Natural Animal Reproduction
What is Reproduction?
Animal Reproduction Basics
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Reproduction
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The process by which offspring are produced.
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Offspring are of same species & have similar traits
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Not essential for an organism to live but is essential if a species
is to stay in existence
Animal Reproduction Basics
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Insemination
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Natural Insemination
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Placing of the sperm in the reproductive tract of the female.
The process of the male depositing semen (fluid containing sperm) in
the reproductive tract of the female.
Occurs during copulation or mating
Copulation
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The sexual union of a male and female animal
Animal Reproduction Basics
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Artificial Insemination
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Involves a technician collecting semen from a male and placing
it in the reproductive tract of a female
http://www.youtube.com/watch?v=stvnGYcKz60
What are some Benefits of AI?
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http://www.youtube.com/watch?v=fmSSTueUhoQ
Animal Reproduction Basics
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Breeding
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Is promoting animal reproduction so the desired offspring
result.
Reproductive Efficiency
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The timely and prolific replacement of a species.
This is the difference between success and failure in animal
production.
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Estrous
Estrous Cycle
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The time between periods of estrus
Estrous cycle of female mammals has four periods
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Cyclical expect during gestation or pregnancy (cattle or swine)
Some animals are seasonal breeds and may go through periods of
anestrus
Anestrus
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The absence of cycling
Often related to the number of hours of light in a day
Examples: Sheep, cats, goats and horses
Four Periods of the Estrous Cycle
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Estrus
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Also known as heat
Period when the female is receptive to the male and will stand for
mating
Length varies between species
Triggered by the hormone estrogen
Changes that take place during estrus
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Restlessness
Mucus discharge
Swollen vulva
Standing to be ridden by other animals
Ovulation takes place during estrus for most species
Ovulation-when a mature ovum is released by the ovary
Four Periods of the Estrous Cycle
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Metestrus
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Ovulation occurs during metestrus in cattle and goats.
The luteinizing hormone triggers the corpus lutea to develop
from follicular tissue that remains after the release of the ova
Four Periods of the Estrous Cycle
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Diestrus
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Period in the cycle in which the system assumes pregnancy.
Fully functional corpus luteum releases high levels of
progesterone.
Progesterone-hormone that maintains pregnancy
Uterus is prepared for pregnancy
Four Periods of the Estrous Cycle
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Proestrus
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Begins with the regression of the corpus luteum and a drop in
the hormone progesterone
Changes in behavior may occur as estrus approaches
What is fertilization?
Fertilization
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The union of a sperm and an egg.
The “roadmap” for fertilization is different between
mammals based upon their reproductive tract.
Process begins by male mammal depositing sperm in
female mammal’s reproductive tract during mating.
Fertilization Continued
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After sperm is deposited, sperm gradually travels through the
female’s reproductive tract until it reaches the infundibulum
(where ovum rest during ovulation)
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Sperm cell pierces an egg cell if present
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Only one sperm cell may fertilize an egg cell
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Crucial to time the presence of eggs cells and live sperm cells in
a mammal.
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After an egg cell is released in a female mammal’s reproductive tract it
has less than 12 hours to become fertilized by a sperm cell.
Sperm cells cannot survive a long duration in a female mammal’s
reproductive tract.
What is a gestation period?
Gestation
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After fertilization occurs gestation begins
Gestation
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The period of time in which an animal is pregnant
Gestation periods vary between species
Gestation Process
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After fertilization occurs gestation continues as a series of cell
divisions as the new animal (embryo) moves towards the
uterus within 3-4 days.
Embryo engages in rapid growth cycle called differentiation
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Develops major organs in the embryo
After differentiation the new animals is known as a fetus
Gestation Process Continued
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At this point fetus is surrounded by watery fluid enclosed in
membranes
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Grows slowly in the uterus
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Fetus has an umbilical cord that is connected from its navel to the
placenta, which lie along the wall of the uterus.
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Umbilical cord connection:
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Blood vessels that supply nutrients and oxygen to fetus
Exit waste products
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The head, nervous system and blood vessels develop first
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Majority of the growth of the fetus occurs in the last stage of the
gestation period.
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Parturition
The process of a pregnant organism or animal giving birth to fetus
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Akalabor
Three steps of Parturition
1.
Start of uterine contractions and the reproductive organs prepare for
the birthing process.
a.
b.
c.
2.
Abdominal muscular contractions occur and mother starts to pass the
fetus.
a.
b.
3.
Birth canal begins to open
Female ‘s muscles begin to relax as fetus prepares to pass
Fetus begins to align with the canal and the mother’s respiratory rate
increases
Fluid is released from the uterine body as lubricant.
Stage concludes with the birth of the fetus.
Expulsion of the placenta
a.
b.
Mother's straining ends and she begins to relax
Placenta detaches from the uterine wall and fetal membranes are released.
Parturition
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http://www.youtube.com/watch?v=63rgERk2GQ&feature=related