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From: TSS ()
Subject: CULLING OF COHORTS OF CATTLE AFFECTED WITH BSE AS SOON AS POSSIBLE, WITH THE PERMANENT RESTRICTION OF COHORTS
Date: June 1, 2007 at 7:24 am PST

May 2007 - 1 -
© Defra

VETERINARY ASSESSMENT OF THE RISK OF REPLACING THE
CULLING OF COHORTS OF CATTLE AFFECTED WITH BOVINE
SPONGIFORM ENCEPHALOPATHY AS SOON AS POSSIBLE, WITH THE
PERMANENT RESTRICTION OF COHORTS

1. EXECUTIVE SUMMARY

Bovine spongiform encephalopathy (BSE) is a fatal neurological disease of
cattle. Consumption of feed contaminated with BSE is believed to be the
principal, if not the exclusive, route of infection with the BSE agent. Scientific
studies have shown that cattle are more susceptible to infection with BSE
during the first year of life. Cohorts are cattle which might have consumed the
same feed as an animal affected with BSE when both were under a year of
age.
In 1996, BSE was linked to a new form (variant) of the human transmissible
spongiform encephalopathy, Creutzfeldt-Jakob Disease. As a result, the
United Kingdom (UK) introduced the Over Thirty Month (OTM) rule which
banned cattle aged over 30 months from entering the food chain. The UK also
extended the ban on feeding of mammalian meat and bone meal, to all
farmed animals. This reinforced feed ban is considered effective from 1
August 1996.
Between 2000 and 2004, the European Commission’s Scientific Steering
Committee and the European Food Safety Authority concluded that cattle
which consumed the same feed as an animal affected with BSE were at
greater risk of being infected with BSE than cattle in the normal healthy
population and that the culling of cohorts was an effective method of
preventing cattle infected with BSE from entering the food chain and of
eliminating future cases of BSE. The results of the European Union’s BSE
monitoring programme between 2003 and 2005 continued to indicate that
cohorts have a significantly higher level of BSE infection than normal healthy
slaughtered cattle.
Since July 2001, Regulation (EC) No.999/2001 has required the culling of
cohorts as soon as possible. However, since 19 January 2007, Regulation
(EC) No.1923/2006 has provided for the European Commission and Member
States to permit the use of BSE cohorts, until the end of their productive lives
following such a request from a Member State. Permission is dependent upon
a favourable risk assessment taking into account the control measures in that
Member State.
The exclusion of cohorts from the food and feed chains is part of a package of
BSE control measures intended to safeguard public and animal health and
maintain consumer confidence. Minimising the number of cattle slaughtered
for human consumption which test positive for BSE is important to maintain
consumer confidence in UK beef and beef products.
In the UK, the culling of cohorts born after July 1996 started in March 2005 in
preparation for the replacement of the OTM rule in November 2005. If infected
May 2007 - 2 -
© Defra
cattle within the cohort sub-population are culled before they develop
detectable disease the future number of BSE cases may be reduced.
The eradication of BSE is paramount in terms of safeguarding public and
animal health, reducing the economic burden of BSE controls and promoting
trade in UK cattle and beef. Together with other BSE controls, the culling of
cohorts as soon as possible, has the potential to support the achievement of
the Government’s Public Service Agreement target of eradicating BSE in
Great Britain by 2010.
In view of the limitations of current control measures, allowing cohorts to be
used until the end of their productive lives would require enhanced monitoring
and enforcement measures and incur additional expense. The greater the
number of cohorts alive, the greater the likelihood of a single cohort animal
by-passing the official controls and entering the food chain. Such breaches
have a negative effect on consumer confidence in UK beef.
On the basis of this risk assessment, veterinary advice is that culling cohorts
as soon as possible provides a higher level of disease control than
permanently restricting cohorts until the end of their productive lives. The risk
assessment recommends that the UK continues to implement the policy of
culling cohorts as soon as possible, but reviews this assessment in two years
time, in the light of the predicted continuing decline in the BSE epidemic.
2. INTRODUCTION

snip...full text 22 pages ;


http://www.defra.gov.uk/animalh/bse/pdf/cohort_controls-risk.pdf

TEXAS MAD COW

(the one they finally confirmed after an act of congress, and after 7+ month delay so GW
could finalize his BSE MRR policy first), not the stumbling and staggering one they refused
to test at all and just sent to be rendered. ...TSS)


