Download bsaa growth hormones in animals worksheet

GROWTH HORMONES IN
ANIMALS
Illinois Biological Science Applications in Agriculture Lesson C2–9 • Page 1
Student Learning Objectives. Instruction in this lesson should result in
students achieving the following objectives:
1 Understand the effects that bovine somatotropin has on the cow.
2 Understand the arguments for and against the use of growth hormone in cows.
3 Appreciate the amount of testing and research a drug needs to go through to
be legally marketable.
Anticipated Problem: What is bovine somatotropin and what effects does its use have
on a cow?
I. Bovine somatotropin, or bST for short, is a naturally occurring protein in cows that
affects milk production.
A. bST is naturally produced by the pituitary gland of the cow. This hormone stimulates
the liver to produce an insulin-like growth factor (IGF-1), that is a protein hormone
that helps turn nutrients into milk. IGF-1 is carried by the bloodstream to the cow’s
mammary glands in the udders, where it stimulates milk production. Growth hormones
can be used for many purposes including increased milk production, increased
growth, and increased growth rate.
B. Additional injections of bST into the bloodstream of the cow have been shown to
increase the amount of IGF-1 produced by the liver, in turn causing an increase in milk
production by the cow.
C. The bST works in cows on the basis of a negative feedback system. A negative
feedback system has the ability slow down or shut down the production of a substance if
too much of that substance is being produced. The growth hormone bST causes an
increase in protein synthesis, amino acid production, and gluconeogenesis, the synthesis
of glucose by the liver from amino and fatty acids. The increased levels of glucose and
proteins will cause the pituitary gland to stop producing the growth hormone until
glucose and protein levels begin to fall.
Illinois Biological Science Applications in Agriculture Lesson C2–9 • Page 3
Anticipated Problem: What are arguments for and against the use of growth hormones
in cows?
II. The major controversy surrounding the use of bST is an emotional one.
A. Supporters of bST use the following arguments:
1. Although synthetic bST is exogenous, or made outside the body, and natural bST is
endogenous, or made inside the body, there is no difference between the two types of
growth hormone.
2. bST has been developed and researched for over 30 years and has been approved for
use by the FDA (Food and Drug Administration).
3. bST is in all milk and has been proven through laboratory testing to be harmless to
humans because it is species specific, meaning that only certain species of organisms
have the ability to utilize the substance.
4. bST provides a significant increase in the amount of milk a dairy farmer produces,
meaning increased profits for the farmer.
B. Opposition to the use of bST use the following arguments:
1. Increased bST levels in cows can lead to a higher incidence of mastitis and lengthen
the period of time before a cow returns to her heat cycle after lactation.
2. Even synthetic bST is a genetically modified substance and therefore should not be
consumed by humans.
3. Modifying the natural bST levels in cows is not healthy for the cow or ethically
correct.
4. Thin cows may become thinner with the use of bST as nutrients are used in increasing
amounts for milk production instead of body maintenance.
Anticipated Problem: What is the amount of testing and research that a drug must go
through to become legally marketable?
III. The approval of any drug for use in humans or animals is a long and extremely
expensive endeavor.
A. All drugs begin with laboratory research and development. Bovine Somatotropin was
first noted for the ability to increase milk production in 1936 by Russian scientists.
B. After years of research, the drug is ready to begin testing with the Food and Drug
Administration (FDA). The FDA independently tests the drug over a period of years to
insure that the drug has the desired effect and does not create any unwanted side effects.
Synthetic bST began serious testing in 1979 and did not receive full approval by the
FDA for production until 1993 by the Monsanto company.
C. As the drug is being researched, tested, and retested, companies interested in
producing the drug must pay for the laboratory costs and testing costs. These costs may
spiral into the hundreds of millions of dollars before the company even begins production
of the drug.
GROWTH HORMONES IN ANIMALS
Part One: Matching
Instructions: Match the term with the correct response.
a. Pituitary
b. Somatotropin
c. Endogenous
d. Exogenous
g. Mastitis
e. Negative Feedback System
f. Gluconeogenesis
_______1. The gland that produces growth hormone.
_______2. An inflammation of the udder of lactating animals.
_______3. An internal system to control the production of a growth hormone.
_______4. Produced inside the animal body.
_______5. A growth hormone shown to increase milk production in cows.
_______6. The synthesis of glucose in the liver into amino and fatty acids.
_______7. Produced outside the animal body.
Part Two: Completion
Instructions: Provide the word or words to complete the following statements.
1. The initials FDA stand for the _________ and __________ ________________.
2. bST increases the amount of IGF-1 produced by the ____________.
3. bST produced in a laboratory is known as ______________.
Part Three: Multiple Choice
Instructions: Circle the letter of the correct answer.
