Sweating and skin temperature responses of normal and anhidrotic horses to intravenous adrenaline.

This research investigates the response of anhidrotic horses (horses that can’t sweat normally) to adrenaline compared to healthy horses, in an effort to better understand the causes of anhidrosis in horses.

Study Design and Methods

• The researchers used a modified ventilated capsule to gather detailed, quantitative data on how both the anhidrotic and normal horses responded in terms of sweating.
• The study involved 10 horses with seasonal anhidrosis and 10 healthy horses, all living in the same environment. Two doses of adrenaline were administered intravenously: 1 microgram/kg/min, and 2 micrograms/kg/min, each infusion for 10 minutes.
• Sweating responses and skin temperatures on the horses’ neck and gluteal region were measured. Samples of plasma and sweat were collected to analyze the total protein and electrolytes, and plasma for adrenaline analysis.

Results

• Anhidrotic horses sweated significantly less, had lower initial and peak sweat rates and had a higher neck:gluteal ratio for sweat production, suggesting regional differences in sweating ability.
• Interestingly, there were no significant differences in plasma adrenaline, indicating that adrenaline response is not necessarily related to the anhidrosis.
• Three-quarters of the anhidrotic horses showed different sweat rate curves over time compared to the control group.
• There was also a correlation between sweat volume and skin temperature on the neck of the control group and on the gluteal region of the anhidrotic group, but this was not seen in the anhidrotic horses.
• There were no significant differences in plasma total protein and electrolyte concentrations between the two groups.
• However, there were significant differences in sweat electrolyte concentrations, although these differences were reduced when sweat electrolytes were expressed per gram of total protein and disappeared when expressed as g/m2.

Conclusion

• The findings of this study provide valuable insights into the response of anhidrotic horses to adrenaline, paving the way for further investigations into this condition.
• Further research is needed to establish the exact causes and mechanisms behind anhidrosis in horses and how to effectively manage and treat this condition.