Mad Cow Disease: Agriculture Issues
E. Segarra and Jean M. Rawson
Agricultural Policy Analyst and Agricultural Policy Specialist
Resources, Science, and Industry Division
cow disease causes brain degeneration and death in cattle,
It has been linked to the deaths of nearly 100 people in
Great Britain who consumed meat from infected animals. BSE
(bovine spongiform encephalopathy) has not been found in
the United States since federal and state agencies began
surveillance in 1989. The cattle industry is the largest
sector of U.S. agriculture (beef and dairy production were
valued at $3 1 billion in 1999), and if BSE were found in
U. S. cattle, losses to the sector from declining meat sales
and exports, and from mandatory herd depopulation, could
severely harm the economic health of US. agriculture as a
whole. This report describes: (1) Europe's measures to stop
the spread of the disease; (2) actions that U.S. Department
of Agriculture (USDA) regulatory agencies are taking to control
the known sources of risk; and, (3) the emergency response
plan that USDA would implement if a case of BSE were confirmed.
The report will be updated as events warrant.
is mad cow disease (BSE)?
Bovine spongiform encephalopathy
(BSE), widely referred to as mad cow disease, is a degenerative
disease affecting the nervous system in cattle. The disease was
first found in Great Britain in 1986. The infective agent is
not completely known, but evidence suggests that a "proteinaccous
infectious particle" or 'prion' is the causal agent. Prions are
fairly new to science, and their importance was not recognized
until the early 1980's. To date, there is no treatment or vaccine
to prevent the disease. BSE is believed to be transmitted when
proteins from an infected animal are fed to cattle. Transmission
between animals has not been observed, but there is some evidence
of mother-to-calf infection through gestation. Most BSE-like
diseases have incubation periods that span years or even decades
(average incubation for BSE symptoms is 2 to 8 years). All affected
BSE been found in the United States?
BSE has not been found in the United States. Since federal
and state agencies began surveillance in 1989, all evidence
shows that U. S. cattle and beef supplies are free of BSE.
At the same time, most specialists agree that scientific
uncertainties about the disease's cause and transmission
warrant precautionary actions aimed at confirming the continued
absence of BSE and preventing the importation of livestock
or animal protein products that could carry the disease.
Other BSE-like animal diseases (collectively known as transmissible
spongiform encephalopathies or TSEs) are present in the
United States, including scrapie in sheep, and chronic
wasting disease of deer and elk. A rare human TSE disease,
the Creutzfeldt-Jakob disease (CJD) has long been known
to occur in the United States, where it normally strikes
about I in every million people each year. In Europe, a
new variant of CJD (nvCJD) has affected close to 100 people
since 1986, and most experts believe that this is a human
form of B SE that is transmitted to humans who consume
meat or products from B SE-infected cattle. 1
is at stake for U.S. agriculture?
Cattle production is the single largest segment of U.S.
agriculture. With a herd of over 50 million animals, the
value of beef and dairy surpassed $31 billion ($19.4 and
$12.3 billion, respectively), or about 40% of total U.S.
agricultural production in 1999. At the consumer retail
level, beef sales have started to rebound from a steady
20-year decline that has seen per capita beef consumption
cut in half from its 1980 levels. In 1999, consumer sales
posted a record $52 billion, with mean yearly consumption
of 69.6 pounds per person. Exports also represent a sizable
portion of U.S. agricultural output. For example, the United
States sold $2.7 billion in beef to trading partners in
1999. Four countries currently buy 95% of U.S. beef exports.
Japan is the principal buyer ($1.4 billion), followed by
Mexico ($454 million), Korea ($331 million), and Canada
A comparison with the European livestock industry experience
shows one possible scenario for what is at stake. In the
EU, the beef industry took two major hits from their BSE
crisis: (1) a 20-30% decline in domestic beef sales due
to negative long-term effects on consumers' confidence,
and (2) losses in international trade in cattle, beef,
and feed. U.S. agriculture leaders express the concern
that if BSE were to appear in the United States, the economic
and physical integrity of U.S. beef industry would be severely
harmed, at least temporarily.
is the state of the science on BSE?
Scientists know that the BSE agent is smaller than viruses.
It is also highly resistant to treatments that normally
kill viruses or bacteria (i.e., heat, ultraviolet light,
radiation, and antimicrobials). Further, the agent cannot
be detected in animals until symptoms appear because it
does not cause inflammation or a detectable immune response
in the host.
Currently, scientists from USDA's Agricultural Research
Service and Animal and Plant Health Inspection Service
(APHIS) 2 are
working at the National Animal Disease Center (NADC) in
Ames, Iowa, to develop tests to diagnose TSE (BSE-like)
diseases before onset of symptoms. NADC is also collaborating
with states, international organizations, and U.S. universities
to study TSE transmission mechanisms between animal species
and to discover natural infection routes of other TSEs
present in the United States, such as scrapie in sheep,
and chronic wasting disease on ranch-farmed elk. Research
specifically on BSE is conducted only in countries where
the disease exists.
are the sources of risk to U.S. agriculture?
