Comparative evaluation of halothane anaesthesia in medetomidine-butorphanol and midazolam-butorphanol premedicated water buffaloes (Bubalus bubalis).

Six clinically healthy male water buffaloes (Bubalus bubalis) 2-3 years of age and weighing 290-325 kg were used for 2 different treatments (H1 and H2). The animals of group H1 were premedicated with medetomidine (2.5 g/kg,i.v.) and butorphanol (0.05 mg/kg, i.v.), while in group H2 midazolam (0.25 mg/kg) and butorphanol (0.05 mg/kg) were used intravenously. Induction of anaesthesia was achieved by 5% thiopental sodium in H1 (3.85 +/- 0.63 mg/kg) and H2 (6.96 +/- 0.45 mg/kg) groups. The anaesthesia was maintained with halothane in 100 % oxygen through a large animal anaesthetic machine. Better analgesia and sedation with a significantly lower dose of thiopental for induction and significantly higher values of sternal recumbency time and standing time were recorded in group H1 than in group H2, whereas no significant (P > 0.05) difference for the halothane concentration was observed between groups H1 and H2. Significant decrease in heart rate was observed in group H1 whereas it significantly increased in group H2. In both groups, RR decreased during the preanaesthetic period, which increased significantly (P < 0.01) after halothane administration. In both groups a significant (P < 0.01) fallin RT was recorded from 20 min to the end of observation period. A significant (P < 0.05) fall in MAP was observed in group H1 from 15 min until the end, while in group H2 MAP increased nonsignificantly (P > 0.05) after premedication and a significant (P < 0.05) occurredafter thiopental administration. In both groups a significant (P < 0.01) increase in CVP and a significant (P < 0.01) decrease in SpO2 were observed after premedication which persisted up to 120 min. ECG changes included significant (P < 0.01) decrease and increase in QRS amplitudes in groups H1 and H2 respectively, a significant (P < 0.05) increase in PR interval was recorded at 15 min in group H1, a significant (P < 0.05) decrease in PR interval in group H2, a significant (P < 0.05) decrease in T wave amplitude in group H1, and a significant (P < 0.01) increase in duration of T wave in group H1 . It is concluded that both combinations can be used safely in buffaloes for surgery of 2 h duration but better sedation, analgesia and muscular relaxation and more dose sparing effect on anaesthetics and shorter recovery times were observed in group H1.

Anesthesia of wood bison with medetomidine-zolazepam/tiletamine and xylazine-zolazepam/tiletamine combinations.

This study was designed to evaluate 2 combinations for immobilization of bison. Seven wood bison received 1.5 mg/kg body weight (BW) of xylazine HCl + 1.5 mg/kg BW of zolazepam HCl and 1.5 mg/kg BW of tiletamine HCl on one occasion. The bison received 60 micrograms/kg BW of medetomidine HCl + 0.6 mg/kg BW of zolazepam HCl and 0.6 mg/kg BW of tiletamine HCL on another occasion. Xylazine was antagonized with 3 mg/kg BW of tolazoline HCl and medetomidine HCl was antagonized with 180 micrograms/kg (BW) of atipamezole HCl. Temporal characteristics of immobilization and physiological effects (acid-base status, thermoregulatory, cardiovascular, and respiratory effects) of the drug combinations were compared. Induction was significantly faster with xylazine HCl-zolazepam HCl/tiletamine HCl. Recovery following antagonist administration was significantly faster with medetomidine HCl-zolazepam HCl/tiletamine HCl. The average drug volumes required were 7.00 mL of xylazine HCl-zolazepam HCl/tiletamine HCL and 2.78 mL of medetomidine HCl-zolazepam HCl/tiletamine HCl. Hypoxemia, hypercarbia, and rumenal tympany were the major adverse effects with both drug combinations.