Projects

PhD PROJECT - INFLUENCE OF FARM HYGIENE STANDARDS AND MANAGEMENT PRACTICES ON JOHNE'S DISEASE PROGRESSION IN SELECTED NORTHERN IRELAND DAIRY HERDS

Background

Johne's disease (Paratuberculosis) is present in dairy herds in Northern Ireland, as well as in many other countries worldwide. However the true herd prevalence is uncertain, and probably underestimated because currently used diagnostic tests lack MAP detection sensitivity. A new rapid, phage-based diagnostic test (PhMS-qPCR assay) for detecting and quantifying the viable causative agent, Mycobacterium avium subsp. paratuberculosis (MAP), has been developed at Queen's University Belfast, which is showing considerable promise as a MAP research and surveillance tool.During the proposed project, this new method will be used to test faeces, milk and farm environmental samples from selected dairy herds in NI as part of a longitudinal study (i.e. multiple sampling visits to each farm over duration of project), and the farm hygiene and management practices on each farm will be assessed in parallel. The aim will be to determine the effectiveness of changes in farm management in reducing the exposure of susceptible animals to the MAP organism and thereby reducing within herd infection prevalence and disease progression. The study will involve developing a farm hygiene standards questionnaire, testing of samples from cattle and farm environments, laboratory testing of milk, faeces, blood, and potentially modelling of results with disease progression.

PHD Student -Kayleigh Meek

Supervisors - Prof. Irene Grant, Prof. Niamh O'Connell (QUB) and Dr Sam Strain (Animal Health and Welfare Northern Ireland)

Timeframe: October 2020 - September 2023

Objectives

  • Evaluation of hygiene practices on selected MAP infected dairy farms (expressly milking hygiene and calving hygiene practices) and effect of possible changes in practices over time, completed through

- Information gathering - in-depth questionnaire about hygiene practices during milking and calving practices,and observation of practices also.

-Regular sample collection - bulk tank milk, milk/faeces from individual animals, environmental samples at key farm locations to monitor viable MAP prevalence and levels.

- vRAMP comparison (subject to express permission from farmers concerned) - qualitative and quantitative summary of info from these known MAP-infected farms so that common risky practices may be highlighted

  • Review and analysis of vRAMP information from first year of AHWNI Johne's disease control programme

  • Calf-to-calf transmission study, completed through:

- Provision ofmissing quantitative data on MAP shedding by calves (or pass through), maternity pen and calf pen hygiene (using E. coli levels as general hygiene indicator), and potential calf-to-calf transmission using the new PhMS-qPCR test and PMS-culture.

- Monitoring the efficacy of on-farm pasteurisation with respect to MAP inactivation (where carried out) for milk fed to calves and MAP testing of calf milk replacer using the PhMS-qPCR assay