A four-year crossbreeding project involving Spanish maternal line called V-line (V) and Saudi Gabali (G) rabbits was carried out to produce six genetic groups of V, G, ½V½G, ½G½V, ¾V¼G and ¾G¼V. Inter se matings for genetic groups of ½V½G, ½G½V, ¾V¼G and ¾G¼V were also practiced. Milk yields (MY) at intervals of 0-7 days (MY7), 7-21 days (MY21), 21-28 days (MY28), and 0-28 days (TMY) and milk components (MC) at 14 days of lactation (fat, protein, lactose, ash, and total solids) were evaluated for 2141 litters of 854 does fathered by 142 sires and mothered by 351 dams. A repeatability animal model was used to estimate the corresponding parameters as the heritabilities, the differences between line V and Gabali in additive direct effects (GIV-G) and maternal additive effects (GMV-G). The individual (HI) and maternal (HM) heterosis, and direct recombination effect (RI) were also estimated.
Heritabilities for MY traits were moderate, ranging from 0.18 to 0.22, while they were low or moderate and ranging from 0.09 to 0.28 for MC. The positive estimates of GIV-G for MY (5.6-14.5%) and MC (4.0-18.7%) were significantly high and in favour of V-line does. Estimates of GMV-G were in favour of V-line dams; being 222 g, 0.67% and -0.08 for MY21, total solids in milk, and fat in milk, respectively. All estimates of HI for MY and MC were positive and most of them were significant; ranging from 9.7 to 22.7 % for MY traits (P |
