1. The Royal (Dick) School of Veterinary Studies and The Roslin Institute, Easter Bush Campus, The University of Edinburgh, Bush Farm, Roslin. EH25 9RG, Scotland, UK.
2. Departamento de Medicina y Cirugía Animal, Facultad de Veterinaria, Universidad Cardenal Herrera-CEU, CEU Universities, Valencia 46115, Spain.
3. Clinic for Small Animals, University of Veterinary Medicine, Hannover 305559, Germany.