Equine Pregnancy Flashcards
How long is an equine pregnancy?
336days from mating
Where does fertilisation occur in the mare? + Movement / attachment?
*Ampulla of oviduct
*Embryo remains in oviduct for 5-6 days when it enters uterus
*Then migrates around uterus up to day 15-16 - movement essential for maternal recognition of pregnancy + prevent= PG release
*On day 15-16 embryo fixed to base of horn + placental attachment post 36days
*Grows in uterine body after 70-80 days -for 6-7months then so big that it occupies part of horn
When does maternal recongniton of pregnancy occur?
- 14 days
- CL produces progesterone
- Endometrial cups secrete eCG from day 35 which maintains primary CL + 2ndary CL formation
*After day 200 CLs degraded + pregnancy maintained by foetal-placental progesterone
What are the problems with endometrial cups?
*Once in place will not regress for 100-150days
*If foal has died - mare will not come into oestrus
*Abortion must be done before day 35
How can you diagnose pregnancy?
- Failure to return to oestrus
- Laboratory tests
- Manual rectal exam
- Ultrasound
What does failure to return to oestrus say? When?
Failure to return to oestrus
* Particularly at day 14-21 after mating.
* Initial screening test but not definitive
* Mares may not show oestrus for behavioural reasons
* Conversely some mares display signs of oestrus during pregnancy
What lab tests could be done? from when?
*eCG - from day 45-90
*Oestrone sulphate from day 120
*Urine sample from day 150
How is manual rectal palpation carried out? When?
*Possible at day 20 (IF v skilled)
*Usually left until day 40
*Feel foetus by day 120
*Replaced by scanning - only used in late pregnancy now
When would you perform rectal ultrasonography? Why?
*Can be done from day 10 - usually don’t scan too early
*Early embryonic death highest in first 14days
*Scan from day 16 - can see if twins + get rid
*Second scan day 24-26 = heartbeat, still can reduce twins + before cups
*Third scan = 6 weeks - just reassess
What is distinctive with ultrasonography of foetus?
*White bits at top and bottom of black hollow cavity on ultrasonography
From what date can you perform transabdominal ultrasonography?
- From 6 months onwards
When does early embryonic death, abortion + stillbirth occur?
- Early embryonic death - from fertilisation to day 40
- Abortion - from day 40 - 300
- Stillbirth - from day 300 onwards
What can cause failure of pregnancy?
- Early embryonic death
- Viral - EHV, EVA
- Bacterial
- Fungal
- Twins
- Maternal illness / stress
- Foetal abnormalities
- Umbilical torsion
What can cause early embryonic death? Dx?
- Congenital / genetic abnormalities
- Breeding on foal heat - first season after foaling
- Uterine environmental problems - fibrosis / endometritis
- Dx = empty on repeat scan / abnormal size or shape conceptus on scan
When does EHV-1 cause abortion?
*Usually late term (>5months)