Standard 1.0 Animal
Reproduction
Objectives
1.1.1 Analyze the male reproductive organs and their
functions.
1.1.2 Analyze the female reproductive organs and their
functions.
1.1.3 Analyze the estrous cycle in common livestock.
1.2.1 Compare and explain natural breeding methods
in animals.
1.2.2 Assess artificial breeding methods in animals.
Objectives
1.2.3 Discuss the advantages and disadvantages of natural
breeding and artificial breeding.
1.2.4Assess and analyze the materials, methods and
processes of artificial insemination.
1.3.1 Assess the advantages of major reproductive
management practices including estrous synchronization,
superovulation, flushing and embryo transfer.
1.3.2 Analyze the process of major reproductive
management practices including estrous synchronization,
superovulation, flushing and embryo transfer.
Terms
 1. artificial insemination- The injection of semen into
the uterus other than by natural mating.
 2. cervix- The narrow neck like passage forming the
lower end of the uterus
 3. copulation- the mating of a male and female
 4. corpus luteum- a reddish-yellow mass that forms
in a ruptured follicle in the ovary of mammals; the
hormone progesterone is released by the corpus
luteum
Terms
 5. diestrus- A period of sexual inactivity between
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recurrent periods of estrus.
6. embryo transfer- moving an embryo from one
female animal to another of the same species
7. estrogen- a hormone produced by the ovaries
8. estrous cycle-the time between periods of estrous
9. estrous synchronization-Using synthetic
hormones to make a group of females come in heat
at the same time.
Terms
 10. estrus- the time during which the female will accept
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the male for copulation; also referred to as being “in
heat”
11. follicle- a small blister-like development on the
surface of the ovary that contains the developing ovum
12. follicle stimulating hormone- a hormone produced by
the pituitary gland that promotes growth of ovarian
follicles in the female and sperm in the male
13. gestation-the time during which the animal is
pregnant
14. hormone- an organic material given off by a body
gland that helps regulate body functions
Terms
 15. metestrus-the luteal phase of the reproductive
cycle in mammalian females, occurring after
ovulation and characterized by development of the
corpus luteum, increased progesterone secretion,
and decreased estrogen secretion.
 16. ovary- A female reproductive organ in which ova
or eggs are produced
 17. ovulation- the release of the egg from the ovary
 18. oxytocin- a hormone that causes contractions of
the uterus during breeding and parturition and
causes milk letdown
Terms
 19. parturition- the act of giving birth
 20. penis- The male genital organ of higher
vertebrates, carrying the duct for the transfer of
sperm during copulation.
 21. proestrus- The period immediately before estrus
in most female mammals, characterized by
development of the endometrium and ovarian
follicles.
 22. progesterone- a hormone produced by the
ovaries that maintains pregnancy in the animal
Terms
 23. scrotum- A pouch of skin containing the testicles
 24. superovulation- the stimulation of more than the
usual number of ovulations during a single estrous
cycle due to the injection of certain hormones.
 25. testis- An organ that produces spermatozoa
 26. testosterone- a male hormone that controls the
traits of the male animal
Terms
 27. uterus- The organ in the lower body of a female
mammal where offspring are conceived and in which
they gestate before birth
 28. vagina-The muscular tube leading from the
external genitals to the cervix of the uterus
 29. zygote- a cell formed by the union of two
gametes
1.1.1 Analyze the male reproductive
organs and their functions.
What are the major reproductive organs in male mammals?
What are the functions of those organs?
 To have a successful livestock operation, a producer
must have an understanding of the various
reproductive organs and their functions.
 In most cases, a livestock operation will have only a
limited number of males available for breeding.
 The male reproductive system contains several
interconnected parts that must all work together for
successful mating.
Testicles or Testis
 The testicles or
testis produce sperm,
the male sex cells (also
called spermatozoa).
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They also produce a
hormone called
testosterone that causes
the appearance and
behavior of the animal to
be masculine.
Two testicles are present
in male mammals.
Epididymis
 The Epididymis is
the storage site for
sperm cells.
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From the testicle,
these cells enter the
epididymis to mature.
Sperm can fertilize a
female’s ova (female
sex cell) as it travels
through the epididymis.
A separate epididymis
is attached to each testicle.
Scrotum
 The Scrotum is a two-lobed sac that
contains and protects the two testicles.
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It also regulates the temperature of the testicles, which is lower
than the body temperature.
When the environment temperature is low, the scrotum
contracts, pulling the testicles toward the body and its warmth.
Maintaining the correct temperature is critical because
extreme temperatures (too hot or too cold) can affect the
production and vitality of sperm
What are the major reproductive organs in male
mammals?
 Vas deferens—The
vas deferens is
essentially a
transportation tube
that carries the spermcontaining fluid from
each epididymis to the
urethra.
 Urethra—The
urethra is a large,
muscular canal
extending from the
urinary bladder.
 Both semen and
urine move through
the urethra to the
end of the penis.
What are the major reproductive organs in male
mammals?
 The penis deposits the semen within the female
reproductive system.
