Growth traits in simple crossbreeding among dam and sire lines

Abstract

Twenty-five genetic groups were produced following a diallel-crossbreeding scheme among five lines: three dam and two sire lines belonging to two Spanish Research Institutions (UPV and IRTA). A total of 2773 young rabbits from 525 kindlings were controlled in different seasons. Growth traits were evaluated during the fattening period lasting from five to nine weeks. On average, genetic groups coming from lines selected for growth rate were heavier (+57 g at weaning and 311 g at 60 days), had a faster growth rate (+9g/d) and a realised higher daily feed intake (+12.9 g/d), improving feed conversion ratio (-0.21), than the groups originated from crosses among lines selected for litter size. Crossbreeding parameters were estimated using the Dickerson model. Maternal genetic and heterosis effects were close to 0 or very low. Direct genetic effects mainly regulated expression of these traits.