1. Department of Anatomy, Physiology and Biochemistry, Swedish University of Agricultural Sciences, P.O. Box 7011, 750 07 Uppsala, Sweden.
2. Department of Large Animal Clinical Sciences, Michigan State University, 736 Wilson Road, D202, East Lansing, MI 48824, USA.
3. Mälaren Hästklinik AB, Hälgesta 1, 193 91 Sigtuna, Sweden.
4. Kentucky Equine Research, 3910 Delaney Ferry Road, Versailles, KY 40383, USA.
5. Atterbomsvägen 56, 112 57 Stockholm, Sweden.