Reproductive system
Male Anatomy
Male reproductive is made up of a pair of testicles, vas deferens, urethra and penis with
its associated organs.
Spermatic cord
Source: http://animalsciences.missouri.edu/reprod/Notes/male/anatomy.htm
Symphasis of the pelvis - immovable bone in the median plane of the body
Rectum - posterior end of the gastrointestinal (GI) tract
Scrotum - external sac that holds testicles outside of the body to keep sperm at 4-5oF
cooler than the body temperature for effective sperm production except in elephant and
rooster in which testicles are located inside body
Testicles - the primary male organs of reproduction (testis is singular; testes is plural)
Functions of the testicles:
1. To produce sperm in the seminiferous tubules
2. To secrete testosterone in the Leydig cells; this is the male sex hormone that
stimulates the development of the male sex characteristics.
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Seminiferous tubules - glandular part of testicles containing the sperm producing cells
Epididymis - a common path sperm take after formation in the seminiferous tubules;
sperm mature and accumulate here prior to ejaculation.
Functions of the epididymis:
1. Provide passageway for sperm out of the seminiferous tubules
2. Storage for sperm
3. Fluid secretion to nourish sperm
4. Place for sperm maturation
Vas Deferens - slender tube from epididymis to urethra, which moves sperm to the
urethra at ejaculation
Spermatic Cord - vas deferens, cremester muscle, spermatic artery, spermatic vain and
spermatic nerves
Bladder - storage for urine
Urethra - long tube from bladder to penis; passageway for urine and sperm out of the
body
Accessory Glands:
Seminal vesicles - lobe type organ near the end of the vas deferens
Function of the seminal vesicles:
add fructose and citric acid to nourish the sperm
Prostate Gland - located at the neck of the bladder
Functions of the prostate gland:
1. Cleans the urethra prior to and during ejaculation
2. Provides minerals for sperm
3. Provides the medium for sperm transport
4. Provides the characteristic odor of semen
Bulbourethral gland - paired organs
To clean the urethra prior to semen passage
Penis retractor muscle - allows extension and retraction of the penis; sigmoid flexure
extends in copulation (taut - sexual rest; relaxed - sexual excitement)
Penis - male organ of copulation, which conveys semen and urine out of the body
Clinical importance
Phimosis inability of penis to protrude out of sheath
Paraphimosis inability of penis to retract into the sheath after protrusion
Penile fracture seen in dogs because of presence of bone in penis
Scrotal hernia migration of internal organ into scrotum
Brucellosis bacterial disease affecting testicles
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Female Anatomy
Female reproductive tract is made up of a pair of ovary, oviduct, uterus, cervix, vagina
and vulva. Reproductive tract of cow is shown below
Source: http://old.cvm.msu.edu/courses/AP/bessie/cowrepro.htm
Ovary - the ovary is comparable to the male testicle and is the site of gamete production.
A bovine animal has 20,000 potential eggs per ovary, (Ova are fully developed at puberty
and are not continuously produced as in the male). All species contain two functional
ovaries except for the hen, which has only a left functioning ovary.
The ovaries have three major functions:
1. To produce gametes
2. Secrete estrogen
Estrogen is the hormone responsible for the secondary sex characteristics in the
female:
o Absence of muscle development
o Development of mammary glands
o Development of reproductive systems and external genitalia
o Fat deposition on hips and stomach (source of energy)
o Triggering of estrous cycle at puberty
o Triggering of heat
3. Form the corpus leutum
That releases progesterone, which is required for the maintenance of pregnancy if animal
get pregnant
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Infundibulum - the flared portion of the fallopian tube near the ovary that catches the
ovulated egg. Cilia movement and muscle contractions push the ovum into the fallopian
tube.
Fallopian Tubes (or Oviducts) - pair of small cilliated tubes leading from the ovaries to
the horns of the uterus (5 - 6 inches). Fertilization occurs in the upper 1/3 of the oviduct.
Egg travels from ovary to uterine horn in 3 - 4 days.
Uterine Horn - the anterior, divided end of the uterus in cow, ewe, and mare. Sow has
only 2 horns, no body; woman has no horns, only body.
Uterus - the muscular sac connecting the fallopian tubes to the cervix. This organ can
have two parts (the body and the horns).
The uterus has three major functions:
1. Sustains the sperm and aids in its transport to oviduct
2. Supports embryo and fetus during gestation
3. Expels fetus at parturition
Cervix - restricted area between the uterus and vagina, which opens at estrus and
parturition. Otherwise, it remains closed to protect the uterus (2 -3 inches).
Vagina - the female organ of copulation
Functions of the vagina:
1. Admits penis
2. Receives semen (except in sow)
3. Passageway for fetus at parturition
Bladder - storage organ for urine.
Urethra - opening of bladder into vagina
Vulva - extended genitalia; opening for both urinary and genital tracts
Clitoris - located just inside vulva, rudimentary male organ
Reproductive Functions of the Female
The female has several major functions during reproduction:
1. produce gamete (ova or ovum)
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ovulation - release of egg(s) from graafian follicle into oviduct where
fertilization can occur if sperm are present.
Ovulation Rates by Species
cow 1 egg per estrus
ewe 1 - 3 eggs per estrus
sow 10 - 20 eggs per estrus
mare 1 egg per estrus
hen ~ 28 eggs per month
At ovulation, the ruptured follicle, or corpus luteum, becomes a temporary
endocrine organ, secreting progesterone
The infundibulum pushes the ovum into the fallopian tube If not, an ectopic
pregnancy may occur. The egg is fertilized in the upper 1/3 of the oviduct and then
moves to the uterus.
2. Develop embryo in uterus from fertilization to parturition (this period is gestation)
3. Expel fully developed young at birth (parturition)
Species Act of giving birth Offspring
Cow
Yak
Calving
Calf
Buffalo
Ewes
Lambing
Lamb
Sows
farrowing
Piglet
Hens
Hatching
Chick
Mares
Foaling
Foal
Doe
Kidding
Kid
Bitch
Whelping
Pup
Queen
Kittening
Kitten
4. Produce milk (lactation) to nourish young
Clinical importance
1. Under developed genital tract due to poor nutrition may result in late onset of
estrus
2. Freemartinism may result in permanent sterility
3. Ovarian cysts may result in infertility
4. Mishandling during calving may cause uterine prolapse
5. AI gun may go into urinary bladder
http://nongae.gsnu.ac.kr/~cspark/teaching/chap3.html
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