Artificial insemination causes uterine hemodynamic alterations in suckled beef cows subjected to an ovulation synchronization program

The objective of the present study was to verify the uterine hemodynamic of suckled beef cows after a timed artificial insemination (TAI) by Doppler ultrasound. Eighteen cows were randomly assigned in one of two groups - non-AI (CG, n=9) and AI group (AIG, n=9). Ultrasound evaluations were performed in five spectral mode moments (30 h before AI, 4, 24, 48, and 168 h after AI) to evaluate the resistance index (RI) of the uterine artery and in four Doppler color mode moments (4, 24, 48 and 168 h after AI) to evaluate the percentage of the uterine horns vascularization. The animals showed similar vascularization in the beginning of the experiment. The data were first evaluated according to the side where ovulation occurred and no effects were observed. Vascularization was assessed in each group at each time. No differences were observed in any of the time points. Time effect was observed in both groups and behavior was similar for the groups. Highest values of RI were observed 48 h after AI, followed by the 168 h and values obtained 24 h after AI. The lowest values of RI were noted 4 h after AI, followed by the observation 30 h before AI. Regarding the effect of time to EV, time effect was not observed in either group. Since there was no interaction group×time, data were analyzed for each group, regardless of the time and for each time, regardless of the group. The RI values were lower for AIG when compared to the CG; however, no differences were observed between the groups as far as uterine vascularization scores. Four hours after AI, the RI values were lower when compared to 24, 48 and 168 h following AI, showing no difference in relation to 30 h before AI. Thirty hours before AI, the RI values were lower when compared to 48 and 168 h after AI, no different than the values observed 24 h after AI. The highest RI value appeared 48 h after AI, where this value was not statistically different from the one found 168 h after AI. On the other hand, there was no difference between the vascularization scores regarding the evaluation periods (p>0.05). Artificial insemination of female bovines reduce uterine artery RI, but does not change the uterine vascular score. Moreover, changes in the uterine hemodynamics in cows are related to the period of evaluation.