BSE could appear in the United States in three ways - through
imports of infected cattle, imports of BSE-contaminated
feed, or through spontaneous mutation of an indigenous
TSE-causing agent into a BSE-causing agent (this is what
scientists suspect happened in England). Various federal
agencies are taking the following steps to address these
sources of risk.
Importation of infected cattle. In 1989, APHIS imposed
an import ban for live ruminants (cows, sheep, and goats)
from countries with BSE infections. Inl99l,APHlS expanded
the prohibition to include meat and meat products from
B SE-infected countries. Finally, in 1997, APHIS prohibited
the importation of live ruminants and most ruminant products
from all of Europe.
APHIS began a domestic BSE surveillance program in 1990.
Initial efforts included locating 496 head of cattle that
were imported from the United Kingdom (U.K.) between 1981
and 1989. APHIS officials state that most of the animals
were found and so far none have shown symptoms of BSE.
Since 1990, APHIS has examined brains taken from more than
11,000 cattle with suspicious clinical symptoms, but has
not found evidence of BSE. USDA's meat inspection agency,
the Food Safety and Inspection Service (FSIS), does not
permit animals showing suspicious neurological symptoms
to be slaughtered for human consumption, and sends the
brains of such animals to APHIS for testing.
Imported cattle feed. As mentioned above, in 1991 USDA
banned the importation of ruminant meat and bone meal,
offal, fat, serum, and glands from U.K., France, Switzerland,
Ireland and Oman. USDA's decision was based on early evidence
coming from the U.K. indicating that feed containing protein
from BSE-infected animals was the most likely source of
contagion. In 1997, as the disease spread through Europe,
the ban was extended to all ruminant meat and bone meal
products coming from the continent. Later, in December
2000, evidence in Europe of cross-contamination between
feeds containing cattle protein and feeds containing non-ruminant
protein (e.g. from hogs or horses), led USDA to ban imports
of all rendered animal protein products from Europe as
well as any other products that may have come in contact
with such products.
According USDA's Foreign Agricultural Service (FAS), between
1989 and 1997 (i.e., before the European Union banned export
of feed containing animal products) the United States imported
9,500 metric tons of cattle and livestock feed from Europe
(including 366 MT from Great Britain). This represents
a tiny fraction of U.S. feed imports (less that 1/2of I%)-
however, little is known of the risk potential posed by
these shipments. USDA is attempting to trace the origin
and composition of the shipments to determine if the feed
contained ruminant protein. Press reports coming from Europe
recently have spotlighted feed exports from Great Britain
as the principal culprit in the expanding BSE epidemic
in that continent. 3
Domestic cattle feed. Scientists speculate that BSE could
also appear in the United States if feed containing rendered
protein from TSE-infected sheep were fed to cattle.4 Research
suggests that this is how BSE emerged in Great Britain.
Researchers maintain that the potential for this to occur
in the United States has historically been less than in
Europe - first, because the volume of sheep protein in
cattle feed is considerably lower due to a far smaller
sheep industry, and second, because unlike Great Britain,
the prevalence of sheep scrapie (another TSE) in the United
States has been very low.
The potential for BSE to occur as a mutation of sheep scrapie
led the Food and Drug Administration (FDA), which regulates
animal feed ingredients, to ban the feeding of virtually
all mammalian proteins to ruminants in 1997. The only exceptions
are blood and blood products; gelatin; inspected, processed,
and cooked meat products for human consumption (such as
restaurant plate waste); milk products; and products containing
pork and equine proteins only. The rule took effect in
August 1997 but full implementation has been difficult.
In a recent report, the FDA found that 20% of licensed
feed mills did not properly label their feeds to say they
contain animal protein, and that 41% of non-licensed feed
mills failed to provide proper warning labels (based on
9,947 compliance inspections conducted between 1999 and
2000). The FDA also found that rendering plants fared about
the same, with 70% to 80% compliance for procedures that
prevent feeds with animal by-products from getting mixed
with non-animal-containing feeds. In response, the feed
industry has set itself a goal of 100% compliance,5 but
a recent case at a Texas feed mill illustrates the difficulty
of achieving that goal. In January 2000, 1,222 cattle were
quarantined when it was found that animal proteins had
inadvertently been mixed in their feed. The feed company
agreed to buy the cattle and to keep them off the market.
has Europe dealt with the BSE crisis?
Since the BSE epidemic began in Great Britain in 1986,
Europe's cattle and meat industries have undergone a significant
increase in regulation. Animal protein feed bans, quarantines,
surveillance, increased testing, herd renewal, and selective
cull measures are now in effect in many EU nations. In
Great Britain, where the BSE epidemic has reached 179,000
confirmed cases in cattle since 1986, these measures appear
to be resulting in a steady decrease in the number of infected
cattle from the 1992 peak. One program, put in action following
the 1996 U.K. beef and cattle ban by the EU, is the so
called "Over Thirty Month Slaughter" scheme (OTMS). Under
this plan, which bans the sale of meat from cattle aged
over 30 months old, the U.K. has destroyed over 4.5 million
animals, at a cost of $4 billion.6 Similar
EU programs (which include feed bans, mandatory animal
testing and tracing, and OTMS) could go into effect in
Germany, Italy and Spain. Germany, for instance, expects
to destroy about 400,000 cattle under a "purchase for destruction" program.
