Formal BVD Control Programmes in Britain: A Brief History
G. Caldow, Scottish Agricultural Colleges
Veterinary Services Group: george.caldow@sac.co.uk
G. Gunn, Scottish Agricultural Colleges Veterinary
Epidemiology Unit: george.gunn@sac.ac.uk
In 1986, Roeder and Harkness1 set out the principle of
BVD control. This was the prevention of infection of naive breeding
stock with BVD virus. Vaccination was suggested as a major tool to
achieve this, but it was also recognised that the detection and
removal of persistently viraemic animals was of paramount importance.
This article stimulated many veterinarians working in veterinary
diagnosis and farm animal practice to carry out eradication of BVD
infection from individual herds throughout the country. This was of
course before BVD vaccines were available, and the test for detection
of the virus was based on virus culture and demonstration of the virus
using the immunoperoxidase staining method. Despite local success, no
national effort was made in the UK at that time.
In 1993, BVD eradication commenced in Scandinavia. The programmes
relied upon the ability to distinguish infected herds from noninfected
herds using bulk-tank antibody testing and spot tests.2
Herds that were free from infection were monitored to demonstrate
continuing freedom and certified as being free from infection. Herds
that were infected were screened and virus carriers removed. Key to
progress was creating a positive attitude to biosecurity in the
farming community.3
In 1994, veterinary practitioners in Shetland were of the view that
the low cattle density on the islands would favour BVD eradication.
They set up a programme with funding from the Shetland Enterprise
Company and Shetland Islands Council. Scottish Agricultural College
(SAC) Veterinary Services and the Moredun Research Institute provided
laboratory diagnosis and consultancy for the project. In the course of
1995 to 1997, a total of 213 herds with 6150 animals were screened,
and 41 persistently infected (PI) animals were detected in 23 herds.4
The project was not pursued as it was considered, prematurely, that
the infection had been eradicated. Evidence of infection was found
subsequently and breakdowns in biosecurity were identified. In I999,
the programme was restarted, and on this occasion, 17 herds with 4054
animals were screened and 22 PIs were detected. By 2002 there were 165
herds free from infection and five under veterinary supervision.
Animals imported to the islands were tested in the lairage on arrival
and quarantined for 14 days on arrival at the farm. In 2004, all herds
in Shetland have achieved negative results in the spot tests.
Bloxham Laboratories were successful in a bid to run the IBR and Leptospira
hardjo programmes of what was the MAFF Cattle Health Scheme in
1996, and announced BVD and paratuberculosis programmes. Scottish
Livestock Services also launched their BVD control programme in 1996.
In 1998, SAC put their Premium Cattle Health Scheme into competition
with the others, and were consultants and providers of laboratory
services to the fourth scheme called HI Health Level II, which covered
the highlands and islands of Scotland. Biobest now carries out the
work done by Bloxham Laboratories and SLS under the label of Herdcare.
In 2002, the Orkney BVD eradication project was initiated from
within HI Health. Orkney Islands Council supported this work
financially and SAC provided laboratory and consultancy services.
Whereas all the other programmes had been heavily influenced by the
Scandinavian approach, the Orkney programme relied on vaccination as
the major way in which to prevent new infections in naive breeding
stock, much as had been originally envisaged by Roeder and Harkness in
1986.1
The number of programmes and different scheme providers was
potentially messy. To prevent this becoming a problem, the Cattle
Health Certification Standards (CHeCS) was created in 1999. The
objective was to establish standards, to unify the programmes and to
ensure quality assurance was a cornerstone to the entire initiative.
The CHeCS programme was used by SAC and this had evolved from close
contact with the Swedish in particular, but also influenced by what
had been happening in Denmark and the Netherlands. The objectives of
the BVD programmes were to identify herds that were free from BVD
infection and to put in place a biosecurity system to maintain freedom
and a testing system to demonstrate continuing freedom. This supported
the concept of quality assurance for infectious disease status at the
point of sale. Programmes were also offered to allow herds to progress
from the infected state to the disease-free state.
The numbers of members of the schemes where SAC Veterinary Services
has a management of consultancy role are detailed in the table.
Overall level of involvement with the scheme has not been encouraging
except where there has been local financial support for the testing.
It is felt that in general the veterinary profession have not been
supportive of this approach to disease control and the fragmented
state of the UK cattle industry has made communication of the message
difficult. However, it is recognised that more could be done to
provide cost-benefit figures for BVD control for the industry. To
date, the most useful information has come from either modeling
exercises5 or individual outbreaks, but there is a clear
need for field data on the comparison between herds with endemic BVD
and those that have established freedom from infection.
In conclusion, there is sound methodology for controlling BVD and
for accrediting freedom from infection as has been shown in
Scandinavia, and now in Shetland and mainland Britain. Progress in
Britain will continue to be slow until such times as we can convince
the veterinary profession and the cattle industry of the cost benefits
that will accrue from BVD control.
BVD Programme Membership
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