1. Hormonal-Induced Cervical Relaxation During Diestrus in Ewes: Cervical Transposing Feasibility and Use of hCG for Rescuing Disrupted Luteal Function.
- Author
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Oliveira MEF, Arrais AM, Vergani GB, Novita Esteves S, Schinaider Do Amaral Pereira V, Garcia AR, Bastos R, Roberto Bourg Melo M, Rios Coelho Alves B, and Ferreira Fonseca J
- Subjects
- Animals, Female, Pregnancy, Embryo Transfer veterinary, Corpus Luteum drug effects, Sheep, Domestic, Feasibility Studies, Chorionic Gonadotropin pharmacology, Chorionic Gonadotropin administration & dosage, Oxytocin pharmacology, Oxytocin administration & dosage, Estradiol pharmacology, Estradiol administration & dosage, Estradiol analogs & derivatives, Progesterone pharmacology, Progesterone administration & dosage, Cervix Uteri drug effects, Diestrus drug effects
- Abstract
Cervical relaxation (CR) was performed in ewes during diestrus, to prospect a feasible protocol for non-surgical embryo transfer (NSET). In Trial 1, naturally mated ewes (n=13) received CR protocols with estradiol benzoate (EB, 1 mg on D6) and oxytocin (OT, 50 IU on D7) only (G-EB+OT) or associated with human chorionic gonadotropin (hCG, 300 IU on D7, G-EB+OT+hCG) and were compared to non-hormonally treated (G-control) ewes. Estradiol concentration increased (P<0.05) from D6 to D7 in G-EB+OT and G-EB+OT+hCG, then decreased (P<0.05) on D8. The G-EB+OT had reduced (P<0.05) progesterone on D8, and 0% (0/5) pregnancy, while G-control had 100% (3/3) conception rate. The treatment with hCG mitigated the progesterone drop on D8 and resulted in 50% (2/4) conception rate. In Trial 2, cervical transposing success after treatment with EB, OT, and hCG on D6 and D7 was assessed in nulliparous (n=25) and multiparous (n=30) ewes. The EB+OT+hCG protocol allowed efficient cervical transposition (~78% of cervical transposition success into ~5 min) in nulliparous and multiparous females and did not alter total and blood perfusion areas of corpora lutea (CL). The use of EB+OT+hCG was efficient to ensure effective cervical transposing in nulliparous and multiparous ewes, with no apparent deleterious effect on CL function, and may contribute to animal welfare, allowing a less invasive NSET procedure.
- Published
- 2024
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