Massey Documents by Type

Permanent URI for this communityhttps://mro.massey.ac.nz/handle/10179/294

Browse

Filters

Settings

Has files: YesSubject: search.filters.subject.Sheep diseases

Search Results

Now showing 1 - 10 of 27
  • Thumbnail Image
    Item
    A study of mycoplasmas of the ovine lung and their relationship to chronic non-progressive pneumonia of sheep in New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Microbiology at Massey University
    (Massey University, 1980) Brian, Peter Norman
    The relationship of mycoplasmas to diseases of the lower respiratory tract in a variety of animals was reviewed and investigations were undertaken to determine the role of micro-organisms, with particular reference to mycoplasmas, in the aetiology of ovine chronic nonprogressive pneumonia (CNP). A survey of the prevalence of mycoplasmas in pneumonic sheep lungs revealed that Mycoplasma ovipneumoniae was present in 98% of the lungs tested, whereas Mycoplasma arginini was present in 4%. Ureaplasmas were not detected in any lungs. To facilitate further investigations into the significance of M. arginini in ovine GNP, the in•~vitro growth of the organism was investigated and its ultrastructure was determined and compared with that of M. ovipneumoniae. Although ultrastructural differences between M. arginini and M. ovipneumoniae were found~ these wouid probably not allow all cells of each of the two species to be unequivocally identified in thin sections of lung material. M. ovipneumoniae, M. arginini and parainfluenza type 3 virus were shown to be sensitive to digitonin when suspended in either conventional laboratory medium, or in lung homogenate. Furthermore, treatment of pneumonic lung homogenate with 10 mg/cm3 digitonin destroyed its ability to transmit ovine CNP. Viruses (in particular PB virus) were not detected in aliquots of the pool of lung homogenate used to transmit CNP so it is likely that the necessary digitonin sensitive component is a mycoplasma. Since M. arginini has a consistently low prevalence in pneumonic lesions, whereas M. ovipneumoniae is found in the vast majority of such lesions, it was concluded that M. ovipneumoniae is responsible for initiating primary lesions of the disease. This however does not imply that M. ovipneumoniae on its own is capable of causing lesions comparable in severity to the fully developed "field" cases. The inactivation of M. ovipneumoniae by formalin, with a view to making a vaccine, was investigated.
  • Thumbnail Image
    Item
    Comparative study of subclinical fascioliasis in sheep and goats : a thesis presented in partial fulfilment of the requirements for the degree of Master of Philosophy in Veterinary Science at Massey University
    (Massey University, 1991) Mengesha, Kinfe Melak
    The literature on the identification of Fasciola spp. and their intermediate hosts, the general life cycle of Fasciola and aspects of the epidemiology, clinical signs, diagnosis and treatment of infections is reviewed. Two experiments were carried out. The first involved 18 weeks observations on 5 adult male goats each infected with 150 metacercartae of F.hepatica and 5 uninfected controls. The second involved groups of 10 sheep and 10 goats each infected with 200 metacercariae with 5 uninfected controls of each species. In both experiments, faecal, haematological, biochemical and pathological examinations were conducted. The animals were also weighed regularly. In the first experiment, although only 15-35 flukes were established, measurable and, in many cases, statistically significant changes in a variety of parameters were observed. A depression in packed cell volumes relative to controls of approximately 20% occurred. Though haemoglobin, mean corpuscular volume and mean corpuscular haemoglobin concentration levels remained within the normal ranges, erythrocyte levels in the infected group were significantly lower than in the controls and there was a tendency for the anaemia to become macrocytic. This suggests that goats may be particularly susceptible to the effects of blood loss associated with Fasciola infections though further work is needed to confirm this. A marked peripheral eosinophilia and elevation in fibrinogen levels were observed in infected animals. Albumin levels decreased, globulin levels increased and the A/G ratio decreased significantly relative to the control group but all levels remained within the normal ranges. In infected animals, gamma glutamyl transferase (GGT) and glutamyl dehydrogenase (GD) levels rose to beyond the limits of the normal ranges although aspartate aminotransferase (AST) levels, which were also significantly elevated, did not. The results indicate that serum GD and GGT are particularly sensitive indicators of damage to the liver parenchyma and bile ducts