We have riding horses near our apiary and they don,t seem particularly
bothered by the bees.
However when I was a youngster I remember working horses on my dad,s
farm being attacked by his bees when they were working near to the bee
hives.These were heavy work horses (Scottish Clydesdales) and when they
were hard at work there was a fair sweaty aroma from them-I assume this
was what upset the bees.
It may be advisable to avoid coming too close to the hives with horses
that have been excercised hard.
 
Alan Riach-Bathgate,Near Edinburgh,Scotland