Lecture 9: Infertility in the mare Flashcards
what is a persistent corpus luteum caused by?
- if a second ovulation (diestrual ovulation) occurs 1 - 4 days before endogenous PGF release (day 15 - 16). an immature CL will not respond to PGF release and continues to produce progesterone
- failure to secrete PGF
- reduce PGF secretion due to chronic uterine infection
- early embryonic death after maternal recognition of pregnancy
describe the spring transition
non-ovulatory
increased day length results in increased secretion of GnRH which causes an increase in FSH but not LH
- this results in follicular activity without ovulation.
- may see erratic prolonged estrus periods
how do you treat a persistent CL?
PGF2alpha
what is the effect of artificial lighting
moves the time of the vernal transition - but does not shorten it beyond physiological 6 - 8 weeks
expose mares to 16 hours of light and 8 hours of dark
Progesterone (regumate): effect on infertility seasonality - management
it suppresses the release of LH
- used for estrus regulation during the transition
- treat for 10-14 days, withdrawal results in LH release and estrus beginning 4-5 days later.
- ovulation occurs 10 days after cessation of treatment
granulosa-theca cell tumor characteristics
- main ovarian tumor
- hormonally active
- unilateral
- benign
granulosa-theca cell tumor: clinical signs
behavioral changes: stallion-like, anestrus, persistent estrus
unilateral enlarged ovary
small, inactive opposite ovary
granulosa-theca cell tumor: Dx
clinical signs: +/- enlarged, firm, no ovulation fossa
ultrasound
serum hormone assays: inhibin, testosterone, progesterone, AMH
granulosa theca cell tumor: effect of inhibin
elevated in 90% - responsible for the inactivity of the contralateral ovary
granulosa theca cell tumor: effect of testosterone
elevated in 50% - responsible for stallion-like behavior
granulosa theca cell tumor: progesterone (baseline)
below 1ngml since normal follicular development, ovulation and CL formation do not occur
granulosa theca cell tumor: effects of AMH
high serum concentrations
its the MOST SENSITIVE test for granulosa theca cell tumors
granulosa theca cell tumor: tx
surgery - most cycle within 2 - 12 months
what other ovarian tumors are there?
cystadenomas, dysgerinoma, teratoma
two types of anovulatory follicles
follicular - lumen remains filled with follicular fluid
luteal - lumen gets infiltrated with echogenic particles –> fibrin strands –> lutenized tissue
how do you dx and tx anovulatory follicles?
dx: measure plasma progesterone 5 -7 days after hte mare stops showing signs of estrus
tx: PGF2alpha - but a good number will repeat the process next cycle
abnormalities of external genitalia
cervical lacerations, pneumovagina, urovagina
cervical laceration dx and tx
dx: vaginoscopy and digital exam
tx: sx
pneumovagina: cause of occurrence and tx
cause: due to secondary changes in perineal conformation - cranio-ventral displacement of the tract, loss of integrity of the vestibulovaginal sphincter, loss of integrity of the vulvar labia
tx: caslick’s vulvoplasty
urovagina: occurrence and tx
occurrence: when cranial vagina slopes cranioventrally. urine collects in teh anterior vagina where it is spermicidal and may cause cervicitis and endometritis
tx: sx
sextually transmitted diseases
contagious equine metritis (CEM) caused by tyorella equigenitalis
equine herpes 3
pseudomonas spp. Klebsiella
equine viral arteritis
causes of persistent uterine infection
break-down of external barriers
contamination
compromised uterine defense
how are STDs and persistent uterine infection dx?
vaginal discharge culture and cytology
how are STDs and persistent uterine infection tx?
treat underlying breakdown of uterine defense (cervical laceration, pneumovagina with caslicks)
intrauterine infusions with abx
uterine lavage
** persistent breeding-induced endometritis (PBIE) **
- sperm cause an inflammatory reaction which is a normal physiological reaction that serves to clear the uterus from excess sperm and contaminants
- may develop into a pathological condition (PBIE) in “susceptible” mares
- interferes with embryo survival if not cleared when the embryo enters the uterus
** PBIE “susceptible mares” **
those with impaired myometrial activity and delayed uterine clearance
** does pyometra cause systemic illness? **
** NO! **
How is PBIE diagnosed and tx?
dx: accumulation of fluid within the uterine lumen for > 12 hours after breeding
tx: assist the uterus to clear the inflammation via uterine lavage or oxytocin
how do pyometras occur?
often a result of impaired uterine drainage resulting from cervical adhesions following a dystocia
how are pyometras dx and tx?
dx: ultrasound
tx: uterine drainage and lavage and hysterectomy
what are two types of endometrial cysts?
how are they tx?
glandular: small < 10mm - result from periglandular fibrosis
lymphatic cysts: larger, can reach several cm, lacunae thought to originate from itnerference with normal lymph drainage of genital tract\
tx = often untreated, but can be removed with laser sx
what can often be misdiagnosed as an early pregnancy?
endometrial cysts