caused by F.hepatica in goats and that GD is more sensitive than AST. Serum bile acids were estimated but no significant change was detected. The ratio between faecal egg counts and the numbers of adult flukes present at necropsy was consistently lower than described for sheep with a mean of approximately 13epg/fluke (range 9-23) at the final sampling and 18epg/fluke (range 11-29) in the previous week when the egg counts were highest. This is potentially of considerable diagnostic importance and needs further investigation. In the second experiment, the number of flukes established was extremely low in both species (mean 0.85% & 2.95% in the sheep and goats respectively) although more goats than sheep became infected. Pre-existing liver pathology in the sheep was a further complication. Consequently, little information of value was generated by the infection of goats and no data that could be used for comparative purposes were obtained from the sheep infection. However, combination of the data from the 13 infected goats from both experiments yielded some useful information in relation to serum enzyme levels. Correlations between the numbers of flukes recovered at necropsy and peak levels of serum enzymes and various haematological parameters in individual animals were examined though only those relating to enzyme levels were statistically significant. The correlation coefficients between peak enzyme levels and fluke numbers indicated that the relationship was strongest with GGT and weakest with AST. However, regression analysis showed that there was no predictive value in the relationship with any of the enzymes because of extremely wide confidence intervals for predicted fluke numbers.
  • Thumbnail Image
    Item
    Studies on Mycoplasma ovipneumoniae in New Zealand sheep : epidemiology and comparison of isolates : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Microbiology at Massey University, New Zealand
    (Massey University, 1983) Ionas, George
    As part of a larger study to examine the role of M. ovipneumoniae in chronic non-progressive pneumonia (CNP) of sheep, the colonisation of the respiratory tract by mycoplasmas was examined in two flocks of lambs over . a nine month period. In both farms M. ovipneumoniae was detected in the ewes at the time of first swabbing of the lambs. The two flocks of lambs differed in the time when the nasal cavity first became colonised by M. ovipneumoniae: thus in Flock 2 M. ovipneumoniae was detected in the nasal cavity relatively early and also became disseminated throughout the flock some months earlier than occurred in Flock 1. Nevertheless, M. ovipneumoniae was widespread in both flocks of lambs by March i.e. at• or before peak seasonal prevalence of CNP. At slaughter in May, Flock 2 (colonised early) had a much higher prevalence of CNP than Flock 1. These findings are consistant with the hypothesis that M. ovipneumoniae colonises the nasal tract of lambs and subsequently invades the lung possibly in response to the stress of exposure to hot dry weather. The second part of this thesis is concerned with the adaptation of Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) to distinguish strains of M. ovipneumoniae with the ultimate objective of comparing M. ovipneumoniae strains isolated from pneumonic lungs to nasal isolates and isolates from apparently normal lungs. Isolates from different sources were heterogeneous when examined by SDS-PAGE, but comparisons were made difficult because of the excessive number of protein bands. In response to this problem fractions of M. ovipneumoniae were examined. Membrane preparations conserved the unique protein bands which in principle allow discrimination between strains, but because the number of protein bands was still excessive we examined surface proteins by labelling intact cells with Fluorescein isothiocyanate (FITC). This approach still gave gels with too many protein bands for convenient comparisons to be made, but had the advantage of allowing the identification of surface proteins, some of which were unique to individual isolates. This encouraged us to combine SDS-PAGE with a classic immunological approach to strain identification i.e. we investigated the possibility of excising protein bands from gels for subsequent use as immunising antigens. One common protein band was excised, it was found to be antigenic and the antisera crossreacted with a single line of identity in gel precipititin tests with all the strains tested. While within the time limit available we have examined only one common protein band, the result suggests that the excision of individual strain-specific protein bands from SDS-PAGE for use as immunising antigens will provide strain-specific antisera which should allow the development of a simple approach to strain identification.
