Data on 3N04 litters of 3 lines of rabbits (N, Z and G) CO/lung from 1301 does, the daughters of 335 sires and 815 dams were analyzed to study the effect of non-genetic factors (year and season of purity. litter interval and number born alive previous) on litter size traits. Evaluation Or sires awl dams by estimating transmitting abilities (i.e. estimation of 13L.UP) from actual production records of intensive reproduction system was the main goal of this study. Line N was the highest in litter size. Season of kindling and litter interval constinued the most important non-genetic factors Th./Nem-big litter size traits. Across all lines studied, variations of uncorrected litter size traits were high and ranged ftoin 30.3 to 63.7 To. Estimates of sire •riance and heritability of litter size traits using REIVIL with sires relationship coefficient matrix (A-') were generally low in (ill lines and ranged from 2.2 to 5.3 To_ Transmitting abilities estimated for dams were somewhat higher than those estimated .for sires, For (111 lines, BLUP for dams 'ranged from 1.5 to 4.3 young, while BL/.JP estimates or sires ranged from 0.9 to 2.0 young, i.e. selection based on dams polormance may be ejfective to improve litter size in rabbits than that based on records of sires.
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