... of litter size variability in sheepMagali SANCRISTOBAL-GAUDY a, ∗,LoysBODINb,Jean-Michel ELSENb, Claude CHEVALET a aLaboratoire de génétique cellulaire, Institut national de la ... approach was compared with moretraditional methods.2. GENETIC MODEL2.1. Threshold model for polytomous data – Likelihood approachAsGianolaand Foulley[10], Foulley andGianola [8]orSanCristobal-Gaudyet ... environmental variability asis usually done for the mean. The year, herd, season and age have no significanteffects on the variability of litter size in the Lacaune population, but the sirefactor has...