Working with horses can be downright dangerous at times, particularly when the horse you are dealing with is hot, sensitive or anxious. When a horse is stressed and goes into "fight or flight" mode, their first instinct as a prey animal is to run. This response is not desirable if they are around humans.
Horses generally fall into two broad categories - those that are usually calm and tractable but react to certain situations and those that are always highly strung. If you own or care for the second type of horse, you may be considering using a calming supplement to help "take the edge off them" while you train them to become braver and less reactive.
Why is choosing the right calming supplement important?
Many people reach for a calming supplement for their horse without fully investigating the cause of their horse's undesirable behaviour. A horse that has become boisterous due to a sudden growth of fresh green grass in their paddock is very unlikely to respond to a calming supplement as this change is due to increased energy levels in the diet. Conversely, a horse in heavy training on a high grain diet that is stressed and has hindgut acidosis may not be producing enough thiamine in the hindgut and would benefit from a thiamine supplement.
A calming supplement should contain ingredients that have been scientifically proven to produce the desired effects in the target species - horses. The huge cost of testing substances in horses means that it can be difficult to find scientific evidence to support the benefits of commonly used ingredients in calming supplements.
The most common ingredients found in calming supplements are Tryptophan, Magnesium, Vitamin B1 (Thiamine). Other B vitamins such as Vit B2 (Riboflavin), Vit B3 (Niacin) and Vitamin B6 (Pyridoxine) as well as Vit E, herbs, and probiotics may also be added. If you know how these ingredients work, then you will be able to make a better choice of calming supplements to suit your horse.
Tryptophan
This is an essential amino acid that is required for the production of serotonin. Serotonin in horses is used in times of stress to send signals to the digestive tract muscles causing them to contract and empty the gut to prepare for a fight or flight response (the giant poo when they get on the float!). Serotonin also has a role as a neurotransmitter in the part of the brain responsible for maintaining a calm attitude. Although most calming supplements contain tryptophan, there is very little scientific evidence to suggest that it is beneficial and, at low doses, it may even cause excitation.
B Vitamins
B vitamins are water soluble and, unlike fat soluble vitamins, they are not stored in the body. Horses get B vitamins from hay, pasture and the actions of hindgut bacteria and these vitamins play a role in the function of the nervous system. Thiamine (Vitamin B1) is often included in calming supplements, however, there is not enough scientific evidence to prove that it has a calming effect. B vitamin supplementation can be useful for horses that are under stress from heavy work, travel or illness.
Magnesium
Magnesium is an essential mineral for horses and, rarely, they can suffer from magnesium deficiency from low levels in their diet. The symptoms of mild magnesium deficiency can include nervous behaviour, tight muscles (tying up) and hypersensitivity. Supplementation with magnesium is warranted if a horse is found to be magnesium deficient.
Chamomile
Chamomile contains a variety of medicinal substances and has been used for centuries to treat many different human ailments. Scientific research has shown that substances in Chamomile act in the brain in a similar way to medications that are used to treat anxiety in humans. Chamomile can be useful in horses that suffer from digestive upsets such as diarrhoea or colic that are due to stress. It works by decreasing inflammation in the lining of the gut and relieving spasms of gut muscles.