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 obtained by 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 min and continued till 45 min 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 min, respectively. Serum cortisol values significantly increased from baseline in the control group 45 min after drug administration (p = 0.001). At time points 45 and 60 min, 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 were effective on increasing the pregnancy rate of recipient goats receiving cloned embryos. No significant differences were detected among different α(2)-adrenergic agonists.