Dissertations / Theses on the topic 'Fields of Research – 300000 Agricultural, Veterinary and Environmental Sciences – 300500 Veterinary Medicine'
To see the other types of publications on this topic, follow the link: Fields of Research – 300000 Agricultural, Veterinary and Environmental Sciences – 300500 Veterinary Medicine.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 33 dissertations / theses for your research on the topic 'Fields of Research – 300000 Agricultural, Veterinary and Environmental Sciences – 300500 Veterinary Medicine.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
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.
Full textAbstract:
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.
2
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.
Full textAbstract:
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
3
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.
Full textAbstract:
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.
4
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.
Full textAbstract:
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.
5
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.
Full textAbstract:
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.
6
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.
Full textAbstract:
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).
7
McDermott, Joshua D. "The ovine lens cytoskeleton." Lincoln University, 2007. http://hdl.handle.net/10182/700.
Full textAbstract:
The lens of the eye is a vital tissue in the visual system, responsible for the collection and focusing of light on to the retina. Comprised of epithelial cells at differing stages of differentiation, the transparency of the lens is dependent on the highly ordered crystalline structure of lens proteins. The lens consists of several proteins including crystallins (α, β, γ) that make up 90% of the soluble protein, and the lens cytoskeletal proteins. Cytoskeletal proteins contribute only a fraction of the total lens protein, but are thought to play an important role in the establishment and maintenance of transparency. Calpain-induced degradation of these proteins may be involved in the development of cataracts. This has been an area of research at Lincoln University where a flock of sheep genetically predisposed to cataract maintained as a cataract development model. The aim of this research was to investigate the distribution of cytoskeletal proteins in the lens, and to examine the effects of calpain proteolysis on these proteins, with the goal of establishing the role of the lens cytoskeletal proteins in the ovine cataract model. A combination of techniques was used including immunohistochemistry, which required the development of a specific protocol for ovine lenses. Cytoskeletal proteins were identified using immunohistochemistry in lens tissue sections and exhibited characteristic distributions. Actin displayed preferential distribution in the short sides of the fibre cells in the cortex of the lens but was absent in the lens nucleus, while spectrin in the cortex and nucleus was associated with the fibre cell membrane. Filensin was observed in the outer cortex of lens sections associated with the fibre cell membrane and cytoplasm, although the pattern of localisation was indistinct due to the abundance of filensin breakdown products. Vimentin displayed membrane and cytoplasmic association in the outer cortex that diminished toward the lens nucleus, with membrane associated vimentin only persisting in the deeper regions of the cortex and nucleus. Additionally, the effect of novel calpain inhibitors (Cat0059 and Cat811) in preventing proteolysis of lens cytoskeletal protein was investigated and compared with calpain inhibitors developed elsewhere (SJA6017). The inhibitors were tested at between 10 and 0.1 μM (100 nM). All inhibitors were effective at 10 μM. SJA6017 provided significant protection to vimentin at 1 μM. Cat0059 was found to protect spectrin and filensin at 1 μM, but not vimentin, while inhibitor Cat811 was found to protect spectrin only. SJA6017 added to assays at 100 nM offered significant protection to spectrin, and Cat0059 was found to protect filensin and spectrin to a significant degree at 100 nM, indicating the novel inhibitors were comparable to those developed elsewhere in terms of their effectiveness. Taken together, the evidence presented in this thesis shows the cytoskeletal proteins as crucial elements in the lens. Their pervasive presence coupled with evidence that lens cytoskeletal proteins are sensitive to calpain-induced proteolysis that is inhibited with novel calpain inhibitors suggests that the lens cytoskeletal proteins may be useful targets in cataract prevention for future research.
8
Lei, Jie. "The role of antioxidants in the hydrogen peroxide-induced opacification of sheep lens." Master's thesis, Lincoln University. Agriculture and Life Sciences Division, 2006. http://theses.lincoln.ac.nz/public/adt-NZLIU20070517.162145/.
Full textAbstract:
The lens of the eye needs to be transparent with a high refractive index to focus images on the retina. In cataracts the lens becomes opaque, eventually leading to blindness. There are many possible causes of cataract but a lot of evidence implicates oxidative damage as contributing to opacification. This includes epidemiological studies showing that diets rich in antioxidants lowered the prevalence of cataract. This research tested the hypothesis that if cataracts were at least partially caused by oxidative damage then their progression would be slowed by application of antioxidants. The antioxidants used were two plant compounds found in the diet, resveratrol and quercetin. The system used was sheep lenses cultured in Eagles Minimal Essential Medium (EMEM). Lenses remained transparent for up to 7 days in EMEM but became opaque within 24 h when exposed to 1 mM hydrogen peroxide (H2O2). The lens is exposed to H2O2 in vivo as it is found in the aqueous humor. Prior Lenses pre-treated with quercetin reduced but did not prevent opacification. Lens cell death, as determined by measurement of leakage of lactate dehydrogenase, was found to increase with H2O2 and the increase was prevented by pre-treatment with antioxidants. The role of the endogenous antioxidant glutathione was also investigated. It was found that H2O2 decreased the amount of reduced glutathione in the lens cortex and increased the levels of oxidised glutathione but only at levels of 2 mM and above. Thus the results of this research indicate that H2O2 at low concentration (1 mM) is able to damage lens cells and cause opacification without affecting the reduced glutathione levels and that the exogenous antioxidants have some ability to protect the lens.
9
Nugent, Graham. "The role of wild deer in the epidemiology and management of bovine tuberculosis in New Zealand." Phd thesis, Lincoln University. Bio-Protection and Ecology Division, 2005. http://theses.lincoln.ac.nz/public/adt-NZLIU20070212.130927/.
Full textAbstract:
The eco-epidemiology of bovine tuberculosis (Tb) in wild deer (mainly red deer Cervus elaphus) in New Zealand was investigated. Bovine Tb is caused by Mycobacterium bovis. Specific aims were to clarify the likely routes of infection in deer, and to determine the status of deer as hosts of Tb, the likely rates and routes of inter- and intra-species transmission between deer and other wildlife hosts, the role of deer in spreading Tb, and the likely utility of deer as sentinels of Tb presence in wildlife. As the possum (Trichosurus vulpecula) is the main wildlife host of Tb, the research also included some investigation of transmission routes in possums.
Patterns of infection were measured in 994 deer killed between 1993 and 2003. Tb prevalence varied between areas (range 836%). Few deer had generalised infection, with 2168% of infected deer having no visible lesions, depending on the area. The retropharyngeal lymph nodes and oropharyngeal tonsils were commonly infected. No dependent fawns less than 0.75 years old were infected, indicating intra-species transmission is rare in wild deer. Where possums were not controlled, the net (cumulative) force of infection in young (14 y) deer was 0.100.24 per year in males and 0.090.12 per year in females, but much lower in older deer (less than 0.05 per year). Possum control reduced the net force of infection quickly, and eventually to zero. However, Tb persisted in possum-controlled areas through immigration of infected deer and, for almost a decade, through the survival of resident deer infected before possum control. Tb was lost from infected deer at an exponential rate of 0.13 per year, mostly as a result of deer recovering from infection rather than dying from it. Wild deer do die of Tb, but there was no discernible effect on age structure. The occurrence of infection in deer was not linked to the local deer or possum density at their kill sites (i.e. in their home range), but the area-wide prevalence of Tb in deer was closely correlated with Tb levels in possums, which were in turn correlated with area-wide measures of possum density. For wild deer in New Zealand, Tb is a persistent but usually inconsequential disease of the lymphatic system. It is acquired mainly by young independent deer, usually orally via the tonsils, and probably as a result of licking infected possums.
