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Weekly Online LessonOnline Lesson ArchiveGrade Level: 8-12
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Cows in Crisis
Imagine being afraid of your favorite
cheeseburger. Over the last 14 years, thousands of Europeans have refused
to eat beef because of fear for their health. The living nightmare is
known as "mad cow disease," scientifically named as Bovine Spongiform
Encephalopathy (BSE), and it has killed about 92 people in Britain, 180,000
cattle in England, Scotland and Wales, and has been detected in cattle
herds from 11 different countries.
The primary way in which
the disease spreads is through cows eating feed that gets some of its
protein content from parts of animals that were infected with it. Once
a cow ingests this pathogen, it can take 2-8 years for the symptoms of
infection to become noticeable. Worse, scientists have found no cure for
it, and, in fact, some are still debating what exactly it is. Many believe
it is a "misfolded protein," similar to one that apparently
causes Alzheimer's disease in humans, which also has no cure.
In this week's lesson, you will learn about why "mad cow disease" is so devastating to both domestic livestock and humans, and take a look at some particulars of the cattle industry.
Pinpointing an elusive killer
To understand
why governments, health agencies and families worldwide fear this disease,
first delve into the science of the killer. Start out by visiting the
U.S. Department of Agriculture site on Bovine Spongiform Encephalopathy and learn about the
history and basic biology of the pathogen. Then read The mysteries of
mad cow disease to find out more about how exactly the
culprit works and why scientists are struggling to understand it well
enough to eradicate it. What do scientists know about the pathogen and
what is still a mystery? How will further study of this disease influence
the knowledge in other medical fields?
The Development of Cattle Country
Domestication of cattle may have begun about 8,500 years ago from apparently
one species. Today, about 50 breeds of cattle exist and have become primary
economic contributors for many nations. Find out more about Cattle Breeds by
reading this historical overview, and then read about several of the types
listed. How do the breeds look different and why? Where were they created?
Take a trip to one of the largest working cattle ranches in the U.S. — the King Ranch in southwest Texas. Check out the pages on the History of the ranch and the Cattle. Also, go on the Virtual Ranch Tour, and visit both the Museum and the Main House. How has the ranch changed since it was first founded? How are cattle fed and cared for? What are the risks, costs and rewards of cattle production?
Learn more about why beef is an important industry to the American lifestyle. Review the Fast Facts, and you can download a PowerPoint presentation about Beef Demand (click on each slide to move to the next one). The charts demonstrate how the prices, production, imports, etc. have changed over time. You can also find out how many farms and how large they are in each state by typing in the two-letter abbreviation. The resulting page will also provide a link to that state's agricultural site with related information.
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