robust monitoring techniques to detect trends and changes in populations, and the determination of the prevalence of chytridiomycosis, caused by the amphibian chytrid fungus (Batrachochytrium dendrobatidis). Two populations of the Auckland Region were selected for this study, one on the mainland (Waitakere Ranges) and the only known offshore island population of this species (Great Barrier Island). For both study sites different monitoring methods were used to obtain some population parameters. Site occupancy models of MacKenzie et al. (2002) gave reliable site-specific estimations of occupancy and detection probability using covariate information and presence-absence data collected from 50 sites in the Waitakere Ranges and four repeated visits during 2008. Elevation and distance searched were found to have an important effect on occupancy levels, while time taken to search the site was important variable determining detection probabilities. Also, parameters were estimated for three age classes separately. Statistical models were used to infer abundance from occupancy analysis, and results were compared with the distribution of relative abundances obtained from repeated transect counts and an established sight/re-sight criterion. In addition, the use of surrogate measures for relative abundance was explored. Detection probability and the distance to first frog found were found to have a significant correlation with relative abundance. These measures can be used to infer relative abundance in future site occupancy surveys. Two surveys and a pilot site occupancy survey were conducted on Great Barrier Island, and presence of frogs was confirmed atthe northern block, and in a small seepage in the central block. No new locations were found. Waitakere Ranges and Great Barrier Is. populations were tested for the presence of chytridiomycosis, and all frogs sampled tested negative (n = 124) which means that if present chytridiomycosis prevalence is lower than 5% with a 95% confidence interval. This and previous evidence suggests that L. hochstetteri may be resistant or immune to the disease. However, to confirm this additional studies are needed.

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Calder, Keith Wallace. "A LEEP forward : biodiversity futures for New Zealand : a thesis in partial fulfilment of the requirements for the Master of Resource and Environmental Planning at Massey University, Palmerston North, New Zealand." Massey University, 2007. http://hdl.handle.net/10179/741.

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Loss of indigenous biodiversity continues in New Zealand. Despite admirable goals in the NZBS 2000 to the contrary, efforts at improved biodiversity conservation have been insufficient to halt loss of significant amounts of indigenous forest and wildlife habitat. Increasing numbers of native species are moving towards critically endangered and extinction. Whatever we are doing in New Zealand, it is not effective enough. The aim of this study is to firstly identify factors contributing to the failure, “to halt the decline of indigenous biodiversity” in New Zealand and to then consider opportunities to overcome these barriers. In considering opportunities, this study then reviews the emerging discipline of landscape ecology as an answer to, at least, some of those factors and the recurring calls from New Zealand ecologists for a more integrated and holistic approach to biodiversity conservation. Recent advances in the planning framework and particularly provisions for biodiversity conservation in England are explored as a model of practical application of landscape ecological principles to land-use planning. From this review, the study proposes a new ‘LEEP’ model for strategic biodiversity conservation that produces a regional-scale spatial conservation map and accompanying policy and implementation guide. Together they provide an integrated and holistic approach to restoring or creating functional landscapes that also recognises and provides for human activities and development. Application of the LEEP model is demonstrated through a case study of the Wellington region. Benefits and potential uses of the map and policy outputs are canvassed. Interviews with leading New Zealand and international ecologists provide an assessment of the current status of landscape ecology and interviewees also act as an expert ‘test panel’ against which the Wellington maps and guides produced from the ‘LEEP’ model are assessed. Finally, suggestions are provided for development of the new model and future research needs towards fuller and more effective implementation of this approach to biodiversity conservation in the New Zealand context.

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Clough, Tim J. "Fate of urine nitrogen applied to peat and mineral soils from grazed pastures." Lincoln University, 1994. http://hdl.handle.net/10182/1030.

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This study has provided fundamental information on the fate of urine nitrogen (N) when applied to pasture soils. In this work the three pasture soils used were a Bruntwood silt loam (BW), an old well-developed (lime and fertilizer incorporated and farmed for more than 20 years) peat soil (OP) and a young peat (YP) which was less developed (farmed for about 10 years). Initial soil chemical and physical measurements revealed that the peat soils were acidic, had higher cation exchange capacities, had greater carbon:nitrogen ratios and were better buffered against changes in soil pH than the BW soil. However, the BW soil was more fertile with a higher pH. The peat soils had lower bulk densities and higher porosities. Four experiments were performed. In the first experiment ¹⁵N-labelled urine was applied at 500 kg N ha⁻¹ to intact soil cores of the three soils. Treatments imposed were the presence and absence of a water table at two temperatures, 8°C or 23° C, over 11-14 weeks. ¹⁵N budgets were determined. This first experiment showed that the nitrification rate was faster in the BW soil and was retarded with a water table present. Significant leaching of nitrate occurred at 8°C in the BW soil without a water table. This was reduced when a water table was present. Leaching losses of urine-N were lower in the peat soils than in the BW soil. Apparent denitrification losses (i.e. calculated on a total-N recovery basis) ranged from 18 to 48 % of the ¹⁵N-applied with the greatest losses occurring in the peat soils. The second experiment examined denitrification losses, over 30 days, following the application of synthetic urine-N at 420 kg N ha⁻¹ to small soil cores situated in growth cabinets. The effects of temperature (8°C or 18°C) and synthetic urine (presence or absence) were measured on the BW and OP soils. Nitrous oxide (N₂0) measurements were taken from all soil cores and a sub-set of soil cores, at 18°C, had ¹⁵N-labelled synthetic urine-N applied so that ¹⁵N-labelled nitrogen gases could be monitored. This experiment showed that the application of synthetic urine and increased soil temperature enhanced denitrification losses from both soils. Denitrification losses, at 18°C, as ¹⁵N-labelled nitrogen gases accounted for 24 to 39 % of the nitrogen applied. Nitrous oxide comprised less than half of this denitrification loss. Losses of N₂0 in leachate samples from the soil cores accounted for less than 0.1 % of the nitrogen applied. A third experiment, using Iysimeters, was performed over a 150 day period in the field. The six treatments consisted of the 3 soils with applied synthetic urine, with or without a simulated water table; each replicated three times. Lysimeters were installed in the field at ground level and ¹⁵N-labelled synthetic urine-N was applied (500 kg N ha⁻¹) on June 4 1992 (day 1). Nitrification rates differed between the soils following the trend noticed in the first experiment. As in the first experiment, nitrate was only detected in the leachate from the BW soil and the inclusion of a water table reduced the concentration of nitrate. In the BW soil, the leachate nitrate concentrations exceeded the World Health Organisation's recommended limit (< 10 mg N L-1) regardless of water table treatment. No nitrate was detected in the leachates from the peat soils but there was some leaching of organic-N (< 5 % of N added) in all the peat soil treatments. Denitrification losses were monitored for the first 100 days of the experiment. In the BW soil without a water table, N₂0 production peaked at approximately day 20 and accounted for 3 % of the nitrogen applied. In the peat soils the measured denitrification losses accounted for less than 1 % of the nitrogen applied. Apparent denitrification losses in the peats were, however, calculated to be approximately 50 % of the ¹⁵N-labelled synthetic urine-N applied. It is postulated that the difference between apparent denitrification losses and those measured could have been due to; loss of dinitrogen in leachate, protracted production of dinitrogen below detectable limits, production of denitrification gases after measurements ceased (i.e. days 100 to 150) and entrapment of dinitrogen in soil cores. Due to the apparent denitrification losses being so high, further research into this nitrogen loss pathway was performed. The fourth and final experiment measured denitrification directly using highly enriched (50 atom %) ¹⁵N-labelled synthetic urine-N. It was performed in a growth cabinet held initially at 8°C. The ¹⁵N-labelled synthetic urine was applied at 500 kg N ha⁻¹ to small soil cores of each soil type. Fluxes of N₂0 and ¹⁵N-labelled gases were measured daily for 59 days. On day 42 the temperature of the growth cabinet was increased to 12°C in an attempt to simulate the mean soil temperature at the end of the field experiment. Up to this time, production of nitrogenous gases from the YP soil had been very low. Interpretation of gaseous nitrogen loss in the YP soil was difficult due to the possibility of chemodenitrification occurring. However, in the OP and BW soils, gaseous losses of nitrogen (determined as ¹⁵N-labelled gas) represented 16 and 7 % of the nitrogen applied respectively. Nitrous oxide comprised approximately half of this gaseous nitrogen loss, in both the OP and BW soils. This work implies that urine-N applied to the mineral soil (BW) could potentially threaten the quality of ground water due to nitrate contamination through leaching. In contrast, denitrification appears to be the major loss mechanism from the peat soils, with the production of nitrous oxide being the primary focus for any environmental concern. Future work should examine the fate of the nitrate leached from the BW soil and the potential for dilution, plant uptake or denitrification below a 30 cm soil depth. A better understanding of the denitrification mechanisms could help reduce denitrification and thereby improve the efficiency of nitrogen use and reduce the output of nitrous oxide.

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Hedley, Carolyn B. "The development of proximal sensing methods for soil mapping and monitoring, and their application to precision irrigation : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Soil Science at Massey University, Palmerston North, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/1217.

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The potential of proximal soil sensing methods for high resolution investigation of soils in the landscape has been investigated. This addresses the need for improved environmental monitoring and management of soils within their environs. On-the-go electromagnetic (EM) mapping has been used to map soils, providing a high resolution (< 10m) spatially defined soil apparent electrical conductivity (ECa) datalayer. Vis-NIR field spectroscopy has been trialled for in situ analysis of soil carbon, nitrogen and moisture. The portable spectroradiometer has been used at 6 sites in the Taupo-Rotorua region for rapid, field analysis of soil carbon (R2 calibration = 0.95, R2 prediction = 0.75,) soil nitrogen (R2 calibration = 0.95, R2 prediction = 0.86) and moisture (R2 calibration = 0.96, R2 prediction = 0.70) by collecting reflectance spectra from the flat surface of a soil core; and at one Manawatu site for soil moisture (R2 calibration = 0.79, R2 prediction = 0.71), where the reflectance spectra were collected directly from a freshly cut in situ soil surface. EM mapping and Vis-NIR field spectroscopy were used in combination to spatially characterize soil moisture patterns at the Manawatu site. Soil available water-holding capacity (AWC) of ECa-defined zones has been assessed at six irrigated production farming sites. Two methods (predicted AWC v ECa; estimated AWC v ECa) have been used to relate soil ECa to soil AWC to predict spatial AWC (R2 = 0.8 at 5 sites). Site-specific soil water balance models have been developed at all sites; and a wireless real-time soil moisture monitoring network has been trialled at two sites, to be used with the ECa-AWC prediction model for the development of daily soil water status maps, for variable rate irrigation (VRI) scheduling. This digital, spatially defined soil water status information is available for upload to a sprinkler system modified for variable rate application. The calculated water savings with VRI were 926% with equivalent energy savings and improved irrigation water use efficiency. Drainage and runoff were reduced by 055% during the period of irrigation, with the accompanying reduced risk of nitrogen leaching. The reduction in virtual water content of product has also been assessed for VRI and compared with uniform rate irrigation (URI) at three study sites. This study suggests that these proximal sensing methods provide a new improved way of monitoring and mapping soils. This facilitates soil inventory mapping, for example soil moisture and carbon mapping. In addition, these high resolution environmental monitoring and mapping techniques provide the information required for optimizing site-specific management of natural resources at the farm scale. On-the-go electromagnetic (EM) mapping has enabled a step change in the pedological investigation of New Zealand soils. Resulting soil ECa maps provide a tool for improving traditional soil map boundaries because they delineate soil zones primarily on a basis of soil texture and moisture in non-saline soils. In this study the maps have been used for site-specific irrigation management at the farm-scale, aiming to increase the energy efficiency of this land management operation. The study has developed a method for improved use of freshwaters by more accurate irrigation scheduling, based on high resolution characterization of spatial and temporal soil differences.

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Mojsilovic, Ognjen. "Estimating bioaccessibility, phytoavailability and phytotoxicity of contaminant arsenic in soils at former sheep dip sites." Lincoln University, 2009. http://hdl.handle.net/10182/1142.

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Recognition that the bioavailability of soil As (As) is influenced by its soil dynamics has initiated research into development of more accurate, site-specific soil guideline values, departing from the assumption that the total soil As content is bioavailable. With the aim of deriving predictive models, the relationship between soil properties and As bioavailability (bioaccessibility and phytotoxicity) was examined on a set of naturally contaminated sheep dip soils (n = 30). Sampled soils were extensively characterised, bioaccessibility was estimated through an in vitro procedure, and soil As toxicity and availability to plants were evaluated using an early growth wheat bioassay. The in vitro bioaccessibility was consistently less than the total soil As content. Arsenic bioaccessibility was negatively correlated to soil iron (Fe), manganese (Mn) and aluminium (Al) contents, and it was positively related to the soil As loading. The in vitro extractable soil As concentrations were successfully modelled using linear combinations of soil As content, soil Fe and Mn determinations and soil pH. Differences in As phytotoxicity, expressed in terms of effective toxic concentration (EC50), between soils were directly related to soil Fe, Mn and Al contents. Available soil phosphorous (P) exerted an ameliorating effect on As toxicity, with the available soil As/P ratio representing the single best predictor of plant growth suppression. Plant P nutrition appeared to influence the relative selectivity for As and P by wheat, with greater selectivity for P demonstrated under P deficient conditions. Plant As uptake, its distribution, and also the plant nutrient status were all adversely affected by increasing soil As exposure. Co-contamination by Zn corresponded to a substantial elevation in proportion of the plant As allocated in shoots. Plant As levels exhibited a saturation-dependent relationship with increasing soil As. The best linear predictors of plant As levels in the non-toxic range were RHIZO-extractable and effective soil As concentrations, the latter based on the diffusive gradients in thin films (DGT) technique. Despite the complexity of soil As dynamics, large proportions in the variances exhibited by the two measures of bioavailability were explained using a small set of readily-available soil properties.