  • Thumbnail Image
    Item
    Neuropathology of ovine ceroid-lipofuscinosis : a thesis presented in partial fulfilment (30%) of the requirements for the degree of Master of Philosophy in Veterinary Pathology at Massey University
    (Massey University, 1987) Shimada, Akinori
    The purposes of this study were to describe the neuropathology of ovine ceroid-lipofuscinosis, to compare findings with those of the related entities in humans and other domestic animals, and to provide morphological information that might help elucidate the pathogenesis of these diseases. An established flock of South Hampshire sheep carrying the ceroid-lipofuscinosis gene have made it possible to perform a longitudinal study on the central nervous system of affected sheep of various ages including foetuses. The most striking gross pathological change of affected sheep was brain atropy. At terminal disease, the brain weights of affected sheep were 55% of those of normal sheep. Atrophy affected mainly the cerebrum. Sudan black and luxol fast blue positive autofluorescent neuronal pigment granules were detected by lightmicroscopy as early as the mid stage of foetal development, the earliest stage examined. Postnatally there were topographical differences in the quantity of accumulated lipopigments in neurones of various areas. Similarly, there were age related topographical differences in secondary degenerative changes. Neuronal loss was most severe in the parietal lobe cortex showing an initial laminar distribution. This pattern was well demonstrated by a concomitant astrocytosis. In addition to the complex electron dense cytosomes similar to those reported in the human syndromes, there were less complex cytosomes of smaller size in affected foetal brains. The latter were clearly bounded by a trilaminar membrane and contained whorls or loose stacks of trilaminar membranes resembling those of the limiting membranes. In some electronmicrographs there was a suggestion of continuity between the surrounding membrane and the internal membranes, but this was not definitely demonstrated. This is provisionally interpreted as being due to an internalization of surrounding limiting membrane rather than a recycling of membrane. Some of these small cytosomes also showed complex multilamellar profiles similar to those of large complex cytosomes. These latter appeared to be formed by coalescence of smaller complex ones. There thus appeared to be a sequence of changes in the development of storage cytosomes. This study revealed that the ovine disease has not only many neuropathological findings in common with analogous human diseases, but also some pathological features which have not been reported in affected humans or animals. Ovine ceroid-lipofuscinosis is thus a useful animal model for the study of the human ceroid-lipofuscinoses.
  • Thumbnail Image
    Item
    Investigation into the inheritance and biochemistry of chondrodysplasia in Texel sheep : a thesis presented in partial fulfilment of the requirements for the Master of Science at Massey University, Palmerston North, New Zealand
    (Massey University, 2005) Byrne, Timothy John
    A skeletal chondrodysplasia characterized by dwarfism and angular deformity of the forelimbs has been recognized over four seasons in Texel and Texel cross lambs on three related properties. Some affected lambs have normal co-twins indicating that the disease is not dietary, but likely to be the result of a genetic disorder. This study reports on the inheritance and biochemistry of this newly discovered chondrodysplasia in Texel sheep. The outcome of a backcross trial between putative carrier ewes and affected rams provided evidence that indicated that the chondrodysplasia has an autosomal recessive mode of inheritance, and that it is likely to be caused by a single gene defect. Analysis of proteoglycan constituents of cartilage by SDS-PAGE, followed by sulfate-specific staining indicated that the biochemical abnormality lies in the level of sulfation of proteoglycans in the extracellular matrix of affected animals. It was also shown by SDS-PAGE that there were no differences in the major collagen constituents of cartilage between unaffected and affected animals. A candidate gene, the diastrophic dysplasia sulfate transporter, was determined based on its involvement in the process of sulfation of proteoglycans and its involvement in characterized human dysplasias, which resemble Texel chondrodysplasia both phenotypically and biochemically. PCR amplification and sequencing of 85.4 % of this gene revealed no nucleotide differences between the exonic DNA of normal, carrier, and affected animals. While this reduced the likelihood that this gene is causative in the chondrodysplasia, it does not eliminate it as a candidate, based on the fact that a mutation may exist in the region not sequenced, including the possibility of splice site mutations.
