I have planned 14 days CIDR application in sheep. I will treat also eCG and PGF2 alfa 2 days prior to withdraw of CIDR. However, I do not exactly sure when I have to carry out Timed Artificial Insemination with fresh semen via intracervical. Normally, eCG and PGF administered on withdraw of CIDR and TAI applied 48 or 56 h after withdraw of CIDR or PRID. Some studies point out 56 hours is best for intracervical artificial insemination. Do you have any experience about 14 days application of CIDR and eCG and PGF 2 days before CIDR withdraw?
I don't have experience on CIDR application and AI, but I strongly believe that the fixed time insemination solve one problem and creates many problems. We have tried to predict the best time for AI by measuring the electrical resistance of cervical mucus (after estrus synchronization with sponges) and our results were very promising. You could check the electrical resistance of cervical mucus starting 12 to 24 hours after the CIDR removal and until 56 or 72 h every 12 or 24h and make the AI when electrical resistance is low (in the range the manufacturer gives for cows and sows). This would give to your study one more point of interest. In your case, and if I cannot check electrical resistance, I would prefer to do the AI earlier than the proposed, for example 24 h after CIDR removal.
Dear Tsiligianni, thank you for your answer, Measuring the electrical resistance of cervical mucus in ewes is interesting approach to determine the best time of AI. I have no device to determine electrical resistance. So I try to determine estrus with teaser ram. Neverthless, I am worry about the time of ovulation because I will inject eCG and PGF 2 days before CIDR removal. I predict the early injection of eCG may trigger early follicular development and ovulation. Do you have any experience about this issue? Thank you again.
If you use teaser rams from 12 - 24 h after CIDR removal you will have a good indicator for the time you must perform AI. In our studies the machine works better than the rams for estrus detection. I told you that I would start checking ewes very early (12h after CIDR removal) because of the early injection eCG or PGF.
Hi, I think the best time for AI depending on the time of estrous beginning and also the time of ovulation. We comThe
peak of oestrus occurred 32–52, 48–60 and 28–96 h after the
end of treatment in CIDR-eCG, PGF2a-PGF2a and GnRHPGF2a-
GnRH groups, respectively. Ovulation started 48 h
after treatment in all groups and extended for 24, 36 and 48 h
for CIDR-eCG, PGF2a-PGF2a and GnRH-PGF2a-GnRH
groups, respectively. Results demonstrated that oestrus and
ovulation synchronization could be efficiently achieved in
Farafra ewes using either CIDR-eCG or PGF2a-PGF2a
regimes; however, the GnRH-PGF2a-GnRH treatment
induced a more spread oestrus and ovulation that may make
the protocol inadequate for timed artificial insemination.pared 3 regimes estrous synchronization in ewes, the result was as following "
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