[1] Univ Tours Haras Nationaux, CNRS, UMR 6175, INRA, F-37380 Nouzilly, France
[2] INRA, Lab Genet Cellulaire, F-31326 Castanet Tolosan, France
[3] INRA, Stn Ameliorat Genet Anim, F-31326 Castanet Tolosan, France
[4] Univ Milan, Inst Endocrine Sci, Ist Auxol Italiano, IRCCS, I-20095 Cusano Milanino, MI, Italy