  • Thumbnail Image
    Item
    The serological and cultural prevalence in sheep of leptospiral infection in the North Island of New Zealand : a thesis presented in partial fulfilment (30%) of the requirements for the degree of Master of Philosophy in Veterinary Pathology and Public Health at Massey University, New Zealand
    (Massey University, 1981) Bahaman, Abdul Rani
    A survey of sheep from the North Island of New Zealand was conducted for leptospiral infection. The results of the serological examination showed 20.5 percent of the sheep had titres ( ≥1:48) to Hebdomadis serogroup, 3.8 percent to serovar pomona, 2.6 percent to serovar tarassovi, 2.3 percent to serovar copenhageni and 2.7 percent to serovar ballum. No titres of 1:48 or greater were detected to serovar australis. It was shown that a minimum dilution of 1:24 resulted in many non-specific or cross-reaction. A minimum dilution of 1:48 was more accurate for detecting the serological prevalence of agglutinins to leptospires in ovine sera. In the cultural survey, serovar hardjo was isolated from three animals in one group of sheep. It was considered that the Hebdomadis titres were more likely to represent previous infection with hardjo than with balcanica. Based on the serological and cultural examinations from the general survey and a study farm, a pattern of infection was recorded. The serological prevalence and the geometric mean titre (GMT) of different age groups of sheep from different farms and the lack of success on obtaining further isolates of hardjo indicated that sheep are not the maintenance host for this serovar in New Zealand. Although infection of sheep by serovar hardjo is not uncommon, it is a sporadic occurrence and endemic infection is unlikely to occur. Preliminary investigations on the use of radioimmunoassay in detecting leptospires or leptospiral antigens in urine are presented.
  • Thumbnail Image
    Item
    The pathology of kidney diseases in sheep : a thesis presented in partial fulfilment (30 %) of the requirements for the degree of Master of Philosophy in Veterinary Pathology at Massey University
    (Massey University, 1981) Tournazos, Pavlos Georgiou
    Renal diseases in sheep form a diverse spectrum of pathology and an extensive literature review of spontaneously occurring and experimentally induced diseases of the sheep kidney is presented in Chapter 1 of this thesis to provide a comparison with the lesions found in a survey of kidneys in slaughter-house killed sheep. The presentation of results of this survey form the major part of this thesis and provides information on these diseases relative to large populations of sheep which is only sparsely reported elsewhere. The abnormal kidneys under study were obtained from 444 of 13,988 sheep slaughtered over a consecutive five day period at the Borthwick's freezing works, Longburn in January 1980. The prevalence of renal disease was 3.18 per cent and no significant variation (p<0.05) in the prevalence of lesions was found between the various lines, chains and daily totals of sheep examined. From these sheep a total of 830 diseased kidneys were found and these were categorized into seven groups according to the major pathological lesion in each. In some kidneys additional minor lesions were present, making a total of 1212 macroscopic lesions identified. White spots and streaks constituted the major gross pathological finding in 188 kidneys; pale, red and brown discolouration in 174, 120 and 179 respectively; scars in 107; cysts in 37 and nodules in 25 kidneys. Abscesses, neoplasms and focal space occupying lesions of uncertain aetiology were included under the category of nodule. Pieces of tissue selected from 181 kidneys to represent the various lesions seen at gross examination were examined histologically. These were identified, recorded and graded according to the anatomical location, pattern of distribution, tissue changes and degree of severity. The main histopathological feature of the white spotted kidneys was chronic, mainly multifocal inflammation of the cortical interstitium. Similar but radially disposed inflammatory lesions with marked fibrosis occurred in the scarred kidneys. The pattern of these lesions suggested a haematogenous distribution of a pathogen in the spotted kidneys while the scarred kidneys were probably the result of ascending inflammation or infarctive processes. Kidneys with pale discolouration showed mild to moderately severe nephrosis of the cortical epithelial cells;, while kidneys with brown discolouration showed corticotubular intracytoplasmic and intralumenal haemosiderin deposition. In some kidneys haemosiderosis was restricted to areas of scarring. Red discoloured kidneys showed patchy or diffuse congestion. Cystic lesions were either parasitic or the result of urinary retention caused by blockage of tubules. In the latter, the blockage was either congenital or associated with chronic inflammation. With the exception of nephrosis and congestion all the lesions were chronic in nature and for most of them a definitive aetiological diagnosis was not established. In fact, in only those lesions containing Echinococcus granulosus hydatid cysts could such a diagnosis be made. Additional studies are indicated for the provision of further information on (a) the prevalence of renal diseases in. different geographical locations, (b) variation of disease types from area to area and (c) the causes of the lesions identified from this type of investigation.
