Development and characterization of an equine behaviour chamber and the effects of amitraz and detomidine on spontaneous locomotor activity.

The research concerns the design and testing of a behavior chamber to measure horse locomotion, as well as investigating the effects of the drugs amitraz and detomidine on such activity.

Development of a Behaviour Chamber for Horses

• The researchers developed a behaviour chamber equipped with four Mini-beam sensors to accurately monitor and record a horse’s locomotor activity.
• The data collected was logged every five minutes over a 22-hour period.
• Findings showed horses were more active during the daytime, a pattern believed to be partially influenced by human activities around them.

Testing and Validation

• For validation, the researchers administered fentanyl citrate and xylazine HCl, known stimulant and depressant agents respectively, to five horses.
• The results showed that fentanyl citrate, at 0.016 mg/kg, significantly increased locomotor activity, lasting for about 30 minutes.
• In contrast, xylazine HCl at 1 mg/kg brought about a significant decrease in locomotor activity lasting for 90 minutes.

The Effects of Amitraz

• Amitraz produced a dose-dependent decrease in locomotor activity in the horses.
• This effect persisted for 75 minutes at a dose of 0.05 mg/kg, 120 minutes at 0.10 mg/kg, and 180 minutes at the 0.15 mg/kg dose.
• In a separate experiment, yohimbine was administered, which reversed the sedative effects of amitraz, providing insights on the similarity in the mode of action of amitraz, xylazine, and detomidine.

The Effects of Detomidine

• The study also showed that detomidine caused a significant decrease in locomotor activity in horses over varying periods of time depending on the dose given.
• That is, an injection of detomidine at 0.02 mg/kg reduced activity levels for 1.5 hours, at 0.04 mg/kg for 3.5 hours, and at 0.08 mg/kg for 5.0 hours.

Significance of the Study

• Overall, the study shows the developed locomotor chamber for horses to be a sensitive and highly reproducible tool for the measurement of spontaneous locomotor activity.
• It also provides researchers a means to determine the average onset, duration, and intensity of the effect of different substances on horse movement.