Physiologic and biochemical effects of subarachnoidally administered xylazine and medetomidine in goats.

Clinicophysiological, haematological and biochemical effects of xylazine (0.05mgkg(-1)) and medetomidine (0.01mgkg(-1)) were studied in nine adult goats after lumbosacral subarachnoid administration. The onset of analgesia by xylazine and medetomidine was observed in 9.11+/-1.07 and 8.66+/-2.37min (mean+/-S.E.), respectively. Both alpha(2)-agonists produced moderate analgesia of hind quarter, perineum and flank, mild ataxia and sedation. The duration of analgesia after xylazine administration was 134.44+/-8.87min and that after medetomidine was 158.33+/-9.96min (mean+/-S.E.). Xylazine and medetomidine induced significant (p<0.05) decrease in heart rate, respiratory rate and hypothermia. Haemoglobin (Hb), packed cell volume (PCV) and total leukocyte count (TLC) decreased significantly. Changes in the physiological and haematological parameters were transient in nature. Xylazine and medetomidine produced a significant (p<0.05) increase in creatinine and glucose levels. However, these parameters fluctuated within normal range and started to recover within 120min. However, serum urea nitrogen (SUN), serum chloride, sodium and potassium did not show any significant change. The effects produced by xylazine and medetomidine were however, comparable at these dose levels. The study indicates that xylazine at 0.05mgkg(-1) and medetomidine at 0.01mgkg(-1) did not induce any serious alteration in the physiological, haematological and biochemical parameters and can be safely used in inducing hind quarter, flank and perineal analgesia in goats.