Multiple congenital ocular abnormalities (MCOA) in Rocky Mountain Horses and Kentucky Mountain Saddle Horses in Europe

The study describes the prevalence of multiple congenital ocular abnormalities (MCOA) in Rocky Mountain Horses and Kentucky Moutain Saddle Horses in Europe. Materials and methods: 35 RMH und KMSH were examined between 1999 and 2010. Their coat color were chocolate (24), seal brown (7), and one each of bay, black, chestnut and palomino. Ciliary body cysts (CBC) were found in 17/35 hor- ses. Two (2/35) horses had multiple congenital ocular abnormalities consistent with anterior segment dysgenesis (ASD). None of the seal brown, black or bay horses had ocular abnormalities, while 18/24 chocolate horses had lesions. One chestnut mare had also bilateral CBC. Fourteen horses (40%) were unaffected. While the prevalence of multiple ocular abnormalities appears to be lower in Europe than in the US, the prevalence of ciliary body cysts is almost the same. Prior to breeding, RMH und KMSH should be carefully examined for the presence of CBC and MCOA. Keywords: Mountain horse, eye, congenital anomaly, anterior segment dysgenesis