A new phase in the control of BVDV in the Netherlands
- an update on the progress -
Linda Van Duijn1, Inge Santman-Berends1, Jet Mars1, Frederik Waldeck1, Paul Wever1, Gerdien Van Schaik1,2
1GD Animal Health, 2Utrecht University
11. Stendaler Symposium ‒ 04. April 2019, Stendal, Germany
© GD Animal Health
• # Cattle and herds in the Netherlands
• History of BVDV control in the Netherlands
• Voluntary BVDV-free programme (1998-2018)
• Prevalence of BVDV
• The national eradication programme
• Results of the first half year
A new phase in the control of BVDV in
the Netherlands
Cattle density in Europe
Dairy herds:
• 16.000 herds
• 2.5 million animals
Non-dairy herds:
• 17.500 herds (mainly small scale)
Cattle Numbers 2018
• 1995: 84% of herds are antibody positive in bulk milk and 50% of adult cattle is seropositive.
• 1998: start of the voluntary BVDV-free programme.
• 2005: start of the BVDV bulk milk programme.
• 2018: start of the national eradication programme in dairy herds.
History of BVDV control in the
Netherlands
Voluntary BVDV-free program (1998-2018)
Programme in detail
INTAKE MONITORING
(follow-up of unfavourable spot test results)
Programme in detail: INTAKE
Programme in detail: MONITORING
(follow-up of unfavourable spot test results)
• BVDV-free programme: 54% of herds.
• BVDV-free programme intake: 9% of herds.
• BVDV- bulk milk programme: 11% of herds.
• No BVDV programme: 26% of herds.
BVDV situation in dairy herds at the
start of the programme (1 July 2018)
BVD prevalence in the Netherlands
0 5 10 15 20 25 30 35
2007 2009 2011 2013 2015
% herds
Beef
Dairy
Herd prevalence in Dutch beef- and dairy herds 2007-2015 (young stock test: antibody test in 5 animals 8-12 months old)
20%
9%
National BVDV eradication programme in 2018
Differentiate green from red herds
Unknown herds
BVDV-free
herds
Because we had 54% BVDV-free herds at the start and 9% in the intake phase of the BVDV- free programme.
Why differentiate BVDV-free herds from
unknown herds?
Three routes for unknown herds to become BVDV-unsuspected herds
Unknown herds
Eartag testing all calves
Bulk milk testing 4 times /year
(antibodies)
Young stock testing
Because we started with a low prevalence in 2018 and we wanted farmers that where most likely uninfected to be able to slowly become BVDV-free at low costs.
Why routes to become BVDV unsuspected?
Three routes for unsuspected herds to become BVDV-free herds
Eartag testing all calves
Young stock testing
Favourable
outcome
If all test results of the herd are favourable for 2- 3 years, depending on the route the herd is in, the herd becomes BVDV-free.
How do unsuspected herds become BVDV-
free?
Unfavourable outcome in unsuspected herds
Eartag testing all calves
Young stock testing
Unfavourable
outcome
BVDV-free herds with suspected new infection:
positive eartag, positive bulk milk test or positive young stock test.
% detected BVDV-positive animals
First Quarter 2018 0.49
Second Quarter 2018 0.66
Third Quarter 2018 0.67
Percentage BVDV positive animals in 2018
(serum + ear tags)
© GD Animal Health
Age of BVD-viruspositive animals in previously BVDV-free and BVDV- unsuspected herds
a b
70%
(< 3 months)+25%
(< 1 year)Most of these animals in newly infected herds are found with the young stock testing.
Some are found because of a virus
positive ear tag and some because the bulk milk tested positive for antibodies.
Age of BVD-viruspositive animals in previously BVDV-free and BVDV- unsuspected herds
a b
2018
# BVDV positive animals detected in
eartags 117
# BVDV positives with mother cow in
same herd 113
# of mother cows tested for virus after
result calve 46
% of mother cows tested for virus after
result calve 40,7%
Result of tested mother cows 42x neg
4x pos
% of tested mother cows with virus positive test result
8,7%
95% Confidence interval 2-21%
Mother cows of BVDV positive calves
compulsary tested in the ear tag programme
Before 1 July 2018: all cattle purchased from Non-free herds are tested for BVD-virus, only when tested negative the free status is regained.
After 1 july 2018: all cattle from non-free herds are tested.
• All animals are tested for antigen and only if no BVD-virus is detected the BVDV free status is regained.
• Female animals (possible Trojans cows) > 1 year are also
tested for antibodies and if tested positive the herds does not regain the BVDV-free status untill the calf of this cow has a BVD-virus negative test result and we know it is not a Trojan calf.
Purchase of cattle
2018
Cows tested for antibodies 14,327
Cows antibodies detected 4,068
Cows with antibodies that gave birth to a calf 938 Calves with available testresult 277
Calves tested BVDV positive 9 (3.3%)
Results of calves born from purchased cows
• We have started our eradication programme (after 20 years of a voluntary programme).
• We have started with a relatively low national BVDV prevalence (9% in dairy) and more than 50% of BVDV-free herds.
• Therefore we designed different routes for unknown herds to become BVDV-free.
• This meant different routes to chose from for the farmer and economical options to become BVDV-free over time.
• We have some first results but with only a few months in the programme it is to early for conclusions on these results and
Conclusions
Eradication of BVDV in the Netherlands
Thank you for your
attention!
Questions?
l.v.duijn@gdanimalhealth.com gdanimalhealth.com
