Pregnancy diagnosis in the mare

Question 1

What pregancy diagnosis methods can be used in the mare and at what times?

Answer 1

• Failure to return to oestrus - day 18-24
• (Elevated plasma progesterone day 18-20)
• Transrectal ultrasound from day 12 (15 common)
• Transrectal palpation from day 21
• Plasma equine chorionic gonadotrophin from day 60 – 120
• Transrectal ballottement of foetus from day 80
• (Plasma or urine oestrogen from day 150)

Question 2

With twins when is one removed? How is this done?

Answer 2

Before day 17 as still mobile
Use the US transducer or hand to crush the conceptus

Question 3

What is the consequence of pregnancy loss
Before maternal recognition?
After maternal recognition but before day 40?
After endometrial cups form?

Answer 3

• Before maternal recognition - resorption
• After maternal recognition but before day 40 - respotion
  After endometrial cups form - mummification

Question 4

if a mare is 14 days from ovulation:
How can you differentiate a pregnancy from an endometrial cyst?

Answer 4

• US the overy for CL
• try and move the conceptus - cyst don’t move
• wait for 30 mins and see if it moves or come back tomorrow and should have moved and be bigger

Question 5

Why might conceptuses be different sizes?

Answer 5

• two ovulations within a few days that have both been fertilised
• Make sure to always look for 2 CLs

Question 6

What would you do if you found twins at day 35?

Answer 6

Give Prostaglanin to lyse the CLs cause an abortion.
Becuase:
* Then get the mare pregnanct again.
* If you don’t terinate then the endometral cups will from at day 40 and the foetuses will be lost later inthe pregnancy but at that point the mare will not be able to bred again that cycle as the foetuses would have been lost too late

Question 7

What is an optimal scanning scheme for pregnancy diagnosis?

Answer 7

• Day 14 and if suspicion of twins then re-examine 2 days later
• Day 21
• Day 35

Question 8

What are the options when dealing with twins in horses?

Answer 8

• Abolish whole pregnancy with PG?
  
  • But likely to occur again at next pregnancy
• Manual rupture of one conceptus at day 14/15
  
  • The smaller conceptus is normally chosen
  • Early conceptuses are not difficult to crush
  • After day 21 greater pressure is required and more fluid is released
  • Mare should be examined again 2 days later to ensure singleton remains