Comparison of estradiol benzoate and cypionate in Girolando cows submitted to a timed artificial insemination

  • Otávia Reis Silva Universidade Federal Rural do Rio de Janeiro https://orcid.org/0000-0002-9697-543X
  • Marco Roberto Bourg de Mello Universidade Federal Rural do Rio de Janeiro, Instituto de Zootécnica, Departamento de Reprodução Animal
  • Lara Nogueira Silenciato Universidade Federal Rural do Rio de Janeiro
  • Joaquim Esquerdo Ferreira Universidade Federal Rural do Rio de Janeiro
  • Samuel Rodrigues Bonamichi do Couto Universidade Federal Rural do Rio de Janeiro
  • Rosane Scatamburlo Lizieire Fajardo Empresa de Pesquisa Agropecuária do Estado do Rio de Janeiro
  • Osvaldo de Almeida Resende Empresa Brasileira de Pesquisa Agropecuária, Embrapa Agrobiologia
Keywords: Follicular dynamics, Estradiol esters, Induction of ovulation

Abstract

The various studies on the manipulation of the estrous cycle culminated in the development of estrous and ovulation synchronization protocols, to the point of defining an optimum moment for artificial insemination. The induction of ovulation is a primordial part for the determination of the moment of the TAI, so to study which hormones and how they behave allows a better understanding of this physiological process and, to manipulate it efficiently. The aim of the present study was to compare the use of estradiol benzoate (EB) and cypionate (ECP) as ovulation inducer in Girolando cows submitted to Timed Artificial Insemination (TAI). Ovulations of 108 Girolando cows were synchronized and the initial day of treatment, recorded as D0, which was when the animals received an intravaginal device containing 1g of progestogen and an intramuscular application (im) of 2mg of EB. After 8 days (D8), the device was removed and 500μg of cloprostenol (im) was administered to all females. Then, the animals were randomly divided into two treatments: BG Group (n = 52) and CG Group (n = 56). The CG animals received 1mg of ECP (im) as the ovulation inducer at the time of device removal, while BG Group cows received 1mg of EB (im) 24 h later (D9). TAI occurred at D10. After device removal, ultrasound evaluations were performed every 12 h up to ovulation. The following reproductive parameters were evaluated: interval from intravaginal device removal to ovulation - IDO (hours); interval from ovulation to TAI-IOT (hours); diameter of the largest follicle at intravaginal device removal (mm); maximum diameter of the DF (mm) at D10; the dominant follicle growth rate (mm/day); synchronization rate - SR (%); ovulation rate - OR (%) and PR - pregnancy rate (%). Only the ovulation rate presented a statistical difference (p<0.05). In conclusion, despite the ovulation rate difference, both estradiol esters administered were effective and presented similar pregnancy rates in Girolando cows submitted to TAI.

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Published
2019-10-10
How to Cite
Silva, O., Mello, M. R., Silenciato, L., Ferreira, J., Couto, S., Fajardo, R., & Resende, O. (2019). Comparison of estradiol benzoate and cypionate in Girolando cows submitted to a timed artificial insemination. Brazilian Journal of Veterinary Research and Animal Science, 56(3), e155078. https://doi.org/10.11606/issn.1678-4456.bjvras.2019.155078
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