The document summarizes the anatomy and physiology of bovine reproduction. It describes the main female and male reproductive organs of cows and their functions in the estrous cycle, fertilization, gestation, parturition, and lactation. It also discusses breeding methods for cattle like natural mating, artificial insemination, and embryo transfer.

2. Bovine
 Ovary – primary
reproductive
organ, produces
gametes and sex
hormones
 Oviduct –
transport sperm
to ovum and
embryo to uterine
horns

3.  Uterus –attachment site of placenta
 Cervix – elastic muscle protects uterus
from contaminants
 Vagina – female organ of copulation
connecting the vulva to cervix; elastic
tissue for birth canal
 Vulva – external
opening of
reproductive canal

4.  Cow: almond shaped
ovaries; one larger than the
other
 Ewe/Doe: almond shaped
ovaries; half the size of the
cow
 Mare: kidney shaped
ovaries; three times larger
than cow
 Sow: cluster of grapes
shaped ovaries; half the size
of the cow
 Bicornuate uterus: 80 – 90%
is uterine horn; sow, cow,
doe, ewe
 Bipariite uterues: 80 – 90% is
uterine body; mare

5.  Functions:
› Hormonal Control
› Transport Sperm
› Produce Gametes
› Facilitate Fertilization
› Nourish Embryo and Fetus
› Participate in Parturition
› Recycle

6.  Polyestrous – cycle year round: cow, sow
 Seasonally polyestrous – cycle in one
season, anestrus in another: Horse
(spring/summer), ewe and doe (fall/winter)
 Monestrous – cycle once then anestrous:
dog
 Monotocous - one offspring each gestation
period: cow, mare, doe, and ewe
 Polytocous – multiple offspring each
gestation period: sow

7.  Testes – sperm and testosterone production
 Epididymis – transport, maturation and storage
 Ductus deferens – transport and ejaculation
 Penis - copulation
 Accessory Sex Glands
› Prostate – secrete neutralizing liquid
› Bulbourethral gland – secrete liquid
lubricant or gelatinous plug
› Seminal vesicles – secrete liquid
lubricant
› Ampulla – glandular enlargement of
ductus deferens
 Thermoregulation controlled by
Scrotum and blood supply

8.  Musculocavernous penis – muscular tissue
fills with blood during erection
 Fibroelastic penis – fibrous tissue elongates
during erection by straightening of
sigmoid flexure
 Bull, Stallion, Ram,
Buck have all
accessory sex glands
 Boar has corkscrew
shaped penis and no
ampulla

9. 1. Ovulation
2. Estrus
3. Fertilization
4. Gestation
5. Parturition
6. Lactation

10.  Estrus (Follicular) –
period when female is
sexually receptive to
male, the “heat” stage;
growth, maturation,
and ovulation of
follicles
 Diestrus (Luteal) –
period when female is
not sexually receptive;
growth and function of
corpus luteum
 Helps the female
physically prepare for
conception
 Anestrus – no ovarian
activity

11. 1. Growing follicle
2. Maturing follicle
3. Ovulation
4. Formation of
Corpus Luteum
5. Regressing
Corpus Luteum

12.  Estrogen – induces changes  Progesterone – induces
associated with estrus changes associated with
› Produced by follicles of pregnancy
ovary › Produced by corpus luteum
› Makes female more and placenta
receptive toward male › Decreases the receptiveness of
› Prepares female for the female to the male
conception physically › Causes cervix to close
› Increases cervical relaxation › At its lowest level during the
and uterine resistance to estrus phase
infection › Suppresses hormonal activity to
› Peaks 1-2 days before maintain pregnancy (if female
ovulation is pregnant)
› If female is not pregnant, the
estrous cycle will continue

13.  Luteinizing hormone (LH)
› Secreted by the
pituitary
› Assists the maturation of
the follicle, ovulation
and formation of corpus
luteum
 Follicle stimulating
hormone (FSH)
› Secreted by pituitary,
transported through
bloodstream to ovaries
› Stimulates the
production of follicles
› Can be given to cause
superovulaiton

