The horse rests with its incisors on any support, contracts its neck and emits a characteristic noise, like a "rot". Despite appearances, the horse swallows no air. This tic brings premature wear of the teeth, which makes it possible to quickly spot the horses tickers.
It is a difficult tic to mitigate, which can affect all horses. Normally, we recommend the wearing of an anti-tic collar. It is effective, but not enough to my liking for horses ticking in support, but its use is widespread. It is also possible to remove any point of support (feeder, etc.) or to deter the horse from touching by applying repellent products. There is a surgical procedure consisting of a hole made in the cheek. In this way, the horse can not suck in the air. But I'm not for this method because it does not solve anything!
The best way to find a solution against this tic is to see with the vet and ask him for a homeopathic treatment (the most effective in my opinion).
I hope this helps !!