Anatomy and Physiology of the Female Reproductive System

Ovum

Female gamete produced by ovaries.

Uterine tubes

Also known as oviducts; site of fertilization.

Embryo

Developing organism in early stages of pregnancy.

Parturition

Process of expelling the fetus at birth.

Vulva

External female genitalia.

Clitoris

Homologous structure to male penis.

Cervix

Connects vagina to uterus; seals during pregnancy.

Uterus

Site for placental attachment and fetal nourishment.

Oviduct

Tube connecting ovaries to uterus; site of fertilization.

Ovaries

Paired organs producing ova and hormones.

Follicle

Structure in ovaries that develops into ovum.

Corpus luteum

Yellow body producing progesterone after ovulation.

Luteolysis

Destruction of corpus luteum if no pregnancy occurs.

Antrum

Cavity formed in tertiary follicle; estrogen produced.

Estrogen

Hormone stimulating female reproductive development.

Progesterone

Hormone maintaining pregnancy and uterine environment.

GnRH

Gonadotropin-releasing hormone initiating reproductive hormone release.

FSH

Follicle-stimulating hormone promoting follicular growth.

LH

Luteinizing hormone triggering ovulation and corpus luteum formation.

Estrous cycle

Series of reproductive events from one heat to next.

Monestrous

One estrous cycle per year; example: fox.

Polyestrous

Multiple estrous cycles per year; example: cow.

Seasonally polyestrous

Cycles during specific seasons; example: mare.

Anestrous

Period when animal is not cycling.

Behavioral signs of estrus

Indicators of female receptivity to mating.

Ovulation

Release of ovum from mature follicle.

Semen deposition

Process of sperm placement in female reproductive tract.

Gestation

The period of development of the embryo or fetus inside the uterus.

Estrus

The period of sexual receptivity in female mammals.

Cow Gestation Period

283 days.

Sow Gestation Period

114 days.

Mare Gestation Period

336 days.

Ewe Gestation Period

147 days.

Fertilization

Union of male and female gametes.

Fetus

Organs defined; species differences more apparent (greater than day 45 in cattle).

Attachment of placenta

Begins at 22 days in cows, 15 days in ewes, 13 days in sows, and 37 days in mares.

Diffuse placental type

Type of placenta found in horses and pigs.

Cotyledonary placental type

Type of placenta found in cattle and sheep.

Palpation

Deep structures of the body are felt by the hands of the observer.

Cattle Pregnancy Detection - Manual Palpation

Pregnancy check at 35 days.

Cattle Pregnancy Detection - Ultrasound

Pregnancy check at 28 days.

Fetal age accuracy

Variable with skill level for manual palpation; accurate with ultrasound.

Fetal gender determination

Accurate at 60 days via ultrasound.

Embryonic pregnancy loss

Fertilization through organ development (day 0 - 45).

Fetal pregnancy loss

Completion of organ development (day 45 - birth).

Neonatal pregnancy loss

Birth to 4 weeks of age (~ one month).

Overall pregnancy loss in cows

30%, with early embryonic loss accounting for 85%.

Developmental Programming

Exposure during a critical period in development may influence later production life of the animal.

Dystocia

Abnormal or difficult labor.

Factors affecting reproductive performance

Nutrition, environment, anatomical defects, endocrine system imbalance, and diseases.

Conception

Mating or union of the male and female gametes.

Male reproductive system

Development of the gamete is a continuous process resulting in an infinite number of sperm.

Female reproductive system

Finite number of gametes; it is a cyclic process.