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Fisher, P. M. "Residual concentrations and persistence of the anticoagulant rodenticides brodifacoum and diphacinone in fauna." Lincoln University, 2009. http://hdl.handle.net/10182/930.

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Brodifacoum is a highly effective anticoagulant rodenticide that presents a secondary hazard to some non-target wildlife. The high acute toxicity of brodifacoum to mammals and birds, and its prolonged persistence in liver predicates secondary risk to predators and scavengers of poisoned rodents. Hence there is a need to improve ability to monitor and predict hazards of brodifacoum to non-targets, and optimise use patterns accordingly. Use of a less persistent anticoagulant rodenticide, diphacinone, is an alternative approach currently under investigation in New Zealand. This thesis describes a series of laboratory and pen studies that address information gaps relevant to the assessment of non-target hazards in continued use of brodifacoum, and of using diphacinone as an alternative. Non-lethal techniques for determining sublethal brodifacoum exposure in birds was investigated in chickens. Elevation of prothrombin time was a less reliable index than residual concentrations in tissues. Samples requiring less invasive procedures, such as dried blood spots or faeces, have potential to detect recent sublethal brodifacoum exposure and refinement of these indices could be useful in proactive monitoring of avian wildlife. Residual brodifacoum in eggs of sublethally-exposed hens raised further questions regarding wider non-target hazard and adverse effects on development of fertile eggs or chicks. A laboratory trial with rats found a positive correlation between residual brodifacoum concentrations in liver and the amount of brodifacoum ingested as bait. An estimated 14-22% of ingested brodifacoum was excreted in rat faeces in the period between ingestion of a lethal dose and death, indicating another potentially significant environmental pathway for brodifacoum transfer. In considering diphacinone as a less persistent alternative rodenticide to brodifacoum, evaluation of residual concentrations and persistence in pig tissues was required to estimate secondary hazard to human consumers and adequate with-holding periods for hunting feral pigs in areas where diphacinone was applied. A pen trial showed that domestic pigs were more susceptible to diphacinone toxicity, and thus primary poisoning risk, than previously estimated. Hepatic half-life of diphacinone in pigs was approximately 14 days, indicating reduced persistence in comparison to brodifacoum and enabling estimates of with-holding periods for hunting feral pigs from areas where diphacinone baits were applied. To investigate potential hazards of diphacinone use to invertebrates a trial using tree weta, a native New Zealand invertebrate, was undertaken. Weta readily ate diphacinone wax block baits with no mortality or weight loss evident, indicating low susceptibility. Residual whole-body diphacinone concentrations did not increase with the amount of diphacinone bait eaten. A simple, deterministic risk assessment suggested that, as a single secondary exposure, the maximum diphacinone concentration measured in weta would present a low risk to non-target birds. Given international recognition of the high secondary hazard and corresponding restrictions on use of brodifacoum, continued availability of brodifacoum to non-licensed users and sustained field applications for possum and rodent control in New Zealand is an exceptional use pattern. New data in this thesis suggest that baiting strategies that minimise the amount of brodifacoum available in the environment are important and regulatory review of some New Zealand brodifacoum applications should address this. In parallel, development of diphacinone as an alternative to brodifacoum should continue, as new data here confirms lower persistence in mammalian liver than brodifacoum, and also indicates low toxicity to invertebrates. However further investigation of multiple-exposure hazard and potential sublethal effects of diphacinone on non-target mammals and birds is warranted before extensive and sustained field applications of diphacinone are undertaken.

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Chappell, Esta Monique. "Morphology, phylogeography and drumming behaviour of a New Zealand ground weta, Hemiandrus pallitarsis : a thesis presented in partial fulfillment of the requirements for the degree of Master of Science in Conservation Biology at Massey University, Palmerston North, New Zealand." Massey University, 2008. http://hdl.handle.net/10179/828.

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Species are one of the fundamental components of biology and the accurate delimitation of species is important in evolutionary, systematic and ecological studies, yet there is still confusion over how species can be recognised. Examining different characters allows multiple lines of evidence for successful and accurate species delimitation and identification. In this thesis, morphological, genetic and behavioural variation is investigated within an endemic species of ground weta, Hemiandrus pallitarsis, in the North Island, New Zealand. Twelve morphological characters were measured, and mitochondrial cytochrome oxidase I DNA sequences were analysed from populations across the distributional range of H. pallitarsis. Both methods provide no evidence of a species complex within H. pallitarsis. Instead, the morphometric results suggest females are significantly larger than males, and ground weta in Palmerston North are significantly smaller than weta further north. Additionally, genetic analyses found substantial population structuring, large genetic distances, and an historical south to north pattern of movement in the North Island. The pattern of vibratory drumming behaviour followed that predicted by morphology and geographic proximity – drumming signals were more similar between geographically close populations and did not match the patterns of genetic isolation. Overall, this thesis was able to show that H. pallitarsis is morphologically, genetically and behaviourally variable across the North Island.

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23

Williamson, Michelle Leigh. "Differential responses of tillers to floral induction in perennial ryegrass (Lolium perenne L.) : implications for perenniality : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Plant Biology at Massey University, Palmerston North, New Zealand." Massey University, 2008. http://hdl.handle.net/10179/842.

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Development of sustainable practices is an important goal in agriculture. One possibility involves the development of perennial cereal crops, but the mechanisms of perenniality first need to be understood. While in annual cereals flowering structures die following seed production, in perennial grasses, perenniality is achieved by maintaining at least one shoot in a vegetative state. There are two views on perennating tiller origin in perennial grasses: some authors suggest that all over-wintering tillers flower in spring and summer, leaving spring-initiated tillers to perennate, while others indicate that spring-initiated tillers are too immature to survive summer conditions, thereby implying that flowering must be prevented in some over-wintering tillers. An understanding of perenniality will therefore require an understanding of flowering control in these species. Temperate perennial grasses have dual induction requirements for flowering, where plants become competent to perceive inductive signals following vernalisation, and flowering is initiated by inductive photoperiods. Two hypotheses were formulated to test these models. The ‘environmental control hypothesis’ stated that all adequately vernalised perennial ryegrass tillers would flower on sufficient exposure to inductive photoperiods. Alternatively, the ‘spatial control hypothesis’ stated that in addition to the environmental mechanisms, a spatial control mechanism acts to regulate flowering. Two experiments were conducted to test these hypotheses. Perennial ryegrass and Italian (annual) ryegrass were induced to flower and differences between the annual and perennial habits at flowering time were observed. However neither hypothesis was proven. In the second experiment, flowering was studied in detail in individual tillers of perennial ryegrass. The eldest tiller flowered in all flowering plants. The second eldest tiller did not flower in 72% of plants with more than one reproductive tiller, while the third eldest tiller flowered in 94% of these plants. These data favour the spatial control hypothesis which suggests that a spatial regulatory mechanism might act to repress flowering in some competent perennial ryegrass tillers. These results were supported by studies of meristem morphology and by a preliminary gene expression study. Maintenance of older, established tillers in a vegetative state might allow the perennial plant a greater chance of survival during summer.

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24

Linden, Danitsja Stephanie van der. "Ewe size and nutrition during pregnancy : effects on metabolic and productive performance of the offspring : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science at Massey University, Turitea, Palmerston North, New Zealand." Massey University, 2010. http://hdl.handle.net/10179/1343.

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Exposure of the fetus to adverse conditions in utero may result in developmental adaptations that alter metabolism and postnatal growth of the offspring. This thesis investigated the effects of dam size and nutrition during pregnancy on growth, metabolic function and lactational and productive performance of the female offspring to two years of age. Four-hundred and fifty heavy (60.8 kg ± 0.18) and 450 light (42.5 kg ± 0.17) dams were randomly allocated to ad libitum or maintenance nutritional regimens from days 21 - 140 of pregnancy, under pastoral grazing conditions. From one week prior to lambing, all dams were fed ad libitum until weaning. After weaning, female progeny were managed and fed under pastoral conditions as one group. Maternal nutrition during pregnancy affected lamb growth to weaning, however, after weaning lamb growth was affected by dam size. Dam size had no effect on glucose metabolism, adrenal function or fat metabolism in 16-month-old female twin offspring. Dam nutrition during pregnancy had a minor effect on glucose metabolism and no effect on adrenal function or lipolysis, however, it did possibly affect gluconeogenesis and/or glycogenolysis, with increased glucose production in ewes born to maintenance-fed dams. Ewes born to dams fed maintenance showed greater milk production, lactose percentage, lactose and crude protein yield. Ewes born to heavy dams showed greater milk production and lactose yield. Dam size had no effect on reproductive performance of the female offspring. Being born to a larger dam showed no advantages over being born to smaller dams, for number of lambs born and weight of lambs at birth and weaning. ‘Grand’dam maintenance nutrition increased lamb birth and weaning weight and lamb growth rates of the ‘grand’offspring. Ewes born to maintenance-fed dams could have an advantage over ewes born to ad libitum-fed dams in physiological stressful situations in life as their liver may be able to supply more glucose to support their growing conceptus and milk production to increase the chances of survival of their offspring. These results indicate that it is possible to programme the offspring by feeding their dams differently during pregnancy under grazing conditions. With a better understanding of how offspring can be programmed through different maternal nutritional regimens, it may be possible to significantly increase the production potential of the New Zealand ewe population.

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Kang, Sideth. "Effect of irrigation on growth and nitrogen accumulation of Kabuli chickpea (Cicer arietinum L.) and narrow-leafed lupin (Lupinus angustifolius L.)." Diss., Lincoln University, 2009. http://hdl.handle.net/10182/1126.

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A field experiment was conducted to examine the responses in growth, total dry matter (TDM), seed yield and nitrogen (N) accumulation of Kabuli chickpea cv. Principe and narrow-leafed lupin cv. Fest to different irrigation levels and N fertilizer on a Templeton silt loam soil at Lincoln University, Canterbury, New Zealand in 2007/08. The irrigation and fertilizer treatments were double full irrigation, full irrigation, half irrigation and nil irrigation and a control, full irrigation plus 150 kg N ha⁻¹. There was a 51 % increase in the weighed mean absolute growth rate (WMAGR) by full irrigation over no irrigation. The maximum growth rates (MGR) followed a similar response. The growth rates were not significantly decreased by double irrigation. Further, N fertilizer did not significantly improve crop growth rates. With full irrigation MGRs were 27.6 and 34.1 g m⁻² day⁻¹ for Kabuli chickpea and narrow-leafed lupin, respectively. Seed yields of fully-irrigated crops were trebled over the nil irrigation treatment. With full irrigation, seed yield of chickpea was 326 and that of lupin was 581 g m⁻². Seed yield of the two legumes was reduced by 45 % with double irrigation compared with full irrigation. Nitrogen fertilizer did not increase seed yields in either legume. Increased seed yield with full irrigation was related to increased DM, and crop growth rates, seeds pod⁻¹ and seeds m⁻². Crop harvest index (CHI) was significantly (P < 0.05) increased by irrigation and was related to seed yield only in narrow-leafed lupin. With full irrigation, the crops intercepted more than 95 % of incoming incident radiation at leaf area indices (LAIs), 2.9 and 3 or greater in Kabuli chickpea and narrow-leafed lupin, respectively. In contrast, without irrigation the two legumes achieved a maximum fraction of radiation intercepted of less than 90 %. With full irrigation, total intercepted photosynthetically active radiation (PAR) was increased by 28 % and 33 % over no irrigation for Kabuli chickpea and narrow-leafed lupin, respectively. Fully-irrigated Kabuli chickpea intercepted a total amount of PAR of 807 MJ m⁻² and fully-irrigated narrow-leafed lupin intercepted 1,042 MJ m⁻². Accumulated DM was strongly related to accumulated intercepted PAR (R² ≥ 0.96**). The final RUE was significantly (P < 0.001) increased by irrigation. With full irrigation the final RUE of Kabuli chickpea was 1.49 g DM MJ⁻¹ PAR and that of narrow-leafed lupin was 2.17 g DM MJ⁻¹ PAR. Total N accumulation of Kabuli chickpea was not significantly affected by irrigation level. Kabuli chickpea total N was increased by 90 % by N fertilizer compared to fully-irrigated Kabuli chickpea which produced 17.7 g N m⁻². In contrast, total N accumulated in narrow-leafed lupin was not increased by N fertilizer but was decreased by 75 % with no irrigation and by 25 % with double irrigation (water logging) compared to full irrigation with a total N of 45.9 g m⁻². Total N was highly significantly related to TDM (R² = 0.78** for Kabuli chickpea and R² = 0.99** for narrow-leafed lupin). Nitrogen accumulation efficiency (NAE) of narrow-leafed lupin was not affected by irrigation or by N fertilizer. However, the NAE of Kabuli chickpea ranged from 0.013 (full irrigation) to 0.020 (no irrigation) and 0.017 g N g⁻¹ DM (full irrigation with N fertilizer). The N harvest index (NHI) was not affected by irrigation, N fertilizer or legume species. The NHI of Kabuli chickpea was 0.50 and that of narrow-leafed lupin was 0.51. The NHI was significantly (r ≥ 0.95 **) related to CHI.

