Association between litter size and the k-casein genotype in the INRA rabbit lines.

Abstract

The reproductive traits of 276 rabbit does belonging to an intercross generation of two synthetic INRAlines, which differed by their genotypes at the k-casein locus being either AA or AB, were recorded at birth andat weaning for a total of 743 litters. They were the daughters of 77 dams whose k-casein genotype was ABand 18 sires whose genotype was AA. A significant association between the k-casein genotype andreproductive traits at birth was found in favour of the AB females, with an increase in litter size (+0.56;P<0.009) as well as in litter weight (+27 g; P<0.023). After standardisation of the litter size at birth, thegenotype of the dam was found to have no effect on weight gain and the viability of the young between birthand weaning or on the litter weight at weaning. Work is now in progress to explain this association.