During the course of the investigation, USDA removed and tested a total of
67 animals of interest from the farm where the index animal's herd
originated. All of these animals tested negative for BSE. 200 adult animals
of interest were determined to have left the index farm. Of these 200, APHIS
officials determined that 143 had gone to slaughter, two were found alive
(one was determined not to be of interest because of its age and the other
tested negative), 34 are presumed dead, one is known dead and 20 have been
classified as untraceable. In addition to the adult animals, APHIS was
looking for two calves born to the index animal. Due to record keeping and
identification issues, APHIS had to trace 213 calves. Of these 213 calves,
208 entered feeding and slaughter channels, four are presumed to have
entered feeding and slaughter channels and one calf was untraceable.

http://www.usda.gov/wps/portal/!ut/p/_s.7_0_A/7_0_1OB?contentidonly=true&contentid=2005/08/0336.xml

Executive Summary

In June 2005, an inconclusive bovine spongiform encephalopathy (BSE) sample
from November 2004, that had originally been classified as negative on the
immunohistochemistry test, was confirmed positive on SAF immunoblot (Western
blot). The U.S. Department of Agriculture (USDA) identified the herd of origin for
the index cow in Texas; that identification was confirmed by DNA analysis. USDA, in close
cooperation with the Texas Animal Health Commission (TAHC), established an incident
command post (ICP) and began response activities according to USDA’s BSE Response Plan of
September 2004. Response personnel removed at-risk cattle and cattle of
interest (COI) from the index herd, euthanized them, and tested them for BSE; all were
negative. USDA and the State extensively traced all at-risk cattle and COI that left the
index herd. The majority of these animals entered rendering and/or slaughter channels well
before the investigation began. USDA’s response to the Texas finding was thorough and
effective.

snip...


Trace Herd 3

The owner of Trace Herd 3 was identified as possibly having received an
animal of interest. The herd was placed under hold order on 7/27/05. The herd
inventory was conducted on 7/28/05. The animal of interest was not present within the
herd, and the hold order was released on 7/28/05. The person who thought he sold the animal to
the owner of Trace Herd 3 had no records and could not remember who else he might have
sold the cow to. Additionally, a search of GDB for all cattle sold through the markets by
that individual did not result in a match to the animal of interest. The animal of interest
traced to this herd was classified as untraceable because all leads were exhausted.


Trace Herd 4

The owner of Trace Herd 4 was identified as having received one of the COI
through an order buyer. Trace Herd 4 was placed under hold order on 7/29/05. A complete
herd inventory was conducted on 8/22/05 and 8/23/05. There were 233 head of
cattle that were examined individually by both State and Federal personnel for all man-made
identification and brands. The animal of interest was not present within the herd. Several
animals were reported to have died in the herd sometime after they arrived on the
premises in April 2005. A final search of GDB records yielded no further results on the eartag of
interest at either subsequent market sale or slaughter. With all leads having been exhausted,
this animal of interest has been classified as untraceable. The hold order on Trace Herd 4
was released on 8/23/05.


Trace Herd 5

The owner of Trace Herd 5 was identified as having received two COI and was
placed under hold order on 8/1/05. Trace Herd 5 is made up of 67 head of cattle in
multiple pastures. During the course of the herd inventory, the owner located records
that indicated that one of the COI, a known birth cohort, had been sold to Trace Herd 8
where she was subsequently found alive. Upon completion of the herd inventory, the other
animal of interest was not found within the herd. A GDB search of all recorded herd
tests conducted on Trace Herd 5 and all market sales by the owner failed to locate the
identification tag of the animal of interest and she was subsequently classified as untraceable
due to all leads having been exhausted. The hold order on Trace Herd 5 was released on
8/8/05.