Many species fed on deer carrion, including possums. Most possums encountering carrion did not feed on it, but a few fed for long periods. Other scavengers such ferrets (Mustela furo), hawks (Circus approximans), and weka (a hen-sized flightless native bird; Gallirallus australis) fed in a way that probably increased the infectivity of carrion to possums. Commercial deer hunting may have facilitated the historical establishment of Tb in possums. Scavenging (including cannibalism) and interactions with dead and dying possums are identified for the first time as potentially important routes for transmission of Tb to possums, and I develop new hypotheses involving peri- and post-mortem transmission in possums that explain many of the epidemiological patterns that are characteristic of the disease in possum.
In continuous native forest, deer home range size averaged 250 hectares for six young females, and over twice that for two males. Over 90% of infected deer are likely to die within 2 km (females) or 6 km (males) of where they acquired Tb, but deer could occasionally carry Tb up to 30 km. Deer will be useful as sentinels, but only where other sentinels are rare, because the force of infection for a deer with a single infected possum in its home range is only 0.004 per year, compared to greater than 0.2 per year for deliberately released pigs. Deer are occasionally capable of initiating new cycles of infection in wildlife, but deer control is not essential to eradicate Tb from wildlife.
10
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.
Full textAbstract:
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
11
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.
Full textAbstract:
Irregular pagination: jumps from xix to 21New 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
12
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.
Full textAbstract:
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.
13
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.
Full textAbstract:
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.
14
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.
Full textAbstract:
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.
15
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.
Full textAbstract:
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.
16
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.
Full textAbstract:
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.
17
Kung, Nina Yu-Hsin. "Epidemiological studies of Avian influenza viruses in Hong Kong : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Massey University, Palmerston North, New Zealand." 2006. http://hdl.handle.net/10179/1487.
Full textAbstract:
Eight studies of the epidemiological dynamics of avian influenza viruses were conducted on poultry in Hong Kong, with special focus on the movement of birds through the live poultry marketing system, and the implications for avian influenza transmission. The first involved analysis of virus isolation data from faecal samples obtained from cooperating stalls in live poultry markets in Hong Kong in a routine sampling program undertaken between 1999 and 2001. This showed that two subtypes of avian influenza viruses, H9N2 and H6N1, have become well established in the Hong Kong live poultry markets, especially in chickens (mainly H9N2) and quail (mainly H6N1). In addition, a wave of H5N1 virus infection occurred in 2001 after it had been absent through the earlier period of the study. The second study was an evaluation of long term changes in the marketing systems for live poultry in Hong Kong, their likely effects on avian influenza epidemiology, and documented evidence of the prevalence of various H subtypes of avian influenza in sampling undertaken during three periods from 1975 to 2001. The third project involved two cross-sectional studies and one longitudinal study on local quail farms in Hong Kong. Results showed that quail could act as a reservoir host for H9N2 and H6N1 subtype viruses, but each subtype differed in its epidemiology. H9 virus usually infected quail at around 10 days of age, whereas H6 infected quail at 15-20 days of age. At 35 days of age (usual market age in Hong Kong), a proportion of market quail were likely to be susceptible to H6 (50%) and H9 viruses (20%), and were able to transmit the virus in the markets. Due to these findings, the Hong Kong Government closed the quail farming operations and restricted the sale of quail in live poultry markets. A longitudinal study was conducted on three live poultry market stalls to assess the time from stall entry to sale, and evaluate the influence of this delay on avian influenza virus transmission to other poultry in the same stall. Participating stalls varied from high volume/rapid turnover to low volume/slow turnover. Turnover for tagged poultry was rapid, although some chickens became infected with H9 virus before sale. Birds which stayed longer, such as quail, became infected and maintained infection in the stall. As well as spread by direct contact and on typical fomites, keeping of pet roosters and re-use of washing water were identified as factors increasing the ability of avian influenza strains to persist in market stalls. An experimental replica of a market stall was created to study the transmission of low pathogenic avian influenza virus (H9N2) in a controlled environment, with different rates of population turnover and different immune status with respect to both H5 and H9 subtypes. Transmission was influenced by distance between birds, the proportion of birds carrying antibody to H9 and the rate of introduction of susceptible birds, but not by the use of H5N2 vaccine. In order to assess the effectiveness of temporary depopulation of stalls, a study was conducted to compare the prevalence of avian influenza virus and Newcastle disease virus before and shortly after the monthly rest day in live poultry markets in Hong Kong, by virus isolation. Prevalence of H9N2 avian influenza virus was reduced by the rest day, but Newcastle disease virus prevalence was unaffected. During the 2002 avian influenza H5N1 outbreak in local chicken farms, a case-control study was undertaken to identify risk factors that may have contributed to this outbreak. A questionnaire was administered by interview to collect the data for this study. Multivariate logistic regression models showed that movement of people and fomites from live poultry markets to farms were important influences on transmission, and that the live bird markets were the likely source of virus for farms. A spatial stochastic computer model was constructed to predict the spread of avian influenza virus in local chicken farms and live poultry markets in Hong Kong, and the effectiveness of control measures. The data used in model parameter setting was derived from the case-control study. The reference model produced an epidemic curve which was similar to the true epidemic curve in the 2002 outbreak. Control strategies such as rest day and vaccination were evaluated within the model, and found to produce results comparable with field experience. Results from these studies clarify various aspects of the epidemiological features and transmission dynamics of avian influenza viruses, and provide guidance on appropriate control and prevention strategies for highly pathogenic avian influenza viruses within poultry marketing systems in Asia.
18
Minamikawa, Miho. "Isolation and partial characterisation of a calcium-dependent lectin-like protein from the flat oyster, Ostrea chilensis : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Pathology at Massey University, Palmerston North, New Zealand." 2006. http://hdl.handle.net/10179/1495.
Full textAbstract:
The (Chilean) flat oyster, Ostrea chilensis, is native to New Zealand and the west coast of South America. It is a commercially important species in New Zealand because of its exquisite taste that attracts premium prices. This thesis describes the first isolation and partial charcterisation of an oyster haemolymph calcium-dependent carbohydrate-binding protein. This protein 'chiletin' was originally isolated from oyster haemolymph by binding to the agarose-galactan matrix of a Sepharose column. Chiletin was predominantly composed of a 24 kilodalton (kDa) band when examined with one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis under non-reducing conditions and a 12 kDa band with reduction of disulphide bonds. The N-terminal sequence of the 24 kDa band was determined to be 'IAGPGWEKYN'. This sequence was not homologous to any known protein. Examination of isolated chiletin with two-dimensional protein analysis gel electrophoresis revealed the presence of three (~12 kDa) subunits ranging in isoelectric point from 5.2 to 6.0. The 24 kDa protein was used to immunise rabbits and a separate antiserum was also raised in rabbits using a synthetic peptide (identical to that above) coupled to keyhole limpet haemocyanin. These antisera were used to confirm the size of the chiletin subunits with Western blots and to examine the elution of chiletin in oyster haemolymph with size exclusion chromatography in phosphate buffered saline (PBS) and 8 M urea. There were four or five different sized conformational aggregates of chiletin present in oyster haemolymph under physiological conditions (PBS). The use of 8 M urea produced two separate aggregates. A major characteristic of lectins is the ability to agglutinate sheep red blood cells and both whole oyster haemolymph and isolated chiletin had this property. Chiletin was identified by immunohistochemistry to be present in a number of tissues. Staining intensity was most consistent in the auricular myocardial cells, followed by the digestive gland epithelium. Chiletin was not induced in haemolymph in response to temperature (30??C) stress or injection of turpentine into the adductor muscle. There have been few immunological studies performed with O. chilensis. The results of the project contribute to what is known about comparative immunology. Greater understanding of how oysters respond to stress and deal with pathogens will ultimately be of benefit to the aquaculture industry.