The EU foresees buying and incinerating up to 2 million
cattle by the end of June 2001, at an estimated cost of
if a case of BSE occurs in the United States?
In 1998, APHIS published a response plan that would go
into effect immediately if a case of BSE were confirmed
in the United States. The plan calls for the Secretary
of Agriculture to declare an extraordinary emergency (under
authority contained in 21 USC § 13 4a) if laboratory tests
were to confirm a BSE diagnosis. This emergency declaration
also authorizes the USDA to transfer the necessary funding
to begin eradication, tracing and quarantine operations
(7USC §147b). The USDA plan also calls for owners to receive
indemnity payments for destroyed animals using Commodity
Credit Corporation (CCC) funds as authorized by law.
Issues in Congress
According to APHIS officials, if BSE were to occur in the
United States, the mechanisms exist to respond immediately
to a crisis using existing appropriated funds and emergency
CCC funds. Depending upon the length and severity of the
crisis, additional appropriations might be necessary. However,
APHIS officials point out a need for additional authorities
to deal with a potential BSE outbreak in the United States.
They argue that new authorities are needed to preempt state
laws for livestock inspections in interstate commerce,
and to carry out measures (e.g., drawing of blood and testing
of animals) to detect diseased animals at slaughterhouses,
stockyards, and other points of concentration. These new
authorities were sought in H.R. 4801, which was introduced
in the 106th Congress, referred to the Agriculture and
Judiciary Committees, but saw no action before the end
of the 2nd session. 7
Current appropriations (FY2001) for animal health monitoring
and surveillance operations are $85 million (P.L. 106-387)
and APHIS estimates that $0.5 million will be spent for
BSE surveillance, education, development of improved testing
methods, and research in collaboration with ARS and FSIS.
Congress also appropriated $3 million for detection and
eradication of TSEs (e.g., scrapie) in FY2001. This represents
a slight increase from FY2000 but is significantly below
the Clinton Administration's request of $8 million.
I - Key regulatory actions taken by the EU and the
United States since 1986.
cow disease first reported in England.
epidemiological causal links for BSE established.
of ruminant material or products to feed cattle banned
in U.K. (SI/1988/1039).
become a notifiable disease in U.K.
banned the import of U.K. cattle.
U.K. banned use of beef offals for feed or human consumption.
banned importation of ruminants from the U.K. (Announcement
required compulsory notification of
starts BSE surveillance program (Announcement by
banned importation of animal products and byproducts
from the U.K. and other countries (56 FR 63865).
banned import of bovine embryos from U.K.(92/290/EC).
banned use of mammalian tissue orbyproducts for feeding
placed restrictions on trade in mammalian animal
wastes and feeds. (97/735/EC).
S. established ban on the use of mammalian protein
to feed ruminants (62 FR 30935)
U.S. banned importation of live ruminants and ruminant
byproducts from all Europe and other countries
(63 FR 406)
placed restrictions in the use of all animal proteins
in animal feed.(01/9/EC).
prohibits imports of rendered mammalian protein and
feed from Europe. (Announcement by the Secretary).
1. For information
on food safety and nvCJD see: http://www.cdc.gov/ncidod/diseases/cjd/cjd.htm (Centers
for Disease Control and Prevention); and CRS Report 96-641
(Archived) "Mad Cow Disease or bovine spongiform encephalopathy:
Scientific and Regulatory Issues" by Judy A. Johnson
and Donna U. Vogt.
is the USDA agency that is responsible for administering
the laws and regulations designed to prevent the importation
and spread of animal diseases.
Stecklow. "Hazardous Trade: Britain's feed exports extended
the risks of 'Mad Cow' disease". Wall Street Journal.
January 23, 2001.
4. In July
2000, USDA moved to seize and destroy two flocks of sheep
in Vermont after tests showed that they were infected with
scraple. These sheep had been imported from Belgium in 1996.
The U.S. District Court gave USDA the go ahead on February
2001, but the decision is under appeal. Scrapie is fatal
to the sheep but poses no known threat to humans.
29, 2001. Joint statement by the National Cattlemen's Beef
Association, the American Feed Industry Association, the
American Meat Institute, and ten other industry groups regardmig
efforts to prevent BSE in the United States.
are reimbursed for cattle at market value. One unintended
consequence of OTMS has been an accumulation of over 460,000
metric tons of Meat and Bone Meal (MBM) and 209,000 tons
of tallow waiting in warehouses to be disposed of as hazardous
sought to consolidate and modernize authorities of the Secretary
to restrict the importation and interstate movement of animals
for reasons of pest or disease control.