Abdelnaby et al. BMC Veterinary Research (2023) 19:205 https://doi.org/10.1186/s12917-023-03692-3 RESEARCH Open Access © The Author(s) 2023. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativeco mmons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. BMC Veterinary Research Ovarian and uterine arteries blood fow velocities waveform, hormones and nitric oxide in relation to ovulation in cows superstimulated with equine chorionic gonadotropin and luteolysis induction 10 and 17 days after ovulation Elshymaa A. Abdelnaby 1,2* , Abdulrhman K. Alhaider 2 , Amal M. Abo El‑Maaty 3 , Refaat S. A. Ragab 1 , Adel A. Seida 1 and Diya A. El‑Badry 4 Abstract To investigate the ovarian responses, ovarian and uterine hemodynamics, circulating ovarian hormones, and nitric oxide (NO) with their relations in superstimulated cows. Eight Holstein Friesian dry cows previously synchronized with CIDR underwent rectal Doppler ultrasound scanning and blood sampling after administrating eCG (1500 I.U) on day 10 of the second ovulation (day ‑5). Cows were treated with 12.5 mg prostaglandin F 2 α (PGF 2 α) on days 10 and 17 after ovulation. Estradiol, progesterone, and NO were measured. Results showed that from ≥ 13 follicles, fve follicles ovulated from both ovaries. The ovulated follicles increased antrum colored area and colored area % till day ‑1. The developed corpora lutea (CLs) attained similar diameter, area, colored area, and colored area % from day 2 till day 15. The peak point of velocity (PSV ) of uterine arteries decreased while that of ovarian arteries increased from day ‑4 to day 0. Both ovarian arteries diameter, resistance index (RI), PSV, end velocity (EDV) and systolic/dias‑ tolic ratio (S/D) positively correlated (P < 0.0001), but their pulsatility index (PI) negatively correlated (P < 0.0001). The uterine arteries PI, RI, PSV, EDV, time average velocity (TAMV) and S/D negatively correlated (P < 0.0001) but their diameters positively correlated. Estradiol increased but progesterone decreased from day ‑5 till day 0. After ovulation, P4 reached maximum values on day 9 and started to decrease till day 19.NO showed one peak on day ‑3 and another one from day 3 to day 9. Conclusions: Blood fow of ovarian arteries is diferent from uterine arteries and depended on pre‑ or post‑ovulation. Keywords Cows, Doppler indices, eCG, Ovarian artery, Uterine artery *Correspondence: Elshymaa A. Abdelnaby Elshymaa.Ahmed@cu.edu.eg; elshymaaahmed@yahoo.com; a.ali@kfu. edu.sa Full list of author information is available at the end of the article