Equine Pregnancy Dx

Question 1

methods for pregancy dx in mare

Answer 1

• behavioral assessment
• vaginal speculum examination
• transrectal palpation**
• transrectal u/s**
• hormonal assays

Question 2

behavioral assessment

Answer 2

• receptive to mating: estrogen influence
• non-receptive: progesterone influence
• “insensitive indiactor” (non-specific indicator)

Question 3

vaginal speculum examination

Answer 3

• external cervix
  
  • long, tight, pale, dry
• indicator of progesterone
  
  • cervix will be tightly closed
• insensitive indicator of pregnancy

Question 4

transrectal palpation

Answer 4

• useful at all stages of gestation (easy to make mistakes)
• rapid
• economical

Question 5

ultrasonographic diagnosis of pregnancy

Answer 5

• as early as 9 days post ovulation
• routinely at 14 days post ovulation

Question 6

hormone assays in pregnancy

Answer 6

• progesterone
  
  • 18-21 days after ovulation
  • luteal tissue: pregnancy, persistent corpus luteum, embryonic death, etc
• equine chorionic gonadotropin
  
  • endometrial cups: 36-120 days of gestation (even if she loses pregnancy)
  • present whether fetus survives or not
• estrogens
  
  • Feto-placenta until after day 60
  • indicator of fetal viability
• minimally useful for pregnancy diagnosis (insensitive)

Question 7

pregnancy diagnosis day 14-18 (transrectal palpation)

Answer 7

• Palpation
  
  • good tone in tubular tract
  • distinct uterine bifurcation
  • active ovaries (follicles)
  • tightly closed cervix
  • false positives

Question 8

Pregnancy diagnosis Day 14-16 (u/s)

Answer 8

• embryonic vesicle(s)
  
  • size (measure)
  • shape: round
  • #

Question 9

diagnosis of twins

Answer 9

• ultrasonographic exam
• day 14-16 gestation
• synchronous vs asynchronous ovulation (evaluate entire uterus)
• low survival rate

Question 10

management of equine twins in early pregnancy

Answer 10

• manual embryo crush
• best during the mobile phase (to day 16-17)
• 90% success rate
  
  • vesicle location
  • experience

Question 11

pregnancy day 17-18

Answer 11

• Day 17-18
  
  • transrect u/s
  • changing shape (triangular, guitar pick)
  • slight uterine edema
  • irregular shape

Question 12

Pregnancy Day 20-25 (transrectal/us)

Answer 12

• transrectal
  
  • toned uterus
  • narrow, elongated cervix
  • preg rarely detected by palpation
    
    • small bulge at base of one of uterine horns
• u/s
  
  • guitar pick shape
  • round/irreg
  • embryo proper (day 21)
  • embryonic heart beat (day 24)
  • development of fetal membranes (allantois)

Question 13

pregnancy day 30 to 35

Answer 13

• transrectal palpation
  
  • toned uterus
  • narrow, elongated cervix
  • hen’s egg bulge
    
    • base of uterine horn
    • day 30
• u/s
  
  • development fetal membranes
  • regression of yolk sac
  • dorsal migration of embryo

Question 14

early embryonic death (EED)

Answer 14

• 1/3 to 1/4 of gestations lost in the first 30 days
• hallmark: no embryonic heartbeat

Question 15

pregnancy day 35 to 40

Answer 15

• transrectal palpation
  
  • good uterine tone
  • narrow, elongated cervix
  • tennis ball-shaped bulge
• u/s
  
  • transition from embryo to fetus (organogenesis)
  • formation and attachment of umbilical cord
  • migration of fetus ventrally (half way down @ 40d)

Question 16

pregnancy day 45-50

Answer 16

• transrectal palpation
  
  • good uterine tone
  • narrowed, elongated cervix
  • softball-shaped vesicle
• u/s
  
  • elongation of umbilical cord
  • further migration of fetus ventrally

Question 17

management of equine twins in late pregnancy

Answer 17

• > 40 day gestation
• occur after formation of endometrial cups (day 36)
  
  • eCG
  • persist after fetal death
• transvaginal ultrasound-guided aspiration
  
  • day 20-45
  • 20-50% success
• cranio-cervical dislocation
  
  • day 60-110
  • 60% success
  • requires surgery (flank)
• transabdominal u/s guided cardiac injection
  
  • day 110-150
  • KCL or procain penicillin
  • >50% success if in experienced hands

Question 18

pregnancy day 60 to 65

Answer 18

• transrectal palpation
  
  • less tone in gravid horn
  • non-gravid horn toned
  • vesicle expands into uterine body
  • child size football-shaped

Question 19

fetal sexing

Answer 19

• day 59-68 (65)
• genital tubercle -> external genitalia
  
  • migrates up under a tail in females
  • migrates down towards umbilicus in males
• day 93
  
  • u/s
  • can ID hindlimbs/udders with teats (female)
  • can ID hindlimbs/prepuse, testes (male)

Question 20

pregnancy day 75 to 120

Answer 20

• uterus pulled ventrally
• basketball shape
• differentiate from bladder
  
  • palpate to cervix
  • ovaries at midline
• difficult to image pregnancy transrectally

Question 21

pregnancy day 100 to 120

Answer 21

• huge flaccid tract
• ovaries no longer sublumbar
• gender identification at 100 days

Question 22

pregnancy day 150 to 200

Answer 22

• uterine descent complete
• fetal ballottment consistent
• transabdominal ultrasound approach best**

Question 23

ultrasound in late gestation

Answer 23

• transrectal u/s
  
  • placenta- integrity and thickness
  • fetal orbit- staging fetal age
  • fetal fluids- echogenicity
  • combined thickness of uterus and placenta (CTUP)
    
    • thickened ascending placentitis (can see separation of allantois and uterus= abnormal)
• transabdominal u/s
  
  • fetal heart rate
  • fetal fluids
  • placenta

Question 24

transrectal evaluation of placenta

Answer 24

• separation: ascending placentitis

Question 25

sensitive indicators of pregnancy

Answer 25

• transrectal ultrasound best
• transrectal palpation

Question 26

insensitive indicators of pregnancy

Answer 26

• behavior
• cervical changes
• hormonal assays

Question 27

Summary of Twin Reduction

Answer 27

• manual crush= most successful
• u/s guided aspiration of fetal fluids= low success rate
• craniocervical dislocation= requires surgery
• u/s guided fetal heart injection= requires expert experience

Question 28

Summary Monitoring Pregnancy

Answer 28

• early embryonic and fetal development
  
  • diagnosis of twins
  • diagnosis of EED
  • staging preg
  • determination of fetal gender
• late preg
  
  • staging preg
  • determination of fetal gender
  • diagnosis placentitis
  • determination of fetal viability