In this wet winter there's a bit of a discussion arising about white markings on the back of some horses. Is it genetically linked, or is it due to scarring from 'rainscald'? I, myself, have only ever seen white 'scribblings' along the spine, or on the rump, which developed after malnourished horses had succumbed to 'rainscald' (longer coats/matted after sweating). The rainscald was readily treated with a couple of Providone (Iodine) scrubs, but the coat came through white, where the coat had scabbed out and a feed boost with supplemented nutrition served to pick up the horses' condition. (Though some later succumbed to colics...through not having had the good fortune of a regularly drenching programme!)
I found this really interesting article; one individual's investigation. There's some great photos and links to more!
http://horseandman.com/horse-stories/unusual-markings-always-fun-and-things-i-wish-they-would-invent/
