Four out of ten struck this year at different times. I use a knife to run over the wound to get the buggers out then treat with summer fly spray which seems to be soothing. Crovect them if its bad, teramycin injection if it's bloody awful. When they come over to me I squirt them with Battles Oil in a misting bottle which makes me feel a bit better, not really sure how good a preventative it is though.