_______1. The ability of a particular species of an organism to utilize a substance is known as:
a. negative feedback mechanism
b. gluconeogenesis
c. species specificity
d. somatotropin
Illinois Biological Science Applications in Agriculture Lesson C2–9 • Page 7
_______2. Growth hormone is produced by the ______________ gland.
a. thyroid
b. pituitary
c. liver
d. lymph
_______3. How does the hormone regulate itself so that too much is not produced?
a. negative feedback mechanism
b. gluconeogenesis
c. series specificity
d. exogenous hormones
_______4. The synthesis of glucose by the liver from amino acids and fatty acids is known as:
a. negative feedback mechanism
b. gluconeogenesis
c. series specificity
d. digestion
_______5. A hormone that is produced within an organism or animal is known as:
a. endogenous
b. exogenous
c. somatotropin
d. FDA
_______6. What are the benefits of the administration of a Growth Hormone, such as bST, in
dairy cattle?
a. increases the growth rate of the cattle
b. increases the amount of growth
c. increases the milk production
d. all of the above
_______7. hy would livestock producers want to administer growth hormone to their animals to
reach market weight sooner?
a. they can sell the animal sooner
b. it would take less feed
c. it would save the producer money
d. all of the above
Part Four: Short Answer
Instructions: Provide information to answer the following statement.
Give two arguments for and two arguments against the use of bST in dairy cows.
Illinois Biological Science Applications in Agriculture Lesson C2–9 • Page 8
Assessment
Technical Supplement
GROWTH HORMONES IN
ANIMALS
1. What is meant by species specific and why is that important in this situation?
Species specificity refers to the ability of only one type of organism (animal in this
case) to be affected by a certain substance. For example, lice are species specific. The
lice that cattle get cannot be spread to humans. With Bovine Somatotropin (bST), it
is only effective for use as a growth hormone with cows and Porcine Somatotropin
(pST) is only effective in swine. This is important because it limits the use of the
various growth hormones, drugs, etc. to one type of animal and is thus ineffective in
others.
2. What safety aspects need to be considered when marketing a product like
bST?
There are several pharmaceutical companies that do a great deal of bio-technical
research in animal agriculture. Some of these companies are Monsanto, Upjohn,
Elanco (Eli Lilly), and American Cyanamid. bST was approved for use in the dairy
industry on February 4, 1994, by the United States Food and Drug Administration
(FDA). Monsanto is the company that first put bST on the market under the product
name of Posilac. This Bovine Growth Hormone (BGH) had been tested by
Monsanto for seven years under the direct supervision of the FDA. It was approved
for use in Mexico in 1990. The safety aspects that must be considered are whether
the products received from using increased growth hormones have any effect on
humans.
The major controversy concerning bST has been an emotional one. This has been
true of similar issues over past years. Twenty years ago many people were concerned
Illinois Biological Science Applications in Agriculture Lesson C2–9 • Page 17
that growth hormones were being used on beef animals to increase feed intake.
Today implants such as Ralgro are commonly used. bST must be used along with
good management in a dairy herd in order to gain increased milk production
economically.
Negatives associated with the use of bST are that cows tend to stay open
(not pregnant) a couple of extra days per lactation, it should not be used on cows
with a history of mastitis because of problems with treatment, and thin cows may
have weight gain problems because the extra bST causes more body reserves of
nutrients to be pulled out for milk production.
3. From your research what is the chemical composition of bST and why is
this significant?
Supplemental bST is a protein hormone identical to the bST produced naturally by
the cow's pituitary gland. Supplemental bST is injected under the cow's skin and
absorbed into the bloodstream. (This injection is recommended to begin the ninth
week of lactation and quit two weeks before dry off.) The blood carries the hormone
to the liver. bST in the liver stimulates the liver to produce an insulin-like growth
factor (IGF-l), a protein hormone that plays an important role in helping to turn
nutrients into milk. IGF-l is carried to the cow's mammary gland, where it stimulates
milk production. Supplemental bST helps increase production by improving
the efficiency with which cows turn feed into milk. To support increased milk
production,
the cow increases its feed intake during bST supplementation. Nutrient
requirements for the cow's body maintenance remain unchanged; therefore, the
cow's increased nutrient intake is used primarily for milk production.
Supplemental bST and naturally produced bST in the cow's pituitary gland are
chemically identical. A high producing cow's pituitary gland produces more bST
than that of a poor producer. Thus you cannot label milk sold in the local supermarket
as being bST free because all milk contains some level of bST hormone.
4. What is meant by a “negative feedback mechanism” when referring to hormones?
Negative feedback mechanism is a control mechanism by which the production of a
hormone can be shut off by the production of that hormone. Thus in some cases
when a hormone is supplemented, the body that normally produces the hormone
slows down or completely stops production.
Illinois Biological Science Applications in Agriculture Lesson C2–9 • Page 18
5. For what other species could this type of drug be effective?
The use of growth hormones in other species is unlimited. Some such uses are:
Swine pST—growth hormone for increased feeding efficiency for greater pork
production.
Beef—Growth hormones have been in use for years.
Sheep—Wool like human hair is produced by the cells of the skin and is in part
controlled by Epidermal Growth Factor (EGF). If EGF is injected, the wool
grows faster and becomes so fine that it falls out as soon as it is brushed. Research
in Australia is progressing and working with various problems.
Salmon—Research is being done in Japan that will accelerate the growth of
salmon and increase their weight at maturity.
There are many more possibilities. The use of growth hormones could result in
meat that is richer in proteins and has less fat and water.
Illinois Biological Science Applications in Agriculture Lesson C2–9 • Page 19