KEY
Note Taking Guide 2
Topic # 3025
Anatomy and Physiology: Reproductive Systems
General Information




Reproduction is a complicated process in all species of animals
The anatomy of both the male and female must be compatible.
Physiological compatibility and timing is also required
Must have similar genetic makeup




The female must be willing in heat to accept the male
Ovum must be mature and ready to be fertilized
Dependent on the proper function of many organs
Any abnormality in the anatomy or physiology of the reproductive tract result in
lower fertility or complete sterility of the animal
Anatomy of the Male Reproductive Tracts





Less complex than the females
Goal is to produce large numbers of viable male sex cells called spermatozoa.
Contributes ½ of the chromosomes to each of his offspring
After mating the role of the male is over
Reproductive organs in the various mammalian species are similar in form and
function
Scrotum





Testes or testicles in the male are the primary sex organs and are held in a sac
called the scrotum
Produce spermatozoa and testosterone
Normally two testicles in a scrotum
Functions as a heat regulating mechanism
4 or 5 degrees below body temp. is essential for spermatogenesis - growth and
maturation of the sperm
Testicles




Some animals only have one or neither testicle drop out of the body cavity into
the scrotum
A monorchid as one fertile testicle
Although the testicle in the body does not produce viable spermatozoa, it does
produce testosterone
Cryptorchid is sterile and means neither dropped.
Urethra

Begins at the opening of the bladder and is continuous with the penis

In mature bulls, the posterior portion of the urethra is S-shaped - known as the
sigmoid flexure
Extends the penis outside of the body and into the vaginal cavity of the female so
that the semen can be deposited.
If the Sigmoid flexure does not work you have the equivalent of the sterile male
The retractor muscle retracts the penis into the protective sheath
"Accessory Sex Glands" along the urethra include the:
Prostate Gland
Two seminal vesicles
Two Cowper's
The accessory Sex Glands provide a medium for the transport of the sperm from
the testes to the vagina.
The Medium:
Adds Volume
Provides Nutrients for the sperm
Cleans and flushes out the urinary tract.
Makes a plug to hold the semen in the vagina (in some species)













Important Roles of Females


Provides ½ of the chromosomes of the young
Nourishes young in her uterus and after birth until weaning
Female Reproductive Tract



Female Tract consists of:
Vulva
Vagina





Cervix
Uterus
Uterine horn
Fallopian tubes
Ovaries
Vulva

Exterior portion of the reproductive tract
Vagina


Region between the vulva and the cervix
Semen is deposited in this region in cows and ewes
Vagina Compared





Length (Vagina + Vestibule)
Cow 35 - 42 cm
Ewe 12 - 17 cm
Sow 16 - 23 cm
Mare 30 - 47 cm
Semen deposit

Cows and ewes have semen deposited here, mares and sows have semen
deposited in cervix.
Cervix





"Mouth of womb"
The opening into the uterus through which sperm must pass to fertilize the egg.
Semen deposited here in mares and sows
Area stretches during birth to allow passage of newborn
Becomes blocked by mucus plug to protect it from harmful infections
Uterine Horns





The two branches of the uterus
Fallopian tubes or oviducts are located at the end of each horn
lined with microscopic cilia
help guide egg (ovum) to the horn
Usually the site of sperm and ovum uniting
Value of Castration

Definition: Removal of the testicles are located at the end of each horm
Ages for Castration




Recommended
Calves: 1 - 3 months
Lambs: 7 - 14 days
Pigs: 1 - 3 weeks
Why Castrate





Makes male animals less aggressive and easier to handle aggression
Due to the effects of "androgens"
androgens: hormones that control the appearance and development of masculine
sex characteristics
Removal of testes stops production
Primary androgen is "testosterone"
References:
http://ampacseed.com/links.htm
http://geocities.com/~cowpokinfun/links.htm
http://babs.co.nz/hurstmere/