Respuesta del estrés al uso de electro eyaculador en carneros con y sin tranquilizante: evaluación de calidad seminal, congelabilidad y parámetros hormonales

Abstract

Actually the techniques most frequently used in the collection of ram semen for preserve the genetic material either for reproductive or conservation reasons are: Artificial Vagina (AV) and Electroejaculator (EE). Regarding EE, there is concern in the scientific community about the stress that can generate the use of this technique in animals and therefore affect their well-being. There are previous scientific researches on this subject, some used tranquilizer and others did not. The aim of this investigation was asses the stress response by the use of electroejaculator in rams treated with and without tranquilizer on the quality and freezing of semen and hormonal parameters. We studied the semen of four sexually mature Corriedale rams, between 2-3 years of age, with weights ranging from 60-90kg. In a treatment, xylazine (2%) was administered at doses of 0,05mg/kg of ram weight and in the other treatment no tranquilizer was injected. Eight collections per animal were performed, four with each treatment and the qualitative-quantitative characteristics of fresh and post-thawed semen were analyzed. To determine the hormonal parameters (cortisol and testosterone) blood samples were taken at three times: 20 minutes before, during and 20 minutes after EE application, hormone levels were measured by ELISA. Statistically significant differences (P <0.05) were found in the volume, concentration, percentage of live spermatozoa and in post-thaw motility, being higher in the tranquilizer treatment, so we conclude that administration of xylazine prior to EE proved to be effective in the analysis of these variables.