Use of a semi-quantitative sweat test in thoroughbred horses.

The research outlines a method for testing thoroughbred horses’ sweat response using the beta 2 agonist, salbutamol sulphate. The results showed that horses with normal sweating responses were visually affected by low concentrations of the substance, while horses with reduced sweat responses or complete anhidrosis (inability to sweat) showed little or no effect, even at high concentrations.

Research Methodology

• The researchers designed a practical test with the aid of a beta 2 agonist, salbutamol sulphate, to assess the sweat responses of different categories of horses.
• The experiment was performed on various categories of thoroughbred horses: 54 horses considered as “free sweaters”, 6 horses showing signs of heat stress post exercise and 2 horses with complete anhidrosis.

Findings of the Research

• The research found that intradermal injections of 0.1 ml of salbutamol sulphate at dilutions of 10(-7) or less were potent enough to cause a local sweating response in horses with normal sweat response. The sweating response was noticeable visually.
• Horses that only exhibited sweat at the sites where they received salbutamol solutions with a concentration between 10(-4) and 10(-6), likely have a reduced sweating response and potentially suffering from partial anhidrosis.
• The horses with long-term, severe anhidrosis conditions did not sweat, even when they were treated with salbutamol solutions at high concentration dilutions of 2 x 10(-3).

Implications of the Study

• This study provided crucial insights on the reaction of horses’ sweat glands to specific stimuli, which could be instrumental in identifying and diagnosing different sweat-related conditions in horses.
• The findings could also be used to develop better conditioning and exercise regimens for horses, especially racehorses, to avoid heat stress and other sweat-related complications.