Mohammed A Elmetwally, Karl Rohn, Sabine Meinecke-Tillmann
Objective: The objective of this prospective study was to investigate whether Doppler- and B- mode sonography could be used to assess a possible influence of maternal temperament on fetal and pregnancy-related end points in small ruminants.
Method: On the basis of behavioural testing related to an anxiety-eliciting stimulus (arena test), 10 sheep and 9 goats were divided into two groups, namely more reactive/ anxious (MR: 6 sheep/7 pregnancies; 5 goats/7 pregnancies) and less reactive/anxious (LR: 4 sheep/6 pregnancies; 4 goats/6 pregnancies). After mating, several end points were assessed by transrectal and/or transabdominal ultrasonography every 2 weeks (wk) from breeding to wk 20 of pregnancy. The resistance index (RI) as well as the pulsatility index (PI) of the maternal uterine (UtA) and the fetal umbilical arteries (UMA) were measured with non-invasive Doppler sonography. Additionally the fetal heart rate (FHR) was determined. Further parameters were measured with B-mode ultrasonography: diameter of amniotic vesicles (AVD; only wk 2-8), diameters of placentomes (PLD), umbilicus (UMD), fetal chest (FCHD) and orbita (FOD), as well as bi-orbital breadth (FBO), fetal occipito-snout length (FOSL), and metacarpal length (MCL).
Results: In sheep, UtA-PI was significantly higher in MR compared to LR ewes at pregnancy wk 6 (P>0.01), 10 (P>0.05) and 12 (P>0.05), while a tendency was recognized at wk 14 (P=0.054). The same was true for UtA-RI during the first 8 wk of pregnancy (P<0.03) when MR and LR animals were compared. Similarly, UMA-RI was higher in fetuses of MR than LR ewes at wk 14 (P< 0.0003) and 20 (P< 0.02) of pregnancy. The differences in UMA-PI reached significance at wk 6, 8, 10 and 20 (P< 0.05–0.003). Furthermore, AVD (P<0.03, wk 2-8), FCHD (P<0.002, wk 8-18) as well as the UMD (P<0.054, wk 8-18) were higher in LR than MR pregnant ewes. In goats, UtARI and -PI were significantly influenced by reactivity/anxiety 58 of the dam (increase in MR, resp.; RI: wk 6, 16, 18 and 20, (P<0.05 – 0.0001; PI: = wk 4, 8, 18 59 and 20, P<0.05-0.01). Both UMA-RI and UMA-PI (wk 8-20, P<0.01 and<0.02, resp.) were higher in MR than LR animals. B-mode end points were similar to those in sheep: AVD (P<0.01, until wk 8), FCHD, PLD (P<0.05-0.005), and FMCL (P<0.01) were larger in LR than in MR goats during wk 8-18. Other fetometric parameters were not affected by temperament of the pregnant dam.
Conclusion: Using Doppler- and B-mode sonography, effects of maternal temperament on fetal growth, as well as maternal and umbilical blood flow in sheep and goats could be successfully demonstrated.
