Effect of xylazine, detomidine, medetomidine and dexmedetomidine during laparoscopic SCNT embryo transfer on pregnancy rate and some physiological variables in goats

Background: The present study was conducted to determine if using α 2 -adrenergic agonists results in decreased stress levels (lower cortisol levels) in goats used for laparoscopic embryo [somatic cell nuclear transfer (SCNT)] transfer; and there is an effect on pregnancy rate when stress levels are lessened. Sixty healthy does aged 24 ± 4 months and weighing 30 ± 3 kg were used in experimental, prospective, randomized and blinded study. In this study, embryos were created via the Somatic Cell Nuclear Transfer (SCNT) method. Animals were randomly assigned to five groups: control (normal saline); xylazine (100 µg kg −1 ); detomidine (50 µg kg −1 ); medetomidine (20 µg kg −1 ); and dexmedetomidine (5 µg kg −1 ). Embryo transfer (through laparoscopic technique) began at 15 minutes and continued till 45 minutes post-treatment. Heart rate (HR), respiratory rate (RR), rectal temperature (RT), and ruminal motility were performed before (baseline) and after drug administration. Pregnancy detection was performed 38 days after embryo transfer. Results Compared to control, HR, RR and ruminal motility were significantly lower in α 2 -adrenergic agonists groups at 5–90, 15–60, and 5–120 minutes, respectively. Serum cortisol values significantly increased from baseline in the control group 45 minutes after drug administration ( p = 0.001). At T45 and T120, serum cortisol concentration was significantly lower in α 2 -adrenergic agonists groups compared with the control. The pregnancy rate in control group (n = 4/12, 33.3%) was significantly lower than xylazine (n = 9/12, 75%; p = 0.041), detomidine (n = 10/12, 83.3%; p = 0.013), medetomidine (n = 9/12, 75%; p = 0.041) and dexmedetomidine (n = 10/12, 83.3%; p = 0.013); but no significant differences were observed among different α 2 -adrenergic agonists groups. Conclusion Alph 2 -adrenergic agonists are effective on increasing the pregnancy rate of SCNT embryo transfer in goats in this study. No significant differences were detected among different α 2 -adrenergic agonists.