Para determinar los cambios hemodinamicos, y fisiologicos y la recuperacion en dos protocolos anestesicos, en hembras caninas sanas durante ovariohisterectomia (OVH) electiva, se utilizaron dos grupos de animales, a cada uno de los cuales se les asigno un protocolo anestesico: Grupo I (fentanil + etomidato), grupo II (fentanil + tiopental). En ambos grupos el mantenimiento se hizo con isoflurano. Cada cinco minutos durante el procedimiento quirurgico se midieron las siguientes variables: frecuencia cardiaca, frecuencia respiratoria, temperatura, dioxido de carbono expirado, presion arterial no invasiva, saturacion de oxigeno. Las variables que presentaron significancia, desde el punto de vista estadistico, fueron: temperatura, con una media en el protocolo I de 37.7 ± 1.4, y de 38.0 ± 1.2 en el protocolo II (p Palabras clave: anestesia en caninos, constantes fisiologicas, esterilizacion canina, hemodinamia, induccion y premedicacion anestesica. Summary To determine the hemodynamic and physiologic changes and the characteristics of the recuperation phase in two anesthetic protocols to be used in healthy female dogs for elective ovary ohisterectomy, two groups of animals were used in order to test two protocols: Group I was given fentanyl + ethomidato and group II fentanyl + thiopental. For maintenance isofluorane was used in both groups. The following variables were measured at five minute intervals during the surgical procedure: cardiac frequency, breathing frequency, temperature, expired carbon dioxide, non- invasive blood pressure and oxygen saturation. Statistically, temperature and capnography were the only ones yielding significant results: temperature presented an average of 37.7 ± 1.4, in protocol I and 38.0 ± 1.2 in protocol II (p Key words: anesthetic induction and premedication, canine anesthesia, canine sterilization, hemodynamics, physiological constants.