Horses and ponies that go grey are special. They go through a beautiful range of shades on their way to becoming completely white or flea-bitten grey. Dapple grey is a particularly beautiful stage that is reached before the horse becomes completely white.
Grey horses also frequently develop melanomas. Grey horses that are 'a a' at the agouti gene have the highest incidence of melanoma. Genetic testing can confirm whether your horse has the gene variant that causes greying with age and increases the incidence of melanoma.
Gene or region and technical reference
Gene: STX17 (causative). Reference: Rosengren Pielberg et al. (2008)
n. Test developed using animal controls.
Gr. Test developed using animal cases.
Grey (left) can produce spectacular coat colours.