Melanoma is extremely common in grey horses, affecting the vast majority of grey horses as they age. Managing this condition appropriately protects equine quality of life.
Most melanomas in grey horses cause minimal welfare impact for many years — benign tumors grow slowly and rarely interfere with function unless located in problematic sites like under the tail. However, large tumors around the perineum can impair defecation, urination, and cause discomfort during riding. Malignant transformation causes pain and systemic illness. Welfare-centered management involves regular monitoring for size changes, signs of ulceration, and internal spread. Treatment decisions balance intervention risk against welfare benefit — removal of small accessible tumors reduces future complications, while treatment of widespread disease requires careful quality of life assessment.