Theriogenology - Exam 1: Estrus, Estrous, and Stressed Us

What are the two hormones produced by a growing follicle?

Estrogen and inhibin

What is the end result of a follicle that produces progesterone?

Corpus luteum

T/F: You can feel the follicle in a horse

False, they are internal ovulators

What hormone is dominant during the luteal phase?

Progesterone

What hormone comes from an empty uterus and initiates luteolysis?

PGF2a (prostaglandin)

Why is prostaglandin useful for herd health?

Can synchronize their cycles

What drug is a short acting GNRH analog?

Gonadorelin

What is gonadorelin not useful in mares?

They require a sustained LH surge, and gonadorelin is short acting

What GNRH analog is useful for sustained LH surges in mares?

Deslorelin

What drug directly stimulates LH to induce ovulation?

hCG

What hormone is used to maintain or prevent pregnancy?

Progesterone

What drug is an ecbolic used to clear fluids from the uterus?

Oxytocin

What drugs utilize PGF2a to induce luteolysis?

Lutalyse and estrumate

What is the clinical sign associated with PGF2a (lutalyse) in humans?

Generalized smooth muscle contraction (don't feel good)

What species has the same progression of hormones whether or not they are pregnant?

Bitch

When does progesterone rise in the bitch?

Prior to ovulation

T/F: The bitch is fertile at ovulation

False, ovulates a primary oocyte which undergoes mitotic divisions, meaning peak fertility is 2 - 4 days after ovulation

How long after physical signs of heat will the bitch ovulate?

2 to 3 weeks

What species are induced ovulators?

Cats, Camelids, and Ferrets

What is the typical cycle length of estrus and post-estrus in the queen?

About 9 days for both (estrus is more variable)

What structure in the mare allows you to flush the uterus without getting fluid in the oviduct?

Oviductal papilla

Which species has a fibrocartilagenous cervix?

Cows

What species's cervix is muscular and tone depends on hormonal influence?

Mares

What species has the longes average estrus cycle?

Bitch (6 mo)

What species has the longest duration of estrus?

Bitch and Queen (9 days)

What species has the shortest duration of estrus?

Cow (15 hr)

What species has a significantly shorter onset of estrus to ovulation period than the duration of estrus, meaning they will show signs even after ovulation?

Mare (duration: 7 days, onset to ovulation: 5 days)

What species have 5 - 6 ducts per teat and teats that ooze, not squirt?

Bitch and queen

What hormone controls milk letdown?

Oxytocin

What must occur for lactation to happen?

Pregnancy and parturition

What hormone causes lactation?

Prolactin

What part of the teat allows for cows to hold a lot of milk?

Cistern

What is the period of sexual receptivity called?

Estrus

What species are seasonally polyestrus?

Mare and Ewe

What are the best detectors of estrus?

Males

What is the primary estrus sign in cows?

Standing to be mounted

T/F: Adverse weather, hunger, thirst, and poor BCS can suppress estrus

True

A cow mounts the head of another cow. Which, if any, is in heat?

The cow mounting

A cow mounts the rear of another cow. Which cow, if any, is in heat?

The cow being mounted

How long after a cow showing signs of estrus should you inseminate?

~12 hours (AM/PM rule)

What discharge from the vagina of a cow indicates estrus?

Mucus

T/F: The doe (caprine) shows signs of estrus with or without the buck

False, few signs without buck

How can you test for signs in a doe without a buck present?

Buck rag (scent on rag)

Insemination for a doe is recommended at what point in relation to estrus?

Late estrus

T/F: Sheep estrus detection is very similar to goats

True

What is the best way to inseminate a sheep?

Laparoscopically since they have a twisty-turny cervix

What are the main signs of estrus in the mare?

Urination and clitoral eversion (winking)

What is the primary physical sign of estrus in swine?

Sawhorse stance/Back pressure test

What is the best time to inseminate swine in relation to estrus?

Middle of estrus

What is the main receptive sign of camelids?

Kushing (in sternal)

What is the end result of spermatocytogenesis (early proliferation)?

B spermatogonia

B spermatogonia undergo mitosis and become what?

