When horses can constantly graze or eat hay, as they do in the wild, they produce sufficient saliva which in turn acts as a buffer against excess stomach acid. But today’s methods of keeping and feeding horses is anything but ideal for their gastric health. Too little turnout and forage, irregular feeding times, training, incompatible stable mates, negative group dynamics at pasture etc. can cause stress in some horses.
If riders and horse owners recognise the symptoms in time they can take measures to avoid stress, change keeping conditions or the horse’s entire management in order to keep things from getting worse. However, it is always advisable to consult your veterinarian for a diagnosis to be sure.