Ultrasound parameters of early pregnancy and Doppler indices of blood vessels in the placenta and umbilical cord throughout the pregnancy period in sheep

Abstract

Background Ultrasonography is one of the most important techniques that enable the detection and monitoring of pregnancy. One such study using this technique is the assessment of the hemodynamics of fetal and umbilical blood vessels. However, there is little data on blood flow in the placentomes, which is the basic structural unit of the sheep’s placenta. Therefore, the aim of this study was to determine the Doppler parameters in the arterial vessels of the caruncles, cotyledons and the umbilical cord as well as measuring venous flow rates during the entire gestation period of the sheep. Additionally, the usefulness of various other ultrasound parameters in the early diagnosis of pregnancy in sheep was analyzed. Results Most of the Doppler parameters in umbilical, cotyledonary and caruncular arteries were significantly correlated with the day of pregnancy (p < 0.01). In the early stages of pregnancy, the peak systolic velocity (PSV), regardless of the location of the artery, was significantly lower than that in the later stages of pregnancy (p < 0.01). PSV was also found to be significantly higher in the umbilical artery than in the cotyledonary and caruncular arteries (p < 0.01). Until the 50th day of pregnancy, the end diastolic velocity (EDV) was not found in the umbilical and cotyledonary arteries. EDV was significantly higher in the caruncular arteries than in the cotyledonary and umbilical arteries (p < 0.01). The resistance index (RI) and pulsatility index (PI) in the early stages of pregnancy were found to be significantly higher than that in the later stages of pregnancy (p < 0.01). The RI and PI were significantly lower in the caruncular arteries than in the arteries of the cotyledons and umbilical cord (p < 0.01). In the umbilical vein, all Doppler parameters were observed to be significantly higher than those in the placentomal veins (p < 0.01 or p < 0.05). Using transrectal ultrasound, pregnancy was detected between 20 and 28 days after mating. The ovaries were observed to have corpora lutea, the diameter of which was fairly consistent from the 17th to the 56th day of pregnancy. Conclusions It has been demonstrated that both the location of the arterial vessel in the placental-umbilical circulation and the gestational age have a significant impact on hemodynamic parameters. The results also provide new insights about the blood flow in caruncular and cotyledonary arteries, which could contribute to a more holistic understanding of hemodynamic changes in the placentas of sheep. Analyzing haemodynamic parameters in the umbilical and placental veins are preliminary studies in sheep, but it could inspire further research in this field. Furthermore, the research conducted confirms the practicality and convenience of transrectal ultrasonography in the early diagnosis of pregnancy in sheep and also indicates that the identification and imaging of the corpus luteum using B-mode ultrasonography can be a very early and simple method of confirming effective mating in sheep.

Chronic Undernutrition in Ovine Twin Pregnancies Abolishes Differences in Birth Weight Due to Sex: An Evaluation of the Role of Nutritional and Antioxidant Supplementation

“…Similar observations extend to twin pregnancies in sheep, where male lambs' birth weight is about 5-10% higher than that of female littermates [4][5][6][7]. Female birth weight is more reduced when the co-twin is a male than in the case of a female co-twin; conversely, the body weight reduction in male twins is not related to their co-twin's sex [6].…”

“…The present results support that maternal undernutrition and subsequent nutritional supplementation during pregnancy have a sex-related differential effect on offspring development. It is widely known that, under adequate environmental and nutritional traits, lamb birth weight is higher in males than females [4][5][6][7]. Our data indicate that birth weight in undernourished twin pregnancies is more unfavorable for male lambs, lowering their weight to a similar value as their female counterparts.…”

Blood Metabolites and Faecal Microbial Communities in Nonpregnant and Early Gestation Ewes in Highly Cold Areas

“…Ultrasonography stands as the main and most commonly utilized technique for diagnosing pregnancy in ewes [4]. Although this method effectively replaces the traditional method of rectal palpation when judging pregnancies and improves the accuracy of diagnosis, it also has many limitations [5]. Ultrasonography necessitates proficient scanning expertise, and farmers frequently face a deficit in requisite technology and expertise.…”