  • Thumbnail Image
    Item
    Ovine ceroid-lipofuscinosis : a thesis presented in partial fulfilment (70%) of the requirements for the degree of Master of Veterinary Science at Massey University
    (Massey University, 1979) Janmaat, Antonie
    Ovine ceroid-lipofuscinosis is a rare inherited neurological disease which has only been diagnosed in one family of the South Hampshire breed of sheep. This breed is of relative recent origin and was established from an initial cross between Southdown and Hampshire Down sheep. Affected sheep show loss of vision and behavioural abnormalities starting at 11-12 months of age, with motor dysfunction commencing soon afterwards. The clinical signs increase in severity as the disease progresses and under field conditions affected animals are not expected to live beyond 2 years. Ovine ceroid-lipofuscinosis is characterized histologically by the intracytoplasmic accumulation of PAS and Sudan black positive autofluorescent lipopigment material in neurons and a wide variety of other cell types. The process leading to the accumulation of lipopigment seems only to damage neurons and there is degeneration and loss of neurons, especially in the cerebral cortex and the visual neuroepithelium of the retina i.e. retinal atrophy. Grossly, affected brains show reduction in size and weigh on average 66% of those of normal sheep. Ultrastructurally, the typical lipopigment inclusion is a round or oval body 0.2 - 5.0 μm in size, of varying electron density, in which a wide variety of membranous profiles may be seen. Some of the membranous patterns have received special names such as curvilinear, fingerprint and crystalloid. Pathological examination of liver, skin and rectal biopsy material of lambs at 4 - 5 months of age shows the presence of accumulated lipopigment, and is a means of early diagnosis before the onset of clinical signs. This observation and the fact that lipopigment has been demonstrated in affected lambs at birth, show ovine ceroid-lipofuscinosis to be associated with a true inborn error of metabolism. The family tree of all affected sheep and the results of sire-daughter matings of a heterozygous ram show the disease to be inherited as a simple autosomal recessive trait. The deleterious gene for ovine ceroid-lipofuscinosis is unlikely to be of economic importance to the sheep industry as the South Hampshire breed was developed to supply sires for terminal crosses associated with table lamb production. The objects of this study were to define ovine ceroid-lipofuscinosis in clinical, pathological and genetic terms, and to compare it with similar diseases in man and domestic animals. It is concluded that the ovine disease does indeed belong to the heterogeneous group of diseases of man and domestic animals known as Batten's disease or the neuronal or generalised ceroid-lipofuscinoses. Of these the ovine entity most closely resembles the late infantile and the juvenile forms of the human syndrome, and the canine disease. It is proposed that ovine ceroid-lipofuscinosis would make a useful experimental model for Batten's disease.