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O'Connor, Katrina Marie. "The ecological footprint of international tourists in New Zealand : a thesis presented in partial fulfilment for the degree of Master of Applied Science in Natural Resource Management at Massey University, Palmerston North, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/1124.

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Ecological Footprint Analysis (EFA) is a technique that was first developed by Wackernagel as a Ph.D. thesis in 1994, then further developed in combination with Rees and published (Rees & Wackernagel, 1995). EFA is employed in this study to assess the resource utilisation of international tourists visiting New Zealand. Tourism is one of the fastest growing industries in the world and the ecological sustainability of tourism is becoming more important term for managing tourism. This is becoming increasingly important with tourism identified as particularly as a significant contributor to carbon emissions. This study uses EFA to assess whether international tourists visiting New Zealand behave in a sustainable manner. Tourists are surveyed and classed into high, mid and low budget tourist types to gain a detailed account of their behaviour with particular reference to food, accommodation, transport, services, activities attractions, goods and waste. The EFA helps to identify areas of a tourist’s trip that have the greatest impact on the environment, thereby identifying ways to improve the sustainability of tourism in New Zealand. It was found that tourists generally consume more whilst on holiday than they do at home and more than New Zealand residents. The results show that international tourists’ behaviour is sustainable and New Zealand has the ecological carrying capacity to allow the number of international tourists to increase without incurring any significant ecological costs to the country. It was found that there is a positive relationship between ‘high’ income tourists and their ecological footprint and that independent travellers have a larger ecological footprint than the package travellers; however, package travellers have a larger food and housing ecological footprint than independent travellers. The energy footprint was the largest out of the six land types of a tourist’s ecological footprint. Food is the consumption category that is the largest contributor to a tourist’s ecological footprint.

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Leeks, C. R. F. "Determining seed vigour in selected Brassica species." Lincoln University, 2006. http://hdl.handle.net/10182/1274.

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Variables for the accelerated ageing (AA) test, methods for reducing fungal contamination during the AA test, using the conductivity test as a vigour test, the effect of seed size on seed vigour and the relationship between laboratory test results and field perfonnance in selected Brassica spp were investigated. In the first experiment, three seed lots of turnip rape hybrid (B. rapa x campestris), turnip (B. campestris) and forage rape (B. napus); and seven seed lots of Asian rape (B. napus), six seed lots of Asian kale (B. oleraceae var. alboglabra L.) and five seed lots of choisum (B. rapa var. pekinensis) with germinations above 90% were aged at two different temperatures (41 and 42°C ± 0.3°C) and three ageing times (24, 48 and 72 ± 15 minutes). The second experiment was divided into three sections. In the first, the same seed lots and species were aged at one temperature (41°C) and time (72 h), but either 40 ml of saturated salts; KCl (83%RH), NaCl (76%RH), NaBr (55%RH); or distilled water (96%RH) were used as the ageing solutions. In the second, one turnip rape hyprid seed lot was aged at three temperatures (41, 42 and 45°C) and two times (72 and 96h), again using the three saturated salts and distilled water as ageing solutions. In the third, three turnip rape hybrid seed lots and three Asian kale seed lots were surface sterilised (1 % sodium hypochlorite) prior to ageing at one temperature (41°C) and time (72 h). In the third experiment, the same species and seed lots used in experiment one at their original seed moisture content (SMC) were tested for conductivity after soaking in deionised water for 4, 8, 12, 16, 20 and 24 h. They were then re-tested after the SMC had been adjusted to 8.5%. In the fourth experiment, three seed lots of forage rape and three seed lots of Asian kale were graded into three seed size categories; large (retained on a 2.0 mm screen), medium (retained on a 1.7 mm screen) and small (passed through a 1.7 mm screen). Graded seeds were then tested for standard germination, AA (41°C/48 h) and conductivity (measured at 16 and 24 h). In the final experiment, the relationships between laboratory tests for the six species (each consisting of three seed lots), field emergence from three sowings, and cold room emergence were evaluated. Both time and temperature influenced post-AA germination. Increasing the ageing period from 48 to 72 hours at 41°C, and 24 to 48 hours at 42°C resulted in decreased mean germination percentage for all species but not always clear separation of seed lots. While there were sometimes few differences between ageing at 41°C and 42°C, the former is preferred because it is already the temperature used for other species. For Asian rape, choisum and turnip, the previously recommended testing conditions of 41°C/72 h provided good seed lot separation, but for Asian kale and turnip rape hybrid, AA testing at 41°C/48 h provided better results. Seed moisture content after ageing ranged from 29-37% depending on species. Fungal growth on seeds during the ageing period appeared to reduce post-ageing germination in some seed lots . Substituting saturated salts for distilled water did not stress seed lots in the AA test, due to the lowered RH%, the exception being seed lots 1210 and 1296. For forage and Asian species, seed lot germination mostly remained above 90% when aged for 72 h at lowered RH%. Increasing the ageing duration from 72 to 96 hours resulted in some decreases in post-AA germination but no clear separation of seed lots. Surface sterilising the seeds prior to the AA test resulted in a lower incidence of contaminant fungi which was associated with a lower percentage of abnormal seedlings. The conductivity test was mostly able to identify vigour differences among forage and Asian vegetable brassica seed lots. Differences in conductivity readings were observed among seed lots in all species. Increasing the period of imbibition resulted in increased conductivity from most seed lots but radicle emergence occurred after 16-20 h of imbibition. Variation was observed in the time to reach 95% maximum of the imbibition curve for most species. Conductivity readings at 16 h would avoid possible influences of radicle emergence on results. Adjusting the SMC to 8.5% resulted in reduced variation in conductivity among replicates of seed lots, due to a reduction in imbibition damage. Seed size had a significant effect on both post-AA germination and conductivity results. In forage rape, large size seeds had higher post-AA germination cf. medium cf. small size seeds. In Asian kale, large size seeds had higher post-AA germination compared with small size seeds. For both forage rape and Asian kale, large size seeds had lower conductivity readings cf. small size seeds. The correlation analyses demonstrated significant relationships between AA testing and field emergence parameters (percentage emergence, emergence index and emergence rate). Significant relationships were also observed between conductivity testing and these field emergence parameters. Based on the correlation analysis, AA testing at 41°C/48 hand/or 42°C/48 h could be recommended to be used as an AA test for turnip and Asian rape; and 41°C/48 hand/or 41°C/72 h for Asian kale and choisum. Based on the correlation analysis, conductivity testing at 16 h can be used to predict the field emergence potential of forage and Asian vegetable seed lots. Vigour tests were consistently able to provide better indicators of field perfonnance than the standard germination test, although these relationships did vary with the different field sowings.

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Dobson-Hill, Brenna Catherine. "Uterine involution in the dairy cow : comparative study between organic and conventional dairy cows : a thesis presented in partial fulfilment of the requirements for degree of Masters of Science in Animal Science, Massey University, Palmerston North." Massey University, 2009. http://hdl.handle.net/10179/1272.

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Organic dairying is growing in popularity in New Zealand and the demand for knowledge is ever increasing. Many more farmers are considering organics as an alternative to their current conventional system. However, limited information is available on organic dairying in a New Zealand pastoral situation particularly in relation to its effect on fertility. The New Zealand dairy industry requires the dairy cow to become pregnant every year at the same time to maximise milk production and utilise the high pasture production in spring. A cow requires 40 to 60 days for uterine involution to occur and for resumption of oestrous cycles. It is critical that the cow becomes pregnant within the six to eight week mating period, however, this can be difficult for late calvers or those cows that had or still have a uterine infection, to undergo uterine involution and be successfully mated. These cows will often not become pregnant and as a consequence be culled for infertility. During the first few weeks postpartum, the bacterial composition of the uterus fluctuates as a result of spontaneous contamination, elimination and recontamination. Most cows are able to eliminate these bacteria, however, 10 to 17% of cows are unable to do this. In these cows, the bacteria persist, cause infection and inflammation, and delay uterine involution. The main objective of this present study was to investigate the effect of different management systems (Organic and Conventional) on productivity and reproduction, particularly the process of uterine involution and its relationship with reproductive outcomes. Uterine involution will be studied through the following measurements: cervical diameter as assessed by measurement per rectum, plasma concentrations of glucocorticoids and bacteriology of the uterus. Lactation characteristics: milk yield, cumulative milk yield, milksolids production and somatic cell count will also be investigated. From the results, it can be concluded that Organic cows have reduced milk yield (P=0.05) and milksolids production (P<0.01) through there were no major differences at peak lactation or in the rate of decline after. However, overall somatic cell count was not affected by management system though the Conventional cows had high somatic cell counts in early lactation (P=0.925). Cervical diameter was affected by the management system with the difference between Organic and Conventional cows almost significant (P=0.06). Cortisol concentrations were significantly higher in Organic cows (0.68 ± 0.08 ng/ml) when compared to Conventional cows (0.95 ± 0.06 ng/ml) (P=0.01). Cortisol concentrations decreased over time postpartum (P<0.01). Additionally Organic cows had a shorter interval from calving to AI (P=0.017). However, none of the other reproductive outcomes were affected by management system. Simple correlations established that reproductive outcomes and bacterial counts, reproductive outcomes and cortisol at Day seven, and cortisol and milk production characteristics, were not independent of each other. Aerobic bacterial counts on Day 28 and the interval from calving to AI were found to be significantly correlated (r= 0.615). Stepwise partial regression analysis, plus analysis of variance calculated on the relationships between uterine involution parameters and reproductive outcomes found multiple weak correlations. It found that cervical diameter, and aerobic and anaerobic bacterial counts on Day 28 were significantly correlated with the interval from calving to first AI (P=0.018). The differences in lactation characteristics are related to the lower pasture production on the organic farmlet reducing the maximal potential milk production and the possibly earlier calving dates of the Conventional cows. The differences in bacterial counts and almost significant difference in cervical diameter may be related to the lower cortisol levels and thus suggest that the Organic cows may be less stressed. As stress suppresses the immune system, it may be possible that the higher bacterial counts are indicitative of a less efficient or slightly weakened immune system which takes longer to eliminate bacteria in the uterus; however this is open to conjecture. The shorter interval from calving to AI suggests that Organic cows may be exhibiting oestrus behaviour earlier postpartum or the Conventional cows are having “silent heats” but this difference is possibly related to human factors. The correlation between parameters of uterine involution and interval from calving to AI, and the lower values for uterine involution parameters in Organic cows suggest the possibility of faster uterine involution and this may result in better fertility in the Organic cows. More research needs to be carried out to further investigate the effect of organic dairying on uterine involution and reproduction outcomes but organic dairying at the very least does not negatively impact on uterine involution and fertility.

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Gibson, Troy John. "Electroencephalographic responses of calves to the noxious sensory input of slaughter by ventral neck incision and its modulation with non-penetrative captive bolt stunning : a thesis presented in partial fulfilment of the requirements of the degree of Doctor of Philosophy in Physiology, Massey University, Palmerston North, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/1010.

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Slaughter by ventral neck incision (VNI) is performed on some animals without prior stunning in New Zealand and other countries. A single incision with a razor sharp blade is made in the ventral aspect of the neck, sectioning both carotid arteries and jugular veins, though, not the vertebral arteries. There are a number of potential welfare concerns surrounding slaughter by VNI including pain due to the incision, which may lead to distress during the time before loss of consciousness. The aims of this thesis were to identify cortical responses indicative of noxious stimulation due to slaughter by VNI using analysis of the electroencephalogram (EEG) power spectrum and to investigate the effects of non-penetrative captive bolt (NPCB) stunning on these cortical responses. The studies utilised adaptations of a minimal anaesthesia model, which has been validated in a range of mammalian species. Surgical dehorning was used as a validation technique for this methodology in cattle and demonstrated a ‘typical’ EEG response to noxious stimulation. Cattle slaughtered by VNI without prior stunning produced specific responses in the EEG that strongly indicated responses to noxious stimulation. Causation was investigated in cattle where blood flow through the brain remained intact during neck tissue incision (NTI) or the major blood vessels of the neck were isolated and transected independently of other neck tissues (BVT). The response to neck incision in intact animals was principally due to the noxious sensory input due to incision of neck tissues and not mainly as a result of loss of blood flow through the brain. NPCB stunning produced states of cortical activity that were incompatible with the maintenance of sensibility and pain perception. Experimental examination of the time to onset of undoubted insensibility was attempted in cattle subsequent to a pilot study in sheep. The generation of somatosensory-evoked potentials was problematic in cattle. The conclusions of this thesis are that incision of neck tissues during slaughter without prior stunning constitutes a substantial noxious stimulus. Were an animal conscious, this stimulus would be perceived as painful until the onset of hypoxiainduced insensibility. This would represent a significant compromise to animal welfare.

