Female reproduction

Define Estrous

The reproductive cycle in females that are of an estrual species

How is estrous calculated?

from the period of estrus and inculcation to the subsequent period of estrus and obvulation

Define Estrus or Heat

The period of time in which a female is sexually receptive to the male for the purposes of mating

Define Anestrous Period

The one when a female is not in estrus. The non-breeding season.

Define Estrus Synchronization

Controlling the estrous cycle so that a high percentage of the females in the herd express estrus (receptivity) at the same time

Define Clone

An individual grown from a single somatic cell of its parent and genetically identical to it

Define A.I

Abbreviation for artificial insemination, a common technique used in reproductive biology that involves placing semen into the reproductive tract of the female by artificial techniques rather than natural mating

Define E.T

Abbreviation for embryo transfer, which is a procedure used to transfer embryos from a donor female to a group of recipient females

Define Haploid

Half the normal number of chromosomes found in sperm and ova (half from mom and half from dad)

Define open

Refers to non-pregnant female

Define Fertility

The capacity to initiate, sustain, and support reproduction

Define dystocia

Difficult birth, intervention required

Role of Vulva/Vagina

Female organ of copulation; birth canal for parturition

Role of Cerivx

Passageway for sperm following breeding; seals off uterus during pregnancy

Role of Uterus

Secretory organ; incubator for embryo and placenta; control of cyclicity (Leuteolysis); contraction for parturition

Role of Oviduct

Passage for ovum and sperm; site of fertilization

Role of Ovary

Produces female gamete and female sex hormones (estrogen and progesterone)

Define Leuteolysis

Destruction of the corpus luteum

Functions of the Vulva/Vagina

Passageway for urine, Receptor for penis during copulation, Expands at parturition for delivery of fetus, Not to be confused with the anus

Protective structures of the Vagina and cervix

• tissue is keratinized to protect against abrasion

• Secretory

• Provides berries

Functions of vagina

• Copulatory Organ

  • Fornix vagina is site of semen deposition (cow/ewe), No glands secretions come from passage of plasma components as well as cervix, It provides lubrication, pH is acidic (5.7). bacteriostatic, Stimulates gland penis of bull temperature and pressure

• Birth Canal

1. Dilates for fetus during parturition

What is the site of semen deposition in cows/ewes?

Fornix vagina 

Functions of the cervix

composed of cartilage surrounded by soft tissue, Openings are the External or Internal Os, Passageway for sperm following breeding, Secrets mucous, seals off uterus during pregnancy, Passageway of fetus, Species specific configuration (rings, spiral, or folds)

What specie(s) have a ring configuration cervix 

Cattle, Goat, Sheep

What specie(s) have a Spiral configuration cervix 

Pigs

What specie(s) have a folds configuration cervix 

Horses 

Functions of the uterus as the organ of pregnancy

incubator for fertilized ovum, nutrients to ovum, Aids in travel of sperm, Secretory organ, Has two horns or branches and a single body, Shape differs between species

Components of the cervix in a cow

Cervix is a very hard and ridgid during estrus composed of thick connective tissue, typically closed except during estrus, cow has 4-5 annular rings, contains crypts which provide surface area for sperm reservoir, Os cervix, Fornix vagina, mucus discharge during estrus

Function of crypts

cause the sperm to get lost, the strongest swimmers survive

Function of the mucus 

helps sperm move through the reproductive tract and protects the baby during parturition 

Components of mare cervix

longitudinal folds, Os cervix, Fornix Vagina, no obstacles in the mare after the fornix vagina (straight shot), mare is opposite of other species as cervix is soft and pliable during estrus flattens on floor of vagina. during pregnancy is tight and closed.

Components of a sow cervix

Os cervix, so cervix has many interdigitating pads

Does a sow have a fornix vagina

No

What species does this cervix belong to?

Cow

What species does this cervix belong to?

Sow

What species does this cervix belong to?

Mare

Follicular Aspiration

stick a needle in the follicle to suck out eggs & allow for a variety of genetic combinations

Why is the uterus the organ of pregnancy

incubator for fertilized ovum, nutrients to ovum, aids travel of sperm, secretory organ, has two horns or branches and a single body, shape differs between species, creates environment for fetus and placenta.

What species has two long uterine horns?

Sow

What species has short uterine horns but big uterine body

Mare

Why does the sow have long uterine horns

it’s a litter-bearing species

What type of uterus does a cow and ewe have?

Bipartite 

What type of uterus does a pig have?

Bicornuate

What type of uterus does a mare have?

Modified bipartite

functions of the uterus

transport sperm, muscle contractions, sperm motility, absorption and phagocytosis, partially prepares sperm for fertilization, provides environment for embryo, supports development of fetus, At birth expels fetus, recovers from pregnancy

How does the uterus transport sperm

estrogen stimulates myometrial contractions so that sperm moves to site of fertilization 

what is the path of muscle contractions in uterus during estrus and ovulation

towards the oviduct during estrus (heat) but following ovulation are towards the cervix until progesterone increases from CL

Why are viable sperm (motile) important?

