COMPARISON OF LONG-TERM PROGESTERONE-BASED PROTOCOL ON REPRODUCTIVE PERFORMANCE OF PREPUBERTAL AND PUBERTAL BEEF HEIFERS.

Autores

  • Emanoel Faleiros Silveira Programa de Pós Graduação em Ciência Animal - PUCPR
  • Luiz Ernandes Kozicki PUCPR
  • Marcio Saporski Segui PUCPR
  • Romildo Romualdo Weiss UFPR
  • Ivo Walter Santos UFPR
  • Melina Andrea Formighieri Bertol UFPR

DOI:

https://doi.org/10.5380/avs.v19i1.32805

Palavras-chave:

Pre pubertal. Pubertal heifers. Progesterone. TAI.

Resumo

The aim of this study was to investigate estrus synchronization in prepubertal and pubertal heifers (crossbred ½ Nelore x Red Angus - commercial herd) submitted to a long-term progesterone-based protocol for timed artificial insemination (TAI), as well as overall pregnancy rates. Four hundred forty-seven heifers underwent ultrasound examination of the ovaries and were assigned to one of 3 groups: (1) prepubertal heifers (PPNS; n = 114) with ovarian follicles <8 mm in diameter and no corpus luteum (CL) that were submitted to natural service (NS) by bulls for 10 days; (2) prepubertal heifers (PPTAI; n = 124) with follicles <8 mm in diameter and no CL that underwent estrus synchronization with injection of 4.0 mg estradiol benzoate (EB) and insertion of a controlled-release intravaginal progesterone (P4) device containing 0.558 g P4 on d 0, followed by P4 device removal and injection of 150 mg prostaglandin F2α and 0.6 mg estradiol cypionate (ECP) on d 8, and TAI on d 10; and (3) pubertal heifers (PTAI; n = 209) with follicles >8 mm in diameter and/or a CL that underwent the same protocol as PPTAI heifers. Overall pregnancy rate was determined by transrectal ultrasonography on d 45 after NS or TAI. Data were analyzed using the FREQ procedure of SAS (SAS Inst. Inc., Cary, NC). Pregnancy rates were as follows: 20.1% in PPNS, 37.0% in PPTAI, and 48.5% in PTAI (P < 0.05). In conclusion, TAI after estrus synchronization with a hormonal protocol using EB and ECP in prepubertal and pubertal heifers resulted in higher pregnancy rates than prepubertal heifers exposed to natural service, and exposure of prepubertal heifers to a long-term progesterone-based protocol effectively synchronized estrus.

Biografia do Autor

Emanoel Faleiros Silveira, Programa de Pós Graduação em Ciência Animal - PUCPR

Médico Veterinário, Programa de Pós graduação em Ciencia Animal - PUCPR

Luiz Ernandes Kozicki, PUCPR

Médico Veterinário, Professor titular da PUCPR, Programa de Pós Graduação em Ciência Animal.

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Publicado

2014-01-23

Como Citar

Silveira, E. F., Kozicki, L. E., Segui, M. S., Weiss, R. R., Santos, I. W., & Bertol, M. A. F. (2014). COMPARISON OF LONG-TERM PROGESTERONE-BASED PROTOCOL ON REPRODUCTIVE PERFORMANCE OF PREPUBERTAL AND PUBERTAL BEEF HEIFERS. Archives of Veterinary Science, 19(1). https://doi.org/10.5380/avs.v19i1.32805

Edição

Seção

Medicina Veterinária Preventiva