Disclosed is an animal feed composition including boron containing constituents, said animal feed composition comprising supplemental boron and supplemental vitamin C wherein the supplemental boron concentration in said animal feed composition is from 1 to 500 ppm, and the supplemental vitamin C concentration in said animal feed composition is from 1 to 1000 ppm. Also disclosed is the use of the said composition the manufacture of an animal feed composition for reducing the incidence and extent of lesions in the cartilage and subarticular bone of an animal.