14.  Ovulation – follicle releases female gamete,
the oocyte
 Corpus Luteum – formed from the follicle after oocyte is
released
 Spontaneous Ovulator – ovulation controlled by estrus
cycle
 Induced ovulation - after copulation
› Seasonal: cat
› Non-seasonal: llama, rabbit
Length of Estrus Timing of Ovulation Timing of Insemination
Cattle 12-19 hours 10-11 hours (after end of 7-18 hours (after onset of estrus)
estrus)
Horse 2-11 days 1-2 days (before end of estrus) 2nd day of estrus and every 2 days of
rest of estrus.
Sheep 24-36 hours 24-36 hours (after onset of 12-18 hours (after onset of estrus)
estrus)
Swine 48-72 hours 35-45 hours (after onset of 16-24 hours (after onset of estrus) then
estrus) 8-24 hours later

15.  Fertilized oocyte travels through oviduct, going through
mitotic divisions
 Morula – solid ball of cells; stage where embryo enters the
uterus
 Blastocyst – hollow ball of cells; stage where embryo
attaches to wall of uterus
 Membranes of embryo interdigitate with endometrium to
form placenta

16.  Four Fetal Membranes – blood,
nutrient and antibody transfer
› Yolk sac – nutrient supply
› Amnion –parturition
lubrication
› Allantois and Chorion
fusion – uterus
attachment

17.  Epitheliochorial – maternal epithelium adjacent
to embryonic chorion
 Diffuse – entire surface forms attachments:
horse, pig
 Cotyledonary – placental attachements in
specifc areas: ruminants
 Placentome – attachment of cotyledon and
caruncle
› Cotyledons – fetal side of placenta
› Caruncles – maternal side of placenta

18.  After Fertilization, embryo at blastocyst
stage implants in uterine wall and
develops placenta
 Gestation is maintained by the hormone
progesterone
› Progesterone – produced by Corpus Luteum
and Placenta
Source of Progesterone Gestation
Goat All from CL 150 days
Sheep CL to day 50 then placenta 150 days
Cow CL throughout gestation. However, after ~ day 200 placenta 280 days
and adrenal are producing enough progesterone to maintain pregnancy.
Sow All from CL 114 days
Mare 1st CL produces progesterone up to ~ 180 days, FSH stimulates follicle 335 days
growth and eCG causes CL's to form from follicles. They secrete
progesterone and are active from day 40-180. Progesterone is low until 270
days- rises in last 5 months due probably to placental progesterone production.

19.  Parturition – Birth process
› Stage 1 – Dilation of cervix
› Stage 2 – Expulsion of fetus
› Stage 3 – Expulsion of placenta
 Lactation – Mammary development and Milk
secretion and ejection
› Colostrum – first milk produced, containing high protein, fat,
vitamin A, minerals, and antibodies
 Hormones
› Prolactin – produced by pituitary; stimulates mammary
gland formation and lactation
› Oxytocin – produced by pituitary; stimulates milk let down,
uterine contraction and prostaglandin release
› Relaxin – produced by Corpus Luteum to relax cervix at
parturition

20.  Straight Breeding – produces purebred
animals
› Purebred
› Inbreeding (closely related animals)
› Line breeding (distant relatives)
› Outcrossing (unrelated animals)
› Grading up (purebred mated to crossbred)
 Cross Breeding – produces hybrid animals
› Two Breed Cross
› Three Breed Rotation (sires rotated)

21.  Live Cover – methods in which male and
female are physically brought together
to breed
› Natural Mating – random mating of males
and females turned out together
 Family Selection
 Pedigree Selection
 Progeny Selection

22.  Artificial Insemination
(AI) – female is
inseminated by a
veterinarian
 Embryo Transfer –
removing the embryo
from a female and
transferring it to a
surrogate female