Resumen

MALIK, V et al. Comparative evaluation of halothane anaesthesia in medetomidine-butorphanol and midazolam-butorphanol premedicated water buffaloes (Bubalus bubalis). J. S. Afr. Vet. Assoc. [online]. 2011, vol.82, n.1, pp.8-17. ISSN 2224-9435.

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) fall in 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.

Palabras clave : buffalo; butorphanol; halothane; medetomidine; midazolam; thiopental.

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