Trace Herd 6

The owner of Trace Herd 6 was identified as possibly having received an
animal of interest and was placed under hold order on 8/1/05. This herd is made up of 58 head
of cattle on two pastures. A herd inventory was conducted and the animal of interest was
not present within the herd. The owner of Trace Herd 6 had very limited records and was
unable to provide further information on where the cow might have gone after he
purchased her from the livestock market. A search of GDB for all cattle sold through the
markets by that individual did not result in a match to the animal of interest.
Additionally, many of the animals presented for sale by the owner of the herd had been re-tagged at
the market effectually losing the traceability of the history of that animal prior to
re-tagging. The animal of interest traced to this herd was classified as untraceable due to
all leads having been exhausted. The hold order on Trace Herd 6 was released on 8/3/05.


Trace Herd 7

The owner of Trace Herd 7 was identified as having received an animal of
interest and was placed under hold order on 8/1/05. Trace Herd 7 contains 487 head of cattle
on multiple pastures in multiple parts of the State, including a unit kept on an island.
The island location is a particularly rough place to keep cattle and the owner claimed
to have lost 22 head on the island in 2004 due to liver flukes. Upon completion of the herd
inventory, the animal of interest was not found present within Trace Herd 7. A GDB search
of all recorded herd tests conducted on Trace Herd 7 and all market sales by the
owner failed to locate the identification tag of the animal of interest. The cow was
subsequently classified as untraceable. It is quite possible though that she may have died within
the herd, especially if she belonged to the island unit. The hold order on Trace Herd
7 was released on 8/8/05.


http://www.aphis.usda.gov/lpa/issues/bse/epi-updates/bse_final_epidemiology_report.pdf


Of all the feeds in use by the producer since 1997, none were discovered to have contained prohibited material (mammalian protein). Since the age of the index animal was determined to be approximately 12 years, investigating and reconstructing a feed history over such a long period of time is challenging. This ranch is a beef cow-calf operation and minimal feed records were maintained. Due to the nature of this investigation, it is difficult to determine what feeds were in use at specific times and what the formulation of those feeds were at the time they were fed. A feed history was developed through interviews with the producer and other farm personnel since they did not maintain any feed history documentation. Interviews with personnel at retail establishments disclosed incomplete records and cash sales that did not always identify the purchaser. Dallas District investigated any and all feed ingredients that were identified as being fed or potentially fed over the course of the last 15 years of this herd’s operation. Feeds discovered during this investigation with potential mammalian protein sources are as below:

One feed, used prior to 1996, before the implementation of the feed ban, was suspected to contain mammalian meat and bone meal, but this could not be confirmed as no formulation records were available.

The producer recalled using a particular feed sporadically during the 1980’s and 1990’s, however, he could not remember the name or manufacturer of the feed and had no records identifying the product. It is not known whether this feed contained an animal protein source. Attempts to identify this feed through interviews with retail sources were unsuccessful.

The producer identified one feed product that has been used since the year 2000 which contains fish meal as a protein source. Further investigation revealed that this product had contained mammalian meat and bone meal prior to 1997, but that it had been reformulated at that time using fish meal to replace the MBM.

A tabular representation of the feed inspection follow-up activities is presented below:


http://www.fda.gov/cvm/texasfeedrpt.htm


APHIS attempted to trace all adult animals that left the index farm after 1990, as well as all progeny born within 2 years of the index animal's death. Together, these animals are called animals of interest.

During the course of the investigation, USDA removed and tested a total of 67 animals of interest from the farm where the index animal's herd originated. All of these animals tested negative for BSE. 200 adult animals of interest were determined to have left the index farm. Of these 200, APHIS officials determined that 143 had gone to slaughter, two were found alive (one was determined not to be of interest because of its age and the other tested negative), 34 are presumed dead, one is known dead and 20 have been classified as untraceable. In addition to the adult animals, APHIS was looking for two calves born to the index animal. Due to record keeping and identification issues, APHIS had to trace 213 calves. Of these 213 calves, 208 entered feeding and slaughter channels, four are presumed to have entered feeding and slaughter channels and one calf was untraceable.

To determine whether contaminated feed could have played a role in the index animal's infection, FDA and the Texas Feed and Fertilizer Control Service conducted a feed investigation with two main objectives: 1) to identify all protein sources in the animal=s feed history that could potentially have been the source of the BSE agent, and 2) to verify that cattle leaving the herd after 1997 were identified by USDA as animals of interest and were rendered in compliance with the 1997 BSE/ruminant feed rule.

