Abstract
The objective ofthe study was toinvestigate the effect ofpre-synchronisation onthe occurrence oftheoestrus and pregnancy rate after fixed time artificial insemination (FTAI) insynchronised ewes during theanoestrous season. Kivircik ewes (n=84) were randomly assigned toone ofthe two treatment groups with (PRE; n=42) orwithout (SYN; n=42) pre-synchronisation. Inthe SYN group, the ewes were subjected toa7-d short-term protocol (P4insertion-6d-PGF2α-1d-P4 removal+ eCG). In the PRE group, the same short-term protocol asintheSYN group was applied with 7 days apart for a pre-synchronised synchronisation protocol. Acervical FTAI was performed with fresh semen at54h after sponge removal. Atthe beginning ofthe synchronisation protocol, theoestrous response (66.7% vs. 0.0%) and cyclicity rates (64.3% vs. 14.3%) based onprogesterone (P4) were higher inthe PRE group compared tothose inthe SYN group, respectively (P<0.01). However, the oestrous response after synchronisation was lower within 96h (57.1% vs. 95.2%; P<0.01) inthe PRE group compared tothat intheSYN group. Although the pregnancy rate after the FTAI was significantly (P<0.05) lower inthe PRE group (14.3%) than theSYN group (35.7%), the overall pregnancy rate after natural mating was not different (95.2%) between the groups. Inconclusion, the pre-synchronisation decreased the oestrous response leading toalower pregnancy rate after theFTAI inthesynchronised ewes during the anoestrous season. Thus, attention should bepaid totwo consecutive administrations ofeCG inapre-synchronisation and synchronisation protocol inewes.
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