Detection of nonpregnant cows and potential embryo losses by color Doppler ultrasound and interferon-stimulated gene expression in grazing dairy cows

Abstract

Many studies have been conducted to estimate pregnancy losses between 19 and 34 d after artificial insemination (AI) in dairy cows managed under confinementbased systems, but few studies have examined embryo mortality during this interval in dairy cows managed under gazing systems. The objectives of this prospective cohort study were (1) to assess the diagnostic value of the corpus luteum (CL) blood perfusion (BP) evaluation by Doppler ultrasound (US) to detect nonpregnant cows at 19 to 20 d post-AI, and (2) to assess the rate of potential embryo mortality between 19 to 34 d post-AI. The CL-BP of all cows included in the study (n = 131) was examined on farm by power and color mode of Doppler US and later using an image processing software by a second evaluator. The endometrium thickness and echotexture were evaluated by B-mode US at the same visit to assess if the nonpregnancy diagnosis could be improved at 19 to 20 d post-AI by this additional diagnostic tool. Blood samples were obtained at 19 to 20 d post-AI for progesterone (P4) measurement by chemiluminescence and to determine the mRNA expression of ISG by real-time PCR. Pregnancy diagnosis based on embryo visualization was performed at 33 to 34 d post-AI by US B-mode. In parallel interpretation, ISG15 and MX2 mRNA expression in leukocytes [sensitivity (Se), 100%] were regarded as suitable biomarkers for early pregnancy and were selected for molecular characterization of pregnancy at 19 to 20 d post-AI. At 19 to 20 d post-AI, 61.1% of the cows had positive CL-BP by Doppler US (Se, 98.0%), 62.7% had ISG mRNA expression in leukocytes over the cutoff point (Se, 95.7%), and 50.8% were positive, based on the combination of ISG mRNA expression, CL-BP by Doppler US, and P4 concentration (Se, 100%), and were considered as possible pregnant. At 33 to 34 d, the pregnancy rate was 37.4% diagnosed by the B-mode US. Based on the expression of the selected biomarkers in cows with active CL, we found that 28.1% of the cows could have potentially lost their pregnancy between 19 and 34 d post-AI. The Doppler US color mode showed similar accuracy and a higher negative predictive value than 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 CL-BP by Doppler US allowed early detection of nonpregnant cows at 19 to 20 d post-AI. The combination of early CL-BP by Doppler US (d 19 to 20) with early embryo detection by B-mode US (d 33-34) could be used to facilitate earlier rebreeding of dairy cows.

The importance of the diestrus stages (early, middle, late) to the diagnosis of the endometrial disease in the bitch

“…In addition, a study on cows showed that ET measured by ultrasonography increased when P 4 concentrations decreased (Suguria et al 2018). Similarly, a recent study on cattle evaluating ET to improve the detection of nonpregnant females post-AI showed that ET is thicker in nonpregnant cows because they return to estrus and have lower P 4 concentrations (Madoz et al 2022). Is possible that the in uence of P 4 on ET be different in normal than pathologic endometrium.…”

Role of Genetic Variants AGT rs699 and ACE2 rs2106809 in Increasing the Risk and Severity of COVID-19 Infection in Iraqi Patients

“…Because it is considered a candidate for reliable peripheral detection markers of early pregnancy, it shows promise for the early detection of pregnancy. The ISGs ratio started to rise from 19-20 days in PBLs of pregnant cows in response to IFNT, while it remained unaltered in non-pregnant cows [32]. The ISGs included ISG15, MX1, MX2, and OAS1 mRNA levels were significantly higher in PBL samples from pregnant compared to non-pregnant cows [33].…”

Recent advances in early pregnancy loss diagnosis in dairy cows: New approaches

“…Dos Santos et al (2023) discovered that pregnancy loss in the fixedtime embryo transfer program in cattle was related to luteal blood perfusion. Additionally, using Doppler ultrasound to detect corpus luteum blood perfusion 19-20 days after AI not only diagnoses nonpregnant cows but also assesses pregnancy loss between 19 and 34 days post-AI (Madoz et al, 2022).…”

“…Previous studies have shown that IFNT regulates embryo implantation by inducing genetic expression of ISG15 (Johnson et al., 2001), MX1 and MX2 (Austin et al., 2004), OAS1 (Madoz et al., 2022), in turn, activating the Janus kinase and transcriptional activator signalling pathways (Kikuchi et al., 2019). Consequently, ISG15 and MX2 levels of peripheral blood leukocytes can predict non‐pregnant or pregnancy loss in dairy cows (Han et al., 2006; Wijma et al., 2016).…”