equine pregnancy

Question 1

whats the duration of equine pregnancy

Answer 1

336 days
(average, in reality its very variable)

Question 2

describe the process from fertilisation to growth in womb

Answer 2

fertilisation occurs in ampulla of oviduct.
embryo enters uterus at day 6 and migrates around. This movement ie essential for maternal recognition of pregnancy and prevention of PG release by endometrium.
day 15-16 embryo fixes in place usually at base of one horn.
placental attachment begins at day 36.
Endometrial cups arise at day 36 aswell.
foetus grows into uterine body

Question 3

when do endometrial cups arise and what do they do

Answer 3

day 35, secret eCG.

eCG maintains primary CL
this maintains pregnancy for first 5 months
endometrial cups begin degeneration at day 70 and are gone by day 150

Question 4

why cant you abort a foal post 35 days

Answer 4

endometrial cups will remain. mare will not come into oestrus for the rest of the season

Question 5

what samples can be taken to diagnose pregnancy and what is measured

Answer 5

blood sample
eCG from day 45-90
oestron sulphate from day 120 onwards

urine sample
oestron sulfate from day 150 onwards

Question 6

from what day can you manually palpate pregnancy

Answer 6

day 20

Question 7

from what day can you diagnose pregnancy through ultrasonography

Answer 7

day 10

Question 8

what is the common scanning routine for a pregnant mare

Answer 8

scan at
day 15-16
day 24-26
week 6

Question 9

name a 2 viral causes of abortion

Answer 9

equine herpes virus 1

abortion often late term with no warning signs
no treatment
vaccinate regularly, isolate and disinfect

equine viral arteritis (rare)
infected mares abort then immune.
stallions become PI

Question 10

why is twin pregnancy unwanted

Answer 10

compete with each other for space and nutrition

if twins in same horn it is likley that one will die naturally and problem will self resolve

if at different horns twins will survive longer and both will be aborted at a later date

Question 11

how is twin pregnancy terminated

Answer 11

manually crushed
NSAIDs given after
scan again in 24 hours to ensure crushing was succesful

Question 12

how would you induce abortion before 3 months

Answer 12

prostaglandin injection

Question 13

how would you induce abortion after 3 months

Answer 13

repeated prostaglandin injections

transabdominal injection of KCl into foetal heart

Question 14

although not regularly required how would you induce foaling in a pregnant mare

Answer 14

repeated oxytocin injections every 15-20 minutes