Recombinant bovine somatotropin in the synchronization of ovulation in crossbred dairy cows (Bos taurus indicus × Bos taurus taurus)

Vet World Vol.13 April-2020 Article-19

Research Article

Veterinary World, 13(4): 746-750

https://doi.org/10.14202/vetworld.2020.746-750

Fabrício Albani Oliveira¹, Ítalo Câmara de Almeida², Larissa Marchiori Sena³, Jurandy Mauro Penitente-Filho⁴, and Ciro Alexandre Alves Torres⁴

1. Federal Institute of Espirito Santo, Alegre, Espirito Santo, 29520-000, Brazil.
2. Department of Veterinary Medicine, Federal University of Espirito Santo, Alegre, Espirito Santo, 29500-000, Brazil.
3. Pitágoras College, Ipatinga, Minas Gerais, 35160-294, Brazil.
4. Department of Animal Science, Federal University of Viçosa, Campus Universitário, Viçosa, Minas Gerais, 36571-000, Brazil.

Background and Aim: The aim of this study was to evaluate the effects of the administration of recombinant bovine somatotropin (rbST) at the moment of implementation of the timed artificial insemination protocol, on follicular dynamics and pregnancy rate in crossbred cows.

Materials and Methods: A total of 346 cows were used in two experiments with a factorial 2×2 design. The cycling cows (Tcycling) and the anestrous cows (Tanestrous) were considered as factor 1 and the administration of rbST (TrbST) or not (Tcontrol) as factor 2. The experimental protocol: (1) Tcontrol – day 0 (D0), insertion of a progesterone-release intravaginal device (PRID) plus 2 mg of estradiol benzoate (EB); D8, PRID removal, plus 0.150 mg of prostaglandin F2α, and 400 IU of equine chorionic gonadotropin; D9, 1 mg of EB; and with artificial insemination at day 10; (2) TrbST – similar to Tcontrol plus 500 mg of rbST on D0. In experiment I, ultrasound examinations were performed in all treatments. In experiment II, the cows' pregnancy rate was evaluated. Data were analyzed with 5% probability.

Results: There was no effect of the protocols on cows cyclicity or follicular growth rate (p>0.05). There was no interaction of the effects, administration of rbST, and the cyclicity of cows on the pregnancy rate. The total pregnancy rate observed was 49.0%. The pregnancy rate in cows receiving rbST was lower for anestrous compared with cycling cows (p<0.05).

Conclusion: The administration of rbST did not alter the patterns of follicular dynamics nor the ovulation rate. However, cows in anestrous that received rbST had lower pregnancy rates than cycling cows. Keywords: biotechnology, dairy cows, fertility, follicle, reproduction.

Keywords: biotechnology, dairy cows, fertility, follicle, reproduction.

How to cite this article: Oliveira FA, de Almeida IC, Sena LM, Penitente-Filho JM, Torres CAA (2020) Recombinant bovine somatotropin in the synchronization of ovulation in crossbred dairy cows (Bos taurus indicus × Bos taurus taurus), Veterinary World, 13(4): 746-750.

Received: 11-01-2020 Accepted: 09-03-2020 Published online: 21-04-2020

Corresponding author: Ítalo Câmara de Almeida E-mail: almeidaicvet@gmail.com

DOI: 10.14202/vetworld.2020.746-750

Copyright: Oliveira, et al. This article is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http:// creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.