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December 30, 2003 -- CropChoice news -- Washington Post, 12/29/03:
The coldly regimented process of raising a dairy cow
in North America forces it at an early age to depend
on dietary supplements that in rare instances can spread
mad-cow disease, according to livestock experts.
In addition, the frequent shuffling of young dairy
cows between specialized feedlots and milking farms
can make it difficult to track an infected animal to
the herd where it was born, these experts say.
When these cattle move — even between Canada
and the United States — they are not necessarily
individually identified, said Mary Beth Lang, a spokeswoman
for the Washington State Department of Agriculture.
"There are ear tags," she said. "But
they can fall off."
On large dairy farms in the United States and Canada,
calves often are separated from their mothers within
24 hours of birth. The reason is money: The milk a dairy
cow produces is worth far more on a supermarket shelf
than in the stomach of her newborn.
So calves, male and female, are shunted away from many
large dairy farms — usually within two weeks of
birth — to specialized feedlots, where they are
quickly weaned from milk and fed protein supplement
pellets, along with hay. These calves depend on supplements
for most of their protein intake until they are about
3 months old, when they are mature enough to digest
cellulose and absorb protein on their own.
Bovine spongiform encephalopathy, or BSE, the brain
malady known as mad-cow disease, can infect cattle that
eat protein supplements made from the remains of cattle
and other ruminant livestock. The disease is not transmitted
by milk, which calves would normally be getting from
their mothers.
"Because of the supplement regime, dairy cattle
are especially susceptible to this problem," said
Arthur Linton, a cattle geneticist and director of Washington
State University's Irrigated Agriculture Research and
Extension Center.
In the United States and Canada, the ground-up remains
of cattle and other ruminants, or animals that chew
a cud, were banned as ingredients for cattle supplements
in 1997. But the General Accounting Office, the investigative
arm of Congress, has twice criticized U.S. enforcement
of the ban as lax.
The U.S. Department of Agriculture (USDA) announced
yesterday that the Washington state dairy cow that tested
positive this month for mad-cow disease probably came
to the United States from the Canadian province of Alberta
in August 2001.
The age of the infected animal remains in dispute.
Canadian records show it was born in 1997, officials
said, whereas U.S. records suggest it was about two
years younger.
U.S. and Canadian investigators are trying to verify
the birth herd of the infected Holstein and 73 other
dairy cows that entered this country the same day.
Dairy calves are not uniquely susceptible to the risk
of mad-cow disease. The only other North American cow
that has tested positive for the disease was a beef
cow. Beef cattle, though they usually stay with their
mothers and suckle until they are at least 8 months
old, are also fed some protein supplements.
But it is only in recent years, as many modern dairy
farms have begun shuffling calves away from their mothers
as soon as they are born, that dairy cows have become
highly dependent on protein supplements for normal development.
On factory farms, female calves, called heifers, are
far more valuable — and usually much more carefully
fed — than bull calves. Bull calves from dairy
herds are usually castrated, becoming steers, and sent
to feedlots, where they are fattened for slaughter,
usually before the age of 2.
A bull calf is typically worth about $100, but a heifer
of the same age and breed is usually worth at least
three times more. When such a cow reaches 27 months
and is pregnant for the first time, she is worth nearly
$2,000.
To protect their investment in these animals, many
large-scale dairy farmers ship heifers to feedlots called
"heifer development operations." There, they
are put in individual pens and weaned from milk as quickly
as possible.
Away from their mothers and quickly weaned, the heifers
cannot develop normally without protein supplements.
It takes 60 to 90 days for them to develop the four-chamber
ruminant stomach that allows them to eat roughage and
extract protein from it.
It is during this period that heifers are especially
susceptible to infection from mad-cow disease, if they
are eating contaminated protein supplements.
The Food and Drug Administration says that although
enforcement of the ban on cattle remains in these supplements
was flawed for a few years, compliance has reached 99
percent.
The USDA said last week it is moving to correct another
byproduct of the modern cattle industry: lack of individual
animal identification as cattle are rotated among various
farms and feedlots and across state and international
borders.
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