Hormone Manipulation: Case 2

You have chosen to use PGF2a (Lutalyse) but first you must remember what it does.

Since mares grow follicles even in diestrus, giving PGF2a without knowing the size of the follicles on the ovary can be dangerous because:

the mare can ovulate without showing estrus if she has a large follicle when PGF2a is given
it causes multiple ovulations
PGF2a decreases estrogen levels
inhibit behavioral estrus

PGF2a only works between day 5-12 of the cycle. If you have no information about where the mare is in the cycle (more than one correct answer)

with a single shot, you have a 33% chance to cause luteolysis
you may cause ovulation without estrus
a single shot may not change the mare's cycle at all
two shots, 12 days apart will result in estrus in 2-4 days after the second shot

You come up with a plan!

You are going to use the 2 shot method. If you can only get the fresh semen June 5-9, when should you give the shots so that you breed during this window?

May 15 & 28

May 17 & June 1

May 25 & June 7

 

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