African Journal of
Biotechnology

  • Abbreviation: Afr. J. Biotechnol.
  • Language: English
  • ISSN: 1684-5315
  • DOI: 10.5897/AJB
  • Start Year: 2002
  • Published Articles: 12486

Full Length Research Paper

Dynamics of the concentration of the hormones triiodothyronine and thyroxine at the beginning of the reproductive season and the effect of application of iodine in Nelore heifers bred in pasture

Adriana Almeida Fonseca Ruy
  • Adriana Almeida Fonseca Ruy
  • Federal Institute of Science and Technology Goiano – Campus Rio Verde (GO), Rua Honório Leão Qd 02 LT 06 Setor Morada do Sol, CEP: 75909-070, Rio Verde, Goiás, Brazil.
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Karen Martins Leão
  • Karen Martins Leão
  • Federal Institute of Science and Technology Goiano – Campus Rio Verde (GO), Brazil.
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Mariana da Mata Silveira
  • Mariana da Mata Silveira
  • Federal Institute of Science and Technology Goiano – Campus Rio Verde (GO), Brazil.
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Viler Carrijo Oliveira
  • Viler Carrijo Oliveira
  • Federal Institute of Science and Technology Goiano – Campus Rio Verde (GO), Brazil.
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Francisco Ribeiro de Araújo Neto
  • Francisco Ribeiro de Araújo Neto
  • Federal Institute of Science and Technology Goiano – Campus Rio Verde (GO), Brazil.
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Marco Antônio Pereira da Silva
  • Marco Antônio Pereira da Silva
  • Federal Institute of Science and Technology Goiano – Campus Rio Verde (GO), Brazil.
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  •  Received: 27 November 2017
  •  Accepted: 11 December 2018
  •  Published: 26 December 2018

Abstract

The aim of this study was to evaluate the dynamics of triiodothyronine (T3) and thyroxine (T4) hormones, their relation with body condition score (BCS) and reproductive stage of 248 Nelore heifers, and the effect of iodine application on the induction of cyclicity of 217 anoestrus heifers in pasture at the beginning of the reproductive season. At day zero (D0), an assessment of the BCS was performed. An examination of ovarian structures was performed by ultrasound (US) and the serum was collected for hormonal analysis. Anestrous animals received 27 mg of iodine or placebo (saline). After 40 days (D40), another US was performed, and BCS and hormonal determination evaluations were repeated. At D0 and D40, the cycling group had a BCS mean and a T3 concentration higher than the anestrous group. BCS and T3 and T4 concentrations influenced cyclicity and probability of pregnancy. The treatment did not affect cyclicity, pregnancy rate and number of days between the treatment and calving.

 

Key words: Bovine, reproduction, thyroid.

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This article is published under the terms of the Creative Commons Attribution License 4.0

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