Nine donkeys of both sex were used in this investigation. The animals were classified into 3 groups (each of 3 animals). Group I received a mixture of chloral hydrate and combelen. Group Il received a combi nation of chloral hydrate and novalgin. Group III received chloral hydrate and thiopental sodium. Temperature, pulse and respiration rates before and after administration of the anaesthetics were record ed. Clinical signs were also demonstrated.
Blood samples were collected for blood gases and acid-base balance analysis. Blood pH, Pco (mm. Hg), Po (mm. Hg), Hco (mmol/L), Tco (mmol/L) and base excess (mmol/L) were measured using Corning pH - blood gas analyser 168.
Animal anaesthetized by the combined use of combelen and chloral hydrate showed clinically the best desired depth of anaesthesia as onset was rapid without injection discomfort. The anaesthetic period was longer and continued for about 11/2 hour. However their use was accompanied with greater alteration in acid-base values than in the other used anaesthetic combinations.