Working Group Report on
the Assessment of the Geographical BSE-Risk (GBR) of
CANADA
2004
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2. EXTERNAL CHALLENGES
2.1 Import of cattle from BSE-Risk2 countries
An overview of the data on live cattle imports is presented in table 1 and is based on
data as provided in the country dossier (CD) and corresponding data on relevant exports
as available from BSE risk countries that exported to Canada. Only data from risk
periods are indicated, i.e. those periods when exports from a BSE risk country already
represented an external challenge, according to the SSC opinion on the GBR (SSC July
2000 and updated January 2002).
• According to the CD, 231 cattle were imported from UK during the years 1980 to
1990 and no cattle imports from UK were recorded after 1990.
• According to Eurostat, altogether 198 cattle have been imported from the UK during
the years 1980 to 1990, Additionally 500 were recorded in 1993; this import is
1 For the purpose of the GBR assessment the abbreviation "MBM" refers to rendering products, in particular
the commodities Meat and Bone Meal as such; Meat Meal; Bone Meal; and Greaves. With regard to imports
it refers to the customs code 230110 "flours, meals and pellets, made from meat or offal, not fit for human
2 BSE-Risk countries are all countries already assessed as GBR III or IV or with at least one confirmed
Annex to the EFSA Scientific Report (2004) 2, 1-14 on the Assessment of the
Geographical BSE Risk of Canada
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mentioned in Eurostat and the updated UK export statistic as male calves, but not
mentioned in the original UK export statistics. According to the CD, detailed
investigations were carried out and it is very unlikely that the 500 calves have been
imported. Therefore, they were not taken into account.
• According to the CD, in 1990 all cattle imported from UK and Ireland since 1982
were placed in a monitoring program.
• Following the occurrence of the BSE index case in 1993 (imported from UK in 1987
at the age of 6 months), an attempt was made to trace all other cattle imported from
UK between 1982 and 1990.
• Of the 231 cattle imported from the UK between 1980 and 1990, 108 animals had
been slaughtered and 9 had died. From the remaining, 37 were exported, 76 were
sent to incineration and one was buried; these were not entering the rendering system
and therefore not taken into account.
• According to the CD, 16 cattle were imported from Ireland (according to Eurostat
20), of which 9 were slaughtered, 3 died. The remaining 4 were incinerated and did
therefore not enter the rendering system. According to the CD, the 6 animals which
were imported in 1990 according to Eurostat, were never imported.
• Moreover 22 cattle have been imported from Japan (through USA), of which 4 were
exported (excluded from the table) and 14 were destroyed and therefore not entering
the rendering system, 4 were slaughtered.
• Of 28 imported bovines from Denmark, 1 was destroyed and 1 was exported. Of the
19 buffalos imported in 2000, 1 was incinerated and the others were ordered to be
destroyed.
• Additionally in total 264 cattle according to the CD (276 according to other sources)
were imported from Austria, France, Germany, Hungary, Italy, The Netherlands and
Switzerland.
• The numbers imported according to the CD and Eurostat are very similar. Some
discrepancies in the year of import can be explained by an extended quarantine;
therefore it is likely that imports according to Eurostat in 1980 and imports
according to the CD in 1981 are referring to the same animals.
• Additionally, between 16.000 and 340.000 bovines have annually been imported
from US, almost all are steers and heifers. In total, between 1981 and 2003,
according to the CD more than 2.3 million, according to other sources 1.5 million
cattle have been imported.
• According to the CD, feeder/slaughter cattle represent typically more than 90% of
the imported cattle from the USA; therefore, only 10% of the imported cattle have
been taken into account.
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Annex to the EFSA Scientific Report (2004) 2, 1-15 on the Assessment of the
Geographical BSE Risk of Canada
2.2 Import of MBM or MBM-containing feedstuffs from BSE-Risk
countries
An overview of the data on MBM imports is presented in table 2 and is based on data
provided in the country dossier (CD) and corresponding data on relevant exports as
available from BSE risk countries that exported to Canada. Only data from risk periods
are indicated, i.e. those periods when exports from a BSE risk country already
represented an external challenge, according to the SSC opinion on the GBR (SSC, July
2000 and updated January 2002).
According to the CD, no imports of MBM took place from UK since 1978 (initially
because of FMD regulations).
• According to Eurostat data, Canada imported 149 tons MBM from the UK in the
period of 1993 to 2001. According to up-dated MBM statistics from UK (August
2001) no mammalian MBM was exported to Canada from 1993 – 1996. As it was
illegal to export mammalian meat meal, bone meal and MBM from UK since
27/03/1996, exports indicated after that date should only have included nonmammalian
MBM. Therefore, these imports were not taken into account.
