Factors influencing pregnancy rate and loss after laparoscopic artificial insemination with frozen–thawed semen in Lohi sheep under sub‐tropical conditions.

This study evaluates factors influencing pregnancy rates per artificial insemination (P/AI) and pregnancy loss in Lohi ewes undergoing laparoscopic AI with frozen–thawed semen under sub‐tropical conditions. Data from three experiments comprising ewes (n = 358) of mixed parity (nulliparous; NP and parous; P), various body condition score (BCS) and assigned to long‐term (LTP, 11 days) and short‐term (STP, 5 days) oestrus synchronization regimen across high breeding season (HBS) and low breeding season (LBS) were analysed. Laparoscopic insemination was conducted 54 h post‐sponge removal. Pregnancy diagnosis and loss were evaluated on days 35 and 90 post‐insemination via ultrasonography. Results showed parity significantly influenced P/AI, with nulliparous ewes achieving higher pregnancy ratios than parous ewes (p =.001). BCS significantly influenced P/AI (p <.05), with a quadratic relationship observed between BCS and season (BCS*BCS*Season; p =.07). Progestin treatment did not significantly influence the ratio of pregnant ewes (p =.07). Pregnancy losses were significantly higher during LBS than HBS (p <.05), irrespective of progestin treatment. In conclusion, parity and BCS significantly influenced P/AI, with BCS demonstrating a quadratic association with season. Ewes bred during LBS experienced higher pregnancy losses than HBS, irrespective of progestin treatment. [ABSTRACT FROM AUTHOR]