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Lopez, Juan Carlos. "The effect of environmental stressors on the immune response to avian infectious bronchitis virus." Lincoln University, 2006. http://hdl.handle.net/10182/643.

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The first aim of this research was to determine the prevalence of IBV in broilers within the Canterbury province, New Zealand, in late winter and to search for associations with management or environmental factors. The second aim was to study how ambient stressors affect the immune system in birds, their adaptive capacity to respond, and the price that they have to pay in order to return to homeostasis. In a case control study, binary logistic regression analyses were used to seek associations between the presence of IBV in broilers and various risk factors that had been linked in other studies to the presence of different avian pathogens: ambient ammonia, oxygen, carbon dioxide, humidity and litter humidity. Pairs of sheds were selected from ten large broiler farms in Canterbury. One shed (case) from each pair contained poultry that had a production or health alteration that suggested the presence of IBV and the other was a control shed. Overall, IBV was detected by RT-PCR in 50% of the farms. In 2 of the 5 positive farms (but none of the control sheds) where IBV was detected there were accompanying clinical signs that suggested infectious bronchitis (IB). Ambient humidity was the only risk factor that showed an association (inverse) with the prevalence of IBV (p = 0.05; OR = 0.92). It was concluded within the constraints of the totally enclosed management systems described, that humidity had an influence on the presence of IBV, but temperature, ammonia, carbon dioxide, oxygen or litter humidity had no effect. In another study environmental temperatures were changed in order to affect the biological function and adaptive capacity of chickens following infection with IBV. The 'affective states' of the animal were assessed by measuring levels of corticosterone (CORT) in plasma and tonic immobility (TI). It was found that low (10 +/- 2°C) and high (30 +/- 2°C) temperatures exacerbated the respiratory signs and lesions in birds infected with IBV as compared to those housed at moderate (20 +/- 2°C) temperatures. The chickens housed at high temperatures showed significantly decreased growth, a higher proportion of hepatic lesions (principally haemorrhages) and a longer tonic immobility period, but there was no significant alteration in the plasma levels of CORT. The birds housed at low temperatures developed a higher proportion of heart lesions (hydropericardium, ventricular hypertrophy) and had significantly higher levels of plasma CORT than birds housed under moderate and/or high temperatures. The specific antibody response to IBV decreased in birds housed under high temperatures. Interestingly the birds housed at high temperatures developed significantly higher levels of haemagglutinin antibodies to sheep red blood cells (SRBC) than those birds housed under low or moderated temperatures. Cell mediated immunity was not significantly affected by heat or cold stress in the first 13 days of treatment but at 20 days the levels of interferon gamma in the birds subjected to low temperatures were lower than in the high temperature group. In other trials, the exogenous administration of low physiological doses of oral CORT (as compared to high pharmacological doses typically used in such experiments) to birds resulted in suppression or enhancement of the immune response depending on duration of treatment and/or dose and nature of the antigen. To our knowledge, this is the first study to show that exogenous CORT can produce an enhancement in the immune response in chickens. iv In conclusion, environmental stressors such as high or low temperatures do affect the physiology of the fast-growing broiler. The adjustments the birds have to make to maintain homeostasis impacts on the course of common infectious diseases, such as IB, that normally is mild in the New Zealand poultry industry. The administration of exogenous CORT showed that this hormone may be part of the physiological stress response and acts as a messenger to prepare the immune system for potential challenges (e.g., infection).

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31

Donaldson, Laura Patricia Constance. "The distribution of fatty acids and presence of environmental contaminants in the blubber of the New Zealand sea lion (Phocarctos hookeri) : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology at Massey University, Palmerston North, New Zealand." Massey University, 2008. http://hdl.handle.net/10179/887.

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The conservation of marine mammals relies on the knowledge of species ecology in order to assess the impacts of anthropogenic activites and make appropriate species management decisions. Blubber biopsies are a relatively non-invasive sampling protocol to provide ecological information; two particular uses are for dietary analysis via fatty acid signature analysis (FASA) and investigating the uptake of organochlorine (OC) and polychlorinated biphenyl (PCB) environmental contaminants. Blubber composition and structure may vary according to body site and depth due to its dynamic functioning. This may result in the vertical stratification and heterogenous distribution of blubber FAs, OCs and PCBs between body sites, giving variable interpretations of diet and contaminant levels depending on biopsy sample site and depth. The aim of this thesis is to determine the FA distribution of blubber from two body sample sites (dorsal pelvic and ventral thoracic) currently used for FASA of the New Zealand sea lion, Phocarctos hookeri (NZSL) and to determine the level of OCs and PCBs in the blubber of healthy NZSLs for comparison to diseased NZSLs recorded in the 1997/98 epidemic. Blubber samples were collected from 29 by-caught NZSLs incidentally captured by the squid fishery around the Auckland Islands (50º42’S, 166º5’E) during the years 2005 to 2007 (not all NZSLs were able to be analysed for each chapter). Full blubber cores from both sample sites were collected from 18 NZSLs. Both sites showed a relative homogeneity of FA profiles, indicating the similar deposition and mobilisation of FAs at the two sample sites. To determine if FA stratification occurred, full blubber cores from both sample sites of 20 NZSLs were divided into inner and outer halves. Both sites displayed the same pattern of vertical stratification or biochemical layering of FAs between the two divisions, indicating that stratification of FAs occurs in the blubber of the NZSL. A range of OCs and PCBs were then determined in full thoracic blubber cores of seven NZSLs. The levels were higher than those previously recorded in NZSLs affected by disease during a 1997/98 epidemic. The SPCB in NZSLs was 0.034-0.192 mg/kg lipids, below the suggested threshold of 17 mg/kg for adverse health affects in marine mammals. From the results of this study I can support current blubber biopsy sampling techniques for FASA in NZSL. Obtaining full blubber cores from either the thoracic or pelvic sample site will give a comparable interpretation of diet. The low levels of blubber OCs and PCBs suggest a minor role of contaminants acting as a possible causative agent toward disease outbreaks in the NZSL. This research provides important information for developing correct and consistent blubber sampling techniques for NZSL and other pinniped species. This will ensure more accurate interpretations of ecological information obtained from blubber biopsies and therefore improved species management and conservation decisions that may be based on such research.

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32

Newcombe, Vernon Claude. "Mercury use in the goldmining industry : a retrospective examination of elemental mercury use in the gold mining industry of the West Coast of New Zealand in the period 1984-1988 : a thesis submitted in partial fulfilment of the requirement for the degree of Master of Philosophy (Science) at Massey University, Wellington, New Zealand." Massey University, 2008. http://hdl.handle.net/10179/832.

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33

Robertson, Louise Mary. "Anthelmintic treatment and digestive organ morphology of captive-reared kaki (Himantopus novaezelandiae) released to the wild : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology at Massey University, Palmerston North, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/1001.

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The continued existence of New Zealand’s critically endangered and endemic black stilt or kakï (Himantopus novaezelandiae) relies on an intensive captive management programme. While this is successful at rearing large numbers of birds for release to the wild, poor survivability of these birds is limiting significant increases in the wild population. Predation and starvation are suspected to be the most common causes of death in released birds, but underlying contributing factors to these mortalities have not been fully evaluated. This research investigates the possible contribution of gastrointestinal (GI) helminth burdens and suboptimal digestive organ development to the high mortality rates of released kakï. Emphasis is placed on evaluating the methods used to assess the importance of these factors and to make informed recommendations for future management. The efficacy of the anthelmintic regime used for kakï was assessed by dosing half of the 80 captive birds with praziquantel (PZQ) prior to release in 2007. Faecal samples were collected before and after anthelmintic treatment, and before and after release to the wild. Post mortem worm counts were conducted on 11 birds that died following release and historical worm count records dating back to 1997 were accessed. The main findings were: PZQ had high efficacy against trematodes; treatment did not prevent re-infection; birds were exposed to helminths at release site; and there was no advantage of treatment for survival. Overall, the results suggest that anthelmintic treatment is an unnecessary cost. Consequently, recommendations were made to cease anthelmintic treatment or reduce its intensity, continue health screening, and incorporate annual efficacy testing to monitor the emergence of anthelmintic resistance. The reliability of faecal screening for GI helminths was evaluated. Faecal egg counts (FECs) were found to be poor indicators of worm burden. The two modified sedimentation methods used to detect trematodes provided relatively low egg recovery rates. Trematode egg shedding varied between days but not by hour of the day or temperature. The collection and analysis of pooled faecal samples proved to be more cost and time-effective than samples from individual birds and the larger masses collected resulted in greater sensitivity. In conclusion, faecal analysis of pooled samples is a useful qualitative indicator of helminth presence or absence but is quantitatively unreliable. In order to assess the importance of digestive organ development to captive-reared and released kak?, the digestive organs of healthy and emaciated captive, released and wild Himantopus sp. were compared. Captive and released kak? had generally smaller digestive organs than wild birds, released birds did not increase digestive organ size to match the high fibre wild diet, and emaciated birds did not have atrophied organs. However, the greatest mortality rates occur soon after release, while the birds were still being supplementary fed. These results suggest that reduced digestive efficiency is probably not contributing significantly to mortality rates and the direct impacts of the translocation are probably greater risk factors. The continued provision of supplementary food to released birds and an increased focus on habitat enhancement and predator control at release sites were recommended. The reliability of comparing fresh and formalin fixed Himantopus sp. gut specimens was evaluated. Significant differences in fresh and formalin fixed organ dry masses and variation in preserved organ lengths indicate that this variation should be considered in future studies. In conclusion, current management practices appear to be successful in ensuring that GI helminths and reduced digestive efficiency do not significantly lower the survivorship of captive-reared and released kakï. There is a need for further research into developing a more direct physiological assessment of the impacts of GI helminths and gut morphology as well as considering the role that starvation may have on poor survivability.

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34

van, Hooijdonk Benedict Michael. "The physiological basis of vigour control by apple rootstocks - an unresolved paradigm : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Plant Physiology at Massey University, Palmerston North, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/1137.

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For millennia, scions have been grafted onto dwarfing apple rootstocks to reduce final tree size. However, it is unclear how scion architecture is first modified by the dwarfing apple rootstock, the time from grafting when this occurs and the endogenous hormonal signalling mechanisms that may cause the initial modifications in growth that then define the future architecture of the scion. In this study, the dwarfing (M.9) rootstock significantly decreased the mean total shoot length and node number of ‘Royal Gala’ apple scions by the end of the first year of growth from grafting when compared with rootstock(s) of greater vigour (MM.106, M.793 and a ‘Royal Gala’ rootstock control). Similarly, the auxin transport inhibitor 1-N-naphthylphthalamic acid (NPA) applied to the stem of vigorous rootstocks significantly decreased mean total shoot length and node number of the scion, and the architectural changes imposed were generally similar to those imposed by M.9. For example, both treatments decreased the mean length and node number of the primary shoot, reduced the formation of secondary axes on the primary shoot and caused a greater proportion of primary and secondary shoots (if present) to terminate growth early. Decreased formation of secondary axes imposed by both treatments was reversed by applying the cytokinin benzylaminopurine (BAP) repeatedly to the scion, whilst applications of gibberellins (GA4+7) reduced the proportion of primary and secondary shoots that terminated growth early, therefore increasing the final mean length and node number of these shoot types. Both M.9 and NPA also significantly decreased the final mean dry mass and length of the root system. Given these general similarities, it is proposed that the basipetal IAA signal is of central importance in rootstock-induced scion dwarfing, and that a shoot/root/shoot signalling mechanism may exist whereby the stem tissue of the M.9 rootstock decreases the basipetal transport of IAA to the root during summer, thereby decreasing root growth and the amount of rootproduced cytokinin and gibberellin transported to scion. Reduced amounts of cytokinin transported to the scion may decrease branching, whilst reduced amounts of gibberellins may decrease the duration for which a large proportion of primary and secondary shoots grow. Analysis of endogenous hormones for newly grafted composite ‘Royal Gala’ apple trees on rootstocks of different vigour provided some additional support for these ideas. It is recommended that future studies elucidate what unique properties of the M.9 bark act to restrict IAA transport, whilst it is concluded that gene(s) regulating rootstock-induced scion dwarfing are likely to control processes within the rootstock that modify the metabolism of IAA, its basipetal transport and the subsequent synthesis of root-produced vigour-inducing hormones including cytokinins and gibberellins.

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35

Harrison-Kirk, T. "The effects of drying and rewetting cycles on carbon and nitrogen dynamics in soils of differing textures and organic matter contents." Lincoln University, 2008. http://hdl.handle.net/10182/656.

