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dc.contributor.authorLogan, Ernest Fergusen
dc.date.accessioned2018-01-31T11:47:12Z
dc.date.available2018-01-31T11:47:12Z
dc.date.issued1972en
dc.identifier.urihttp://hdl.handle.net/1842/28448
dc.description.abstracten
dc.description.abstractThe role of colostral whey and immunoglobulins in the aetiology and pathogenesis of colibacillosis in calves was investigated.en
dc.description.abstractNewborn colostrum deprived calves were given colostral whey intraperitoneally prior to challenge with a pathogenic E.coli serotype 078K80(B). Administration of whey above a certain level, calculated in terms of its immunoglobulin content, protected calves against septicaemia but failed to inhibit enteric disease as manifested by severe diarrhoea. In order to prevent colisepticaemia the effective protective dose (ED) 95/30 kg. body weight of the pool of whey used contained -26g. immunoglobulin M (IgM) and 1.5g. immunoglobulin G (IgG).en
dc.description.abstractPurified colostral IgM and IgG given separately to calves, at levels in excess of those found in the ED.95 of whey, both failed to prevent septicaemia. However, IgM significantly prolonged survival time (p < 0.016) and delayed the onset of septicaemia (p < 0.014) when compared with untreated control calves challenged with the same serotype.en
dc.description.abstractIn order to investigate the protective function of IgM further, a crude IgM-enriched preparation was isolated from pooled abattoir blood by euglobulin precipitation. This preparation, even in small doses again prolonged survival time (p < 0-002) and delayed the onset of septicaemia (p < O.001) when given intraperitoneally to neonatal agammaglobulinaemic calves which were subsequently challenged with E.coli serotype 078K80(B). At higher doses, occasionally septicaemia was inhibited completely but this occurred sporadically. Like the whey, IgM similarly failed to influence, to any extent, enteric disease.en
dc.description.abstractTo prevent septicaemia consistently it was found necessary to administer the IgM fraction intravenously in two doses given at a four day interval. Serological and immunological examination of these calves' sera revealed that the levels of passively acquired IgM dropped rapidly within a few days and this drop was paralleled by a similar fall in specific antibody to the challenge E.coli serotype 078K80(B) as measured by indirect haemagglutination and antiglobulin tests.en
dc.description.abstractFrom these results, it was concluded that IgM was the immunoglobulin responsible for the protection of the calf against septicaemia. Moreover, since colostrum, under natural conditions protects the calf from septicaemia and enteric disease, it was postulated that colostral immunity was of a complex nature involving two separate systems (1) systemic - preventing septicaemia and (2) local - within the lumen of the small intestine, inhibiting enteric disease.en
dc.description.abstractThe local intestinal protective function of colostral whey was demonstrated in hypogammaglobulinaemic calves. Market calves, under one week old were divided into four groups, (1) control calves, (2) calves which were given an IgM rich fraction intravenously, (3) calves which were given an IgM rich fraction intravenously and colostral whey orally and (4) calves which were only given colostral whey orally. They were placed collectively in premises previously contaminated by calves with colibacillosis. All the control calves died, 5 with colisepticaemia, 2 with severe diarrhoea. The IgM fraction administered alone inhibited septicaemia in all cases, but not enteric disease. Calves given the IgM fraction and colostral whey orally had prolonged survival times (p < 0.02) over the other three groups and the onset of diarrhoea was significantly delayed (p < 0.007). Since in this study it was demonstrated that the colostral whey had not been absorbed from the small intestine, it is concluded that colostral whey in addition to providing systemic immunity has a local protective function within the gasgro-intestinal tract.en
dc.description.abstractFrom the proximal small intestine of calves which had severe diarrhoea, mucoid strains of E.coli were isolated in large numbers. Several of these isolates were shown to belong to enterotoxigenic strains as adjudged by their ability to dilate ligated rabbit intestinal loops. One of these serotypes O101K(A?) was administered orally to colostrum- deprived calves which had been protected systemically from septicaemia by the intravenous use of the IgM preparation. 13 calves so treated suffered from severe diarrhoea within 24 hours of infection and 11 died. None of the calves was bacteraemic but the challenge organism was isolated from the proximal small intestine of all those which died and from the faeces of the 2 survivors.en
dc.description.abstractIt was considered that this was an acute form of enteric colibacillosis. In the calves which died, there was very marked haemoconcentration, the packed cell volume increasing by as much as 50% of pre-challenge levels. It was postulated that the haemoconcentration may have resulted from the absorption from the small intestine of endotoxin. Immunological analysis of daily faeces samples demonstrated the presence of immunoglobulins of the IgG, IgM and IgA classes within 48 hours of infect ion.en
dc.description.abstractFrom the results of the complete study, it is concluded that colostral immunity to colibacillosis is of a complex nature involving two separate, independent systems, (1) systemic - mediated largely by IgM - preventing septicaemia and (2) locally within the gastrointestinal tract inhibiting diarrhoea. Moreover, for the survival of a calf in a contaminated environment, it is necessary that both systemic and local intestinal protection be present in adequate proportions.en
dc.publisherThe University of Edinburghen
dc.relation.ispartofAnnexe Thesis Digitisation Project 2017 Block 16en
dc.relation.isreferencedbyAlready catalogueden
dc.titleStudies on the immunity of the calf to colibacillosisen
dc.typeThesis or Dissertationen
dc.type.qualificationlevelen
dc.type.qualificationnamePhD Doctor of Philosophyen


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