There are a number of zebra striped fly rugs available here, as I believe there is some research that suggests flies are discouraged by the stripes. I haven't read the research or tried the rugs (or painted my horse!) so can't say if I believe it or it works or not.
Just yesterday I was at my vet's and saw a Friesian with one of those zebra striped fly sheets. The tail guard went way low on his behind and he/she was trying to swish flies and was hampered by the sheet. So for now I will reserve judgement on this new study.
Proud member of People Who Hate to Kill Wildlife clique