Reproductive System Flashcards
What is winking
Rhythmic contractions of the vulva when a mare is in estrus
Estrus + diestrus =
estrous cycle
How long is estrus
~ 6 days
How long is diestrus
~ 15 days
Follicle stimulating hormone leads to
Production of estrogen
What is the follicle
A small secretory cavity, sac or gland that secretes estrogen
What does estrogen stimulate
The pituitary gland to release luteinizing hormone
What does luteinizing hormone do
Trigger ovulation of the ovum from the follicle
What happens after ovulation
Estrogen and LH decrease. Progesterone is needed to inhibit heat and promote pregnancy (hopefully)
Where does progesterone come from
The corpus luteum = the sight of the ovulated follicle, where follicle used to be
What does the mare do incase the egg did not get fertilized
Builds an ovum in a follicle for the next round with FSH
What does the Graafian follicle do
Produces inhibin which inhibits FSH production, becomes corpus luteum
Where does the signal of whether or not the mare is pregnant come from
From the fertilized ovum in the uterus, floats around and makes contact with uterine wall
What happens in the absence of a fertilized ovum
Prostaglandin is released from uterus, destroys corpus luteum (which is producing progesterone). We have FSH producing another follicle
***draw slide 14
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What are the ways a mare’s reproductive tract can be examined (7)
Rectal palpation
Ultrasound
Vaginal Speculum
Uterine culture and cytology
Uterine biopsy
Hormonal assays
Endoscopy
**list the ways that a mare may be prevented from going into estrus
Daily oral progesterone
Acupuncture staples
Marble
Long-acting progesterone
Progesterone implants
Ovariectomy
How does daily oral progesterone work
Tells the mare they are pregnant, can suppress estrus
Regu-Mate
How does a marble work
Simulates a fertilized embryo, stops from coming into estrus
Ovariectomy vs ovariohysterectomy
Ovariectomy = just ovaries taken out
Ovariohysterectomy = uterus and ovaries “spay”
Progesterone related ways of preventing a mare from coming into estrus
Daily oral progesterone (Regu-Mate)
Long-acting progesterone (injectable)
Implants
Inflammation of the uterus that may be accompanied by an infection with microorganisms
Endometritis
Clinical signs of endometritis
Infertility
Abnormal, frequent heat cycles
How is endometritis diagnosed
Uterine culture
Uterine cytology
Uterine biopsy
Ultrasound showing fluid build up
How is endometritis treated
Lavage with fluids and/or antimicrobials
Oxytocin (makes uterus contract; squeeze out debris/fluid from lavage)
Endometritis can lead to
infertility, chronic inflammation
Complications of endometritis
Pyometra
What is pyometra
Large accumulations of pus (up to 60L) in the uterus
What does pyometra stand for
Pyo = pus
Metra = uterus
How serious is pyometra? Complications?
Difficult to treat
May be recurrent
Results in permanent damage to uterus = permanent infertility
Most common type of ovarian tumor seen in mares
Granulosa cell tumour
What does a granulosa cell tumour release
testosterone
Behaviour changes in mare with granulosa cell tumour
Stallion-like behaviours
How do we diagnose a granulosa cell tumour
Clinical signs
Rectal palpations
Ultrasound
Blood tests (hormone levels)
What does a granulosa grow from
An ovary
How do we treat a granulosa
Surgery (removal)
How serious is granulosa? Complications?
Unilateral: unaffected ovary may ovulate normally
Complications related to surgery
Common, minor procedure to suture the dorsal aspect of the vulva closed is…
Caslicks procedure
Why do a caslicks procedure
If the angle/conformation/length of the vulva makes it so that the mare is defecating into her vulva = fecal contamination with bacteria
Indications for a caslicks procedure
Windsucking (of vulva)
Tipped vulvar conformation
Recurrent uterine infections from contamination
Two functions of male reproductive system
Produce sperm, deliver sperm into mare
What kind of estrus do mares undergo
Seasonal polyestrus
Do stallions reproductive system shut down in the winter like mares?