19
Perkins, Nigel Ross. "Epidemiology of health and performance in New Zealand racehorses : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Epidemiology at Massey University, Palmerston North, New Zealand." 2005. http://hdl.handle.net/10179/1580.
Full textAbstract:
The aim of this research was to describe training and racing patterns, and causes of wastage in New Zealand Thoroughbred racehorses. Two separate studies were performed. The first involved analysis of data from before and after construction of a new training track at the Matamata Racing Club. Comparisons of measures of performance failed to detect any adverse impact that could be attributed to the new track. The second involved a longitudinal study over a 34-month period, and that involved 1,571 horses. Duration of training preparations and spell periods were associated with horse age, and with the reason for ending a training preparation. Most horses began a training preparation doing slow work and then progressively advanced to a first start. Incidence rates were estimated for starts per 100 training-days, and other summary measures were estimated including training-days to first start, and between successive starts. A total of 834 musculoskeletal injuries (MSI) were observed, resulting in either a spell period, retirement, or death of the horse. There were 165 respiratory disease events, and 58 conditions involving other body systems. Multivariate statistical models were used to explore risk factors for different types of MSI. Older horses were at higher risk of lower limb MSI, and injury to either the superficial digital flexor tendon (SDFT) or suspensory apparatus (SA), while they were at lower risk of shin soreness and other conditions. Male horses had higher risk of tendon and ligament injury than females. Lower risk of injury was observed in Autumn and Winter months compared with December, and in the 1999-2000 year relative to 1997-1998. Measures of cumulative exercise intensity showed a complex relationship with risk of injury that varied with type of injury. The risk of SDFT and SA injury was higher for those preparations without starts, while that for shin soreness was increased after the first start. For lameness conditions other than shin soreness or injury to the SDFT, the hazard was increased after the first start in a preparation, but the magnitude of effect was dependent on the number of days from the beginning of a preparation to the first start.
20
Piripi, Susan Amanda. "Chondrodysplasia of Texel sheep : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Massey University, Palmerston North, New Zealand." 2008. http://hdl.handle.net/10179/800.
Full textAbstract:
Chondrodysplasia of Texel sheep is a newly described recessively inherited disorder distinct from other chondrodysplasias described in sheep. Phenotypically normal at birth, affected lambs develop microscopic lesions as early as 9 days of age, and usually demonstrate gross deformities and markedly reduced rates of bone growth by 2 to 3 weeks. Individual bone growth rates are most severely affected in the proximal bones of the forelimbs. Chondrodysplastic lambs typically have short stature, angular limb deformities, a barrel-shaped chest and a wide-based stance. Gross lesions include tracheal narrowing and contortion, enlarged costochondral junctions, and erosion of articular cartilage in major limb joints. Microscopic lesions are confined to hyaline cartilage, and are characterised by degeneration of the interterritorial matrix and dense perichondrocytic rings consisting predominantly of type VI collagen. These lesions are identical in appearance to those in achondrogenesis 1b and diastrophic dysplasia, two diseases caused by defects of the diastrophic dysplasia sulphate transporter (DTDST) in human beings. An investigation to measure the uptake of radiolabelled sulphate by dermal fibroblasts in vitro did not provide evidence of a defect in the DTDST in chondrodysplastic Texel sheep. A linkage disequilibrium study of ovine chromosomes 1, 5, 6, 13 and 22 using microsatellite DNA markers was unable to identify evidence of a mutation causing this form of chondrodysplasia. Capillary electrophoresis of unsaturated chondroitin sulphate disaccharides demonstrated a relative reduction in the ratio of chondroitin 4-sulphate to chondroitin 6-sulphate in affected animals of all ages. This biochemical feature enables the potential determination of the phenotype of newborn lambs prior to the emergence of gross or microscopic lesions. The pathology of the disease, combined with the findings of the genetic, biochemical and in vitro studies, suggest that a mutation may be present in the CHST11 gene. This gene is a good candidate for future studies aimed at discovering the genetic defect in chondrodysplasia of Texel sheep and developing a test to identify heterozygous animals.
21
Norton, Solis. "The epidemiology of Johne's disease in New Zealand dairy herds : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University." 2007. http://hdl.handle.net/10179/1447.
Full textAbstract:
Johne's disease (JD), caused by Mycobacterium avium subspecies paratuberculosis (MAP) is a chronic, debilitating enteritis of cattle, other domestic livestock and some wildlife species. JD was first identified in the late 1800s and today it is a worldwide problem in dairy cattle. Heavily infected cows have reduced milk production, a higher risk of removal from the herd and low slaughter value. Several countries have implemented national level control strategies. In New Zealand, JD was first reported in 1912 and today the prevalence of infected dairy herds is thought to be high. To improve our understanding of the epidemiology of JD and to evaluate the feasibility of a national control strategy, four studies were conducted. The first study was a questionnaire based case-control study to identify associations between management practices and the occurrence of clinical JD on farms from four regions of New Zealand. The second study was on the effect of sub-clinical JD on milk production and the risk of removal from the herd in four dairy herds over four milking seasons. The effect of misclassification of disease status on productivity estimates was also studied. In the third study diagnostic test result data from the productivity study was combined with a novel Bayesian regression model to estimate performance of the ELISA and faecal culture tests as a function of covariates and utilising repeated tests on individual cows. Finally, results from these three studies were used to adapt an existing JD simulation model, 'JohneSSim', to represent the epidemiological behaviour of JD in New Zealand dairy herds. Control strategies for the disease were simulated and evaluated based on their cost effectiveness. Of the 427 farmers responding to the questionnaire, 47% had suspected clinical cases of JD in their herd in the preceding 5 years. Only 13% of suspected infected herds had an average incidence of greater than 0.5 cases per 100 cow years at risk. The disease was not considered a serious problem by 20% of herd managers who reported the presence of disease in the preceding 5 years. The presence of Jersey cows in the herd and the purchase of bulls had strong positive associations with the presence of clinical JD. Grazing calves in the hospital paddock, larger herds, the purchase of heifers, and the use of induction were also positively associated with JD. In the productivity study the herd-level prevalence of JD by ELISA and/or faecal culture ranged from 4.5% (95% CI 2.6-6.9) to 14.2% (95% CI 9.2-20.6). Daily milksolids production by JD positive cows was 0.8% (95% CI -6.1%-4.5%) less than that of JD negative cows. However in herd D, JD positive cows produced 15.5%, (95% CI 6.75%-24.2%) milksolids less than JD negative herd mates daily. This equates to a loss of 53kg of milksolids/305 day lactation, or NZD 265/lactation, given a price of NZD 5/kg of milksolids. In herd D only, the annual hazard ratio of removal for JD positive cows was significantly increased. It was 4.7 times and 1.4 times higher in cows older than 5 years and younger than 5 years. The results were insensitive to misclassification. Analysis of the diagnostic test data demonstrated the strengths of our Bayesian regression model. While overall estimates of sensitivity and specificity by this method were comparable to estimates by existing methods, it showed a broad trend of increasing sensitivity in higher parity groups and higher sensitivity in early, relative to late, lactation. It also showed that estimates of prevalence may in fact decline with repeated, relative to single, testing. Our novel approach demonstrated trends that could not be shown by existing methods, but could be improved by application to a larger data set. Simulation showed that control strategies for JD based on either test-and-cull, vaccination, breeding for genetic resistance, or removal of offspring from clinically affected cows, were not cost effective for the average infected herd. Improvement of the hygiene associated with calf management provided the greatest reduction in the within-herd prevalence of JD. While JD is present in a high proportion of New Zealand dairy herds, the incidence of clinical cases is usually low, and most farmers consider it to be of little importance. However, JD causes significant losses in productivity in some herds. The disease would probably be best controlled on a herd-by-herd basis, given the limited success of national-scale control programs for JD in other countries. The education of dairy farmers regarding risky management practices, and the offer of a risk assessment to farmers wishing to control the disease, would provide a combination of wide reaching and targeted approaches, of low cost, for JD control. It seems likely that JD will persist in some capacity in the years ahead, but will remain of minor concern next to major animal health issues, such as infertility and mastitis. Clarification of the effect of genetic strain on the virulence of MAP may help explain differences in the effect of the disease between herds. This knowledge could then be used to further improve the efficiency of JD control.
