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Luteotropic effects of human chorionic gonadotropin administered 7.5 days after synchronous estrous induction in Morada Nova ewes.

Authors
  • Vergani, Gabriel Brun1
  • Fonseca, Jeferson Ferreira da2
  • Trevizan, Juliane Teramachi1
  • Pereira, Verônica Schinaider do Amaral3
  • Garcia, Alexandre Rossetto3
  • Esteves, Sergio Novita3
  • Brandão, Felipe Zandonadi4
  • Souza-Fabjan, Joanna Maria Gonçalves4
  • Oliveira, Maria Emilia Franco5
  • 1 Department of Pathobiology and Veterinary Theriogenology, School of Agricultural and Veterinarian Sciences, São Paulo State University, Jaboticabal, SP, Brazil. , (Brazil)
  • 2 Embrapa Caprinos e Ovinos, Rodovia MG 133, Km 42, Cep 36.155-000, Coronel Pacheco, MG, Brazil; Departamento de Veterinária, Universidade Federal de Viçosa, Av. Peter Henry Rolfs, s/n, CEP 36570-000, Viçosa, MG, Brazil. Electronic address: [email protected] , (Brazil)
  • 3 Embrapa Pecuária Sudeste, Rodovia Washington Luiz, Km 234 s/nº, Fazenda Canchim, Caixa Postal: 339, CEP: 13560-970, São Carlos, SP, Brazil. , (Brazil)
  • 4 Faculdade de Veterinária, Universidade Federal Fluminense, Rua Vital Brasil Filho, 64, CEP 24230-340, Niterói, RJ, Brazil. , (Brazil)
  • 5 Department of Pathobiology and Veterinary Theriogenology, School of Agricultural and Veterinarian Sciences, São Paulo State University, Jaboticabal, SP, Brazil; Embrapa Caprinos e Ovinos, Rodovia MG 133, Km 42, Cep 36.155-000, Coronel Pacheco, MG, Brazil. Electronic address: [email protected] , (Brazil)
Type
Published Article
Journal
Animal reproduction science
Publication Date
Dec 01, 2020
Volume
223
Pages
106644–106644
Identifiers
DOI: 10.1016/j.anireprosci.2020.106644
PMID: 33197710
Source
Medline
Keywords
Language
English
License
Unknown

Abstract

This study was conducted in ewes to assess effects of human chorionic gonadotropin (hCG) administration after imposing an estrous induction treatment regimen. Ewes (n = 115) were treated with a 60 mg medroxyprogesterone-intravaginal-sponge for 6 d plus 200 IU of equine chorionic gonadotropin (eCG) im and 37.5 μg d-cloprostenol im 36 h before sponge removal (Day 0). After natural mating, ewes having at least one corpus luteum (CL; n = 108) were administered either 1 mL of saline (G-Control; n = 53) or 300 IU of hCG (G-hCG; n = 55) on Day 7.5 after sponge removal (Day 0). Ovarian ultrasonography and blood collection were performed on Days 7.5, 13.5, 17.5, 21.5, and 30.5. Accessory CL (aCL) were observed in 81.5 % (G-hCG) and 0.0 % (G-Control) of ewes (P = 0.0001). Diameter, area, and volume of luteal tissue were greater (P < 0.05) in G-hCG from Day 13.5 to 30.5. Progesterone (P4) concentrations were greater (P < 0.05) on Days 13.5, 17.5, 21.5 and 30.5 for ewes of the G-hCG group. Pregnancy percentage was similar (P = 0.25) between groups [47.1 % (G-control) compared with 60.0 % (G-hCG)], although total number of lambs produced by estrous synchronized ewes was greater (P = 0.005) in ewes of the G-hCG group (90.9 % compared with 66.0 %). In conclusion, hCG administration 7.5 days after sponge removal from Morada Nova ewes during the non-breeding season is an effective treatment to induce aCL formation, improve luteal tissue biometry and P4 concentrations, and to enhance the total number of lambs born. Copyright © 2020 Elsevier B.V. All rights reserved.

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