What
is Bovine Spongiform Encephalopathy (BSE)?
Bovine spongiform
encephalopathy (BSE), commonly referred to as "mad
cow disease," belongs to the family of diseases known
as transmissible spongiform encephalopathies (TSE). The
causative agent of BSE has not been fully characterized,
but three possibilities have been proposed: an unconventional
virus, a prion (a self-replicating protein), or a virino
(incomplete virus) comprising naked nucleic acid protected
by host proteins. The theory accepted by most scientists
is that BSE is caused by a prion. The agent does not invoke
a detectable immune response or inflammatory reaction
in its host and is extremely resistant to sterilization
processes. The brain of affected animals appears “sponge-like”
when observed microscopically in these various forms of
TSE.
What
is a Prion?
A prion is
an altered protein. It is not DNA or a virus, which were
previously the only known mechanisms for a protein to
have the ability to replicate, or reproduce. Prions do
not replicate, however, they attach to other proteins
and cause them to change into the same form as the prion.
In normal situations this is not a problem and naturally
occurs in the body. With normal prions the cell breaks
down the prions and reuses their parts. The cell does
not have the ability to break down the abnormal prions
associated with TSE diseases and therefore a buildup occurs.
Do TSEs
occur naturally?
Yes, disorders
of this nature have been known for centuries. The following
is a list of known related disorders:
Scrapie in
sheep (diagnosed in 1732 with a breed susceptibility in
Suffolks)
Chronic Wasting Disease in Elk/deer
Feline Spongiform Encephalopathy
Transmissible Mink Encephalopathy (diagnosed in 1940’s)
Creutzfeldt-Jakob in humans (CJD, diagnosed in 1920, appears
to have a genetic and/or sporadic component (1 case per
1,000,000 population per year))
Kuru in humans in New Guinea (diagnosed in 1900, ancestral
cannibalism)
How do
cattle get BSE?
The only known
way for cattle to contract BSE is through consuming feeds
that contain specific byproducts from affected ruminants
(brain, spinal cord, eyes and distal small intestine.)
What
are “downer cows”?
“Downer cows”
are cattle that cannot walk or rise from a lying position,
due to any number of reasons.
Are all
"downer cows" infected with BSE?
No, over the
past year approximately 15,000 downer cows were tested
for BSE in 2002-2003 and the one case in Washington was
the only positive report. Additionally, 57,352 (as of
September 30, 2003) cattle have been tested from slaughter
plants by USDA. Our diagnostic labs in Kentucky have routinely
tested cattle exhibiting neurological symptoms for many
years and no cases of BSE have been found.
I had
a cow that had symptoms like BSE. Did she likely have BSE
or are there other disorders with similar symptoms?
It is highly
unlikely that your animal had BSE. There are a multitude
of neurological disorders or other diseases that cause
weakness, trembling or other symptoms that mimic BSE.
Cattle with something as simple and common as pinkeye
can demonstrate similar symptoms. Common diseases affecting
the brain of cattle may include: listeria (circling disease),
polioencephalomalacia (thiamine/B1 vitamin deficiency),
rabies, grass tetany, milk fever, and ketosis.
Can you
test live animals for BSE?
No, currently
the only reliable test is on brain tissue which requires
the animal’s death for collection.
Can BSE
be passed to offspring from infected parents?
It is not likely
that cattle can transmit BSE to offspring; however, the
research is not conclusive. Research in Great Britain
indicated an increase of approximately 9% occurrence of
BSE in calves from infected dams. There is no evidence
that this resulted from direct transmission rather than
from inherited susceptibility/resistance. Research in
other species indicates that susceptibility/resistance
is inheritable. For example, some lines of sheep are resistant
to Scrapie which is a transmissible spongiform encephalopathy
in sheep.
What
can I do to insure that my cattle don’t get it?
The practice
of feeding animal by-products that may contain prions
has been banned in the US and Canada since 1997. Compliance
with this law is mandatory.