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The urethra in the penis is surrounded by spongy tissue that
fills with blood when the male is sexually aroused, which
causes an erection that is necessary for copulation (mating)
to occur.
 The sigmoid flexure (found in bulls, rams, and
boars) and the retractor muscle extend the penis
from the sheath, which is a tubular fold of skin.
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Horses and other mammals do not have a sigmoid flexure.
1.1.2 Analyze the female
reproductive organs and their
functions.
1.1.2 Analyze the female reproductive organs and
their functions.
 The ovary produces female gametes, which are sex
cells that can unite with other sex cells.
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These are called ova (eggs).
A female mammal will typically have two ovaries, which also
produce the female sex hormones: estrogen and progesterone.
Within each ovary, there are hundreds of tiny follicles or
cavities.
The ova are produced in the follicles.
Each ovum is the largest single cell in the body.
1.1.2 Analyze the female reproductive organs and
their functions.
 The uterus of
mammals is a Yshaped structure
consisting of the body,
two uterine horns, and
the cervix.
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Size and shape of uterus
varies on each mammal.
The upper part of the
uterus consists of the two
uterine horns.
1.1.2 Analyze the female reproductive organs and
their functions.
 The cervix is the
lower outlet of the
uterus and is
composed primarily of
connective tissue that
constitutes the
gateway between the
uterus and the vagina.
1.1.2 Analyze the female reproductive organs and
their functions.
 The vagina serves as
the female organ of
copulation at mating
and as the birth canal
at parturition.
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It is the passage between
the cervix and the vulva.
The lining is moist during
estrus and dry when the
animal is not in estrus.
1.1.3 Analyze the estrous cycle
in common livestock.
Phases of the Estrous Cycle in Cattle
 Estrus (Day 1)
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Cow stands to be mounted
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The female will accept the male.
Mucous discharge from increased mucous production
Progesterone production is low
Lutenizing hormone (LH) spikes to a high which stimulates
ovulation
Phases of the Estrous Cycle in Cattle
 Metestrus (Days 2-6)
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Ovulation occurs
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Corpus Luteum (CL) starts developing
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Ovulation-release of the egg.
corpus luteum- a reddish-yellow mass that forms in a ruptured
follicle in the ovary of mammals; the hormone progesterone is
released by the corpus luteum
Bloody discharge
Progesterone levels start increasing as CL develops
Prostaglandin is not effective in stopping the CL (lysing the
CL) in this stage, therefore prostaglandin is ineffective at
restarting the cycle during this phase
Phases of the Estrous Cycle in Cattle
 Diestrus (Days 7-18)
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CL is producing increasing amounts of progesterone
CL matures
Prostaglandin will lyse (stop) the CL and initiate a return to
estrus during this phase
Phases of the Estrous Cycle in Cattle
 Proestrus (Days 18-21)
 (If fertilization occurred)
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Progesterone will continue to be produced at high levels and will
protect the embryo throughout the pregnancy
Embryo will embed in to the wall of the uterus and fetus will develop
 (If fertilization did not occur)
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The CL will begin to regress
As the CL regresses, progesterone levels will also start to decrease
allowing the Lutenizing Hormone (LH) and estrogen levels to
increase
Because the CL is already decreasing, prostaglandin may be
ineffective during this phase as well
1.2.1 Compare and explain natural
breeding methods in animals.
REPRODUCTIVE PROCESSES
OF AGRICULTURAL
ANIMALS
Beef Cattle
 Age at Puberty:
8-15 Months
 Ovulate on an
estrous cycle
 (18-24 days)
 Gestation Length:
 9 months
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Parturition
Copulation
Sheep/Goats
 Age at Puberty:
5-6 Months
 Ovulate on an
estrous cycle
 (16-18 days)
 (Affected by
day length)
 Gestation Length:
 5 months
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Parturition
Copulation
Pigs
 Age at Puberty:
5-6 Months
 Ovulate on an
estrous cycle
 (19-22 days)
 Gestation Length:
 3 months,
3
weeks, 3 days

Parturition/Farrowing
Copulation
Horses
 Age at Puberty:
12-18 Months
 Ovulate on an
estrous cycle
 (18-24 days)
 Gestation Length:
 11 months
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Parturition
Copulation
Rabbits
 Age at Puberty:
6 Months
 Induced ovulators
 (ovulate after
mating occurs)
 Gestation Length:
 30 days
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Parturition
Copulation
Llama/Alpaca
 Age at Puberty:
20-24 Months
 Induced ovulators
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 (ovulate
after mating
occurs)
 Gestation Length:
 12
months
Parturition
Copulation
Chicken
 Age at Puberty:
4-6 Months
 Release egg on
regular cycle
 (24 hours)
 Incubation Length:
 21 days
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Hatching
Copulation
1.2.2 Assess artificial breeding
methods in animals.
WHAT IS ARTIFICIAL INSEMINATION?
1.2.2 Assess artificial breeding methods in
animals.
 Artificial insemination is the placing of semen in
the female reproductive tract by artificial techniques.
 The use of this technique has increased over the past
several years due to advancements in technology.
 The process varies by species, but it typically involves
specialized equipment and a trained technician.