Primary spermatocytes

Primary spermatocytes undergo meiosis I and II to become what?

Spermatids

Spermatids undergo metamorphic changes (spermiogenesis) to become what?

Spermatozoa (long, flagellated)

Recall the three stages of creating spermatozoa

Proliferation, meiosis, and differentiation

The process of spermatozoa entering the seminiferous tubules is called what?

Spermiation

What physical feature is lost during spermiation?

Cytoplasmic droplet

Meiosis must occur on the basal or adluminal side? Why?

Adluminal, to avoid autoimmune phagocytosis

What three factors determine sperm output?

Testis size, age (maturity), and season

What are the testosterone producing cells?

Leydig cells

Where do sperm gain the ability to be motile and fertilize?

Epidiymis

Where are sperm stored until ejaculation?

In the tail of the epididymis

The movement of seminal fluids from accessory sex glands is called what?

Emission

What are the two main roles of the cervix?

Removing non-motile sperm and as a sperm reservoir

T/F: The uterus eats sperm

Well, phagocytosis does occur in the uterus, so you decide

The removal of sperm surface proteins leading to hyperactive motility is called what?

Capacitation

What is the site of fertilization?

Ampullary-isthmic junction

T/F: The amount of sperm does not affect chance at fertilization since it only takes one

False, they move with the crowd, so more is better

What should you do with a 15 m/o bull with a scrotal circumference 2 cm too small?

Throw him away, there are more bulls in the sea

What do you do with a 4 y/o stallion with only 20% normal morphology sperm?

Breed him and hope for the best

Defects in what part of the testis are ejaculated first?

Epididymis (tail)

Head and mid piece defects indicate a problem where?

With spermatogenesis

Droplet defects indicate a problem where?

Epididymis

Tail defects indicate a problem where?

Post-ejaculation

What muscle maintains thermoregulation in the testicle?

Dartos muscle

What is the skeletal muscle of the testicle?

Cremaster muscle

What gene encodes testis determining factor?

SRY

What gene maintains Sertoli cells?

SOX9

Sertoli cells produce what hormone?

Anti-Mullerian Hormone (inhibits female tract)

What do Leydig cells produce?

Testosterone?

What turns testosterone to DHT?

5a-reductase

T/F: Sertoli cells inhibit Mullerian ducts, and Leydig cells maintain Wolffian ducts

True

What is an incongruity between chromosomal, gonadal, and phenotypic sex?

Disorder of Sexual Development (DSD)

Ovarian and testicular tissue united or separate in an animal makes them a what?

Hermaphrodite

What classifies a pseudohermaphrodite?

Gonadal tissue of one sex, but accessory reproductive organs of the other

2+ genetically different sets of cells with different phenotypes is what?

Chimera (from multiple zygotes) or mosaic (from single egg)

Pregnancy with a male and female twin in cows is what?

Bovine Freemartin

What is the outcome of bovine freemartinism for the female twin?

Exposed to masculinizing hormones (poorly developed female tract)

A male calico is what form of DSD?

Trisomy (XXY) or polyploidy (XXXY)

What are the three main causes of male pseudohermaphrodite (Male with some female structures)?

Androgen insensitivity (no test reception)

5a-reductase deficiency

Abnormal AMH

What is the most common disorder of sexual development?

Cryptorchidism

When are infections of the uterus most easily overcome?

During estrus

When are ascending infections of the female tract most likely to occur?

Estrus (open cervix)

Breeding

Parturition

What is the most common bacteria associated with pyometra?

E. coli

Pyometra is a disease of what period in the cycle?

Metestrus

When is cystic endometrial hyperplasia most likely to occur in the cycle?

Diestrus

What is the difference between abortion and stillbirth?

Whether or not the fetus is independently viable (stillbirth has potential)

What is the initial driver of fetal autolysis?

Fetal stress

What are the two outcomes of the fetus in a failure of pregnancy?

Mummification (dehydrates, closed cervix)

Maceration (liquefies, open cervix)

What incidental placental structure in cows can be confused with bacteria?

Amniotic plaques