What
age cattle normally have BSE?
Cattle don’t
“normally” have BSE but when it is diagnosed it is typically
seen in cattle between 3 and 6 years of age; primarily
dairy cattle. One case of BSE has been confirmed in a
24 month old animal in Japan.
Why do
the cattle associated with the confirmed cow have to be
destroyed?
There is no
scientific reason to destroy them if they do not demonstrate
symptoms of BSE since they cannot transmit it to other
animals. However, because the only method of testing is
to harvest brain tissue you will probably see some, if
not all, of these animals sacrificed for testing. The
additional herds now under quarantine are not a result
of more cases but rather the expanding search for the
cattle that entered the US with the confirmed animal.
Can humans
develop BSE?
There has been
an observed association with a new variant Creutzfeldt-Jakob
disease (vCJD) in the United Kingdom since BSE was first
diagnosed. Case diagnoses appeared after BSE diagnosis,
then case numbers increased for several years, peaking
in 2000, but the case numbers are now decreasing annually.
vCJD affects younger people (28 years old versus >
60years for CJD) and has a longer clinical duration (14
months versus 5 months for CJD).
Between 1996 and 2002 most vCJD cases (129) have been
diagnosed in the United Kingdom, six cases in France,
and one case each has been diagnosed in Canada, Ireland,
Italy, and USA (WHO website). The one known case in the
US is a young woman that spent the first 13 years of her
life in England.
United Kingdom
CJD stats
http://www.doh.gov.uk/cjd/cjd_stat.html
If a
person were to eat beef from cattle with BSE what are the
health risks?
There has been
no direct association between meat from BSE cattle and
human health risk. The only known transmittance of BSE
from cattle to humans is when humans consume tissue from
the central nervous system (brain and spinal cord) of
an infected animal.
Are there
any common human food products that have cattle central
nervous system tissue in them?
No, not if
products are produced under current guidelines and regulations.
The upgraded USDA processing guidelines should virtually
eliminate the possibility of these parts of the carcass
finding their way into processed foods by accident. Consumers
should be aware that almost any part of a carcass, even
brains and ox tails, considered a byproduct by many, might
well be considered a delicacy by some segment of the population
and therefore be available for purchase in some meat cases.
This situation is becoming more prevalent as the US becomes
more diverse in major ethnic population markets.
What
happens to the infected products when rendered?
The Washington
State case was rendered into candle wax and soap. Rendering
could mean the product could possibly go for uses such
as pet foods, poultry or swine feed supplements and fertilizers
to name a few.
Is there
danger to my pet from eating rendered nervous tissue?
Rendered products
have been major components of companion animal feeds for
many years and no associated problems have ever been found
with canine pets. However, there is a similar disorder
found in felines and it appears that it can be caused
by consumption of feed contaminated with the BSE agent.
Explain
the newly announced USDA rules changes.
On December
30,2003 Secretary of Agriculture Ann Veneman announced
changes in procedure in the meat processing industry.
First and foremost, non-ambulatory disabled “downer” animals
are now banned from human food or contact with human food
processing. AMR, or advanced meat recovery technology,
is no longer acceptable as a means of processing cattle
over the age of 30 months for human food. Air injection
stunning is now banned. Cattle can no longer be tagged
“inspected and passed” if they are suspected of having
BSE. They must be held until they are tested negative
for BSE.
Is our
beef safe?
Yes, we have
one of the safest and comparatively cheapest food supplies
in the world. Every animal that is harvested for commercial
sale is inspected both pre and post harvest by a trained
USDA inspector. This is why we know about the one case
in Washington State – a federal inspector identified the
need to test this one animal.
How will
the new USDA rules affect prices?
Downer cows
have not been accepted by stockyards in recent history.
