Data on 15435 of weaned rabbits for three lines (N, Z and G) from 359 sires born between 1987 and 1995 were analyzed to estimate sire transmitting abilities and to evaluate the effect of various genetic and some environmental factors on body weight (at 8, 12 and 16 weeks of age) and daily gain (during the intervals of 8-12, 12-16 and 8-16 weeks). Two methods of Henderson method 3 (3A43) and restricted maximum likelihood (REML) procedure taking into account the relationships among sires, fcl were compared in estimating variance components and heritability estimates. Line N was intermediate in growth traits between the lowest line Z and the highest line G. Year and season of birth were the most important non-genetic factors affecting body weight and gain. Parity effect constituted a significant source of variation in most growth traits at different ages Body weight and daily gain of the rabbits nursed in small-sized litters were the highest until a certain litter size 4 or 5 for K 7 for Z and 6 for G) and decreased thereafter. Males were significantly heavier and grew more than females in all lines.
REAL method caused in general an increase in sire variance and a decrease in error variance. lvEs,43 method gave underestimated heritability because it ignored relationships among sires. |
