Abstract
Oxytocin hormone, which is frequently used in order to hasten uterine involution process and to ensure milk ejection, is also effective in regulation of vascular tone. Doppler ultrasonography is a highly practical technique that allows the evaluation of blood flow characteristics of tissues and organs. In this study, it was aimed to investigate the hemodynamic changes of mammary artery caused by oxytocin administration in postpartum ewes. The study was conducted with 20 primiparous Kivircik ewes which lambed singleton. The ewes were randomly divided into oxytocin and control groups (n=10 for each group). A dose of 10 IU/sheep oxytocin and 1 ml/sheep saline solution were administered intramuscularly bid on the first 3 days postpartum to oxytocin and control groups, respectively. The pulsed Doppler ultrasonography is used to measure pulsatility and resistance indices (PI and RI, respectively) of external pudendal artery. Although oxytocin group tended to have relatively higher PI and RI values, significant differences were detected only in PI values of the first and second days postpartum (p<0.001 and p<0.05, respectively) between groups. It has been concluded that oxytocin administration increased the resistance of mammary artery in early postpartum ewes.