Proceedings of the 10th International Colloquium on Paratuberculosis

#79 Vaccination for Paratuberculosis in New Zealand farmed deer herds
Peter Raymond Wilson, Lesley Stringer, Cord Heuer, Kathy Goodwin-Ray, Jaimie Hunnam, Colin Mackintosh,
IVABS Massey University, Palmerston North, New Zealand; AgResearch Invermay, Mosgiel, New Zealand
Aim: To evaluate Silirum ® in farmed deer.
Method: Initial studies demonstrated 0.5, 1.0 and 2.0ml doses to three-month-old farmed red and red x
wapiti deer (C. elaphus) were clinically safe, produced equivalent antibody and cellular immune responses,
and caused few significant injection site lesions. Subsequently, six commercial deer farms previously reporting
≥5% annual incidence <strong>of</strong> clinical disease in young deer were selected for investigation <strong>of</strong> efficacy and crossreactivity
with bovine tuberculosis tests.
In March-April 2008, 180 - 1120 deer/farm were randomised to vaccination (0.5ml Silirum ® , n=1671) and
control (n=1664) groups at 3.5 – 4.5 months <strong>of</strong> age, and managed toge<strong>the</strong>r on pasture. Clinical disease, mortality,
weight and slaughter data were collected, and 25 vaccinated and control deer per farm faecal sampled
for Map culture in November 2008. In January 2009, 180 vaccinated and 181 control deer from three farms underwent
a comparative mid-cervical test (CCT) for bovine tuberculosis, also interpreted as a single mid-cervical
test (MCT).
Results: By May 2009 when 95% <strong>of</strong> deer had been slaughtered, disease had been diagnosed in nine
vaccinated and 22 control deer on four farms, a tentative overall efficacy <strong>of</strong> 59% against clinical disease
(p=0.02). Some injection site residual lesions were evident but did not affect carcass processing or value. Fifty
nine (47%) vaccinates and 68 (55%) controls were faecal culture positive (p=0.2). Tuberculosis testing yielded
44% vaccinates and 23% controls MCT positive, respectively, and correspondingly, two and three were CCT
positive. Two controls remained positive to an ancillary Elisa test. Final data will be presented.
Conclusion: Despite <strong>the</strong> low incidence <strong>of</strong> clinical Ptb, <strong>the</strong>se data suggest that Silirum ® may aid control <strong>of</strong>
clinical disease in young farmed deer. Fur<strong>the</strong>r data are now needed to better quantify efficacy. Tuberculin testing
suggests that <strong>the</strong> risk <strong>of</strong> indistinguishable cross-reactivity is low in herds without tuberculosis.
#83 Prevalence reducing factors in <strong>the</strong> Danish control programme on bovine paratuberculosis
Søren Saxmose Nielsen, University <strong>of</strong> Copenhagen, Denmark
A risk-based control programme on paratuberculosis in Danish dairy cattle was initiated in 2006. In total, 1265
herds (~28% <strong>of</strong> all dairy herds and ~40% <strong>of</strong> all dairy cows) were enrolled in <strong>the</strong> programme by April 2009.
Cows are categorised as High-Risk or Low-Risk animals based on 3-4 annual milk antibody ELISA tests. High-
Risk animals require management practices reducing calves exposure to milk and faeces from <strong>the</strong>se cows.
Moreover, repeated test-positive cows are recommended to be slaughtered prior to next calving.
The objective <strong>of</strong> this study was to assess <strong>the</strong> development in within-herd test-prevalences for different
management practices.
A questionnaire on management practices was distributed to all participating herds in January 2009. A
total <strong>of</strong> 1075 (85%) herd-managers returned <strong>the</strong> questionnaire. Only <strong>the</strong> 679 herds that started in 2006 were
included in <strong>the</strong> present analyses, because <strong>the</strong> effect <strong>of</strong> changes in management on prevalence would be expected
at <strong>the</strong> earliest after 2 to 3 years.
Results <strong>of</strong> univariable analyses showed that: a) culling <strong>of</strong> repeated test-positive cows reduced <strong>the</strong> testprevalence
by 7%-points; b) cleaning <strong>of</strong> calving area subsequent to High-Risk cows’ calvings led to a reduction
<strong>of</strong> 3%-points; c) separation <strong>of</strong> High-Risk animals from Low-Risk animals resulted in a reduction <strong>of</strong> 2%-points;
and d) use <strong>of</strong> colostrum from Low-Risk animals only, resulted in a reduction <strong>of</strong> 1.5%-points. Feeding practices
using milk from High-Risk cows did not reduce <strong>the</strong> prevalence.
The control programme has been running for ~3 years in <strong>the</strong> herds included, and it is assumed that <strong>the</strong>
full effect will only be observed after 4-8 years. However, already after 3 years, reduced prevalences were observed
due to changes in specific management practices. The reductions are not additive due to possible confounding,
which could not be assessed at this point in time because <strong>of</strong> <strong>the</strong> distribution <strong>of</strong> management factors.
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