SEAC Sheep subgroup statement
Defra is consulting stakeholders on four strategic options for the
future operation of the National Scrapie Plan (NSP). The SEAC sheep
subgroup’s views were sought as part of this consultation.
The subgroup concluded that the strategy of the NSP underlying breeding
for scrapie resistance remains appropriate. However, the basis for
the strategy should be kept under review in the light of emerging
scientific findings with respect to the possible detection of scrapie
infections in animals of genotypes currently thought to be most resistant
The subgroup was of the view that those strategies that reduced the
prevalence of infection in the national flock most rapidly were the
most desirable. On this basis Option A was considered inadequate.
The subgroup considered that although Options A and B addressed scrapie
in VRQ sheep these would not reduce scrapie in ARQ sheep, which may
be more susceptible than assumed in the modelling, or the hypothetical
possibility of BSE in sheep, which appears to preferentially target
the ARQ allele. The subgroup considered a solution close to Option
D was the most scientifically desirable given the importance of reducing
the prevalence of scrapie and the potential risk of BSE.
The subgroup recognised there may be potential practical difficulties
and in some cases genetic constraints for the sheep industry as well
as cost issues associated with option D and therefore recommended
that an additional option, Option E (mandatory Option B combined with
voluntary Option D) be considered. This option, together with a further
option, Option F (Option E combined with voluntary ewe genotyping
and removal of VRQ ewes) were modelled. The subgroup considered the
outcome of the additional modelling work and agreed that Option D
remains the most scientifically desirable. Option F offered no significant
advantage over Option E. Members agreed that Option E, given high
voluntary take up, was also a scientifically valid strategic option
for the NSP.
SEAC sheep subgroup
13 October 2004
Options for the NSP
The EU minimum rules require the genotype testing of all rams intended
for breeding within flocks of ‘high genetic merit’ (Defra
are proposing to apply the definition of ‘high genetic merit’
to all pure-bred flocks which sell homebred rams for further breeding)
and the subsequent slaughter of those found to be carrying the VRQ
allele (compensation will be paid for animals slaughtered). It does
not require the genotype testing of rams sold for breeding elsewhere.
Consequently, the sale of untested (and hence possibly VRQ) rams for
further breeding is not prohibited. However, any untested rams purchased
for use within another flock of ‘high genetic merit’ would
need to be genotyped before being used for breeding and those carrying
the VRQ allele removed in line with the requirements of the EU legislation.
EU minimum plus additional genotyping of rams\shearlings\ram lambs
intended for sale and further breeding elsewhere.
In addition to the EU minimum requirements as described above at
Option A, this option would also provide for the genotype testing
in all flocks of ‘high genetic merit’ of rams\shearlings\ram
lambs intended for sale and further breeding irrespective of whether
they are to be used in other flocks of ‘high genetic merit’
or elsewhere further down the breeding pyramid e.g. in a commercial
fat\slaughter lamb producing flock.
EU Minimum plus additional ram testing as Option B and voluntary ewe
testing during the period 2005-2010 conditional on the removal of
ARQ/ARQ breeding rams in participating flocks from 2010.
As Option B above, with an additional voluntary ewe genotyping scheme\service
targeting female replacements conditional on the removal of ARQ/ARQ
breeding rams from participating flocks from 2010. The Option is currently
based on testing 200,000 female replacements across all sheep sectors
per year. This is an indicative figure based on possible field and
laboratory testing resource considerations (and may require fine tuning).
Compulsory NSP Ram Genotyping Scheme (RGS)
The current voluntary NSP’s RGS provides for the genotyping
of all existing stock rams and for the removal of those carrying the
VRQ allele. It also applies sale and on farm use restrictions for
Type 3 (ARQ\AHQ\ARH) rams (end 2005 and 2008 respectively for terminal
sire breeds and end 2007 and 2009 respectively for hill breeds). Additionally,
it also provides for annual progeny testing of males (and females
where there are fewer than 40 male animals available for testing i.e.
each testing visit will comprise 40 animals in total) intended for
further breeding. Under Option D, these arrangements would be made
compulsory for all flocks of ‘high genetic merit’.
Strategy B (implementation of the minimum requirements set down in
EU legislation (EU 2003) with the addition of sale restrictions on
VRQ-bearing rams for all flocks of high genetic merit from 2005) and
voluntary implementation of the current NSP purebred flock scheme.
Strategy E with the addition of ewe genotyping (and removal of VRQ-bearing
ewes) in those flocks participating in the voluntary NSP scheme.
Page last updated: 29 July 2005