The feed history investigation identified 21 feeds or feed supplements that were used on the farm since 1990. These feed ingredients were purchased from three retail feed stores and were manufactured at nine feed mills. This investigation found that no feed or feed supplements used on the farm since 1997 were formulated to contain prohibited mammalian protein. Due to this finding, FDA has concluded that the animal was most likely infected prior to the 1997 BSE/ruminant feed rule.


http://www.usda.gov/wps/portal/!ut/p/_s.7_0_A/7_0_1OB?contentidonly=true&contentid=2005/08/0336.xml


CATTLE ON FEED IN TEXAS


FOR IMMEDIATE RELEASE
P01-05
January 30, 2001
Print Media: 301-827-6242
Consumer Inquiries: 888-INFO-FDA

--------------------------------------------------------------------------------

Note: On Dec. 23, 2003, the U.S. Department of Agriculture reported that a cow in Washington state had tested positive for bovine spongiform encephalopathy (BSE, or mad cow disease). As a result, information on this Web page stating that no BSE cases had been found in the United States is now incorrect. However, because other information on this page continues to have value, the page will remain available for viewing.

FDA ANNOUNCES TEST RESULTS FROM TEXAS FEED LOT


Today the Food and Drug Administration announced the results of tests taken on feed used at a Texas feedlot that was suspected of containing meat and bone meal from other domestic cattle -- a violation of FDA's 1997 prohibition on using ruminant material in feed for other ruminants. Results indicate that a very low level of prohibited material was found in the feed fed to cattle.

FDA has determined that each animal could have consumed, at most and in total, five-and-one-half grams - approximately a quarter ounce -- of prohibited material. These animals weigh approximately 600 pounds.

It is important to note that the prohibited material was domestic in origin (therefore not likely to contain infected material because there is no evidence of BSE in U.S. cattle), fed at a very low level, and fed only once. The potential risk of BSE to such cattle is therefore exceedingly low, even if the feed were contaminated.

According to Dr. Bernard Schwetz, FDA's Acting Principal Deputy Commissioner, "The challenge to regulators and industry is to keep this disease out of the United States. One important defense is to prohibit the use of any ruminant animal materials in feed for other ruminant animals. Combined with other steps, like U.S. Department of Agriculture's (USDA) ban on the importation of live ruminant animals from affected countries, these steps represent a series of protections, to keep American cattle free of BSE."

Despite this negligible risk, Purina Mills, Inc., is nonetheless announcing that it is voluntarily purchasing all 1,222 of the animals held in Texas and mistakenly fed the animal feed containing the prohibited material. Therefore, meat from those animals will not enter the human food supply. FDA believes any cattle that did not consume feed containing the prohibited material are unaffected by this incident, and should be handled in the beef supply clearance process as usual.

FDA believes that Purina Mills has behaved responsibly by first reporting the human error that resulted in the misformulation of the animal feed supplement and then by working closely with State and Federal authorities.

This episode indicates that the multi-layered safeguard system put into place is essential for protecting the food supply and that continued vigilance needs to be taken, by all concerned, to ensure these rules are followed routinely.

FDA will continue working with USDA as well as State and local officials to ensure that companies and individuals comply with all laws and regulations designed to protect the U.S. food supply.


http://www.fda.gov/bbs/topics/NEWS/2001/NEW00752.html

WE KNOW NOW, and we knew then that 5.5 grams of tainted mad cow feed is/was enough to kill 100 cows. ...TSS


THE FDA RUMINANT TO RUMINANT FEED BAN OF 8/4/97 WAS NOTHING MORE THAN A PIECE OF PAPER, nothing else.

look at the table and you'll see that as little as 1 mg (or 0.001 gm) caused 7% (1 of 14) of the cows to come down with BSE;


