4. Infertility in mares - BP | Quizlet- ZC

Categories of factors causing infertility in mares

1. Anatomical

2. Physiological / function - anestrus, repeat oestrus cycle

3. Infectious

4. Managmental causes

What is normal chromosomal numbers / pairs

64 or 32 pairs

Chromosome for females

64XX

What is Turner's syndrome, what is it characterised by

Chromosomal abnormality

- small ovaries

- poorly developed uterus

- permanent anestrus

Name 2 variation of normal females chromosomes / chromosomal abnormalities

1. 63XO - females with single X

2. Tuners syndromes

Reproductive hormone deficiencies are associated with what organ?

Pituitary

Abnormality in pituitary / def in repro hormones can cause:

1. Prolonged estrus

2. Prolonged diestrus

3. Silent ovulations

4. Reproductive failure

Successful treatment for abnormalities in hypothalamic-pituitary-ovarian homeostasis

Synthetic progesterone

(Rebound effect)

What is follicular atresia

Break down of ovarian follicles

Follicle will develop normally to 30mm

But there is no emergence of DF & follicles are broken down

Causes of follicular atresia

1. Ovarian hypoplasia - under or incomplete development

2. Ovarian cysts

3. Infection & malnutrition

What is persistent Cl

Luteolysis of CL doesnt occur after 14d w/o pregnancy

Creating long or short estrous cycle

Cause of persistent CL

Failure of release of PGF2a

Due to:

- uterine infection

Treatment of persistent CL

Exogenous PGF2a

What are anovulatory follicles & consequences

Large follicles with fail to rupture & ovulate

Fill with blood & persistent as hemotomas for a few cycle

May be able to produce progesterone

Consequences - anestrous

When do anovulaotry follicle commonly occur

Transition periods into & out of season

Ovarian teratomas: origins & features

Origin: germ cells

Features: contain hair, teeth, bone etc.

RARE

Ovarian hypoplasia: what is it, & potential causes

Under development of ovaries - small & immature

Associated with / potential causes:

- chromosome abnormalities

- hormonal abnormalities

What is the most common ovarian tumor in horses

Granulosa (theca) cell tumor

Characteristic of ovarian granulosa cell tumor: age, structure

Important cause of anestrus

Affects one ovary

Age 5-7

Polycystic or large solid structures - 18bs (~8kg)

How big can granulosa cells tumours get

8kg (unilateral on one ovary)

Symptoms of granulosa cell tumor

1. Prolonged estrus / anestrus

2. Testosterone producing cysts = aggressive, stallion behaviour & muscle development

What age of mares are affected by granulosa cell tumor

5-7

Granulosa cell affects 1 or 2 ovaries?

One ovary

Treatment of granulosa cell tumor

Surgical removal

Consequences of multiple ovulation

Multiple pregnancy

Major cause of abortion bc mare cannot carry twins to term

What is endometritis

Inflammation of uterine endometrium

Infecitous cause of infertility

Causes of endometritis

1. Opportunistic bacteria - St. zooepidemicus, S. Aureus

2. Veneral bacteria - Taylorella Equi genital is, Kleb. Pneumonia, Pseudomonas Aeruginosa

3. Non-infecitous agents

What is the major problem with uterine infections

They are often undetected for ages

Most common cause of acute endometritis

Streptococcus zooepidermicus - 75%

Consequences of streptococcus Zooepidemicus endometritis

1. Initiates infection of cervix & uterus

2. Promotes proliferation of other bacteria

3. Causes destruction of RBC

Name opportunistic bacteria causing endometritis, which is most common

Streptococcus zooepidemicus - most common 75%

Staphylococcus aureus - less common, only under stress

Veneral soruces of bacteria

1. Semen

2. Repro tract mare & stallion

Only transferred through these routes, may be asymptomatic

Veneral bacteria causing endometritis

1. Taylorella Equigenitalis

2. Klebsiella pnuemonie

3. Pseudomonas Aeruginosa

What type of endometritis is caused by Klebsiella Pneumoniae

Acute & chronic

Little to no c/s

Where can pseudomonas Aeruginosa be found & c/s in mare

Found: stallions semen

C/S: rare, but yellow green discharge (remember is it colourful one)

Name 5 causes of abortion in horses

1. Infectious: bacteria or fungi

2. Twins

3. Hormonal def

4. Congential abnormalities

5. Ergot alkaloid toxicity / infection of caterpillar setae

Normal gestation length

330-340d

Normal umbilical cord length

36-84cm

What is placental weight in thoroughbred

5.7+/- 0.08kg / 11% of foals bw

Bacteria causes of abortions

1. Streptococcus most common

2. Leptospira

3. Norcardia

4. Klebsiella

5. Staphylococcus

Most common bacterial cause of abortions

Streptococcus

Viral causes of abortions, usually cause abortions at what stage in gestation

8-11 months

Or as early at 5

How long after mare catches virus will the foal be infected

20-90 days

Name viral cause of abortions

Equine herpesvirus - EHV-1

Virus can be latent & reactivated by stress & shed into environment

Percentage occurrence of Placentitis in thoroughbreds

3-5%

Late term pregnancy lost / late term pregnancy wastage is also termed

Placentitis

What percentage is placental insufficiency responsible for abortion, still brith or neonatal death

>60%

Clinical signs indicating Placentitis

1. Premature udder development

2. Premature lactation

3. Valvular discharge

4. Soft cervix

5. Abortion

Premature udder development & lactation is a sign of what?

Placenititis

How is Placentitis diagnosed

1. Upper limits for the combined thickness of the uterus & the placenta (CTUP) by transrectal USG in late gestation

2. Plasma progesterone levels

3. Foetal heart rate

Diagnostic indicators of placental failure by USG are:

1. Anomalies

2. Fetal abnormalities, position or acivity

3. Increase of decrease foals HR

4. Accumulation of blue between chorioallantoic membrane & endometrium = placental separation

5. Thickened placenta

6. Abnormalities of umbilical cord

7. Increase or reduced allanotsis or amniotic fluids

8. Increase echogentiivtiy of allantoic or amniotic fluids

What does CTUP mean & what is it used for

Combined thickness of the uterus & placenta

Diagnosed Placentitis

Normal CTUP measurement days:

151-270

271-300

301-330

>331

Normal plasma progesterone levels

21-30

30-60

60-110

110-300

Normal HR of foals in gestation months:

1, 3, 6 months