• According to the CD, imports of MBM have taken place from Denmark, Germany,
France, Japan and US.
• According to Eurostat Canada imported MBM from Denmark, Belgium, France and
Ireland.
• According to the CD further investigations concluded that all imported MBM from
Denmark consisted of pork and poultry origin and was directly imported for
aquaculture, the imported MBM from France was feather meal, the imported MBM
from Germany was poultry meal for aquaculture and the imported MBM from
Belgium was haemoglobin; therefore these imports were not taken into account.
• The main imports of MBM were of US origin, according to the CD around 250.000
tons, according to other sources around 310.000 tons between 1988 and 2003.
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2.3 Overall assessment of the external challenge
The level of the external challenge that has to be met by the BSE/cattle system is
estimated according to the guidance given by the SSC in its final opinion on the GBR of
July 2000 (as updated in January 2002).
Live cattle imports:
In total the country imported according to the CD more than 2.3 million, according to
other data 1.5 million live cattle from BSE risk countries, of which 231 (CD)
respectively 698 (other sources) came from the UK. The numbers shown in table 1 are
the raw import figures and are not reflecting the adjusted imports for the assessment of
the external challenge. Broken down to 5 year periods the resulting external challenge is
as given in table 3. This assessment takes into account the different aspects discussed
above that allow to assume that certain imported cattle did not enter the domestic
BSE/cattle system, i.e. were not rendered into feed. In the case of Canada, the 500 cattle
imported from UK according to Eurostat were not taken into account and it is assumed
that all incinerated, buried, exported animals and the animals still alive did not enter the
rendering system and were therefore excluded from the external challenge.
MBM imports:
In total the country imported according to the CD around 300.000 tons, according to
other sources nearly 360.000 tons of MBM from BSE risk countries, of which 149 tons
came from the UK. The majority consisted of MBM imported from the US. The
numbers shown in table 2 are the raw import figures and are not reflecting the adjusted
imports for the assessment of the external challenge. Broken down to 5 year periods the
resulting external challenge is as given in table 3. This assessment takes into account
the different aspects discussed above that allow to assume that certain imported MBM
did not enter the domestic BSE/cattle system or did not represent an external challenge
for other reasons. As it was illegal to export mammalian meat meal, bone meal and
MBM from UK since 27/03/1996, exports indicated after that date should only have
included non-mammalian MBM. In the case of Canada all imported MBM from UK,
Germany, Belgium, Denmark and France was not taken into account.
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3. STABILITY
3.1 Overall appreciation of the ability to avoid recycling of BSE
infectivity, should it enter processing
Feeding
The annual Canadian production of MBM is approximately 575,000 tons of which
approx. 40,000 tons are exported each year, mainly to USA.
Use of MBM in cattle feed
• Before the feed ban, dairy cattle received supplementary feed containing MBM
during their productive life (maximum 200-400 g MBM per day). Beef cattle in the
western part of the country do not usually receive complementary feed. Beef cattle
in the eastern part receive normally no supplement protein but the calves could have
access to creep feeds containing MBM, after weaning the ratios may have contained
supplemental protein containing MBM (100-400 g per day).
• According to the CD, MBM is mainly fed to pigs and poultry and included in pet
food.
• According to the CD, only a proportion of dairy cattle may have received MBM.
Feed bans
• Before 1997, there was no legal restriction to include MBM into cattle feed.
• An MBM-ban was introduced in August 1997; it is forbidden since to feed
mammalian MBM to ruminants except if of pure porcine, equine and non
mammalian origin, i.e. in practice a ruminant-to-ruminant ban (RMBM-ban).
Annex to the EFSA Scientific Report (2004) 2, 1-15 on the Assessment of the
Geographical BSE Risk of Canada
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Potential for cross-contamination and measures taken against
• Cross-contamination in the about 600 feed mills is assumed to be possible as long as
cattle and pig feed is produced in the same production lines, and premises.
• Cross-contamination during transport is possible, particularly if the same trucks are
used for transporting ruminant MBM (RMBM) and non-ruminant MBM (porcine or
poultry MBM which still might be included into cattle feed) or for transporting
pig/poultry feed and cattle feed.
• On-farm cross-contamination is regarded to be possible.
• Cross-contamination of cattle feed with RMBM can not be excluded. Hence, as
reasonable worst case scenario, it has to be assumed that cattle, in particular dairy
cattle, can still be exposed to RMBM and hence to BSE-infectivity, should it enter
the feed chain.
Control of Feed bans and cross-contamination
• With the introduction of the RMBM ban (1997) the feed mills (approximately 600)
were checked for compliance with the ban, including good manufacturing practices
(GMP) and record keeping, i.e. the separation in production of MBM containing
ruminant material (RMBM) from non-ruminant MBM.