  • Thumbnail Image
    Item
    Colonisation of the ovine respiratory tract by Pasteurella (Mannheimia) haemolytica : a thesis presented in partial fulfilment of the requirements for the degree of Master of Veterinary Studies at Massey University
    (Massey University, 2003) Ahmed, Muftikhar
    Pasteurella (Mannheimia) haemolytica is a member of the normal bacterial flora of the nasopharyngeal, tonsillar and oral mucous membranes of sheep. The history, characteristics and pathogenicity of this organism are reviewed and the associated diseases of the ovine respiratory tract are discussed. In New Zealand, P. haemolytica is associated with two major disease entities; acute pneumonic pasteurellosis and chronic non-progressive pneumonia (CNP). Clinical or acute pneumonic pasteurellosis occurs as a sporadic disease with low prevalence on certain farms whereas CNP is very widespread and economically important as it causes poor growth rates and downgrading of carcasses during slaughter. The epidemiological relationship between the nasal carriage of P. haemolytica in healthy ewes and their lambs was investigated and it was found that although lambs occasionally became infected from their dams they were more commonly infected from other sources. A very significant difference between the rate of nasal carriage on four farms in the Manawatu district was observed and a peak prevalence of P. haemolytica was seen in the February-March period. A close relationship between nasal carriage and pneumonia was found on one farm (Farm 4), which initially had a pure and vigorous growth of P. haemolytica from the nasal swabs obtained from young lambs. When 6 lambs were kept in close contact for a period on one farm, all developed a high rate of nasal carriage of P. haemolytica within 5 days. DNA fingerprinting of the isolates from ewes and their offspring showed a variety of restriction endonuclease patterns using pulsed field gel electrophoresis (PFGE). The pulsed field profiles of isolates from the nasal cavity of ewes and their new-born lambs showed that lambs are more likely to obtain the first strain of P. haemolytica from in-contact ewes, lambs or the environment rather than from their mothers. The pattern of isolation of P. haemolytica in lambs on three farms without pneumonia showed that most strains of the organism were present on only one occasion and within two months the nasal cavity was occupied by other strains. On one farm (Farm 4), some strains of P. haemolytica were present throughout the whole life of the lambs and one these strains was later isolated from pneumonic lesions at slaughter.
  • Thumbnail Image
    Item
    The retinal pathology of ovine ceroid-lipofuscinosis : a thesis presented in fulfilment of the requirement for the degree of Master of Veterinary Science at Massey University
    (Massey University, 1984) Graydon, Russell John
    Ovine ceriod-lipofuscinosis is an animal model of a rare genetic disease of man and some domestic animals. The disease is characterized by blindness idiocy and premature death. In order to investigate the development of pathological changes in this model it was important to be able to accurately diagnose those sheep affected at an early age before clinical disease was apparent. In this thesis a number of methods such as skin biopsy, bone marrow examination and brain biopsy were investigated and it was concluded that brain biopsy was the most suitable and reliable method for establishing the preclinical diagnosis of ceroid-lipofuscinosis. On clinical grounds the ovine disease most closely resembled the juvenile form of human disease and blindness was the important clinical finding in both diseases. A time course study of the development of retinal pathology was carried out. Electroretinography was used as a clinical tool to ascertain the functional status of the retina. Pathological changes to the retina were investigated using light and electron microscopy. Electroretinography revealed a decline in rod and cone 'b' wave amplitudes over a relatively short time span. Changes to the rod responses preceeded, and were generally more dramatic than those of the cones. These changes paralleled a loss of rod and cone photoreceptor cells. Although there was some variation between animals and between readings it was suggested that electroretinography was a useful method of monitoring changes to the retina and may be useful in assessing therapeutic strategies. In affected retinas photoreceptor cell outer segments appeared to be shorter than those of controls. By 84 weeks of age the outer nuclear layer was reduced to a single row of nuclei with only remnants of outer segments present. Electron microscopy confirmed these findings and showed that the formation of abnormal dystrophic outer segments of photoreceptor cells was a significant early pathological change. Most cell types in the retina contained autofluorescent lipopigment bodies in their cytoplasm with the ganglion cells usually containing the largest amount. Ultrastructural studies showed that the storage bodies were made up of electron dense granular material and a variety of membranous and tubular structures giving them a similar appearance to those which were reported in the central nervous system. Very small electron dense 'smudges' were seen in the cytoplasm of some cells and these may have been early storage body precursors. This study showed that electroretinography could be used to monitor the development of blindness in ovine ceroid-lipofuscinosis. It also revealed early severe pathological changes to the photoreceptor outer segments which may be of pathogenic significance in ovine and juvenile human ceroid-lipofuscinosis and therefore worthy of further investigation.