Ovulation induction with human chorionic gonadotropin in criollo mares

  • Jordana Beal Universidade Federal de Santa Maria, Santa Maria, RS
  • Mara Iolanda Batistella Rubin Universidade Federal de Santa Maria, Centro de Ciências Rurais, Departamento de Clínica de Grandes Animais, Santa Maria, RS
  • Flavio Desessards de La Corte Universidade Federal de Santa Maria, Centro de Ciências Rurais, Departamento de Clínica de Grandes Animais, Santa Maria, RS
  • Luiz Sérgio Segala de Oliveira Universidade Federal de Santa Maria, Centro de Ciências Rurais, Departamento de Clínica de Grandes Animais, Santa Maria, RS
  • José Henrique Souza da Silva Universidade Federal de Santa Maria, Centro de Ciências Rurais, Departamento de Zootecnia, Santa Maria, RS
  • Carlos Antonio Mondino Silva Universidade Federal de Santa Maria, Centro de Ciências Rurais, Departamento de Clínica de Grandes Animais, Santa Maria, RS
Keywords: Criollo, Follicular diameter, Equine, hCG

Abstract

The effect of age, follicular diameter and month of the breeding season (September to January) on the hCG induction of ovulation was evaluated using 123 Criollo mares. Age varied between two and 24 years and the animals were examined daily by rectal palpation and ultrasonography with a 5 MHz linear transducer. When ovarian follicles reached a diameter of 30 to 35 mm, ovulation was induced with an i.v. injection of 1000 IU (n = 39); 1500 IU (n = 41) or 2000 IU (n = 43) of hCG. The mares were bred the next day and examined daily until ovulation was detected. The percentage of mares ovulating before 24 h of hCG injection was 10.3%, 7.3% and 4.7%; until 48 h after injection 92.3%, 85.3% and 86.0% of the mares treated with 1000, 1500 and 2000 IU of hCG, respectively, ovulated. The month of the breeding season, age of the mares and follicular diameter had no influence on ovulatory response. The three hCG doses used in Criollo mares (P >; 0.05) result in the induction of ovulation within 48 h after injection when a pre-ovulatory follicle with a 30 to 35 mm diameter was identified. A single dose of 1000 IU of hCG is efficient to induce ovulation in Criollo mares.

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Published
2011-08-01
How to Cite
Beal, J., Rubin, M., La Corte, F., Oliveira, L., Silva, J., & Silva, C. (2011). Ovulation induction with human chorionic gonadotropin in criollo mares. Brazilian Journal of Veterinary Research and Animal Science, 48(4), 332-335. https://doi.org/10.11606/S1413-95962011000400009
Section
UNDEFINIED