No, lasts year round. produces sperm through the winter, numbers decreased
What is spermatogenesis
Making sperm
Where does spermatogenesis take place, how long does it take
In the seminiferous tubules within the testicles
55 days
If a stallion is sick, how does that affect sperm
Sick today, treated with drugs means sperm have been damaged/wiped out, will not know for 55 days
After spermatogenesis, how long does it take for sperm to mature/be motile. Where does this happen?
Maturation in epididymis for 4-5 days
How long do sperm spend in the epididymis
Variable, 2 days to weeks until ejaculation or urination
What controls the breeding event?
The nervous system - stimuli
Describe a breeding event
Stallion sees mare in heat, drops penis within 1-2 mins
Mounts within 3 minutes, 5-8 intravaginal thrusts
3-5 short thrusts while ejaculating, flags tail, dismounts
Average volume of ejaculate
30-100 milliliters
Steps involved with examination of the stallion (6)
Physical exam of external genitalia
Ultrasound
Endoscopy
Culture and cytology
Breeding observation
Semen analysis
What is examined during physical exam of stallion
Testicles, scrotum, sheath and penis
Width of testicles (related to amount of sperm)
Exposed to mare in heat so penis can be examined
An endoscopic exam of the urethra can identify
Source of bleeding if blood in semen
Stricture of the urethra
Where are samples collected from for culture/cytology of a stallion? Why?
Outside of penis, tip of urethra, tip of penis
Check for diseases
What is assessed during breeding observation
Stallion libido
Response to mare in heat
Ability to develop an erection, mount and ejaculate
What is examined during semen analysis
Total volume
Number of sperm
Morphology of sperm
Activity and movement of sperm
What is Cryptorchidism
One or both testicles fail to drop into scrotum
Colt is called a ‘crypt’
What is the peritoneum
Lining surrounding abdominal cavity
When do testicles normally descend
last 30 days of gestation or first 10 days following birth
How is cryptorchidism diagnosed
Testicles not palpated by 4-6 months
Measure testosterone
Stimulate with human chorionic gonadotropin
Why not remove a testicle if only one is dropped
May still behave like a stallion in the future because other teste is producing testosterone but not viable sperm, bought/sold = complicated
Recommended treatment for cryptorchidism and complications?
Surgery (opening the abdomen)
Surgical complications
Aggressive “gelding” if not removed
How serious is cryptorchidism
Should not be used as a stallion
When the intestines slip through the inguinal rings, possibly into the scrotum, this is…
Inguinal and scrotal hernias
What does the inguinal ring do? What happens when it is too big or small
Allows testes to be pulled through by gubernacular bulb
Big = hernia
Small = crypt
How is inguinal and scrotal herniation diagnosed
Enlarged scrotum
Colic episodes
Ultrasound exam
Treatment for scrotal and inguinal herniation
Surgery to reposition the intestines and close inguinal rings
How serious is scrotal and inguinal herniation
Serious if not recognized early
Damage to intestines
Complications of scrotal and inguinal herniation
if castration is performed, intestines can drop through castration site
Trapped intestines in inguinal rings or scrotum can be twisted or strangulated
Penile prolapse is
When the penis of a stallion of gelding has become damaged and the horse is no longer able to pull it back into its sheath
Causes of penile prolapse
Trauma
Viral or bacterial diseases
Administration of acepromazine
How is penile prolapse diagnosed? What is the treatment
Condition of the penis
Manually replaced into sheath
Support against belly with bandage to prevent swelling/damage
NSAIDs and exercise to reduce swelling
How serious is penile prolapse? Complications
Very, can lead to permanent damage
Permanent paralysis and loss of ability to breed
What should never be administered to stallions
Acepromazine
What is castration
Removal of the testicles
What should be checked before castration
Both testicles descended
Tetanus vaccine
Two methods of castration
Standing
Down
Most important part of castration recovery? Complication?
Exercise to encourage drainage from surgical site
Premature closure of surgical site=fluid accumulation
Other complications of castration
Excessive bleeding
Infection
Inguinal hernia
Rule of thumb about bleeding during castration
If you can count the drops then he’s okay, usually
How often do sheaths need to be cleaned
6-12 months
What can be found in the pocket at the tip of the penis
Bean; accumulation of thick whitish material
