Records on 884 litters and 3051 bunnies of the Bauscat (B) and Giza White (G) breeds were used to construct different selection indices.
A series of selection indices and subindices were constructed for both B and G does. An index or subindex based on litter size at weaning, mean bunny weight at weaning, litter size at birth and litter weight at birth could be practically applied to improve the productivity of B and G does, under local Egyptian conditions. Preweaning mortality did not contribute significantly to the different selection indices and subindices. Litter weight at birth made a large contribution to the different indices and subindices constructed. Litter size at weaning contributed little in the subindices to be used to select for mean bunny weight at weaning. Mean bunny weight at weaning made a lower contribution to the subindices to be used to select for litter size at weaning. The expected genetic gain in litter size at weaning was slight in all of the selection indices and subindices constructed because of low heritability values for this trait. Considerable genetic improvement for doe productivity of the G breed might be achieved through selection for mean bunny weight at weaning.
Four selection indices and subindices were constructed for B and G rabbits. The index or subindex based on 6-week weight and 8-week weight was the best criterion for selection for the genetic improvement of 6-week weight and 12-week weight. Six- and 8-week weight contributed substantially while 12-week weight contributed little to the value of most of the selection indices and subindices constructed. The highest total genetic gain attributable to 6- and 12-week weight was obtained when the selection indices or subindices including 6-week weight and 8-week weight were used. |
