Spectral Doppler ultrasound in selecting an equine embryo receiver

Abstract

The aim of this study was to evaluate whether the RI and PI values would help in choosing the best embryo recipient, and observe whether CL vascularization would influence P4 production. During the breeding season 2018/2019, the study was conducted using 35 mares, which is used for reference to collect data for the project on the day of embryo transfer. The utilized mares were divided into five groups followed by the day after ovulation, with D0 being the day of ovulation. Therefore, the five groups are as follows: D4—mares that were on the 4th post‐ovulation day; D5—mares that were on the 5th post‐ovulation day; and doing so successively for D6, D7 and D8. On the day of embryo transfer, the CL of the mares that selected as recipients was evaluated by B‐mode and power flow mode ultrasonography and the right and left dorsal branches of the uterine arteries by spectral Doppler ultrasonography. Blood samples were taken on the day of the embryo transfer for a dosage of P4 concentration by radioimmunoassay. No statistical difference was found between the variables when the mares were separated into pregnant and non‐pregnant mares, or when they were separated by age groups. When the groups of mares were compared by the day of embryo transfer, the statistical difference was found between the groups D5 × D6 (p = .0053) and D6 × D8 (p = .0036) in RI variable. In PI variable, the statistical difference was found between the groups D4 × D8 (p = .049), D5 × D6 (p = .0446) and D6 × D8 (p = .0024). We conclude that the mares with RI measurement of uterine arteries near 1.0 are correlated to mares with high CL vascularization and elevated P4 concentration.

The effects of aging and gestational month on uteroplacental vascular perfusion, and umbilical artery hemodynamics in pregnant jennies

“…The pulsed wave Doppler was activated via its spectral graph of both the middle uterine (right and left) and umbilical arteries. Doppler indices expressed by resistance (RI) and pulsatility indices (PI) were automatically calculated, and the blood flow rate (bpm) was also measured.The artery was determined after identification of the aorta location and the external iliac artery as both middle uterine arteries are located at the right and left sides [ 26 ], as shown in Fig. 2 .The waves were determined as three successive spectral waves in both the uterine and umbilical regions.…”

Clinical Overview of Luteal Deficiency in Dairy Cattle

“…Therefore, P4 therapy is recommended to reduce the incidence of pregnancy failure in mares and bitches of suspected sub-luteal function [ 59 , 60 ]. In contrast to the cow, controversial results are shown using Doppler ultrasonography to assess the CL function in the selection of equine embryo transfer recipients [ 61 , 62 ]. Turning the point to women, and as has been noted above, luteal deficiency has long been considered a main factor associated with low fertility [ 1 , 2 , 3 , 4 , 5 ].…”

Advances in the ultrasound diagnosis in equine reproductive medicine: New approaches

“…A recent study also showed that spectral Doppler measurement of the blood flow of the uterine arteries is an indirect way to the evaluation of CL functionality and thus a helpful tool for the selection of recipient mares for ET. Mares with RI values near 1.0 are correlated with mares with high CL vascularization and elevated P4 plasma concentrations (Ferreira et al, 2020). The relation between the area of colour flow Doppler of CL and progesterone concentrations has been also evaluated in mares after embryo transfer (Brogan et al, 2016).…”

“…In recent years, several studies have investigated the possibility of using Doppler imaging in embryo transfer programs, particularly in the selection of recipient mares and cows (Brogan et al, 2016; Pugliesi et al, 2018). The high sensitivity of Doppler ultrasound in the evaluation of CL functionality has promoted its use for the identification of recipients with good quality CL on the day of embryo transfer and thus with greater receptivity potential (Brogan et al, 2016; Ferreira et al, 2020) (Figure 3a). A recent study also showed that spectral Doppler measurement of the blood flow of the uterine arteries is an indirect way to the evaluation of CL functionality and thus a helpful tool for the selection of recipient mares for ET.…”