Bremsningens effekter hos häst : utvärderat med hjälp av termografi, hormonanalyser och hematologi

Abstract: Twitching is frequently used in horse management because of its sedating and pain-relieving effects. In this study, the effects on the horse's nervous system by twitching were investigated by thermography of the skin temperature. The temperature is regulated by the sympathetic nervous system through postganglionic sfincters at the capillaries of the skin. The effects on the endocrine activity have also been studied by the measuring of ACTH and cortisol in blood plasma. Furthermore, bloodsamples has been analysed regarding red and white bloodcells. A total of nine horses where included in this study. The thermograms show that the horses generally increase their heat radiation during twitching, which can be interpreted as a decreased tonus of the sympathetic nervous system. It is probably this decrease in the activity of the sympathetic nervous system that provides the sedating effect of twitching. Previous studies have showed that the pain-relief is an effect of the release of ACTH-RH and β-endorphin, which is reflected in this study by an increase of ACTH and cortisol. The haematology analyse shows a decrease in the number of circulating red as well as white blood cells.