Beef producers are not expected to experience a reduction
in prices due to the changes. If there is any reduction
in prices it would logically be in the slaughter cow sector
of the market as the uses for the resulting product would
have some limitations and there would be a somewhat lower
yield of product due to the processing limitations. Downer
animals will now be a loss to whoever owns them as has
been the case for most beef producers for some time now,
these animals will be rendered.
What
are the short run market impacts?
Prices for
slaughter cattle and wholesale beef have declined – largely
due to uncertainty and expectations of increased domestic
supplies. Prices declined from record-high levels, so
now slaughter cattle are selling near the prices of a
year ago and $10 per cwt. over the price level of mid
2002.
The U.S. exports
about 9% of its beef production. Because countries have
temporarily closed their doors to U.S. beef, the supply
of beef on the domestic market will be increased as the
beef intended for export is diverted to the U.S. market.
Economic research suggests this will have about a 14%
to 18% negative impact on slaughter cattle prices, which
would drop them to the mid $70s/cwt.
Feeder cattle
prices follow expected slaughter cattle prices. Futures
prices for the summer months dropped by $5 per hundredweight
as of Jan. 5. The predicted feeder cattle impact would
be a $10 per cwt. negative impact on prices for 700 to
800 pound feeders, with a greater impact on lighter calves.
Feeder cattle markets are still uncertain, but seem to
be settling at levels about $5 to $10 per cwt. lower than
mid December.
What
is happening to beef demand?
U.S. research
and the Canadian experience suggest that there will not
be a great negative consumer response. Initial retail
market surveys seem to support this analysis, although
some categories of consumer are changing their eating
habits. One consumer survey suggested that as many as
one-third of consumers were changing their beef consumption,
however, if this includes groups already at the low beef
consumption level, the total impact will be small.
Per capita
beef consumption is likely to increase this year. If retail
prices follow the wholesale trends, many consumers will
respond to the “bargains” and increase their purchases.
What
are the longer term prospects?
Since the trade
embargoes caused the greatest negative price impact, reopening
doors to U.S. exports is the most important factor in
a price recovery. Other lasting impacts will be the uncertainty
of consumer demand and production. In the next few months,
the supply of beef will be very uncertain. Feedlots may
hold back on production. However, if they expect price
recovery, they will hold cattle longer and the cattle
will go to market at heavier weights.
From the long
term view of cow-calf operations, the BSE case may be
a positive factor since it is likely to halt any expansion
of the cow herd. The result will be a longer period of
comparatively tight supplies.
What
is being done in response to the recent incidence of BSE
in the US?
Many activities
were already on-going that will have an impact on our
response to BSE. The primary change is that the time-line
for implementation of these activities will likely be
moved up in response to BSE. The primary focus is around
development and implementation of an animal identification
and tracking program. Specific activities within this
focus include source verified to farm of origin CPH 45
feeder cattle sales; electronic identification and tracking
of feeder cattle through the feed-yard and to the packing
plant as well as building and maintaining a data base
of health and carcass quality for Kentucky feeder cattle.
How might
a national ID system work?
The system
outlined in the U.S. Animal Identification Plan (USAIP)
would require producers to identify livestock with an
electronic ID tag the first time they move in commerce.
This movement would trigger the calculation of a premise
ID number for the person or entity marketing the animal
or animals. This premise ID would then become the sole
identity of that entity in a database for traceability.
Sale barns and marketers of livestock would be required
to record the dates and locations that livestock move
in commerce. The state veterinarian has the responsibility
of defining a premise and providing access to the system
to calculate the numbers. Animals that move in contained
groups that stay intact from original owner to harvest
can be identified with a lot number (probably hogs and
poultry but could include retained ownership and contract
cattle).
What
is the proposed timeline for implementation of a national
ID system?
The USAIP sets
out a timeline that was formulated prior to the BSE case.
It states that states should have a program for administering
the allocation of premise ID’s by July 2004. The timelines
are somewhat species specific from that point forward.