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Many researchers have reported differences in soil C and N dynamics between soils of different textures and/or soil organic matter contents. However, it has proven difficult to determine the exact relationships and mechanisms between C and N dynamics and soil texture/SOM. There are few studies that consider how these soil physical and chemical conditions influence the effects of drying and rewetting on the mineralisation of C and N and the microbial transformations that follow. The objectives of this study were: 1) To determine the effects of repeated drying and rewetting cycles on C and N dynamics in soils of differing textural class and organic matter levels. 2) To use C & N mineralised at constant moisture contents to calculate mineralisation during dry/wet cycles for comparison with actual mineralisation. Two soil types with contrasting textures were chosen and 6 paddocks on each soil type were selected to produce an OM gradient for each soil. Three moisture treatments were chosen to simulate moist (field capacity at -0.01 MPa), moderately dry (120% of wilting point at -1.5 MPa) and very dry (80% of wilting point at - 1.5 MPa) field conditions. The dry moisture treatments were then combined with a rewet treatment where they were either rewet or maintained dry (+ or – rewet), resulting in a total of five dry/rewet treatments. Soils were packed into funnel tops to a BD of 1.1 g/cm³ and sealed in glass jars fitted with septa to allow gas sampling. Drying was achieved using silica gel which allowed continued gas measurement during drying periods. Gas samples were collected throughout the experiment and analysed for CO₂ by IRGA and N₂O by GC. At the start and end of the study, soils were analysed for Min N, MBC, MBN, HWC, DOC, POM, total C and total N. The correlation between calculated and actual C mineralisation data indicates that the intercept is not consistent with the origin and that the slope is not consistent with the 1:1 line. While those paddocks with high %C had high cumulative C mineralisation, there didn’t appear to be any strong relationship between soil texture or OM content and the difference between actual and calculated C mineralisation. A plot of calculated C mineralisation rates against the actual C mineralisation rates shows that much of the error in the calculated cumulative data arises from an underestimation of the mineralisation flush when the dry soil is rewetted, especially during the first dry-rewet cycle, and an over estimation of the rate at which respiration decreases as the soil dries. In order to use C mineralisation data from soils held at constant moisture contents to accurately predict C mineralisation in soils exposed to dry-rewet cycles, knowledge of the stress history for the soil would be required e.g. size, duration and frequency of rainfall events, dry rates etc. The N₂O-N emission data is inherently more variable than the C mineralisation data. The fine-textured soils tend to have much higher N₂O-N emissions than the coarser soils, probably due to the creation of anoxic sites upon rewetting in the fine-textured soils. The data indicates that prediction of N₂O-N emissions in soils exposed to dry-rewet cycles using emission data from soils held at constant moisture contents would be very inaccurate, primarily due to the inherent variability of N₂O-N emissions in soils.

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36

Page, Girija. "An environmentally-based systems approach to sustainability analyses of organic fruit production systems in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Sustainable Agricultural Systems at Massey University, Palmerston North, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/825.

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An environmentally-based systems approach to sustainability analyses of organic fruit production systems in New Zealand. This research introduces an approach for the assessment of the sustainability of farming systems. It is based on the premises that sustainability has an environmental bottom line and that there is very limited substitutability between natural capital and other forms of capital. Sustainability assessment is undertaken through analyses of energy and material flows of the system and their impacts on the environment. The proposed sustainability assessment approach is based on two high level criteria for sustainability: efficient use of energy and non-degradation of the environment from energy and material use. Sustainability assessment of organic orchard systems in New Zealand was undertaken to demonstrate this approach. Five indicators which address the two criteria for the sustainability of the orchard systems are the energy ratio, the CO2 ratio, changes in the soil carbon level, nutrient balances, and the leaching of nitrogen. Organic kiwifruit and organic apple systems are modelled based on their key energy and material flows and their interactions with the natural environment. The energy and material flows are converted into appropriate energy and matter equivalents based on coefficients taken from the published literature. Sustainability indicators are estimated over one growing season using two computer modelling tools, Overseer® and Stella®, in a life cycle approach. Sustainability assessment of the organic orchard systems suggests that the approach is useful for evaluating energy use and key environmental impacts that occur in soil, water and atmosphere. The results indicate that the model organic orchard systems are sustainable in terms of energy use and are a net sink of CO2-equivalent emissions. The implication of this result is that organic orchard systems potentially could trade carbon credits under the Kyoto Protocol. The findings also suggest that the sustainability assessment approach is capable of identifying the trade-offs within the sustainability indicators associated with particular management practices. Further research to improve and validate the proposed approach is essential, before it can be practically used for decision making at the orchard level and for policy making at the national level.

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37

Gillies, Craig. "Aspects of the ecology and management of small mammalian predators in northern New Zealand." 1998. http://hdl.handle.net/2292/1942.

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Each chapter in this thesis has been written as a separate paper intended for later publication. Rather than write one summary, an abstract for each chapter has been given in the order they are presented in the thesis. Chapter I. The prey species of domestic cats (Felis catus) in two suburbs of Auckland city, New Zealand. The prey brought in by 80 cats (Felis catus), over a year was monitored in two suburbs of Auckland New Zealand. The survey technique followed that of Churcher & Lawton (1987) where cat owners were asked to record (and if possible keep) the prey their cats brought in. The results for the year indicated that there were distinct differences in the type of prey taken by cats in each area. Rodents were the most important prey brought in by domestic cats in an urban / forest fringe habitat and invertebrates were the main prey brought in by domestic cats in a fully urban habitat. Birds and lizards were the second and third most important prey groups in both study areas. Rat and mouse snap trap indexes which were run at each study location, did not detect rodents in the urban habitat. The results from the urban/forest fringe concurred more with studies of feral cat diet in New Zealand whilst those from the urban area compared more to studies of domestic and stray cat diet in urban areas overseas. There were seasonal trends in the prey captured in each area and in both areas cats hunted less over the winter months. Chapter II. Diets of coexisting alien mammalian carnivores in Northern New Zealand. 120 feral cats, 85 stoats (Mustela erminea), 28 weasels (M. nivalis) and 16 ferrets (M. furo) were caught over three years, in Northland, New Zealand. The gut contents of these animals were examined and their food habits described. The main prey groups of cats were (in order of importance by weight), lagomorphs, rodents (Rattus spp & Mus musculus), other mammals, birds and invertebrates. The main prey of stoats were rodents, birds, lagomorphs, skinks (Cyclodina spp) and invertebrates. Skinks, followed by mice, were the main prey of weasels. Rabbits (Oryctolagus cuniculus) were the most commonly occurring prey item in the ferret guts. The food habits for cats and stoats were compared between different habitats within the Northland region where these animals were collected from. There was little difference between habitats, but invertebrates occurred more frequently and lagomorphs less frequently in the diet of animals from forest habitats compared to those from forest / pasture and coastal habitats. No differences were found in the prey of male and female cats, but invertebrates occurred more frequently in the guts of sub-adult cats compared to adult cats. Skinks occurred more frequently in the guts of female stoats, which tended to take smaller prey items than males. Chapter III. Home range of introduced mammalian carnivores, feral cats (Felis catus), stoats (Mustela erminea) and a ferret (M. furo) at Trounson Kauri Park, Northland, New Zealand. The minimum home ranges of eleven feral cats, four stoats and one male ferret were examined by radio telemetry at Trounson Kauri Park in Northland New Zealand. The average minimum home range of male feral cats was 305 ± 74ha. This was not significantly larger than the 122 ± 35 ha minimum average home range of female cats. The minimum average home range of three male stoats was 108 ± 19 ha and the minimum home range of one female stoat was 50 ha. The male ferret had a minimum home range of 179 ha. There was no overlap spatially, in the home range of three adult male cats. There was also very little spatial overlap in the home range of four female cats. There was substantial home range overlap with four sub-adult male cats. The home ranges of these sub-adult male cats also overlapped spatially with those of the adjacent females and adult males. The home ranges of two male stoats overlapped spatially to some degree and the home range of another male stoat overlapped that of the female stoat substantially. The home range of the male ferret overlapped the home ranges of all of the cats occupying similar areas of the park. The home ranges of two male stoats overlapped the home ranges of the adjacent cats but not into the "core" areas of those cats ranges. Chapter IV. Secondary poisoning of introduced mammalian carnivores during possum and rodent control operations at Trounson Kauri Park, Northland New Zealand. Predatory mammals were monitored by radio telemetry through a 1080 then brodifacoum poison baiting operation at Trounson Kauri Park in Northland, New Zealand to target possums (Trichosurus vulpecula) and rodents (Rattus rattus, Rattus norvegicus & Mus musculus). All six feral cats (Felis catus), and the single stoat (Mustela erminea) and ferret (Mustela furo) being monitored at the beginning of the operation died of secondary poisoning following the 1080 operation. A further two cats and four stoats were radio tagged and monitored through the ongoing poisoning campaign using brodifacoum in a continuous baiting regime. None of these radio tagged carnivores died of secondary poisoning. However, tissue analysis of additional carnivores trapped at Trounson found that cats, weasels (Mustela nivalis) and to a lesser extent stoats did contain brodifacoum residues. The duration that the radio tagged predators were alive in and around Trounson Kauri Park suggested that the secondary poisoning effect was much reduced under the continuous baiting strategy, compared to the initial 1080 poison operation. Chapter V. Managing alien mammals in mainland New Zealand: The implications for predator/prey interactions in complex communities. Recent advancements in alien pest mammal control technologies have enabled conservation managers to attempt long term, large scale, predator and browser control programmes at mainland sites in New Zealand. At Trounson Kauri Park (in Northland, New Zealand) feral cats, ferrets, stoats and weasels plus rodents and possums were controlled for two and a half years. Early results from Trounson suggested that some native birds and plants responded positively and quickly to the control of these alien pest mammals. However, the management also affected the predator-prey and predator-predator interactions, within the mammalian community, with changes in the predator guild and some prey species increasing in abundance. The long term effects of these responses within the mammalian community to control efforts are unclear. A review of the international literature served only to confirm the view that managing alien mammals where re-invasion is constant will be a complex task. Conservation management at mainland sites like Trounson Kauri Park, may in effect be acting as crude mammalian predator removal experiments. Monitoring changes in predator-prey interactions and predator-predator interactions at this and other intensive management sites over sufficient time frames could provide scientists with the critical ecological data required to construct useful predictive models. The ability of managers to target specific pests at critical times would represent a significant advancement in controlling predatory mammals on the New Zealand mainland.

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38

Ito, Masayoshi 1967. "Non-filterable metals (NFM) in the atmosphere." 2003. http://hdl.handle.net/2292/1954.

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A new air sampler, the Mist-UV sampling system, has been developed to trap and detect metals and metal compounds present in atmospheric samples, as non-filterable metal (NFM). The Mist-UV system is based on the combination of two ideas, mixing the filtrated air sample with nitric acid mist and simultaneous ultraviolet irradiation of the mist. Atmospheric NFM in the introduced air samples, which were first passed through a 0.2 µm filter, were oxidised by UV irradiation and dissolved in the nitric acid mist. The trapped metals resulting from the NFM in nitric acid were quantitatively determined using ICP-MS. Using the Mist-UV system, measurements of atmospheric NFM concentrations were carried out to obtain their temporal and spatial trends in Auckland, New Zealand. Five metals (Mg, Al, Cu, Ba and Sr) were detected as NFM in ambient air. Elevated atmospheric concentrations of Mg, Cu, and Ba were detected in midsummer and in daytime samples. The UV oxidisable fraction dominated the NFM and high enrichment factors (EFcrust) were found for these metals. This suggested that natural emissions of organometals or reduced metals were responsible for the elevated atmospheric concentrations. Meteorological factors, particularly air temperature, light irradiation and rainfall, promoted biogenic activity and resultant NFM emissions. Remarkably high concentrations of Al and Sr as NFM were discovered in several air samples and were dominated by the non-oxidisable compounds. This implies that the sources of Al and Sr were mainly from inorganic or oxidised metals associated with fine particulates. Wet and dry soils appeared to be the sources of Mg+Ba and Al+Sr, respectively. Plant emissions are recognised as important sources of Mg, Cu and Ba as NFM in ambient air, whereas the suspension of fine particulates derived from road dust and soil enriched with non-oxidisable compounds are seen as the major sources of Al and Sr. The emissions from automobiles and seawater samples were found to be unimportant NFM sources. The NFM concentrations were found to be significantly higher than concentrations of particulate metals, therefore the atmospheric importance and role of NFM cannot be ignored in the estimation of global metal circulation and budgets.

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39

Adeeb, Farah. "A Study of near-surface ozone concentrations in the city of Auckland, New Zealand." 2006. http://hdl.handle.net/2292/2571.

