Hormonal-Induced Cervical Relaxation During Diestrus in Ewes: Cervical Transposing Feasibility and Use of hCG for Rescuing Disrupted Luteal Function

• Published in: Journal of applied animal welfare science Vol. 27; no. 4; pp. 635 - 651
• Main Authors: Oliveira, Maria Emilia Franco, Arrais, Aline Matos, Vergani, Gabriel Brun, Novita Esteves, Sergio, Schinaider Do Amaral Pereira, Verônica, Garcia, Alexandre Rossetto, Bastos, Rosemary, Roberto Bourg Melo, Marco, Rios Coelho Alves, Bruna, Ferreira Fonseca, Jeferson
• Format: Journal Article
• Language: English
• Published: England Taylor & Francis 01-10-2024; Taylor & Francis Ltd
• Subjects: 17β-Estradiol; Animal welfare; Animals; Benzoates; Cervix Uteri - drug effects; Chorionic gonadotropin; Chorionic Gonadotropin - administration & dosage; Chorionic Gonadotropin - pharmacology; Corpus Luteum - drug effects; Diestrus - drug effects; Embryo transfer; Embryo Transfer - veterinary; Estradiol - administration & dosage; Estradiol - analogs & derivatives; Estradiol - pharmacology; Feasibility; Feasibility Studies; Female; Gonadotropins; non-surgical; Oxytocin; Oxytocin - administration & dosage; Oxytocin - pharmacology; pharmacological; Pituitary (anterior); Pregnancy; Progesterone; Progesterone - administration & dosage; Progesterone - pharmacology; Sex hormones; Sheep, Domestic; transcervical; Transposition; Embryo transfer; transcervical; animal welfare; non-surgical; pharmacological
• ISSN: 1088-8705; 1532-7604; 1532-7604
• DOI: 10.1080/10888705.2022.2141576

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.