• The feed mills had previously – since 1983 – been regularly checked in relation to
production of medicated feed.
• No examinations are performed to assess cross-contamination with RMBM of the
protein (e.g. non ruminant MBM) that enters cattle feed. Differentiation would
anyway be difficult.
Rendering
Raw material used for rendering
• Ruminant material is rendered together with material from other species, but
according to the CD only in the production of MBM prohibited for use in ruminant
feeds.
• Slaughter by-products, including specified risk material (SRM) and fallen stock are
rendered.
• The country expert estimated that 20% of the rendering plants, processing 20% of
the total amount of raw material, are connected to slaughterhouses. Their raw
material is more than 98 % animal waste from these slaughterhouses while less than
2 % is fallen stock. No estimation was given for the remaining 80% of the rendering
capacity.
• There are 32 rendering plants of which 3 are processing blood exclusively.
Rendering processes
• The rendering systems (parameters) were specified for 6 plants producing mixed
MBM, none of these fulfilled the 133/20/3 standard. Of these, 5 have dedicated
facilities to produce products for use in ruminant feed and products not permitted for
use in ruminant feed.
• The remaining plants process porcine or poultry material exclusively.
SRM and fallen stock
• There is an SRM ban for human food in place since 2003.
Annex to the EFSA Scientific Report (2004) 2, 1-15 on the Assessment of the
Geographical BSE Risk of Canada
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• However, SRM are rendered together with other slaughter waste and fallen stock.
However, according to the CD, MBM with SRM is not permitted to be fed to
ruminants.
Conclusion on the ability to avoid recycling
• Between 1980 and 1997 the Canadian system would not have been able to avoid
recycling of the BSE-agent to any measurable extent. If the BSE-agent was
introduced into the feed chain, it could have reached cattle.
• Since 1997 this ability gradually improved with the introduction of the ruminant
MBM ban and its implementation.
• Since cross-contamination cannot be excluded, and as SRM is still rendered by
processes unable to significantly reduce BSE-infectivity, the system is still unable to
avoid recycling of BSE-infectivity already present in the system or incoming.
3.2 Overall appreciation of the ability to identify BSE-cases and to
eliminate animals at risk of being infected before they are processed
Cattle population structure
• Cattle population: 12.15 Million in 1988 increasing to 14.6 Million in 2001;
• Of the total cattle population, 2.2 million are dairy cattle and 12.4 million are beef.
• The cattle population above 24 months of age: approx. 6.0 Million.
• Of the approximately 2.2 Million dairy cattle 2 Million are located in the two eastern
provinces Ontario and Quebec.
• Mixed farming (cattle and mono-gastric species) is usually not practiced; the
country expert estimated the proportion of mixed farming to be less than 1%.
• Individual regions traditionally have ID systems under provincial authorities. Brand
inspectors are present when cattle are assembled. It is estimated by the Canadians
that the level of a national, uniform ID for cattle is less than 10%; most of those
individual pedigree animals. Mandatory ID for the milk-fed veal sector was
implemented in Quebec in 1996, but does not contain information on the herd of
origin. An agreement of the relevant industries to develop a national cattle ID and
trace back strategy was reached on 1 May 1998 (starting in 2001).Since 2002, a
national identification program is existing. Al cattle leaving any farm premises must
be uniquely identified by ear tag.
BSE surveillance
• BSE was made notifiable in 1990.
• Every cow over one year of age exhibiting central nervous system signs suggestive
of BSE submitted to a laboratory or presented at an abattoir is subjected to a BSE
laboratory diagnostic test (histology and over the past years also PrPSc-based
laboratory tests).
• In addition, cattle submitted for rabies examination and found rabies negative are
examined for BSE. Samples are prepared immediately upon arrival to the federal
laboratory responsible for the rabies diagnostic for possible later BSE examination,
i.e. formalin fixation.
• Since the 1940's, a rabies control program has been in place, where farmers,
veterinarians and the general public are well educated about this neurological
Annex to the EFSA Scientific Report (2004) 2, 1-15 on the Assessment of the
Geographical BSE Risk of Canada
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disease. In 1990, when BSE was made notifiable, this awareness was extended to
suspicions of BSE.
• Since 1993 the number of brains examined per year did exceed the number
recommended by OIE (300 - 336 for countries with a cattle population over 24
months of age of 5.0 to 7.0 Million) in all years, except in 1995 (table 4).
year 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003
samples 225 645 426 269 454 759 940 895 1´020 1´581 3´377 3´361
Table 4: Number of bovine brains annually examined for CNS diseases, including BSE.