Won’t be absorbed

How does absorption and phagocytosis occur in the uterus?

occurs by uterine epithelium and leukocytes which fight infection

How does the uterus prepare sperm for fertilization? 

Estrogen stimulates uterine secretions which capacitate sperm (zona pelucida)

What must take place before a sperm cell can penetrate the egg

capacitation

How does the uterus provide an environment for the embryo?

uterine secretions stimulated by estrogen and progesterone

How does the uterus support development of the fetus

quiescent myometrium - progesterone, immunological protection from rejection by the maternal immune system

How does the uterus expel fetus at birth

Strong rhythmic myometrial contractions (progesterone low)

how does the uterus recover from pregnancy

uterine involution

define uterine involution

Myometrial contractions and enzymatic activity shrink the uterus back to its normal size

If a female is not pregnant, what does the uterine endometrium release?

Prostaglandin (PGF2a) to cause the CL to regress 

If a female is pregnant, what chemical signal does the embryo provide?

interferon tau

What species releases ECG to signal pregnancy instead of Interferon tau

Equine Chorionic Gonadotrophin

Define oviduct

tube that connects the ovary to the uterus

What are the three distinct regions in the oviduct 

Infundibulum, Ampulla, Isthmus 

What is the function of the infundibulum region?

Surrounds ovary

What is the function of the ampulla region?

Transports oocyte

What is the function of the isthmus region?

Transports sperm

Where is the site of fertilization

Ampulla-Isthmus Junction (AIJ)

What are the ovary’s two main regions?

Cortex and Medulla

Where is cortex found on Cows, sheep, and pigs

outer of the ovary

Where is cortex found on horses?

inner of the ovary

What does the cortex region of the ovary do?

Produces female gamete (ovum or oocyte)

• released from follicle

Induces ovarian structures

• produces hormones

What does the Medulla region of the ovary do?

support tissue including blood vessels and immune cells

Where is the medulla located on the ovary for cows, sheep, pigs

Inner of the ovary

Where is the medulla located on mares

outer of the ovary

What are the days in the estrous cycle of a cow is progesterone present in the system?

day 7 - day 18

What gland is used during the flehmen response

Vomeronasal gland

How many ovaries does a farm animal have?

Two

What connective tissue is in the ovary?

Tunica Albuginea

What are the functions of the ovary?

• produces the female gamete (the ovum)

• Procures female sex hormones (estrogen and progesterone)

What is the largest single cell in the body?

The ovum

Define the follicle 

Blister-like Structure on the ovary that contains ovum and hormone-rich fluid 

What is the estrogen-rich fluid in the graffian follicle called?

Liquor Folliculi

What is the embryo to corpus luteum ratio

1:1 ratio (for every embryo there is a corpus luteum)

On day 0 of a cow’s estrus cycle, which structure would we find on the ovary?

Graafian Follicle

Define a Graafian follicle

Mature follicle

Define Atretic follicle

deteriorated follicle

Define cystic follicle 

Continuous corpus luteum or Graafian or atretic structure 

what is the zona pellicuida?

eggshell

Define corpus luteum

• “Yellow body” forms after ovulation

• Produces progesterone, which is important for maintaining pregnancy

• Solid tissue which is composed of luteal cells that originate from granulosa and theca cells of the Graafian follicle

What does progesterone do

inhibits estrus and parturition, blocks myometrial contractions, stimulates endometrial secretion of nutrients, stimulates the production of a luteolytic agent to kill the CL if no embryo is present (prostaglandin PGF2a)

Why is progesterone important

want the uterus to be still, not give premature birth

What can progesterone be used as

synchronization tool and birth control

Ovarian shape of the mare ovary

Single ovulation from the interior cortex is funneled to the oviduct via a specialized structure called the ovulation fossa

What is the only species with an ovulation fossa?

Mare (horse)

Ovarian shape of the sow ovary

Multiple ovulations form the cortex located on the exterior or surface of the ovary 

What is a UFO

unfertilized ovum

What are the stages of the structures on the ovary

Primordial/Primary/secondary/tertiary follicle → graafian follicle → (Ovulation) → corpus hemorrhagicum (CH) → Corpus luteum (CL) → Corpus Albicans (CA)

Summary of what goes on in the ovary

Follicles develop on the ovary and undergo stages of maturation until one becomes a Graafian follicle, follicles not selected for ovulation become atritic and regress, and following ovulation the follicles will transition through CH, CL, and CA structures

Define ovulation 

when the oocyte is released from the follicle 

function of granulosa cells

produce estrogen and testosterone

Function of thecca internal cells

produce testosterone

What stimulates LH receptors

Stimulated by hormones FSH and LH