A blow is alot like a snort. The horse exhales through it's nose with it's mouth shut. The blow doesn't create the vibrating or fluttering noise that the snort does. This sound is usually used when a horse is curious, or when the it meets another horse. The strength of the "blow" and the horses body movements that follow will tell you what it is saying.
"ARE YOU A FRIEND?"~ When two horses meet nose to nose and blow on each other... During this exchange, the two horses will tell each other if they are friends or foes.
"I AM YOUR FRIEND"~ The horses conyinue blowing gently followed by other gentle actions like nuzzling the other horses coat.
"I AM NOT YOUR FRIEND, GET AWAY!"~ One or both of the horses will nip at the other and/or stomp the front feet, strike out or squeal.
"WHAT IS THIS?"~ The horse "blows" towards an object it is curious about. Usually it's something new that it has never seen before.
"IT'S OKAY"~ The horse relaxes & nudges or ignores the object.
"IT'S DANGEROUS"~ The horse tenses up and/or shies away from the object.