• According to the CD approx. 98% of the examined cattle were older than 24 months
and approx. 90% exhibited neurological symptoms. Although the identification
system of Canada does not document the birth date or age of the animals, according
to the CD, examination of the dentition is used to ascertain the maturity of the
animals.
• The list of neurological differential diagnoses for the 754 brains examined in 1997
included encephalitis (70 cases), encephalomalacia (19), hemophilus (7),
hemorrhage (2), listeriosis (38), meningoencephalitis (36), rabies (22), tumors (2),
other conditions (135) and no significant findings (423).
• Compensation is paid for suspect BSE cases as well as for animals ordered to be
destroyed (90-95% of market value with a maximum of 2,500 Can$ per cow).
• Diagnostic criteria developed in the United Kingdom are followed at ADRI,
Nepean. According to the very detailed protocol for the collection, fixation and
submission of Bovine Spongiform Encephalopathy (BSE) specimens at abattoirs
under inspection by the Canadian Food Inspection Agency, the specimen shall be
shipped to National Center for Foreign Animal Disease, Winnipeg, Manitoba.
• In 2003, around 3000 animals from risk populations have been tested.
• According to the CD, it is aimed to test a minimum of 8000 risk animals (animals
with clinical signs consistent with BSE, downer cows, animals died on farm animals
diseased or euthanized because of serious illness) in 2004 and then continue to
progressively increase the level of testing to 30,000.
• In May 2003, Canada reported its first case of domestic BSE. A second case was
detected in the US on 23 December 2003 and traced back to Canadian origin. Both
were born before the feed ban and originated from Western Canada.
3.3 Overall assessment of the stability
For the overall assessment of the stability, the impact of the three main stability factors
(i.e. feeding, rendering and SRM-removal) and of the additional stability factor,
surveillance, has to be estimated. Again, the guidance provided by the SSC in its
opinion on the GBR of July 2000 (as updated January 2002) is applied.
Feeding
Until 1997, it was legally possible to feed ruminant MBM to cattle and a certain fraction of
cattle feed (for calves and dairy cattle) is assumed to have contained MBM. Therefore
feeding was "Not OK". In August 1997 a ruminant MBM ban was introduced but feeding
of non-ruminant MBM to cattle remained legal as well as feeding of ruminant MBM to
non-ruminant animals. This makes control of the feed ban very difficult because laboratory
differentiation between ruminant and non ruminant MBM is difficult if not impossible.
Annex to the EFSA Scientific Report (2004) 2, 1-15 on the Assessment of the
Geographical BSE Risk of Canada
Due to the highly specialised production system in Canada, various mammalian MBM
streams can be separated. Such a feed ban would therefore be assessed as "reasonably
OK", for all regions where this highly specialised system exists. However, several areas
in Canada do have mixed farming and mixed feed mills, and in such regions, an RMBM
ban would not suffice. Additionally, official controls for cattle feeds to control for the
compliance with the ban were not started until the end of 2003. Thus, for the whole
country, the assessment of the feeding after 1997 remains "Not OK".
Rendering
The rendering industry is operating with processes that are not known to reduce infectivity.
It is therefore concluded that the rendering was and is "Not OK".
SRM-removal
SRM and fallen stock were and are rendered for feed. Therefore SRM-removal is assessed
as "Not OK"
snip...
4.2 Risk that BSE infectivity entered processing
A certain risk that BSE-infected cattle entered processing in Canada, and were at least
partly rendered for feed, occurred in the early 1990s when cattle imported from UK in
the mid 80s could have been slaughtered. This risk continued to exist, and grew
significantly in the mid 90's when domestic cattle, infected by imported MBM, reached
processing. Given the low stability of the system, the risk increased over the years with
continued imports of cattle and MBM from BSE risk countries.
4.3 Risk that BSE infectivity was recycled and propagated
A risk that BSE-infectivity was recycled and propagated exists since a processing risk
first appeared; i.e. in the early 90s. Until today this risk persists and increases fast
because of the extremely unstable BSE/cattle system in Canada.
5. CONCLUSION ON THE GEOGRAPHICAL BSE-RISK
5.1 The current GBR as function of the past stability and challenge
The current geographical BSE-risk (GBR) level is III, i.e. it is confirmed at a lower level
that domestic cattle are (clinically or pre-clinically) infected with the BSE-agent.
This assessment deviates from the previous assessment (SSC opinion, 2000) because at
that time several exporting countries were not considered a potential risk.
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full text;
http://www.efsa.eu.int/science/efsa_scientific_reports/gbr_assessments/scr_annexes/563/sr02_biohaz02_canada_report_annex_en1.pdf
TSS