22
Lockhart, Caryl Yolanda. "Surveillance for diseases of poultry with specific reference to avian influenza : a dissertation presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University." 2008. http://hdl.handle.net/10179/813.
Full textAbstract:
This thesis addresses issues related to surveillance for disease in commercial and non-commercial poultry populations. The motivation for this work has largely arisen from the unprecedented outbreaks of highly pathogenic avian influenza (HPAI) H5N1 that have occurred in 52 countries in Asia, Africa and Europe since 2003. A series of studies are presented using data derived from two countries, Vietnam and New Zealand. The two Vietnamese studies provide in-depth epidemiological analyses of the outbreak of HPAI H5N1 from December 2003 to March 2004. The three New Zealand studies deal with issues related to the development of effective surveillance strategies for HPAI — informed both directly and indirectly by the findings from the Vietnamese studies. This approach provides an example of how ‘lessons’ learnt from countries that have experienced large scale infectious disease epidemics can be used to assist in the design of surveillance activities in (as yet) unaffected countries. The descriptive analyses of the 2003 – 2004 outbreak of HPAI H5N1 in Vietnam indicate that the epidemic was seeded simultaneously in the north and south of the country in the later part of 2003 with 87% of provinces affected by February 2004. HPAI risk was concentrated around the Mekong and Red River Deltas. The broad scale spatial distribution of disease is likely to have been associated with regional differences in the poultry farming, trade in poultry, and environmental conditions such as the presence of bodies of water which would support reservoir species for the virus. A Bayesian zero-inflated Poisson regression model was used to quantify the influence of environmental and demographic factors on the spatial distribution of HPAI positive communes. In areas where disease was reported, our results show that HPAI risk was positively associated with the presence of irrigation and negatively associated with elevation. After controlling for these fixed effects, a single large area of elevated risk in the Red River Delta area was identified, presumably arising from similarities in the likelihood of reporting disease or the presence of factors increasing disease transmission and spread. Further investigations to elucidate likely transmission mechanisms, targeting this area of the country, would be a profitable area of future research. The second part of this thesis presents three studies that address issues related to the development of effective surveillance strategies for HPAI in New Zealand. The first was a cross-sectional study to enumerate the prevalence of backyard poultry ownership in two areas (one urban and the other rural) close to a large provincial city in the North Island of New Zealand. The prevalence of poultry ownership was 2% (95% CI 1% – 4%) in the urban area and 19% (95% CI 12% – 30%) in the rural area. The relatively low numbers of land parcels where poultry are present indicates that these areas, in the event of an infectious disease incursion, would be unlikely to pose a risk for spread of infectious agent. A cross-sectional survey of all members of the Poultry Industry Association of New Zealand was conducted in the later half of 2007. Respondents were asked to document contacts made with other enterprises related to feed, live birds and hatching eggs, table eggs and poultry product, and waste litter and manure. Patterns of contact were analysed using social network analyses. Each of the four networks had scale-free properties, meaning that for each movement type there were small numbers of enterprises that had contacts with large numbers of enterprises (potential ‘super-spreaders’ of disease). The presence of an undetected infectious disease in enterprises with super-spreader characteristics increases the likelihood that an epidemic will propagate rapidly through the population, assuming there is a directly proportional relationship between the number of contacts an enterprise makes and the probability that disease will be transferred from one location to another. While the finding that feed suppliers had large numbers of poultry farm contacts in the feed network came as no surprise, what was of greater interest was that there were small numbers of poultry farms that reported off-farm movements of feed. This should serve as an important reminder for disease control authorities: movement (and other) restrictions applied during the course of an animal health emergency should be applied across a range of industry sectors, recognising that some industry participants may practice activities that are not entirely typical for their enterprise type (e.g. poultry farms on-selling feed to other farms). In the absence of perfect and up-to-date network data, knowledge of the characteristics of individual enterprises that render them more likely to be atypical (e.g. size, type, and geographic location) would be of value, since this information could be used to inform a risk based approach to disease surveillance and control. A scenario tree model was developed as an approach for evaluating the effectiveness of New Zealand’s passive surveillance system for HPAI. The model was developed in two stages. In the first, factors thought to influence the geographic distribution of NAI risk of introduction and spread (and therefore surveillance strategy) were combined to create a spatial risk surface. In the second stage, a scenario tree model of the passive surveillance system for NAI was developed using the spatial risk surface and the HPAI surveillance strategy prescribed by Biosecurity New Zealand. The model was most sensitive to farmers reporting the presence of suspected cases of disease. This implies that the sensitivity of the system as a whole stands to increase if the importance of reporting suspicious clinical signs is reiterated to poultry producers. The studies presented in this thesis have presented a range of techniques and methodological approaches that are sufficiently generic to be used in any country to inform the design of surveillance strategies for a variety of animal diseases, not just those of poultry. Although epidemiology, as a discipline, is endoured with a vast range of analytical techniques that can be used to enhance the understanding of factors influencing the spread of disease among animal populations, the quality of data used to support these techniques is often lacking. The challenge in the years ahead, for both developed and developing countries, is to set in place the appropriate infrastructures to collect details of animal populations consistent in quality over time and space.
23
Lizarraga-Madrigal, Ignacio. "Spinal analgesic interaction between non-steroidal anti-inflammatory drugs and N-methyl-D-aspartate receptor systems : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science, Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand." 2006. http://hdl.handle.net/10179/1466.
