GENETIC EVALUATION OF SOME ECONOMIC TRAITS IN A MATERNAL LINE OF RABBITS

Abstract

Genetic evaluation of growth and litter traits was carried out in a line of rabbits selected for litter size at weaning. The evaluation was performed on 483 does and 10847 offspring over six consecutive years of production from 2005 to 2011, using BLUP under an animal repeatability model. The high proportions of animals with positive transmitting ability estimates for slaughter weight makes this trait much better to select for than weaning weight or daily weight gain, if we are looking for growth improvement. Whereas, for litter traits studied, Litter size at weaning seems to be the best trait to use as a selection criteria for improving the reproductive performance rather than Litter size at birth or Number born alive. Estimates of rank correlations were low between weaning weight and both of slaughter weight & daily weight gain While, correlation among ranks of transmitting ability value between slaughter weight and daily weight gain was moderate. Genetic trends estimated as a regression coefficient of trait breeding values on year of birth, which present generation number, for growth and litter traits were about 9 and 58 g/ year for weaning weight and slaughter weight, respectively. Whereas, for daily weight gain during the fattening period, the genetic trend increased yearly by 1.08 g/ d. The value of genetic trend for litter size at weaning, which used as criteria of selection in this line, means that, we can get one kit more from each litter each 12 generations.