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Factors influencing the effectiveness of the Gudair vaccine for controlling Johne's disease in sheep flocks in Australia
- Source :
- Preventive veterinary medicine. 193
- Publication Year :
- 2021
-
Abstract
- Ovine Johne's disease is a chronic debilitating disease of sheep caused by Mycobacterium avium subsp. paratuberculosis (Mptb) which results in diarrhoea, emaciation and mortalities in infected animals. Vaccination with Gudair® has been a key strategy for controlling the disease in Australia since its approval in 2002. Previous research conducted in Australia has demonstrated that the vaccine is quite effective in reducing sheep mortalities. While some farms have also been successful in reducing the prevalence of the disease in their flocks to undetectable levels, sheep in other flocks continue to shed Mptb in faeces even after an ongoing vaccination program . This study was conducted to investigate management, husbandry and biosecurity factors associated with paratuberculosis infection in Gudair® vaccinated sheep flocks in Australia. We enrolled 64 sheep farmers and interviewed them to obtain information about their management and biosecurity practices. Pooled faecal samples were collected from sheep at each farm and cultured to create two outcome variables: Mptb positive (yes/no) and disease prevalence level (nil, < 1 %, ≥ 1 %). Binary and ordinal logistic regression analyses were conducted to evaluate the association of management, husbandry and biosecurity factors with these outcome variables. Farms were more likely to have Mptb positive sheep and a higher disease prevalence in their flocks if they: (a) provided supplementary feed on the ground (instead of in a trough); (b) had a greater number of neighbours with sheep; and (c) had introduced rams from a greater number of sources. The results suggest the effectiveness of Gudair® vaccination to control OJD can be improved if sheep producers maintain other risk management strategies and biosecurity practices. Extension agencies should advise farmers not to relax their biosecurity practices and to purchase rams from only low-risk sources, even if they are continuing to vaccinate their flocks.
- Subjects :
- Male
Veterinary medicine
040301 veterinary sciences
030231 tropical medicine
Biosecurity
Prevalence
Paratuberculosis
Sheep Diseases
Biology
0403 veterinary science
03 medical and health sciences
0302 clinical medicine
Food Animals
medicine
Animals
Feces
Sheep
Australia
04 agricultural and veterinary sciences
Animal husbandry
medicine.disease
Vaccination
Mycobacterium avium subsp. paratuberculosis
Bacterial Vaccines
Animal Science and Zoology
Flock
medicine.symptom
Emaciation
Subjects
Details
- ISSN :
- 18731716
- Volume :
- 193
- Database :
- OpenAIRE
- Journal :
- Preventive veterinary medicine
- Accession number :
- edsair.doi.dedup.....2ced4c3240de8ffe77e914c92e8b55c4