Full textAbstract:
Activation of spinal N-methyl-D-aspartate (NMDA) receptors stimulates cyclooxygenase and nitric oxide pathways. Compounds that block the activity of these NMDA receptor systems reduce pain hypersensitivity. However, their usefulness is limited by the side effects they produce. One way of reducing side effects is by combining drugs that produce the same overt effect by different mechanisms, which hopefully increase the net effect. In these series of studies, drugs that interact with NMDA receptor systems and their combinations were screened in vitro to identify spinal antinociceptive synergistic combinations that could be assessed in vivo. Based on developmental changes in thresholds, conduction velocities and blocking actions of the local anaesthetic lignocaine in neonatal rat L4/L5 dorsal root potentials, it was decided to use spinal cord in vitro preparation from 5- to 7-day-old rat pups. In single drug studies, the NMDA receptor channel blocker ketamine (1-50 µM) and the non-steroidal anti-inflammatory drug (NSAID) ketoprofen (200-600 µM), but not the NSAID salicylate (1000 µM) and the nitric oxide synthase inhibitor Nω-nitro-L-arginine methyl ester (L-NAME; 1-100 µM), reduced spinal NMDA receptor-mediated transmission. Ketamine also depressed non-NMDA receptor-mediated transmission. Using isobolographic and composite additive line analyses, fixed-ratio combinations of ketamine and ketoprofen, ketamine and L-NAME, and ketopofen and L-NAME synergistically depressed NMDA receptor-mediated transmission. The two former combinations had a subadditive effect on non-NMDA receptor-mediated transmission, and the latter had no significant effect. These studies identified that all combinations synergistically reduced both nociceptive transmission and potential side effects. In free-moving sheep implanted with indwelling cervical intrathecal catheters, 100 µ1 subdural administration of ketamine (25-400 µM) and ketoprofen (200-3200 µM) alone and in a fixed-ratio combination (873.95-3350.78 µM, 0.045:0.955) did not raise nociceptive thresholds as assessed by mechanical stimulation of one foreleg. Subdural administration of NMDA (2 mM) decreased mechanical nociceptive thresholds, and this was prevented by the highest concentrations of ketamine and ketoprofen alone and in combination. These findings demonstrated that NMDA receptor channel blockers and NSAIDs alone or in combination had no direct hypoalgesic effects when given onto the spinal cord of sheep, but they prevented NMDA-induced pain hypersensitivity. Simultaneous blockade of NMDA receptor systems could have important clinical implications.
24
Porphyre, Thibaud Francois Christophe. "Factors associated with the transmission dynamics of bovine tuberculosis in New Zealand : a dissertation presented in partial fullfilment [sic] of the requirements for the degree of Doctor of Philosophy at Massey University, Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, Turitea, New Zealand." 2008. http://hdl.handle.net/10179/761.
Full textAbstract:
This thesis presents the results of a series of studies on the epidemiology of TB in brushtail possum and domestic cattle populations in New Zealand. The first set of studies provides an analysis of the results of routine TB testing carried out in the Featherston area from July 1980 to June 2004. The median annual incidence rate of TB reduced from 4.7 cases per 1000 cattle-years at risk for the period 1986 to 1991 to 1.8 cases per 1000 cattle-years at risk for the period 1992 to 2003, coincident with the use of poisoning to control possums in the surrounding forest park (a major possum habitat area). We identified clusters of cattle TB cases adjacent to the forest park and found no evidence of spatio-temporal interaction of TB risk among farms. Our findings support the hypothesis that possums living in the forest park are a source of bovine TB in this area and that farm-to-farm transmission was not an important mechanism of infection spread. A mixed-effects Poisson regression model was developed to investigate the influence of farm-level covariates on the number of cattle confirmed with TB. The model showed that, despite intensification of possum control activities, proximity to forest parks remained a significant predictor of the number of confirmed TB cases per farm per year. Our analyses identified a significant, 3-fold increase in TB risk in dairy cattle relative to beef conditional on the size of local possum habitat, and confirmed the positive influence of cattle population size and the presence of previous infection status as a determinant of the number of confirmed TB cases per farm per year. The second set of studies investigates details of capture events recorded during a longitudinal, capturemark- recapture study of possums in a 22-hectare study site near Castlepoint, from April 1989 to August 1994. Social network analyses were used to identify contact patterns and to estimate the influence of contact on R0 for bovine TB. The average number of contacts per possum ranged from 20 to 26 per year. We estimated that TB would spread if an average of between 1.94 and 1.97 infective contacts occured per year per infected possum. We evaluated the effect of sex, habitat and contact behaviour of 26 postmortem confirmed TB cases in possums with those of 104 matched controls. Unit increases in the number of infected contacts increased the odds of TB infection by 2.61 (95% CI 1.29 – 5.29, P <0.01). Our results show that individual contact behaviour is a determinant of the presence of TB foci within this population and challenge the hypothesis that contact with many individuals increases the probability of infection. A model to predict spatial variation in possum abundance was developed using a Geographic Information System. Details of possum capture events were obtained from 157 10-trap lines distributed within 42 randomly located transects at Molesworth Station. Two GIS-based models were developed to predict the number of possums caught per line using Poisson regression techniques. The first model used remotely sensed environmental data; the second used a combination of remotely sensed and fine-scale data. Both models provided adequate predictive ability with Pearson correlation coefficients greater than 60%. We conclude that the prediction maps produced from this model provide a useful decision support tool for possum control managers. These results have implications for the management of TB in this area of New Zealand, providing the information that will allow effective control activities to be applied at significantly lower cost.
25
Todd, Sarah Elizabeth. "Metabolism of selenium in cats and dogs : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Physiology and Nutrition at Massey University, Palmerston North, New Zealand." 2006. http://hdl.handle.net/10179/1496.
Full textAbstract:
The main objective of this PhD was to provide fundamental information regarding some metabolic aspects of selenium metabolism in cats and dogs. The total selenium content of a range of commercially available petfoods was analysed using a fluorometric method. The petfoods contained a wide range of selenium concentrations, with up to 6 µg Se/g DM found in cat foods. Mean concentrations of selenium in dog and cat foods were 0.40 and 1.14 µg Se/g DM respectively. All petfoods analysed met the recommended current minimum dietary selenium requirements. The use of blood parameters for the assessment of selenium status was investigated in a study in which cats were fed inorganic and organic selenium supplemented at concentrations of up to 2.0 µg Se/g DM for 32 days. Plasma selenium concentrations reflected dietary selenium intakes, however there were no differences between the different levels of supplementation. Whole blood selenium concentrations showed less distinct patterns and were thought to be a more useful indicator of longer term selenium status. Activities of glutathione peroxidase in plasma and whole blood showed no response and the response of cats to supplementation of the different forms of selenium were similar. In the same study, faecal and urinary excretion (µg/kg BW/d) were measured and apparent absorption and retention were estimated during the last seven days of the 32 day trial. Faecal excretion of selenium remained constant whereas urinary excretion of selenium increased with increased dietary intake. The form of selenium had no effect on excretion or apparent absorption however there was a trend in which more selenium was retained in cats fed organic selenium. A study was conducted with cats and dogs fed high levels (10 µg Se/g DM) of inorganic and organic selenium for 21 days to determine whether there were species differences in their metabolic response. Cats and dogs exhibited the same pattern of response, however cats showed higher plasma selenium levels, lower levels in liver and excreted more selenium compared to dogs. It was concluded from this data that cats and dogs differ in their metabolism of selenium. The effect of heat processing on the addition of inorganic and organic selenium to petfoods was investigated in cats fed 3.0 µg Se/g DM for 11 days. Apparent absorption was higher in cats fed inorganic selenium added after processing, whilst less selenium of organic origin was excreted in the urine when added after processing. These preliminary results suggest heat processing may decrease the apparent availability and utilisation of selenium in petfoods.
26
Mullner, Petra. "Estimating the contribution of different sources to the burden of human campylobacteriosis and salmonellosis : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy at Massey University, Palmerston North, New Zealand." 2009. http://hdl.handle.net/10179/1232.
