Transcript structure of a cows udder

EXPLORING DAIRY
ANIMALS AND
DAIRY PRODUCTS
Interest Approach
 Ask the students to raise their hands if they
like ice cream. Ask them to raise their hands
if they like pizza. Now ask them if they know
where the ice cream and the cheese on their
pizza comes from. Ice cream and cheese are
made from milk and milk comes from dairy
cows, but how do the cows produce the milk
and how is the milk made into other products
that we want and that are safe for us to
consume? Use this discussion to lead into the
lesson.
Student Learning Objectives. Instruction in this
lesson should result in students achieving the
following objectives:
 1 Understand the anatomy of dairy cattle and
how they produce milk.
 2 Explain how milk is processed for human
consumption.
 3 Describe dairy products and how they are
made.
Terms. The following terms are presented in this
lesson (shown in bold italics):
 Curds
 Homogenization
 Lumens
 Pasteurized
 Silage
 Teat
 Udder
 Whey
OBJECTIVE 1: Understand the anatomy of dairy
cattle and how they produce milk.
 Anticipated Problem: How does a dairy
cow make milk?
 I. Dairy cows take the food and water
they consume and turn it into milk to
feed their calves. The milk is also used
by humans.
OBJECTIVE 1 continued
 A. Dairy cows must be fed properly in order to produce milk.
 1. Dairy cows eat a total of 90 pounds of feed a day.
 2. They eat about 40 pounds of grain and hay and 50 pounds
of silage a day. Silage is chopped plant material that has
been allowed to ferment. Silage may contain leaves, stems,
grain heads, and other plant parts. Most silage is made from
green, growing crops, such as corn, grass, or sorghum.
 3. Cows also drink 25 to 50 gallons of water each day.
 4. With this amount of food and water, a dairy cow can
produce about 100 glasses of milk a day.
OBJECTIVE 1 continued
 B. Cows make milk in their udder.
 1. The udder is a pouch that hangs underneath the
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cow that contains the mammary glands.
2. The udder is divided into four sections.
3. Each section of the udder has a small tube called
the teat that lets the milk out.
4. Inside the udder are lumens that make small
drops of milk. Once the lumens make enough milk to
fill up the udder, milk comes out of the teat when the
cow is milked or when she feeds her calf.
5. A cow’s udder can hold 25 to 50 pounds of milk.
STRUCTURE OF A COWS UDDER
Central Wall or Median
Suspens ory Ligament
Fine Membrane
Between Quarters
Alveoli
Outer Wall or Lateral
Suspens ory Ligaments
OBJECTIVE 2: Explain how milk is processed for
human consumption.
 Anticipated Problem: How is milk
processed for human consumption?
 II. There are many steps involved in
getting milk from a dairy cow into the
store.
OBJECTIVE 2 continued
 A. Milk must be properly collected from the
cow.
 1. People have been milking cows for a
very long time. For many years farmers
milked cows by hand. When milking was
done by hand, it took one hour to milk six
cows. Today in the United States most of
the milking is done by milking machines.
With these machines producers can milk
100 cows in one hour.
OBJECTIVE 2 continued
 2. Milking machines are
placed on each of the cow’s
teats and gently suck the
milk out of the cow’s udder.
 3. The milk is then pumped
into a large tank at the farm.
 4. A truck from the dairy
company comes to the farm,
tests the milk, and then
takes it to the dairy to be
processed.
OBJECTIVE 2 continued
 B. Milk must be safe for humans to consume.
 1. At the dairy plant, milk is pasteurized, which
means it is quickly heated to a high temperature and
then quickly cooled.
 2. The pasteurization process kills germs and bacteria
that are naturally present in the cow’s milk. Germs
and bacteria canmake humans sick and can cause
the milk to spoil quickly.
 3. Homogenization breaks the fat globules in the milk
into tiny particles. If this step does not take place, the
fat or cream would sit on the top of the milk.
 4. After processing, the milk is poured into jugs and
cartons to be sold in stores. The milk is never touched
by human hands when it is in the plant, so it is one of
the safest foods you can eat.
OBJECTIVE 3: Describe dairy products and how
they are made.
 Anticipated Problem: How is milk
changed into other dairy products?
 III. Through many processes, milk is
made into many different dairy products.
OBJECTIVE 3 continued
 A. Ice cream is one of the most popular dairy
products. Sugar and flavoring are added to
milk and then frozen into ice cream.
OBJECTIVE 3 continued
 B. Cheese is made by allowing milk to sour and separate into
whey and curds.
 1. Curds are the chunks that form in soured milk and are the
beginnings of cheese.
 2. Whey is the liquid that remains after the curds form.
 3. The curds are separated from the whey and aged and
flavored to make the cheeses you eat every day.
OBJECTIVE 3 continued
 C. Butter is the cream, or fat, that is present
in milk. The fat is removed from the milk and
churned or shaken into a solid form called
butter.
OBJECTIVE 3 continued
 D. Yogurt is made by
adding certain bacteria to
concentrated, pasteurized
milk. The milk is then
heated at 110°F for four or
five hours to allow the
bacteria to grow. The
smooth, custard-like texture
that is formed is the result
of the growth of the
bacteria. Flavoring or fruit
can be added to the
mixture.
REVIEW
 1.
How does a dairy cow make milk?
How is milk processed for human
consumption?
 2.
 3. How is milk changed into other dairy
products?