MadozLV_Detection of early pregnancy and embryo losses by color Doppler ultrasound and interferon-stimulated genes expression in grazing dairy cows

Pregnancy diagnosis based on embryo visualization was performed at 33-34 d post-AI by ultrasound B-mode. At 19-20 d post-AI, the pregnancy rate was 58.7% diagnosed by Doppler-US and 62.7% diagnosed by ISG mRNA expression in leukocytes, while at 33-34 d, it was 37.4% diagnosed by B-mode US. Based on these results, we found that 31.3% of the cows pregnant by Doppler ultrasound and ISG mRNA expression in leukocytes at 19-20 d experienced embryo loss and were non-pregnant at 33-34 d post-AI.

In parallel interpretation, ISG15 and MX2 mRNA expression in leukocytes were regarded as suitable biomarkers for early pregnancy and were selected for molecular characterization of pregnancy at 19-20 d post-AI. The Doppler ultrasound’s color mode showed similar accuracy and a higher negative predictive value as the genes selected as biomarkers. The additional B-mode ultrasound evaluation of the uterine stratum vasculare and the endometrium thickness improved the diagnostic accuracy.

Therefore, assessing the corpus luteum blood flow by Doppler-US allowed detecting early and quickly non-pregnant cows at 19-20 d post-AI; and performing pregnancy diagnosis by the B-mode US at 33-34 d allowed detecting pregnancy losses. This combination could be a useful, practical application for, e.g., resynchronization protocols in veterinary dairy practice.