Full textAbstract:
This thesis is concerned with the molecular epidemiology of Campylobacter jejuni and Salmonella in New Zealand and the development of source attribution tools for these pathogens. Although campylobacteriosis is the leading enteric zoonosis worldwide, the pathogen's complex epidemiology and di culties with existing typing schemes, have posed challenges for the control of this disease. The rst study of this thesis gives an overview of existing approaches to microbial risk assessment and source attribution, with particular respect to campylobacteriosis, and describes their advantages and shortcomings. Further, the chapter discusses phenoand genotyping techniques for Campylobacter spp. and the value of including microbial typing data in risk assessments. In the second study, data from a sentinel surveillance site in the Manawatu region was used to investigate the molecular epidemiology of human campylobacteriosis cases. This analysis revealed the presence of a dominant C. jejuni clone, namely sequence type (ST) 474, which accounted for 30.7 % of human cases in the study and identi ed risk factors for infection with ruminant and poultry associated STs. The third study investigated the link between C. jejuni in human cases and samples taken from poultry. By applying epidemiological and population genetic techniques this part of the thesis provided further evidence that poultry is a major contributor to human infection. In the fourth study an existing Bayesian source attribution model was modi ed and consecutively applied to New Zealand's major foodborne zoonoses: campylobacteriosis and salmonellosis. The majority (80 %) of human campylobacteriosis cases attributable to C. jejuni were estimated to have been acquired from poultry sources, whereas wildlife source were estimated to contribute only a minor proportion of cases. In the fth study the Salmonella dataset was descriptively analysed and a large proportion of human cases was found to be caused by `exotic' Salmonella types. In the nal study of this thesis four di erent genetic and epidemiological source attribution methodologies were applied to the same dataset in a comparative modelling framework. iv The studies in this thesis show that epidemiological studies combined with molecular tools and modeling can provide valuable risk-based tools to inform the surveillance and control of zoonotic pathogens. Methods from these studies may be readily applied to the control of other (food borne) zoonoses and provide new opportunities for epidemiological investigations and source attribution modelling of major pathogens.
27
Perera, Kalyani. "Characterisation of a secreted immunogenic protein, phase-1 flagellin (FliC) of Salmonella enterica subspecies enterica Brandenburg : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Microbiology at Massey University, Palmerston North, New Zealand." 2007. http://hdl.handle.net/10179/1450.
Full textAbstract:
Cell-envelope associated and secreted proteins of Salmonella are integral for host-pathogen interactions, and for the induction of protective immune responses. An array of exported proteins of S. Brandenburg was identified through constructing an expression library using alkaline phosphatase gene technology. A partial digest of S. Brandenburg strain S59 was cloned into the vector pJEM11, and expressed in E. coli. The DNA inserts from randomly selected alkaline phosphatase positive clones were sequenced, and the sequences were analysed using public databases to find the ones that may play a role in host immune cell activation. The phase-1 flagellin (fliC) gene identified from an alkaline phosphatase positive phenotype was chosen for further studies. The complete nucleic acid sequence of the fliC gene was obtained by PCR amplification. The complete ORF, part of the variable region (V456) and region IV (V4) of the fliC gene were cloned into the pET14b vector for the expression of N-terminal histidine-tagged fusion proteins. The proteins were purified through metal affinity chromatography, and were evaluated for their humoral immunogenic properties by Western blotting with sera collected from 81 sheep naturally infected with S. Brandenburg. All 81 naturally infected sheep had IgG antibodies against recombinant FliC, V456, and V4 proteins. Furthermore, Western blotting of sera from 6 salvexinTM+B-vaccinated sheep (Trial 2004) had IgG antibodies against the 3 recombinant proteins. Whole blood cells of vaccinated sheep did not show interferon-gamma production upon stimulation with recombinant FliC and V456 proteins. Western blotting of sera from sheep vaccinated with salvexinTM and salvexinTM+B (Trial 1999), and those from rabbits vaccinated with S. Brandenburg, S. Hindmarsh and S. Typhimurium suggested that recombinant V4 contains epitopes specific for S. Brandenburg. Therefore, V4 was used to develop a novel indirect enzyme-linked immunosorbent assay (ELISA) for the detection of serum IgG antibodies in S. Brandenburg infected sheep. The ELISA showed a specificity of 100%, and a sensitivity of 93.8%. Furthermore, a new PCR assay was developed targeting rfbJ(B) gene in a single reaction, and genes invA, fliC and fljB in a multiplex reaction for the identification of S. Brandenburg from pure cultures. The sensitivity and specificity of the PCR assay was calculated to be 100%.
28
Walton, Julie K. "Neospora caninum : studies toward isolation in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Studies at Massey University, Palmerston North, New Zealand." 2008. http://hdl.handle.net/10179/1089.
Full textAbstract:
Background: Neospora caninum is a parasite that causes disease, largely in cattle and dogs. It is a disease of significant interest within New Zealand due to its association with bovine abortion. The economic impact of bovine abortion justifies the development of a bovine vaccine against N. caninum. Aim: To develop and optimise diagnostic procedures for the detection of Neospora from a variety of blood and tissue samples and to isolate a New Zealand strain of Neospora caninum. Methods: A local strain of Toxoplasma gondii and an imported Neospora caninum strain, Nc-Liverpool, were used to optimise tachyzoite growing conditions in bovine endothelial (BE) cells and Vero host cell cultures. A serum study using 112 tissue culture flasks was performed to determine whether foetal bovine serum or horse serum supplemented media provided the optimal growing conditions for Nc-Liverpool tachyzoites. Nc-Liverpool tachyzoites were also used to determine the optimal growth period between passage, and harvest for cryopreservation and cryopreservation conditions. Percoll gradients were also tested using Nc-Liverpool tachyzoites. A known Neospora positive canine sample and murine tissues infected with Toxoplasma, were used during the development of the immunohistochemical diagnostic technique. Antibody concentrations and incubation temperatures were tested to reduce cross-reactivity and increase specific stain intensity. Immunohistochemistry was performed on sections of all tissue samples used for N. caninum isolation and experimentally infected murine tissue. Several PCR techniques were developed, the final PCR used being a combination of the different techniques, which produced a 250kb band. PCR-3 used the NF6/GA1 primer combination for Neospora detection and TF6/GA1 for Toxoplasma detection, additional Mg2+ and an annealing temperature of 55°C were required. Whole tissue was processed via DNA elution whereas cell culture and Percoll purified tachyzoites were used following crude lysis techniques. All bovine and canine tissues used for parasite isolation as well as all experimentally infected mouse tissues were tested for N. caninum using PCR. An immunoblot technique was developed for the detection of N. caninum antibodies in murine blood samples. Lysed Nc-Liverpool tachyzoites were used as antigen with varied results. The primary and secondary antibodies were commercially available and used at concentrations of 1:1,000 and 1:25,000 respectively. BALB/c and CF1 mice were experimentally infected with Toxoplasma gondii and Nc-Liverpool. Forty female BALB/c and 40 female CF1 mice were used in 2 studies to determine the optimal Nc-Liverpool inoculation dose and immunosuppression requirements. Mice were immunosuppressed with 2.5mg of methylprednisolone acetate (MPA) and Nc-Liverpool inoculation ranged from 1.3x106 to 5x103 tachyzoites. Upon death, the brain and blood was harvested from the mouse carcases. Attempts were made to isolate a New Zealand strain of N. caninum from bovine and canine central nervous system (CNS) tissue, and to maintain the parasites in cell culture and by small animal passage, in order to attenuate the parasite strain for use as a live large animal vaccine. Twenty one bovine tissue samples were used for N. caninum isolation attempts, 18 of which were positive for Neospora antibodies using a commercial IFAT. Isolation tissues were purified using a 30% Percoll gradient and inoculated onto 8 cell culture flasks and into 8 immunosuppressed mice (BALB/c and CF1). Results: Nc-Liverpool tachyzoites were found to be viable when grown at 37°C in antibiotic-MEM supplemented with either FBS or ES and grew optimally in FBS despite Neospora antibodies being detected using an IFAT. Passaging cultures at approx. 