In cattle that move in interstate commerce, identification
would begin in July of 2005 with intrastate movements
being tagged by July 2006. It is a widely held belief
that these target dates will likely move closer in light
of the BSE case in Washington State. In Kentucky we have
the ability to put producers into a voluntary system that
will begin to compile historic information on livestock
ahead of a federally mandated program. This is the major
focus of the Kentucky Beef Network.
What
is EID?
Electronic
Identification is a system of incorporating a radio frequency
chip (RFID) into the ear tags of livestock. This chip,
when read by a scanner, gives out a 15 digit number. The
chip does not store any information other than the number
and only sends the number when contacted by a reader.
There are two tag technologies on the market right now,
full and half duplex. Each has its own uses and capabilities.
Scanners come in many forms from handheld wands to walk
thru loop units. The best comparison to EID technology
is the bar-code technology used in retail stores. The
bar-code does not store any information but serves as
an identity for that product in the computer system that
operates the inventory management and pricing systems
in the store.
What
is premise ID?
In the USAIP
the cornerstone of an animal ID program is a premise ID
number that would be assigned to each person or location
(entity) marketing livestock. The number would be a random
number with no particular coding or means of using it
for traceability by itself. The number would be assigned
to the entity after collection of basic contact and location
information upon the first entry to the market place.
Producers will be able to preregister for premise IDs
through their state veterinarian. The state veterinarian
has the authority to define a premise for that state and
has the responsibility to either administer a system for
assigning these numbers or contracting with someone to
provide that service.
What
can I do now to prepare for national ID?
Be prepared
to tag your livestock on the farm before they go to market.
If you choose not to do so you will most certainly be
charged a fee for applying tags. Most importantly, producers
need to begin to keep records if they do not already.
The KY BQA manual along with the IRM records books are
good sources for suggested records forms (cattle movement,
birth dates, basic production and health information will
be important). Above and beyond the issue of having records
for traceability, it is commonly thought that the ability
of a database system to share source verification information
will create an environment for value added marketing for
those practicing good management.
Will
the way we market cattle change as a result of a national
ID program?
It is commonly
held that livestock will need to be tagged with an EID
before being sold or tagged at the markets. The responsibility
for tagging or paying for the service of tagging resides
with the person marketing the cattle. There is no reason
to think that the manner in which we market livestock
will change or even slow down as long as producers will
complete some basic tasks to pull the responsibility of
tagging out of the markets. You will see RFID scanners
in place in the markets and on many farms to record the
numbers as livestock move. The possibility exists that
because of individual identification, markets may well
be in a position to provide producers with individual
data on the livestock as the data is collected for traceability.
There will be some cost associated with collection and
handling of the data collected. Current estimates are
that an EID system will probably add $2-3/head to the
marketing cost on cattle if producer will tag them on
farm and as much as $5-6/head if they have to be tagged
in the markets.
Who owns
the data in this database?
The KBN database
is producer owned and privately operated for a reason
– the data can be protected and access to it limited.
You own the data that is entered on your animals and have
the authority to open or limit access to that data at
your discretion with the exception of an incident of a
request for traceability from the USDA resulting from
a case of animal disease. This traceability function would
apply once a mandated national system is in place. Until
that time you can use the system to accumulate data for
your benefit and verification.
Can I
be proactive and voluntarily begin an ID program now to
accumulate data to protect my operation?
Yes, when premise
ID’s become available in the near future, apply to the
State Veterinarian’s office for and receive a premise
ID number. Next, contact the Kentucky Beef Network and
purchase electronic tags for insertion into your cattle.
The charge for voluntarily identifying livestock and their
entry into the KBN database is $3/head including the tag.
The KBN and others working with them can collect information
for cattle moving in purebred or special feeder sales.
Cattle moving off the farm in load lots can also be tracked.
Value Added Target Marketing, a cooperative effort between
UK Extension and the KBN, will assist in obtaining data
on your cattle from the feed-yard and packer. Beginning
to gather this information now, in advance of a national
program, may reap significant benefits to Kentucky producers.