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Whole document restricted, see Access Instructions file below for details of how to access the print copy.
This research provides insight into large-scale spatial variation of ozone (O3) distribution in the Auckland region and was designed to increase our understanding of O3 behaviour and distribution in a coastal-urban situation. The research was also carried out with a view to assisting regulatory agencies optimize future monitoring networks, and to help identify locations where human health and natural resources could be at risk in the future. Although the research was limited to one region, the results are valuable for improving the conceptual understanding of formation of high ozone concentrations in a more general sense in the New Zealand and Southern Hemisphere. The work reported in this thesis is aimed at studying O3 concentrations and the influence of the most relevant meteorological variables on an average coastal New Zealand city where precursor emissions are mainly due to traffic exhaust. It deals with the use of Principal Component Analysis method for determining O3 concentrations as a function of meteorological parameters. The study region includes the entire Auckland isthmus, and extends from Whangaparaoa in the North to Pukekohe in the South. Surface O3 data from four sites (Whangaparaoa, Musick Point, the Sky Tower and Pukekohe) for a 4-year period(October 1997 to October 2001) for the Auckland region were examined. Ambient concentration of O3 was characterized in terms of diurnal, weekday/weekend, seasonal and spatial variations in concentration using O3 measurements from the four air quality sites. The monthly average ambient background O3 concentrations at the monitoring sites during this study ranged from 16-30 ppb, much lower than those found in the Northern Hemisphere. The measured seasonal O3 record in the Auckland region, in common with many other remote sites in the Southern Hemisphere, exhibited a summer minimum and a winter maximum. Background concentrations of O3 (as seen in air of marine origin) made a significant contribution to the observed ambient concentrations. A unique feature of Auckland's air quality was the dilution of polluted city air due to the mixing of east coast air into the cleaner west coast circulation leading to overall lower average O3 concentrations in summer. The magnitude, frequency and spatial extent of maximum O3 concentrations were identified, and the observed patterns linked to the prevailing meteorological, topographic, and emission characteristics of the region. However, at no time at any site or season did the O3 concentration exceed the l-hour New Zealand Ministry for the Environment guideline of 75 ppb. O3 depletion was observed to occur at the urban sites, with O3 scavenging by nitric oxide believed to be the dominant depletion mechanism. The seasonal cycle was characterized by elevated O3 concentrations in the winter (nighttime level >24 ppb) and low mixing ratios in the summer (nighttime levels in the range 14-20 ppb). The afternoon O3 maxima found at the three low elevation sites under the impact of "Auckland city" plume were on average, 1.5 to 1.7 times higher than those associated with the "marine sector". A state of the art diagnostic meteorological model, namely CALMET, was used to generate wind fields for the Auckland region. These wind fields were then used to construct backward trajectories on days when high O3 concentrations (episodes up to 6l ppb) were observed. The un-even distribution of the meteorological monitoring sites provided justification for running the diagnostic model CALMET and exploring the utility of using such a model when topography/land use prohibits monitoring sites in certain sections of the domain. It was found that the high O3 events recorded at the monitoring sites during the study period coincided with transport episodes originating from Auckland's urban and industrial areas. For the occurrence of high O3 concentrations at downwind sites, it was found that not only wind direction from the urban areas of Auckland, but that high solar radiation was important as well. On four out of the five cases when photochemical production of O3 was found to occur, high O3 concentrations were associated with a particular type of diurnal evolution of wind direction wind fields associated with the sea breezes. In addition to the analysis of ambient o3 concentrations and O3 episodes, field measurements were carried out in an attempt to detect and subsequently understand the interaction between particulate matter and O3 in the Auckland region, a multivariate statistical analysis approach was utilized. Particulate matter in the size range 2.75-6.25 μm accounted for over 70% of the total aerosol concentration at all sampling sites. Surface area of particulate matter variable (especially in the size class 2.75-4.25 μm) was statistically significant in explaining variation in O3 concentration. However, the net change in the adjusted R2 indicated that the effect of adding particulate matter in the multiple regression model for the present dataset was relatively minor except at Musick Point.

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Aleksa, Adriana Irene. "Vulnerability of Indigenous Forests in Changing Landscapes." 2008. http://hdl.handle.net/2292/3370.

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Indigenous forests all over the world are suffering habitat alteration, loss of original extensions, and increase of isolation levels, affecting their existence and sustainability. In New Zealand about 70% of the original forest cover has been destroyed since human settlement, converting them to a rare and threatened resource. Part of the problem is because native forests are often immersed in a landscape where other land uses are competing for the same space. Effective conservation management of these indigenous forest remnants requires information about their vulnerability to threats, in space and time. Few studies provide an integrated assessment of the extent to which socio- economic effects are responsible for native vegetation vulnerability and how these relationships change through time. In this study socio-economic drivers at different scales are related to land cover changes. To analyse vulnerability of indigenous forests a temporal dataset was developed from aerial photography for the years 1942, 1961, 1984, and satellite images for the years 1999 and 2006. They were managed within a GIS, recording the extent and distribution of these forests and other principal land covers in a study area of ca. 80,000 ha in the Northland region. Information about incentives to land production and to conservation was compared to changes of composition, configuration and conversion of land cover. Spatial conditioners of change, such as elevation, land use capability and land legal protection, were also assessed as possible constrainers of indigenous forest loss. Results showed that the incentives to land production had changed their significance for vulnerability of indigenous forests through time. These became conditioned by other land covers and incentives to conservation, and besides, indigenous forest was a quite stable cover where the physical characteristics of their location were unsuitable for land production. I concluded that at scale of decades, changes in area of indigenous forest were reversible; non- linear; driven by political, institutional and economic changes but that, biophysical characteristics of the landscape can preclude conversion. Such conclusions may help to set priorities for the long term protection and management of indigenous forests.

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41

Sandiford, Anna. "Palynology and tephrostratigraphy of Quaternary coverbed sequences of the Auckland area, New Zealand." 2001. http://hdl.handle.net/2292/2218.

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This thesis presents the results of detailed palynological and tephrostratigraphic investigations of five sites around the Auckland Isthmus, which collectively contain a fragmented record spanning approximately the last 1.2 million years. A range of additional methods were applied including, radiometric dating, palaeomagnetism, identification of other palynomorphs and fossil wood, and calculation of deposition rates. Study of two late Quaternary sites provided information on the Last Glacial Maximum (LGM) environment of the Auckland Isthmus. This suggested LGM forest was spatially restricted, dominated by beech forest with minor podocarp elements and contained within extensive shruband grassland. Late Quaternary sites were more easily studied than early to mid Quaternary sites because the depositional environment in which they were found provided greater palynological and tephrostratigraphic detail. Detailed published late Quaternary tephrostratigraphy also allowed for tight chronological control, accurate interpolation of ages of uncorrelated tephra and assessment of the accuracy of radiocarbon dates. Forty late Quaternary tephra layers were identified, adding to the record of eruptions sourced from the Auckland Volcanic Field, Taupo Volcanic Zone and Taranaki Volcano. Since c. 24 ka the frequency of Late quaternary tephraforming events of significant volume to be recorded in the sediments on the Auckland Isthmus is 1 every 600 years. Study of early to mid Quaternary sites was hampered by lack of published tephrostratigraphic records for correlation. Last appearance data for four extinct taxa were tentatively extended. Significant depositional hiatuses were noted; the period between c. 1.0 Ma and c. 44 ka was particularly unsatisfactorily recorded. Three key tephra markers and nine previously undocumented tephra layers were documented. Spatial variation and alternating vegetation structure characterised cooler and warmer environments of the early to mid quaternary record. Extensive high diversity conifer-angiosperm forest occurred during warmer periods while reduced diversity beech-dominated forest contained within extensive shrub/grassland characterised the cooler periods. Certain combinations of taxa occurred during glacial/stadial and interglacial/interstadial periods and an attempt was made to generalise these. It was apparent the extremes of the LGM were not reached during this time, and-that climate oscillated between cool and warm periods sometimes characterised by vegetation assemblages without modem analogue. Extensive depositional hiatuses at one site, deposition of extremely thick, reworked, homogenous marine silt at a second site, and dipping bedding planes at a third site suggest sea level variation and/or tectonism were influential in the Quaternary depositional history of the Auckland Isthmus. However, not enough evidence was present to quantify this.

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42

Hoang, Van Cam. "Mucin changes associated with abomasal parasitism in sheep : a thesis presented partial fulfillment of the requirements for the degree of Doctor of Philosophy at Massey University." 2009. http://hdl.handle.net/10179/1273.

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Mucins play important roles in host-pathogen interactions, influencing host resistance, establishment of infection, as pathogen recognition sites and a source of nutrients. They are highly glycosylated molecules and changes in monosaccharide composition during parasitism have been reported. Effects of parasites on monosaccharide component of fundic and duodenal mucins of sheep were investigated in 3 age ranges (i) 4-4.5, (ii) 6 and (iii) 8-9 months old: (1) noninfected; (2) infected with 10,000 Haemonchus contortus and euthanased 21 days post infection (p.i.); (3) infected with 50,000 Teladorsagia circumcincta and euthanased 28 days p.i. Three days-old lambs and 9 weeks-old lambs: (a) milk-fed, (b) solid-fed and (c) solid-fed, infected with T. circumcincta were also included. The effects of H. contortus and T. circumcincta infection in mucin changes were significantly different in the fundus, however, both of them shared some similarities. Infected sheep showed lower proportion of fucose and sialic acids in fundic and duodenal mucins compared with non-infected animals, the level of sulphation varied depending on the age of infected sheep: decrease in young sheep but increase in older animals. H. contortus infection also caused increased proportions of GlcNAc and Gal in fundic mucins and duodenal mucins respectively at all ages, however, in T. circumcincta infection, it was shown that the alterations of mucins were age-dependent. T. circumcincta infected sheep showed the significant changes at young ages (4-6 months-old) while 8-9 months-old animals showed less change in fundic mucins compared with non-infected animals. Effects of H. contortus and T. circumcincta infection differed in the fundic mucins but were similar in the duodenum. The study showed that parasitism caused the modifications of monosaccharide composition in gastrointestinal mucins of sheep. These alterations may result from parasite species differences, causing different effects from the host’s immune response. The changes in mucin profiles observed in the duodenum of sheep infected with abomasal nematodes suggested that the host may respond to parasitism. This would facilitate the use of mucins from accessible sources, without euthanasing the animals, to investigate the changes in mucin compositions which can be used to diagnose the susceptibility or resistance of sheep to parasites

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43

Boxall, Naomi. "The epidemiology of Campylobacter jejuni in commercial broiler flocks in New Zealand : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University, Palmerston North, New Zealand." 2005. http://hdl.handle.net/10179/1589.

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Irregular pagination: jumps from xix to 21
New Zealand maintains the highest incidence rate of human campylobacteriosis of the industrialized countries (334.2 cases per 100,000 in 2002), it accounts for more than 56% of all disease notifications in the country. New Zealand is unique globally, with a 'notification-based surveillance system for notifiable diseases that is complemented by laboratory reporting. In other countries (Australia, US, UK), the notification system is entirely laboratory based. Thus, the high incidence of Campylobacteriosis in humans may be related to the methods of reporting rather than the reality of the disease situation. However, the reason for such high incidence has not yet been fully elucidated, and several studies conducted in New Zealand and overseas have implicated the consumption of poultry meat as the main cause of human infections. The reduction or elimination of Campylobacter jejuni in the food chain, particularly from poultry meat products, is a major strategy in efforts to control campylobacteriosis. One approach to this is to prevent C. jejuni colonization of broiler chickens, This approach has been used to control Salmonella contamination of poultry, but the measures put in place for control of Salmonella have not controlled C jejuni. It is generally unknown how frequently C. jejuni colonizes commercial broiler chickens in New Zealand, or what could be done to prevent these infections from occurring. The present study was undertaken in order to describe some of the basic epidemiology of C. jejuni in commercial broiler flocks in New Zealand. The thesis is intended to further describe the epidemiology of colonisation of commercial broiler chickens by C. jejuni in NZ, and present possible risk factors that could be controlled in future to decrease the number of positive flocks of birds that are processed. The thesis set out to elucidate first the extent of C. jejuni colonisation of birds, flocks and farms while the birds were on the farm, having had minimal risk of exposure to Campylobacter spp., by sampling 15 birds in 80 flocks belonging to two companies prior to the first partial depopulation, an event during which the flock are exposed to potentially contaminated fomites and biosecurity levels are dropped, doors opened and personnel movements are extensive. The resulting prevalence estimates are 25.6% of farms, and 12.5% of sheds, are likely to be used to rear broiler chickens colonised with C. jejuni. When a positive flock is discovered, 76.9% of the birds are likely to be colonised with C. jejuni. These figures are results across the whole study population of farms and sheds, as there were no significant differences between prevalence estimates between companies. Following this prevalence estimation, a longitudinal study was conducted involving 12 sheds, to determine whether the environment or the birds were colonised with C. jejuni first. Although 12 sheds were observed every other day from day 14 to the end of the rearing period, it was determined that the birds were positive either first, or at the same time as the environment. Having said that, the sensitivity of the testing method for the environment was dubious, as there were instances where a shed that had positive samples collected on one occasion appeared negative the next, before returning a positive result on the third consecutive sampling occasion. A cross-sectional study of 810 flocks was undertaken to determine the most relevant risk factors for colonisation of the broiler chickens with C. jejuni. Because of the vertically integrated structure of the poultry industry, these 810 flocks corresponded to data collected from 77 farmers about their farms and the 219 sheds on those farms. The caeca from ten birds from each flock processed were pooled and examined for the presence of C. jejuni. These results were used to create a case definition, such that the flocks could be analysed with the questionnaire data, and different risk factors were seen in each season. More flocks reared for Company One were colonised by C. jejuni than for Company Two. Protective factors included having hard (i.e. gravel, asphalt or concrete) pathways to the growout houses, being near to another broiler farm, using the reticulated town water supply for the birds drinking water, using tunnel or crossflow shaped growout houses, using a Chore-TimeTM feed delivery system within the growout house and chlorinating the water supply to the birds (only in winter). The odds of raising flocks colonised with C jejuni increased if rodents were seen on the farm, if the growout houses were constructed with a concrete nib wall, if gas heaters were used during brooding, if cattle were farmed on the property, or if workers were employed on the farm. Sanitising the annex at least as frequently as once per run decreased the odds during summer, and tended to have a similar effect in other seasons. Chlorinating the water supply appeared to have a protective effect in only one season, though the trend appeared towards protection in the other seasons. The risk factor was validated by sampling the drinking water that broilers chickens had access to for the FAC to sec whether the levels that were present in the drinking water could have an effect on C. jejuni 11 sheds that were known to chlorinate the water were sampled to determine whether they met the drinking water standards for humans in NZ, or met the requirements presented by one of the companies involved. Only three sheds met the human drinking water standards for FAC, and two of these (one from each company) met Company Two's requirements. This thesis is for both regulatory and industry stakeholders to assist with developing risk management approaches to diminishing the number of C. jejuni positive flocks. Where management practices are altered, it is hoped that the efficacy of such practices be measured by examining the changes in the rates of C jejuni colonization within the industry

