Quantitative intradermal terbutaline sweat test in horses

Abstract

The aim of the current study was to quantify sweating responses to intradermal terbutaline in normal horses. Seven Thoroughbred horses were used. Terbutaline (10-fold dilutions from 1000-0.001 mg/l) and a saline control were injected intradermally (0.1 ml/site) and sweat collected for 30 min into absorbent pads taped over each injection site. Tests were performed monthly for 11 successive months and temperature, relative humidity and dewpoint were measured at the time of testing. There was no significant effect (P<or=0.05) of environmental variables or time of year on sweat responses at any dose. There was significant effect (P<0.001) of terbutaline concentration on sweat weight, with significant increases at every concentration from 0.1-1000 mg/l. This quantitative intradermal terbutaline sweat test should be a useful aid to the study of equine sweating and anhidrosis.