It looks like the horses have an extra strap around their necks that I don't see in other photos of mounted troops. Looks like in at least one instance the strap is tucked into the uhlan's belt so that leaning forward or back could give a command to the horse....just a guessI wonder how they guide their mounts. In photos of kettle drummers, reins attached to stirrups are evident. I don't see that here.