[1] Kansas State Univ, Coll Vet Med, Dept Anat & Physiol, 228 Coles Hall,1710 Denison Ave, Manhattan, KS 66506 USA
[2] Iowa State Univ, Coll Vet Med, Dept Vet Diagnost & Prod Anim Med, 2203 Lloyd Vet Med Ctr,1800 Christensen Dr, Ames, IA 50011 USA
[3] Iowa State Univ, Dept Biomed Sci, Coll Vet Med, 2008 Vet Med,1800 Christensen Dr, Ames, IA 50011 USA
[4] Univ Tennessee, Dept Large Anim Clin Sci, Coll Vet Med, 2407 River Dr, Knoxville, TN 37996 USA