The vaginal and uterine blood flow changes during the ovsynch program and its impact on the pregnancy rates in Holstein dairy cows

Abstract

Aim OvSynch is a hormonal protocol for synchronization of estrus and use of artificial insemination (AI) at an optimal time without adverse effects on the ovaries or uterus. This study investigated the use of noninvasive color Doppler ultrasound to assess changes in uterine and vaginal blood flow during the Ovsynch program for synchronization of estrus and its relation to the pregnancy rates in Holstein cows. Materials and methods The experimental cows received an intramuscular dose of 10 µg of a GnRH analogue (G1), followed 7 days later with an intramuscular injection of synthetic prostaglandin F2α (P: PGF2α) analogue (500 µg cloprostenol sodium), and given a 10 µg, injection of the GnRH analogue (G2) i.m. (2.5ml/animal) 48 h after the PGF2a treatment, and the cows were bred 14–16 h after. Uterine and vaginal perfusion were investigated by performing transrectal Doppler ultrasonography of both the middle uterine and vaginal arteries in Holstein cows at different time points during the Ovsynch program to determine: peak systolic velocity (PSV), time-averaged maximum velocity (TAMV), the volume of blood flow (BFV), pulsatility index (PI), resistance index (RI), resistance impedance (S/D) and diameters of uterine (UA) and vaginal (VA) arteries. Steroid hormones were also considered. Transrectal ultrasonography (TUS) was performed at 32 and 60 days to confirm the pregnancy per artificial insemination (P/AI). Results The uterine PSV, TAMV, and PV were greater at the time of the cloprostenol sodium and second GnRH injections (p < 0.05) than at the time of the first GnRH injection. The vaginal PSV, PV were greater at the time of the cloprostenol sodium than at the time of the first and second GnRH injections (p < 0.05). The receiver operating characteristic curve (ROC curve) indicated a higher correlation between the uterine and vaginal blood flow and the rate of the pregnancy (p < 0.05). The ROC curve for the vaginal artery was 0.920 and that for uterine blood flow was 0.870 (p < 0.05) at the G2 (p < 0.05). The serum levels of progesterone, estrogen and cortisol were correlated with the P/AI (p < 0.05). The P/AI significantly decreased from 43.9% at 32 d to 35.37% at 60 d. Conclusion These results indicate that noninvasive Doppler ultrasonography is a valid method to evaluate changes in the characteristics of uterine and vaginal blood flow in cows during the Ovsynch protocol. Furthermore, vaginal and uterine blood flow are two determinant factors for the higher conception rates in Holstein dairy cows.

Effects of mating, artificial insemination and intravaginal deposition of raw semen or seminal plasma on vaginal and uterine blood flow in German Holstein cows

“…The application of color Doppler ultrasound was proven to be a feasible, safe, accurate method for evaluation of changes in uterine blood ow in cows (3,15), mares (16, 17), buffaloes (18, 19) and small ruminants (20)(21)(22), but there are no reports of studies of vaginal blood perfusion in veterinary reproduction using color Doppler ultrasound.…”