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Penny, G. M. "Supply chain (re)alignment in New Zealand’s sheep meat and dairy industries : knowledge, networks and learning at the farmer-processor site." 2003. http://hdl.handle.net/2292/2418.

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Emerging from the agricultural crisis of the 1988s, producers and processing companies in New Zealand's sheep meat and dairy industries, found themselves in an evolving neo-liberalised environment. By the late 1990s major structural (re) alignment had taken place in production and processing to accommodate shifts in markets and regulation, centring on 'food safety', 'quality' and "availability" For both farmers and processing company staff, this meant venturing into unfamiliar jointly occupied spaces and unchartered relational territory, Through a participatory research approach using multiple methodologies, this thesis examines supply chain (re)alignment at a macro and micro-scale, focussing on the farmer-processor relationship and knowledge, network and learning processes of farmers in (global) lamb and dairy supply chains in New Zealand. In seeking to account for evolving agri-food chain relations at multiple scales, this research turns to the global commodity chains (GCC) literature and draws on pragmatic solution-oriented ideas emerging from the developing field of Supply Chain Management (SCM). It also includes theoretical input from the cognitive and behavioural sciences to interpret the empirical data on farmer's knowledge, networks and learning in different supply chains, which it argues are key features of globalising agri-food economies. In this research these literatures and theories are enveloped by a broader yet, incomplete, theoretical foundation - that of evolutionary political economy (EPE), which is extended in this thesis, The thesis argues that an EPE framework provides a useful window on the governance of New Zealand's relations at a distance because it allows the specificity of micro-scale coordination activities and relations (in jointly occupied spaces) in New Zealand to be embedded in local and macro scale governance regimes and historical development processes. The findings show global market and regulatory pressures continue to drive supply chain (re)alignment in New Zealand, and chain building is occurring in different ways at the farmer-processor interface, between and within the different industries. Farmers' place specific on-farm knowledge co-evolves with off-farm knowledge through a combination of concrete experience, trial and error, socialisation and reflection, with both on and off farm knowledge becoming more overt in practice and strategy as supply chain specifications becomes more precise. Farmers utilise a range of networks (informal, formal, specialist and general), which serve as both information channels and learning forums. New Zealand's agricultural industries are like many in competitive globalising economies -'new' know ledge is being generated and used to broker global and local social, economic and environmental contexts and values, and in the process, supply chain partners' capacities and relations evolve.

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45

Ayanegui, Alcérreca María Alejandra. "Epidemiology and control of leptospirosis in farmed deer in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Clinical Science at Massey University, Palmerston North, New Zealand." 2006. http://hdl.handle.net/10179/1470.

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Missing pages 93, 264 & 313 from electronic and Vault (preservation) copy.
Leptospirosis has been reported in farmed deer in New Zealand since 1980 but knowledge was limited. Studies presented in this thesis investigated the epidemiology and distribution of infection associated with serovars Hardjobovis, Pomona, and Copenhageni in farmed deer, efficacy of a vaccine and the influence of maternally derived antibody, and aspects of exposure of humans to leptospirosis. Serology, bacteriology, and pathology were employed as determinants of infection and vaccine efficacy. A serological survey of 2016 deer from 110 herds confirmed leptospirosis throughout New Zealand with 61.3% of herds infected with Hardjobovis and 3.6% with Pomona alone, 16.4% with dual infections with those serovars, and none with Copenhageni, giving an overall herd prevalence of 81.3%. Epidemiological studies involved serological analysis of samples from a serum bank involving weaner, yearling and adult deer (n=10/group) from 15 farms sampled 3-monthly for 21 months, and intensive blood and urine sampling of young deer on three farms over 1-2 production cycles (n=15-65/group). Infection with Hardjobovis followed an age-related endemic cycle with some animals infected by 3-4 months of age and seroconversion peaking at up to 57% at 12-15 months and mild kidney lesions typical of a host-adapted organism. Infection with Pomona followed an epidemic pattern with seroprevalence of up to 100%, more severe kidney lesions, clinical signs and evidence of reduced growth and reproduction, typical of an accidental host relationship. Leptospira were observed in 30.4% of urine samples and 37.0% of kidneys. Vaccination with "Leptavoid 3" (Schering-Plough Animal Health Ltd) was studied on one non-infected, one Hardjobovis infected, and two dual Hardjobovis/Pomona infected herds. Vaccination produced sustained titres in uninfected young and adult deer, and no maternally derived antibody interference was observed in progeny vaccinated at approximately 3-4 months of age. In infected herds, vaccination enhanced seroprevalence and antibody titres, and reduced urine shedding by 44% and culture from urine and kidneys by 37% in the face of continued natural challenge. Analysis of previous data combined with pooled data from the above studies, indicated that 73.0% of lines and 29.0% of individual deer at slaughterhouses had kidney lesions indicative of leptospirosis with a relative risk (RR) of 1.08 and 1.6 for the relationship between seropositivity to Hardjobovis and Pomona, respectively. The overall RR between positive serology, lesion and culture was 2.1. The kidney culture rate ranged from 2.5-33% between herds demonstrating significant risk of exposure to humans, particularly slaughterhouse workers. This study has provided an understanding of the epidemiology in farmed deer and control options available to the industry.

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46

Freitag, Thurid. "Uropathogenic Escherichia coli of dogs and cats : pathotypic traits and susceptibility to bacteriophages : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Clinical Sciences at Massey University, Turitea, Palmerston North, Aotearoa, New Zealand." 2006. http://hdl.handle.net/10179/1541.

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The purpose of this study was to investigate the feasibility of using bacteriophages - viruses that can lyse bacteria - to control infections caused by uropathogenic Escherichia coli (UPEC) in dogs and cats. Prior to phage experiments, UPEC were subjected to virulence factor genotyping by multiplex polymerase chain reaction assay and phylogenetic 'fingerprinting' by Pulsed-Field Gel Electrophoresis (PFGE). Twenty-five of 30 assessed virulence factor gene (VFG) markers were detected at least once in 31 UPEC isolated from 20 UK cats and 89 UPEC isolated from dogs (56), cats (22) and people (11) living in New Zealand (NZ). The PFGE banding patterns of UPEC isolates from different individuals were markedly dissimilar unless isolates had been collected at the same hospital within one month of each other. In contrast, ≥2 UPEC strains isolated from each of 3 UK cats diagnosed with multiple UTIs were indistinguishable by PFGE. Antibiograms inaccurtely predicted UPEC clonality and, of clinical importance, underestimated the number of relapsing or persistent infections in these cats. A comparison of VFG profiles and PFGE banding patterns of UPEC isolated from NZ and UK cats demonstrated a geographically uneven distribution of pathotypic and phylogenetic traits and indicated that, among other factors, the source of UPEC must be considered when comparing UPEC from different host species. When comparing UPEC isolates from NZ dogs, cats and people, strains with similar VFG profiles were found among the different host species. Other strains, with VFG profiles that differed according to the host species of origin were also detected. The latter finding, which is in contrast to the results of previous studies, may be of interest to researchers aiming to predict the potential zoonotic risk posed by particular UPEC strains sourced from dogs and cats. Forty bacteriophages (phages for short) were isolated from sewage waters and propagated on UPEC strains. The ability of these phages to cause bacterial lysis was tested on 31 canine UPEC, 22 feline UPEC and 7 faecal E. coli. In contrast to faecal E. coli, UPEC strains were highly susceptible to phages. Ten phages with a particularly broad host range each lysed ≥27/53 (≥51%) UPEC strains. Used in combination, these 10 phages were predicted to be able to lyse 49/53 (92%) of the UPEC strains in the collection. Morphological and genotypic studies on 5 of these 10 phages demonstrated that 4 of them belonged to the lytic T4-like genus, while one phage showed similarity to the temperate phage P2. Overall, results of this project indicate that the majority of canine and feline UPEC - with very diverse PFGE banding patterns and VFG profiles - are susceptible to lysis by naturally occurring phages. Hence, phages show promise as therapeutic agents for treatment of canine and feline UTI and, perhaps, for other infections caused by UPEC.

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47

Mupeyo, Bornwell. "The effect of feeding willow upon the death of established parasites and upon parasite fecundity : a thesis presented in partial fulfilment of the requirements for the degree of Animal Science at Massey University, Palmerston North, New Zealand." 2010. http://hdl.handle.net/10179/1712.

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Two indoor feeding experiments were conducted at the Animal Physiology Unit (APU) of Massey University, involving young sheep, to investigate the effect of feeding forage willow upon the death of established parasites and upon parasite fecundity, using chaffed lucerne as the control diet. Experiment 1: Twenty-four (24) parasite-free weaned hoggets weighing 29.9 ±1.2 kg (SD) were individually penned and fed chaffed lucerne ad libitum during a preexperimental adaption period of 5 weeks. They were then fed either lucerne chaff or chopped willow for a further 5 weeks (n = 12/group) and intakes were adjusted such that the DMI of the two groups was similar during weeks 9 & 10. All lambs were infected with L3 larvae parasites comprising 20,650 Teladorsagia, 1,320 Trichostrongylus and 330 Cooperia through oral drenching 12 days before willow feeding started. This was done after confirmation that the sheep were free of nematodes through FEC analysis. Total faeces were collected for 3 day periods towards the end of weeks 9 & 10, to measure diet digestibility and total faecal egg excretion. The sheep were slaughtered at the end of week 10. Voluntary feed intake (VFI), FEC and liveweight were measured weekly, whilst burdens of individual parasites and carcass characteristics were measured after slaughter. Duplicate samples of each feed offered and individual animal refusals were taken daily and pooled weekly per animal for chemical analysis. Female worm fecundity was calculated by two methods. Blood samples for immunological analysis were collected on days 20, 34, 51 and 70, and analysed for components of white blood cells (WBC) and for lymphocyte subsets. Experiment 2: A 2 x 2 changeover experiment was conducted, involving two time periods (Period 1 and Period 2 each of 14 days) with the same diets as used in Experiment 1, fed to 9 individually penned parasite-free young sheep randomly allocated to experimental diets. The parameters investigated were FEC and larvae hatching. Initially, a period of 7 days was allowed for acclimatisation in which both groups were fed on half willow and half lucerne chaff. This was followed by Period 1 with 4 lambs fed lucerne and 5 fed willow, after which the diets were changed over for Period 2. Total faeces produced were collected from all animals on the last day of each period using bagged sheep. A known number of Teladorsagia eggs (500 epg) was then added to faecal samples from these sheep and faeces-egg mixtures were made from which FEC was determined, to see if egg recovery was affected by these diets. Faecal samples for Period 2 with added eggs were also incubated for 10 days to measure hatchability. The recovery of added Teladorsagia eggs in Experiment 2 was 85% in lucerne-fed lambs and 53% willow-fed lambs (P<0.001); these were used as correction factors for Experiment 1 data. Larvae that hatched per gram of wet faeces in Experiment 2 tended to be lower for sheep fed willow than lucerne chaff (71% vs 83% of eggs added; P=0.08). Willow feed offered had lower DM (P<0.001) and CP (P<0.05) content, but had a significantly higher OM content (P<0.01) than lucerne chaff. Condensed tannin content of chopped willow was 27 g/kg DM, with only traces for lucerne. Apparent digestibility for DM (62.4% vs 59.5%; P≤0.05), OM (64.8% vs 59.9%; P≤0.001), DOMD (58.1% vs 55.0%; P≤0.01) and calculated ME (9.48 MJ/kg vs 8.96 MJ/kg; P≤0.01) were higher for the willow diet. VFI was similar for both groups during the adaption period (P>0.05) but declined with the introduction of willow in week 6 (P<0.001) and then progressively increased until it was similar to lucerne-fed sheep in weeks 9 & 10 (P>0.05). Calculated DM intake per head/day during the last two weeks of Experiment 1 was similar for the two groups (P>0.05); while the willow group had higher ME (P<0.01) and CP (P<0.001) intake per animal/day. Liveweight increased for the two groups during the adaption period (P>0.05), then declined for willow-fed lambs in week 6 (P<0.001) but later increased and by week 10 was similar to that of lucerne-fed lambs. The willow-fed lambs had lower carcass GR than the lucerne-fed lambs (P<0.01) when carcass weight was used as a covariate. Adjusted total daily egg production in Experiment 1 was lower in willow-fed sheep than lucerne-fed sheep, due to reductions for Haemonchus spp. (P<0.05) and Teladorsagia spp. (P<0.05). The per capita fecundity for Haemonchus worm spp. (P<0.05) and the in utero fecundity in both abomasal Teladorsagia spp. and small intestinal Trichostrongylus spp. (P<0.001) were lower for willow-fed sheep. There was reduced production of larvae for both Haemonchus spp. and Teladorsagia spp. (P<0.05) in willow-fed sheep. Feeding willow reduced the burden of Haemonchus adult worms in the abomasum (P<0.01) but reduced female worm burden only in Teladorsagia spp. (P<0.05) and reduced Cooperia spp. in the small intestines (P<0.01). Total WBC, total lymphocytes, subsets of lymphocytes and other white-cell groups were not affected by willow feeding (P>0.1). It was concluded that feeding chopped willow to young sheep reduced nematode worm burdens in the abomasum, especially both male and female Haemonchus spp., and reduced female worm burdens of Teladorsagia spp. Female worm fecundity of both species was also reduced by willow feeding. These reductions have been associated with CT content in the willow feed and the reduced worm burdens have been attributed to the death of the established worms by CT, since there was no evidence of immune priming in willow-fed sheep. Compounds present in the faeces of willow-fed sheep have been found to mask some of the nematode eggs, making them invisible by microscopic examination while keeping their viability. It is postulated that this could be due to binding of nematode eggs to insoluble CT associated with indigestible fibre in the faeces of willow-fed sheep. Conventional methods of measuring FEC therefore underestimated nematode eggs present in the faeces of willow-fed sheep and this needs to be checked for other CT-containing forages.