4 day intervals resulted in the greatest parasite growth. However, cryopreserved parasites should be harvested 2 days post inoculation (PI) for optimal viability. Viable parasites could be isolated using a 30% Percoll gradient and centrifuged at 2,700 x g (3,400 rpm) in a bucket centrifuge for 10 minutes. Tissue cysts could be detected using immunohistochemistry but some degree of cross reaction remained despite optimisation. Cysts were not found in tissues used for isolation attempts or in mouse brains following inoculation with Nc-Liverpool, however cysts were commonly found in mice experimentally infected with T. gondii tachyzoites. PCR-3 was successfully used to detect N. caninum and T. gondii infected tissue and tachyzoites from tissue culture. PCR-3 could detect N. caninum DNA in the brain tissue of 9/24 mice experimentally infected with Nc-Liverpool, even though most mice were culled within 1 week. Although production of N. caninum antigen was only moderately successful, N. caninum antibody detection in mouse blood using one specific antigen batch was reliable and specific. The immunoblot could only detect N. caninum antibody approximately 14 days PI, but was sensitive enough to detect 100% of mice experimentally infected with Nc-Liverpool tachyzoites. PCR-3 strongly correlated with the immunoblot results from 14 days PI. BALB/c mice were found to be far more sensitive to Nc-Liverpool than CF1 mice and developed severe disease at concentrations of approximately 1x106 Nc-Liverpool tachyzoites. Neither BALB/c nor CF1 mice developed peritoneal exudate, irrespective of the parasite inoculation concentration. Despite Neospora DNA being present in the brains of experimentally infected mice, re-isolation and continuous parasite passage from the brains could not be achieved. No mice experimentally infected with either Nc-Liverpool or isolation attempts were found to have brain cysts when tested using immunohistochemistry. Only 1 mouse inoculated with bovine isolation material was found to have a Neospora positive PCR. Through the detection of DNA, antigens and antibodies, parasites were determined to have been present in 10 of the 18 IFAT positive bovine isolation samples, indicating that 55% of calves born to seropositive dams were infected with N. caninum. However, despite numerous attempts to isolate Neospora parasites from naturally infected canine and bovine tissue and culturing using the optimised Nc-Liverpool technique, maintenance of a live culture of a New Zealand strain of N. caninum could not be established. Conclusions: Findings from this study could be used to assist in the maintenance of Neospora caninum and Toxoplasma gondii parasite strains and for detection or diagnosis of these parasites in host tissues.
29
Kamaludeen, Juriah. "Studies on the occurrence of anthelmintic resistance in goat parasites in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Studies in Parasitology at Massey University, Palmerston North, New Zealand." 2010. http://hdl.handle.net/10179/1652.
Full textAbstract:
Two studies were conducted to investigate anthelmintic resistance in goat parasites in New Zealand. In Study 1 parasites from goats on a farm with a long history of problems with anthelmintic efficacy were used to infect sheep for a controlled slaughter study. Nineteen lambs were acquired, effectively drenched and housed. Each was infected with a mixture of larvae comprising Haemonchus contortus, Teladorsagia circumcincta, Trichostrongylus colubriformis and Oesophagostomum venulosum. After 28 days lambs were restrictively randomised into 3 groups based on faecal egg counts. Group 1 was left untreated (n=6), Group 2 (n=6) was given a single dose of abamectin (0.2mg/kg) + levamisole HCL (8mg/kg) + oxfendazole (4.5mg/kg) (“Matrix Oral Drench for Sheep”®, Ancare, New Zealand) and Group 3 (n=7) was treated at twice the dose rate of Group 2. Fourteen days after treatment all animals were killed for total worm counts. The mean burdens of T. circumcincta in Group 1 was 337, in Group 2 was 68 (efficacy 80%) and in Group 3 was 10 (efficacy 97%). The mean burdens of T. colubriformis in Group 1 was 375, in Group 2 was 220 (efficacy 41%) and in Group 3 was 81 (efficacy 78%). Although the worm burdens in these lambs were low, all animals were infected with each of these two species except for T. circumcincta in Group 3 where only 3 lambs were infected. Efficacy against other species was 100%. These results clearly indicate that a single dose of a combination drench was ineffective against two species and even when a double dose was used the efficacy against T. colubriformis was only 78%. In Study 2 a survey of drench efficacy was conducted on 17 goat farms using the DrenchRite® larval development assay. Evidence of concurrent resistance to benzimidazoles, levamisole and ivermectin was detected in T. colubriformis and T. circumcincta on 11/17 and 3/14 respectively. Only 5 of 14 farms had previously undertaken some form of testing for drench resistance prior to this survey. Evidence from these two studies suggests that severe anthelmintic resistance is common on goat farms in New Zealand
30
Dukkipati, Venkata Sayoji Rao. "A search for genetic factors influencing immune responses to a killed Mycobacterium avium subspecies paratuberculosis vaccine in Australian fine-wool merino sheep : thesis in fulfilment of the degree of Doctor of Philosophy in Animal Science, Institute of Veterinary, Animal and Biomedical Sciences, College of Sciences, Massey University." 2007. http://hdl.handle.net/10179/755.
Full textAbstract:
VSR Dukkipati (2007). A search for genetic factors influencing immune responses to Mycobacterium avium subspecies paratuberculosis. Doctoral thesis, Massey University, Palmerston North, New Zealand. A study was conducted to identify associations between genetic markers and immune responses in Australian fine-wool Merino sheep to a killed Mycobacterium avium subspecies paratuberculosis (Map) vaccine (GudairTM). Blood samples and immune response data (antibody and interferon gamma, IFN-gamma results) were obtained from 934 sheep from a longterm Map vaccination trial undertaken on three independent properties in New South Wales, Australia. Blood samples were genotyped for eight microsatellite markers that included four (DYMS1, OLADRW, OLADRB and SMHCC1) from the Ovar-Mhc region, two each from the SLC11A1 (OVINRA1 and OVINRA2) and IFN-gamma (o(IFN)gamma and OarKP6) gene regions. Vaccination with GudairTM induced strong antibody and IFN-gamma responses as early as two weeks post-vaccination. Between-property differences in magnitude and trend of immune responses, concomitant with season of vaccination and magnitude of natural infection prevalent in individual flocks, were evident. Immune responses in controls on all the three properties remained consistently low, except for slightly elevated IFN-gamma levels at a few time points in controls of properties 2 and 3, concomitant with exposure to natural infection. There were only 2 alleles and 3 genotypes for marker o(IFN)gamma but other loci exhibited extensive polymorphisms, the most occurring at OLADRW which had 42 alleles and 137 genotypes. Heterozygosities varied between 33% (OVINRA2) and 87% (SMHCC1), while polymorphic information contents ranged from 0.31 (o(IFN)gamma) to 0.88 (OLADRW). Genotypes at loci DYMS1, OLADRB, SMHCC1, OVINRA1 and o(IFN)gamma were in Hardy- Weinberg equilibrium (HWE), while those at OarKP6 were in HWE only when rare alleles (<1.0% frequency) were pooled with the closest size class. Departure from HWE, resulting from possible preferential amplification of alleles in heterozygotes, was evident at OLADRW and OVINRA2. Associations between immune responses and genetic polymorphisms at the marker loci were examined by analysing both genotypic and allelic affects. The study revealed several genotypes/alleles at different marker loci to be significantly associated with antibody and IFN-gamma responses to vaccination with GudairTM. However, the majority of those effects were inconsistent across the three properties. Based on significance and consistency in effects across the three properties, five genotypes (two at DYMS1 and one each at OLADRB, SMHCC1 and OVINRA1) and three alleles (one each at DYMS1, OLADRB and o(IFN)gamma) were considered either ‘probable’ or ‘most likely’ to be associated with low IFN-gamma responses, while a genotype at o(IFN)gamma was considered ‘most likely’ to influence high IFN-gamma responses. An allele at OarKP6 was considered ‘probable’ to be associated with low antibody responses to vaccination. Considering the significance of IFN-gamma responses in protection against Map, it is likely that the identified genotype/alleles influencing IFN-gamma responses to vaccination would also influence immune responses to natural Map infections. However, further studies need to be conducted to determine the role of these marker genotypes/alleles in protection against paratuberculosis under natural infection conditions. Key words: paratuberculosis, OJD, Johne’s disease, sheep, immune response, genetic markers, gene polymorphisms, MHC, SLC11A1, IFN-gamma
31
Youl, Jennifer Marie. "Lead exposure in free-ranging kea (Nestor notabilis), takahe (Porphyrio hochstetteri) and Australasian harriers (Circus approximans) in New Zealand : a thesis presented in partial fulfillment of the requirements for the degree of Masters of Veterinary Science in Wildlife Health at Massey University, Palmerston North, New Zealand." 2009. http://hdl.handle.net/10179/1031.
