Animal Reproduction
Extension beyond the Textbook
Conditions for Fertilization
Anatomy of Male & Female must
be compatible
 Female must be in Heat
 Egg must be mature

What is the function of the Male?
produce large numbers of live sex cells
(spermatozoa)
 contribute 1/2 chromosomes

What are the Male Reproductive
Organs?
Testicles - produce spermatozoa & male hormone
Testosterone
 Scrotom - sack which carries testicles

– functions as a heat regulator
Monorchid - one fertile testicle
 Cryptorchid - both testes remain in body cavity
(sterile)
 Castration - removal of testicles

– lack sex drive
– gain weight quicker
What are the Male Reproductive
Organs?
Epididymis - tube connects to testes
 storage of spermatozoa (200
billion at a time)
 spermatozoa mature as they
migrate through
 Vas Deferens - tube connects to
epididymus

– if removed, can't reproduce = vasectomy
What are the Male Reproductive
Organs?
Urethra - begins at bladder and continues
through penis
 Sigmoid Flexure - "S" shape in urethra
allows for extension of penis outside of
body for reproduction

Accessory Sex Glands
prostate
 two seminal vesicles
 two cowpers glands

What is the function of the
Accessory Sex Glands?
provide medium for transporting
sperm
 adds volume
 provides nutrients
 cleans & flushes urinary tract

Artificial Insemination
Class
ml/ejaculate SpermConc No. Females
Bull
5-6
800-1,200
300-500
Ram
1
800-4,000
40-100
Boar
200-300
25-1,000
15-25
Stallion
50-150
30-800
8-12
What is the function of the
female?
contribute 1/2 chromosomes
 care for young in uterus and after
birth until weaning

What are the Female
Reproductive Organs?
Vulva - exterior portion of reproductive
tract
 provides visual signs of heat
 Vagina - between vulva & cervix

– Cows & Ewes: semen is deposited here
– Mares & Sows: semen is deposited in the cervix
What are the Female
Reproductive Organs?
Cervix - "Mouth of the womb"
 opening into uterus
 at birth cervix stretches to allowbaby to pass
(most painful part)
 during pregnancy cervix becomes blocked
with a mucous plug to prevent infection

What are the Female
Reproductive Organs?
Uterine Horns - two branches of uterus
 Fallopian Tube - uterine horn becomes a
small tube

– lined with cilia which aid in egg migration
Ovaries
located at end of fallopian tubes
 possesses large number of eggs in all stages
of development
 this is all the eggs she will ever have, unlike
the male
 very few eggs reach maturity
 if not fertilized, the egg is reabsorbed by the
body

Reproduction in Males
After sexual maturity, sperm production is
continuous
 Testosterone is responsible for:

– growth, development & activity of accessory
glands
– survival of spermatozoa
– secondary sex characteristics:male voice, sex
drive
Reproduction in Males
Semen - collective term for all fluid
ejaculated
 sperm and fluid from accessory
glands

Reproduction in Females
Farm animals reach sexual maturity at 4
months (sow) to 24 months (mare), then
Female comes in heat (estrus)
Egg released by ovary
Egg travels down tube until fertilized by
sperm
 Estrogen - female hormone which regulates
estrus

What does "in heat" mean?
Heat is the time when a female is receptive
to the male and will allow breeding to take
place
 Heat is actually divided into 4 phases of the
cycle.

Estrous Cycle:
Proestrus: ovary is about to release an egg
Estrus: female receptivity
Metestrus: uterus prepares for pregnancy
– fertilized egg attaches to uterus
Diestrus: longest period of cycle
– inactive

Estrous Cycles stop after conception, and
begin soon after Parturition (birth)
Females also show external signs
of "Heat"
aggressive behavior
 swelling and/or color change of vulva

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Beef Terms
A Mature Male is called a:
Bull
A Mature Female is called a:
Cow
The act of Giving Birth is called:
Calving
Gestation =
283 days
A Castrated Male is called a:
Steer
An Immature Female is called a:
Heifer
What do you call a mature male hog?
Boar
 What do you call a mature female hog?
Sow
 What do you call the act of giving birth?
Farrowing
 What do you call a castrated male hog?
Barrow
 What do you call an young female hog?
Gilt
 What is the gestation for hogs?

Poultry Terms
 What do you call a mature male?
Rooster
 What do you call a mature female?
Hen
 What do you call a young female?
Pullet
 What do you call a castrated male?
Capon
 Chickens Hatch
 What is the incubation period?

What do you call a mature male horse?
Stallion
 What do you call a mature female horse?
Mare
 What do you call a castrated male horse?
Gelding
 What do you call a young horse?
foal or colt

What do you call an immature female
horse?
Filly
 What do you call the act of giving birth for
horses?
Foaling
 What is the gestation for a horse?
330 days
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