Please use this identifier to cite or link to this item:
|Title: ||Field evaluation of the tracer weaner model : early detection of sheep with Mycobacterium avium subsp. paratuberculosis.|
|Authors: ||NSW Agriculture. Elizabeth Macarthur Agricultural Institute|
|Keywords: ||Ovine Johne’s Disease|
|Issue Date: ||Nov-2002|
|Publisher: ||Meat and Livestock Australia Ltd|
|Citation: ||North Sydney, NSW|
|Series/Report no.: ||OJD.14|
|Abstract: ||Experiments were conducted on two separate farms in the endemic area for OJD to determine whether
tracer animals could be used to detect infective levels of S strain M. a. paratuberculosis on pasture.
Culture from tissues was shown to be the most sensitive method for the detection of early infection in
sheep after natural exposure to S strain M. a. paratuberculosis. The organism was detected in at least
one naive introduced sheep from every potentially exposed group, 6 to 12 months post-exposure.
Antemortem diagnostic tests (skin testing, IFN-γ and faecal culture) were shown to have low sensitivity at
this early stage of naturally acquired disease. The prevalence of infection early after exposure was similar
in sheep first exposed as neonates, as weaners or as adults. Lambs born from an infected flock became
tissue culture-positive sooner than naive lambs suckling uninfected ewes introduced to the same infected
environment. These findings suggested that groups of naive sheep, used as tracer animals and tested by
tissue culture at slaughter after 6 months exposure, might be useful to assess pasture infectivity in
disease control programs.|
|Description: ||This work has been digitally archived on behalf of Meat & Livestock Australia Limited by the Sydney eScholarship Repository at the University of Sydney Library.|
|Rights and Permissions: ||Copyright Meat & Livestock Australia Limited|
|Type of Work: ||Technical Report|
|Appears in Collections:||Ovine Johne’s Disease Research & Development Program|
This work is protected by Copyright. All rights reserved. Access to this work is provided for the purposes of personal research and study. Except where permitted under the Copyright Act 1968, this work must not be copied or communicated to others without the express permission of the copyright owner. Use the persistent URI in this record to enable others to access this work.
|OJD.014 Final report.pdf||254.21 kB||Adobe PDF|
Items in Sydney eScholarship Repository are protected by copyright, with all rights reserved, unless otherwise indicated.