Full textAbstract:
Lead is a highly toxic metal that has been used by humans for over 2000 years. Over this time it has become increasingly apparent that despite its usefulness, lead is one of the most highly toxic substances known to man. Current research into lead exposure of humans focuses on low-level chronic exposure and its effects on learning and behaviour. However, investigations into lead exposure of wildlife are still focussed on mortalities, particularly of waterfowl and raptors, with little known about low-level exposures or the effects on other species. This study examines the exposure of free-ranging kea (Nestor notabilis) from the Aoraki/ Mt Cook village and national park, takahe (Porphyrio hochstetteri) from Tiritiri Matangi, Kapiti and Mana Islands, and the lead associated syndrome of clenched-claw paralysis and leg paresis in harriers (Circus approximans) in New Zealand. Thirty-eight kea had detectable blood lead with concentrations ranging from 0.028 mg/L to 3.43 mg/L (mean = 0.428 mg/L ± 0.581). Analysis of tissue samples found that seven of 15 birds died with elevated tissue lead. Lead exposure may be an important contributing factor in kea mortality. As a result of these findings, lead abatement in areas frequented by kea is being considered. Eighteen of 45 takahe had detectable blood lead concentrations ranging from 0.015 mg/L to 0.148 mg/L (mean = 0.028 mg/L ± 0.042). Analysis of tissue samples from offshore island and Murchison Mountains birds found that all had detectable lead. Despite levels of lead exposure in the population being low and unlikely to result in overt clinical signs, it is widespread and there may be significant exposure of birds living around old buildings. An investigation into the clinical signs, pathology and response to treatment of clenched-claw paralysis and leg paresis in wild harriers was carried out. Harriers with clenched feet had significantly higher blood lead concentrations than those without. In conclusion, lead is a major factor in the expression of this clinical syndrome but other factors not yet identified are playing a role. This study demonstrates that lead is widespread in the New Zealand environment exposing a diverse range of avifauna, and has made some progress towards exploring some of its effects on health and survival.
32
Lloyd, Janice Kathryn Foyer. "Exploring the match between people and their guide dogs : a thesis presented in fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Science at Massey University, Turitea, Aotearoa/New Zealand." 2004. http://hdl.handle.net/10179/1732.
Full textAbstract:
Practical aid to understanding vision impairment on page xxvii unable to be scanned. Please see http://www.rnzfb.org.nz/eye-conditions for this information.The relationship between guide dog handlers in New Zealand and their guide dogs was investigated to identify the reasons why some partnerships are successful while others are not. A two-part study was designed to explore the match between the handler and the dog to improve the outcome of the matching process. A focus group discussion with people who had a range of visual acuity and experience with mobility aids was conducted as a preliminary measure to help develop the survey questionnaire that was used in the second part of the study. Fifty current and/or previous handlers, who had used a total of 118 dogs, were interviewed about their prior expectations and the outcome of the partnerships. Results indicated that the majority of matches were successful, and quality of life was improved for most participants because of using a dog. Around a quarter of the matches were considered unsuccessful, although not all mismatched dogs were returned. Mismatches arose predominantly from problems concerning the dogs' working behaviour followed by the dogs' social/home behaviour. However, dogs were also returned for health problems and a few were returned for personal issues concerning the handler. Compatibility between the handler and the dog, and the fulfilment of expectations were positively associated with better matches. Factors relating to mobility, including a handler's ability to control a dog, made the biggest contribution to success, but non-work related issues, such as companionship and enhancement of social interactions were also significant. Other factors that appeared to be associated with a good outcome included an accurate assessment of workload, having a good relationship with the guide dog instructor, and having a little useful vision - especially if this deteriorated over the time a dog was used. Other findings suggested that the use of a dog improved travel performance, regardless of how well the participants' perceived their travel ability to have been before the dog was acquired, and that second dogs were less favoured than the first ones. These results have permitted a series of recommendations to be proposed to the guide dog industry regarding characteristics of handler and dog that are important for a successful match.
33
Stewart, Mairi. "Non-invasive measurement of stress and pain in cattle using infrared thermography : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Animal Science at Massey University, Palmerston North, New Zealand." 2008. http://hdl.handle.net/10179/750.
Full textAbstract:
The aim of this thesis was to validate the use of infrared thermography (IRT) to non-invasively measure stress and/or pain in cattle. The main approach was to measure changes in heat emitted from superficial capillaries around the eye (referred to as eye temperature) in response to various aversive husbandry procedures used routinely on farms. In addition, various exogenous challenges were given to investigate the role of the hypothalamic-pituitary-adrenal (HPA) axis and the autonomic nervous system (ANS) in regulating the eye temperature response. No evidence was found to support the hypothesis that an increase in eye temperature was due to HPA activity in cattle. A rapid drop in eye temperature occurred immediately after disbudding, an electric prod, startling and shouting. It is suggested that this was caused by the redirection of blood from the capillary beds via sympathetically-mediated vasoconstriction. Therefore, the role of the ANS was tested by measuring eye temperature, heart rate variability (HRV) and plasma catecholamine responses simultaneously. Somatic pain from disbudding and initial responses to surgical castration included a synchronised drop in eye temperature, increases in catecholamines and changes in HRV indicative of increased sympathetic activity. The role of the sympathetic nervous system was further confirmed by a drop in eye temperature that occurred following an epinephrine challenge. In contrast, deeper visceral pain from castration caused a more marked increase in eye temperature and changes in HRV indicative of increased parasympathetic tone. The underlying mechanism driving the increase in eye temperature is unknown; however, it is possible that it may be caused by vasodilation due to increased parasympathetic activity. These differences in ANS responses to different procedures, detected by IRT and HRV, may be due to the nature of the pain and the relative fear associated with the procedure. In summary, this research showed that during stress or pain, the heat emitted from superficial capillaries around the eye changes as blood flow is regulated under ANS control and these changes can be quantified using IRT. A combination of IRT and HRV is a non-invasive way to measure ANS activity and assess acute welfare impacts of husbandry practices in cattle. Further research using pharmacological inhibition and stimulation of the ANS activity would be beneficial to fully understand the underlying regulatory mechanisms of the eye temperature and HRV responses in cattle and other species during stress and/or pain. The full capability of IRT and HRV for detection of disease and emotional states and the effects of different intensities of pain, individual traits and previous experience also deserve attention.