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48

Subharat, Supatsak. "Epidemiology, diagnosis and vaccination control of leptospirosis in farmed deer in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Clinical Science at Massey University, Palmerston North, New Zealand." 2010. http://hdl.handle.net/10179/1678.

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Leptospirosis is a bacterial zoonotic disease of global importance. It is caused by infection with pathogenic Leptopsira species. Leptospirosis encompasses a wide spectrum of clinical or subclinical disease in both humans and animals. In New Zealand (NZ), leptospirosis is considered to be the most important occupational zoonosis. Livestock farming plays an important role as a major occupational risk factor for human leptospirosis and farmed deer is one of the contributing factors. Commercial farming of deer began in NZ in the early 1970s. It remains the world’s largest and most advanced deer farming industry. Leptospirosis in farmed deer can cause illness and possibly sub-clinical production losses. Farmed deer also play an important role in the transmission of leptospirosis by shedding the organisms in their urine, putting both other animals and humans at risk. Leptospira serovars Hardjobovis and Pomona are the most commonly found serovars in this stock group. The first substantial case report of leptospirosis in farmed deer was in the 1980s but it was not until 2006 that a substantial epidemiological study of this disease in farmed deer was reported. The purpose of this research was to improve and extend current knowledge on the epidemiology of leptospirosis on mixedspecies deer farms, to develop and validate a novel molecular diagnostic tool and to enhance understanding of control measures and their outcomes by means of vaccination. A pilot longitudinal seroprevalence survey of leptospirosis on mixed-species deer farms was conducted. Results from this study revealed that leptospiral infection averaged 70% in all species on mixed-species farms in the lower North Island of NZ. Co-grazing with infected sheep and/or cattle was positively associated with deer herd serological status to both serovars Hardjobovis and Pomona which suggests the possibility of inter-species transmission. Results from this study justify further investigation of leptospirosis on mixedspecies farm at the national level. A collaborative study between Massey University and the WHO/FAO/OIE reference laboratory for leptospirosis in Brisbane to investigate for exotic serovars in farmed deer revealed seropositivity to Arborea which has never been found before in NZ. Attempts to isolate Arborea from kidney samples of farmed deer were unsuccessful and require further investigation. Real-time PCR assay was developed and validated against culture as the gold standard for use on deer kidney tissue and urine as a research and diagnostic tool for determining infection, carrier and shedding status of deer. This research revealed that the real-time PCR assay was highly sensitive (sensitivity: 85% for kidney and 96.7% for urine) and specific (specificity: 99.2% for kidney and 100% for urine). It is a useful tool for the rapid and cost-effective detection of pathogenic leptospires in clinical samples. It can also be used to quantify the concentration of leptospires from clinical samples and identify the likely infecting serovar in NZ when adjunct with a DNA sequencing technique. Vaccination control for leptospirosis has proven to be efficacious and likely to be costeffective. Present research has determined the effect of a commercial bivalent leptospiral vaccine (Leptavoid-2, Intervet/Schering-Plough Animal Health Limited, NZ) on leptospiral shedding, growth and reproduction of farmed deer under NZ pastoral conditions. The study was designed to simulate an infection-free herd scenario followed by exposure to natural challenge. Results have shown the potential of vaccine to improve mean weight gain (up to 6.5 kg) and weaning rate (average 6.9%) in infected herds and prevent urinary shedding after natural challenge with Hardjobovis. It also provides the first evidence of adverse subclinical effects on deer production by Hardjobovis alone. A pilot study to investigate the presence and localisation of pathogenic Leptospira in the uterus and foetus of female deer revealed evidence of a foetal infection using real-time PCR. This finding suggests a possible explanation for effects of leptospiral infection on NZ farmed deer reproduction. However, further study is required to justify this proposition. This research has contributed significantly to understanding of epidemiology of leptospirosis in NZ farmed deer, providing objective data to assist producers in decision-making on leptospirosis control. Furthermore, this study has made available a valuable diagnostic resource for future leptospirosis studies, and has provided direction for future research into leptospirosis on farmed deer and mixed-species farms.

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Jansen, van Rensburg Monique. "Parasitism, disease and breeding ecology of little blue penguins (Eudyptula minor) on Tiritiri Matangi Island, New Zealand : a thesis submitted in partial fulfilment of the requirements for the degree of Master of Science in Conservation Biology, Massey University, Auckland." 2010. http://hdl.handle.net/10179/1634.

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Appendix 4.4 removed due to copyright restrictions: Suepaul, R.B., Alley, M.R., Jansen van Rensburg, M., 2010, Salt gland adenitis associated with bacteria in blue penguins (Eudyptula minor) from Hauraki Gulf (Auckland, New Zealand). Journal of Wildlife Diseases, 46(1) : 46-54.
According to the New Zealand Threat Classification, little blue penguin (LBP) (Eudyptula minor) populations are under ‘gradual decline’. Although long-term data are available for some mainland populations, the status of LBP on offshore islands remains largely unknown. Most studies have focussed on breeding success and foraging ecology. However, there is a paucity of data pertaining to diseases and parasites, and the potential effects of these factors on LBP health, reproductive success and survival. To date, the LBP population on Tiritiri Matangi Island, Hauraki Gulf, Auckland, New Zealand, has only been monitored periodically, despite the island being an important habitat for LBP throughout their annual cycle. The overall aim of this study was to examine the relative importance of parasites and disease in relation to key aspects of LBP life-history, including: the annual cycle; reproductive success; energetic demands, immunity; and mortality. During 2006 and 2007, the reproductive success of LBP on Tiritiri Matangi Island was investigated with respect to lay date, nest site attributes, parental quality and ectoparasite loads. A nest treatment experiment was conducted to explore flea (Parapsyllus longicornis) and tick (Ixodes eudyptidis) effects on breeding success. Overall reproductive output was low, estimated at 33.3%, with an average of 0.67 chicks fledged per pair. Lay date and body condition (BC) appeared to be the main drivers of reproductive success, with early breeders fledging significantly more chicks than late breeders. Increased BC improved reproductive success. Although late breeders exhibited higher BC scores, increased chick mortality indicated that late nests face a reproductive trade-off. Treatment did not prove effective in reducing ectoparasite loads and there was no correlation between ectoparasite abundance in the nest and reproductive success. Throughout their geographic distribution, penguins are host to a range of ectoparasites. Using Ixodes eudyptidis ticks as indicators, ectoparasite-host dynamics were investigated over the course of one year, in relation to LBP life stages, body condition (BC) and haematological parameters. To investigate the presence of vector-borne diseases, blood parasite prevalence was determined using molecular techniques and microscopy. Tick load exhibited significant seasonal variation, being highest during periods of increased host availability i.e. moult and breeding. However, these increases in abundance were not associated with body condition or decreased reproductive success of adults. Nonetheless, LBP exhibited seasonal fluctuations in haematological parameters, with decreases in white blood cell concentrations during periods of increased energy demands and high tick loads. Blood parasite prevalence was low (<1%), determined to be Plasmodium sp. infection. No other blood parasites were found. These results indicate that the lifecycle of I. eudyptidis is tightly linked with that of its LBP hosts, and that infested individuals exhibit physiological responses to tick load. LBP exhibit annual fluctuations in mortality and experience periodic mass mortalities. To examine factors associated with mortality, post-mortems were conducted on 32 LBP from the Hauraki Gulf. Additionally, 128 LBP necropsy records were obtained from the National Wildlife Database (HUIA) for the period spanning April 1993-January 2009, and the causes of mortality were reviewed. Starvation and disease accounted for the highest mortality levels, with 65% of deaths attributed to either one or both of these factors. Furthermore, there was a strong association between starvation and parasites. Parasitic disease and diseases of uncertain aetiology were the most common disease types. In all age groups, the likelihood of infectious, non-infectious and disease of unknown aetiology was significantly higher in LBP that harboured one or more parasite species. Results from this study suggest that starvation and disease, including parasites, are significant factors associated with mortality of LBP in New Zealand, as has been found in Australian LBP populations. Parasites and disease are increasingly recognised as a challenge to the conservation of wildlife, and information regarding endemism of pathogens and parasites within populations is vital for determining ecosystem health, and identifying aberrant diseases.

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50

Mshanga, Deogratius Andrew. "Development of in vitro assays for detection of anthelmintic resistance in cattle nematodes : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science (Animal Science) at Massey University, Palmerston North, New Zealand." 2007. http://hdl.handle.net/10179/1231.

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The principle aim of the current research was to modify the larval development assay (LDA) for use with Cooperia from cattle. A series of experiments were conducted in order to modify the LDA protocol to determine the most appropriate culture media and incubation temperature. These initial experiments concluded that, of the protocols examined, a culture medium of 1/8th the concentration of E. coli (EC) + 1/4th the concentration of yeast extract (YE) as generally used to culture sheep nematodes, at a culture temperature of 18ºC, resulted in the optimum number of Cooperia larvae developed to the third larval stage (L3). However, the number of eggs that developed to L3 was still generally low. A comparison was then made using isolates from a farm with a history of resistance in Cooperia to ivermectin (IV) and benzimidazoles (BZ) and two farms with a history of no resistance in this parasite. These experiments were undertaken using 1/8EC + 1/4YE media protocol and 1/2EC + 1/2YE concentration of the standard culture media for sheep nematodes. These three isolates were cultured at temperature of 18ºC and 25 ºC in the commercially available DrenchRite® 96-well microtitre assay plates which contained BZ, levamisole (LV) and IV in doubling dilutions within an agar matrix. The LD50 values were determined from a dose response curve. The resulting LD50 values were very variable, especially for the IV analogues. There was no obvious difference between the resistant and susceptible farms for the LD50 values of BZ or IV. A secondary aim of this research was to investigate the potential usefulness of the larval feeding inhibition assay (LFIA). This was adopted as published and it was determined it could be used to distinguish between susceptible and resistant Teladorsagia circumcincta with a resistance ratio of at least six. This research concluded that further research is required to fully optimise the LDA for Cooperia in cattle but adequate dose response curves were determined to indicate it struggles to distinguish BZ and IV resistance. The LFIA deserves to be further investigated as it offers some scope to detect ivermectin resistance in cattle nematodes as the dose response curves demonstrated a good repeatability for T. circumcincta from sheep. Comparing LDA and LFIA, both assays seemed to be useful but the latter was considered to have greater potential.

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Dissertations / Theses on the topic 'Fields of Research – 300000 Agricultural, Veterinary and Environmental Sciences'

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