Heritability of productive qualities in replacement gilts of Large White breed at linear breeding

The aim of the work is to study the productivity of Large White gilts that were estimated and selected for herd replacement in the process of line formation. Within 6 generations of selection the age of live weight 100 kg achievement reduces on 6 days, fat thickness on 1,7–2,0 mm, the depth of longissimus muscle increases on 4,9 mm and lean meat output in carcass on 1.4%. The size of litter of dams in selection group increases up to 13,0 piglets, the number of pigs at weaning — to 11,4, the litter weight at 30 days — to 92,4 kg. The productivity increase of replacement pigs is caused by though not high but reliable hereditability indices, calculated according to results of dispersion analysis of data's of 968 gilts, selected from 3 sires groups and 6 dams groups of adjacent generations F₂–F₃, F₃–F₄, F₄–F₅. The influence of sires (factor A) is maximum for age at 100 kg weight (h²=36,5%) and for lean meat output (h²=3,3%) in dams group F₃–F₄; the fat thickness over 6–7 pectoral ribs (h²=4,8%) and the depth of longissimus muscle (h²=5,4%) in dams group F₂–F₃. The influence of dams (factor B) is low in all groups. The mutual influence of both factors apparent in dams group F₃–F₄ in fat thickness in three points of scanning (h²=3,8-7,9 %) and in longissimus muscle depth (h²=2,6%); in dams group F₄–F₅ — in 100 kg weight age (h²=6,7%) and in fat thickness over the 6–7 pectoral ribs (h²=7,0%).

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