Do magnesium supplements help horses complete stressful tasks?
16 Apr 2017
A group of researchers in the Canada set out to see if magnesium supplements could reduce stress in horses performing difficult tasks.
Six horses were given either acepromazine (a tranquillizer commonly used by vets), a magnesium-based anxiety formulation or a placebo paste. They were then asked to complete five everyday management tasks. The horses were selected for the study, based on the owners reporting them having an aversion to at least one of the tasks.
These tasks the horses had to complete were:
- Loading onto an equine weighbridge
- Loading onto a two horse trailer
- Unaccompanied transport in a two horse trailer
- Jugular venous sampling
- Ten minutes in a stall with an unfamilar object
The study was conducted over a three-week period and the horses completed one session each week doing the same five tasks but given a different treatment each time (placebo, acepromazine or magnesium calming product).
The horses commenced the tasks in the above order, 30 mins after the oral treatment was given. The horses had 10 mins to complete each task and time to complete task, heart rate, as well as plasma cortisol levels, were measured. (Cortisol is a stress hormone and levels in the blood can indicate how stressed an animal is.)
Acepromazine and the magnesium formulation significantly reduced the average heart rate when animals performed task 1, the weigh bridge task. This task occurred 30 minutes after the oral treatment was given which is when acepromazine is known to take effect. The effectiveness and time duration of magnesium calming supplements has not previously been studied.
Neither the acepromazine, the magnesium calming supplement or the placebo had any significant effect on any other task after the first task. Blood cortisol was increased after completion of the tasks showing that the tasks were stressful. None of the treatments had any significant effect on plasma cortisol levels or time taken to complete tasks.
This studied showed that magnesium calming supplements may assist horses with performing stressful tasks and may be most effective after 30 minutes of dosing. However, further studies need to be conducted. Would the magnesium calming supplement have reduced average heart rate in any of the other tasks if they had been performed in a different order?
This study also showed that the task horses found most stressful was loading onto the trailer, this task caused the highest average heart rate.
A company that produces magnesium calming supplements funded the study, however, the researchers state that this did not affect the outcome in any way.
Pearson, W. and MacNicol, J., 2017. Acute Effects of a Single-Dose Nutritional Product on Stress Response and Task Completion in Horses. Journal of Equine Veterinary Science, 51, pp.86-91.