White Stuff in corner of mouth

My horse has white stuff in the corner of his mouth in the mornings before feeding him. Does anyone know what this is?

Do you feed him oats at night?

I used to have a gelding that at every feeding time he had a quirky habit of sticking his tongue out the side of his mouth and rubbing the corner of his mouth/lips with it until it was frothy with slobber. It was his own little aniticipation of grain and was harmless. He still does it (my Mom still has him) and it is not a result of any health issues. Some horses paw at their buckets or bang on walls, perhaps your horse is just slobbering in anticipation.

Of course, I have to mention the possibility of a tooth issue or a sticker or something caught in his gums or tongue, but if it's only right before feeding time, it's likely just anticipation, like pavlov's dog experiment.

A simple thing to rule out feeding anticipation is to remove that stimulant (the food) for a few days or a week or so to see if you still get that build up. Have you ever had a dentist/vet do your horse's teeth? Your horse should get his teeth done annually

Yes, I do give him a handful of sweet oats as a treat. I will try holding back and see if its makes a difference. Thanks for the reply.

I feel like it really could be an anticipation act but wasn't sure if it could be a health issue, so thought I would pose the question. Thanks for your helpful advice.

I will try taking away the oat treats at night to see if it makes a difference. I recently had a dental float done on him. Thanks for taking the time to respond.

Oats make some horses get foamy and it seeps out the corners. My horse used to get it and it would look like he had dried toothpaste on his cheeks. It's harmless.