Risk of oral infection with bovine spongiform encephalopathy agent in primates

Corinne Ida Lasmézas, Emmanuel Comoy, Stephen Hawkins, Christian Herzog, Franck Mouthon, Timm Konold, Frédéric Auvré, Evelyne Correia, Nathalie Lescoutra-Etchegaray, Nicole Salès, Gerald Wells, Paul Brown, Jean-Philippe Deslys
Summary The uncertain extent of human exposure to bovine spongiform encephalopathy (BSE)--which can lead to variant Creutzfeldt-Jakob disease (vCJD)--is compounded by incomplete knowledge about the efficiency of oral infection and the magnitude of any bovine-to-human biological barrier to transmission. We therefore investigated oral transmission of BSE to non-human primates. We gave two macaques a 5 g oral dose of brain homogenate from a BSE-infected cow. One macaque developed vCJD-like neurological disease 60 months after exposure, whereas the other remained free of disease at 76 months. On the basis of these findings and data from other studies, we made a preliminary estimate of the food exposure risk for man, which provides additional assurance that existing public health measures can prevent transmission of BSE to man.


snip...


BSE bovine brain inoculum

100 g 10 g 5 g 1 g 100 mg 10 mg 1 mg 0·1 mg 0·01 mg

Primate (oral route)* 1/2 (50%)

Cattle (oral route)* 10/10 (100%) 7/9 (78%) 7/10 (70%) 3/15 (20%) 1/15 (7%) 1/15 (7%)

RIII mice (icip route)* 17/18 (94%) 15/17 (88%) 1/14 (7%)

PrPres biochemical detection   

The comparison is made on the basis of calibration of the bovine inoculum used in our study with primates against a bovine brain inoculum with a similar PrPres concentration that was

inoculated into mice and cattle.8 *Data are number of animals positive/number of animals surviving at the time of clinical onset of disease in the first positive animal (%). The accuracy of

bioassays is generally judged to be about plus or minus 1 log. icip=intracerebral and intraperitoneal.

Table 1: Comparison of transmission rates in primates and cattle infected orally with similar BSE brain inocula


Published online January 27, 2005

http://www.thelancet.com/journal/journal.isa

It is clear that the designing scientists must

also have shared Mr Bradley’s surprise at the results because all the dose

levels right down to 1 gram triggered infection.


http://www.bseinquiry.gov.uk/files/ws/s145d.pdf

2

6. It also appears to me that Mr Bradley’s answer (that it would take less than say 100

grams) was probably given with the benefit of hindsight; particularly if one

considers that later in the same answer Mr Bradley expresses his surprise that it

could take as little of 1 gram of brain to cause BSE by the oral route within the

same species. This information did not become available until the "attack rate"

experiment had been completed in 1995/96. This was a titration experiment

designed to ascertain the infective dose. A range of dosages was used to ensure

that the actual result was within both a lower and an upper limit within the study

and the designing scientists would not have expected all the dose levels to trigger

infection. The dose ranges chosen by the most informed scientists at that time

ranged from 1 gram to three times one hundred grams. It is clear that the designing

scientists must have also shared Mr Bradley’s surprise at the results because all the

dose levels right down to 1 gram triggered infection.


http://www.bseinquiry.gov.uk/files/ws/s147f.pdf

2) Infectious dose:

To cattle: 1 gram of infected brain material (by oral ingestion)

http://www.inspection.gc.ca/english/sci/bio/bseesbe.shtml

ALABAMA MAD COW


Summary:

Despite a thorough investigation of two farms that were known to contain the index cow,
and 35 other farms that might have supplied the index cow to the farms where the index
case was known to have resided, the investigators were unable to locate the herd of
origin. The index case did not have unique or permanent identification, plus, the size and
color of the cow being traced is very common in the Southern United States. Due to the
unremarkable appearance of solid red cows, it is not easy for owners to remember
individual animals. In the Southern United States, it is common business practice to buy
breeding age cows and keep them for several years while they produce calves. Most
calves produced are sold the year they are born, whereas breeding cows are sold when
there is a lapse in breeding, which can occur multiple times in cows’ lives. For all of
these reasons, USDA was unable to locate the herd of origin.


http://www.aphis.usda.gov/newsroom/hot_issues/bse/content/printable_version/EPI_Final.pdf

Terry S. Singeltary Sr.
P.O. Box 42
Bacliff, Texas USA 77518



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