Reduction of first GnRH dosage in high-yielding holstein cows synchronized with Ovsynch or Heatsynch

Authors

  • Flávio Aragon Lima Policlínica Veterinária Pioneiros, Carambeí, PR
  • Márcio Barciela Veras Policlínica Veterinária Pioneiros, Carambeí, PR
  • José Nélio de Sousa Sales Universidade de São Paulo, Faculdade de Medicina Veterinária e Zootecnia, Departamento de Reprodução Animal, São Paulo, SP
  • Gabriel Armond Crepaldi Universidade de São Paulo, Faculdade de Medicina Veterinária e Zootecnia, Departamento de Reprodução Animal, São Paulo, SP
  • José Ricardo Garla de Maio Ouro Fino Saúde Animal, Cravinhos, SP
  • Pietro Sampaio Baruselli Universidade de São Paulo, Faculdade de Medicina Veterinária e Zootecnia, Departamento de Reprodução Animal, São Paulo, SP

DOI:

https://doi.org/10.11606/issn.1678-4456.bjvras.2010.26836

Keywords:

FTAI, Ovulation synchronized, Dosage GnRH, Dairy cows

Abstract

The objective of this study was to evaluate the effect of treatment with 10 or 20 µg of GnRH and type of FTAI protocols (Ovsynch and Heatsynch) on pregnancy rate of lactating dairy cows submitted to the synchronization at FTAI (n = 581). The animals were distributed among four treatments, allocated factorial design 2x2: Treat 1- Ovsynch (20 µg GnRH on D0; PGF on D7; 10 µg GnRH on D9 and FTAI on D10; n = 141), Treat 2- ½ Ovsynch (10 µg GnRH on D0; PGF on D7; 10 µg GnRH on D9 and FTAI on D10; n = 159), Treat 3- Heatsynch (20 µg GnRH on D0; PGF on D7; 1 mg EB on D8 and FTAI on D10; n = 147) and Treat 4- ½ Heatsynch (10 µg GnRH on D0; PGF on D7; 1 mg EB on D8 and FTAI on D10; n = 134). The Group Ovsynch (Treat 1 and 2) presented greater pregnancy rate than Group Heatsynch (Treat 3 and 4) at 28 days (45.7% (137/300) and 39.9% (112/281), respectively; P = 0.07) and at 56 days of gestation (41.0% (123/300) and 34.2% (96/281), respectively; P = 0.06). There were no statistical difference (P >; 0.10) on pregnancy rate at 28 (44.4% (128/288) vs 41.3% (121/293); P = 0.50) and 56 days (38.2% (110/288) vs 37.2% (109/293); P = 0.68) between the dosages of the GnRH. The pregnancies losses (between 28 and 56 days) were not different between the FTAI protocols and GnRH dosage (P >; 0.10). We concluded that the Ovsynch protocol presented greater pregnancy rate at FTAI than Heatsynch protocol and the administration of 10 µg of buserelin Acetate, at the beginning of these protocols did not decrease the efficiency of FTAI protocols in high-yielding Holstein cows.

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Published

2010-04-01

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UNDEFINIED

How to Cite

Reduction of first GnRH dosage in high-yielding holstein cows synchronized with Ovsynch or Heatsynch. (2010). Brazilian Journal of Veterinary Research and Animal Science, 47(2), 125-131. https://doi.org/10.11606/issn.1678-4456.bjvras.2010.26836