GENETIC ANALYSIS OF SOME PRODUCTIVE AND REPRODUCTIVE TRAITS IN NEW ZEALAND WHITE RABBITS

A total of 625 progenies of New Zealand White rabbits, kept at Sakha Experimental Rabbits, Kafr-El-Sheikh, Government, belonging to Animal Production Research Institute, Ministry of Agriculture, Dokki, Cairo, Egypt, during 2010-2017 were used to estimate the genetic parameters and phenotypic and genetic trends for some reproductive and productive traits. Traits studied were litter size at birth (LSB), litter weight at birth (LWB), kit body weight at 4 wk (BW4), body weight at 6 wk (BW6), body weight at 8 wk (BW8) and body weight at 10 wk or marketing weight (BW10). Data were analysed using a multivariate animal model. Direct heritability estimates were 0.05, 0.20, 0.23, 0.24, 0.31 and 0.34 for LSB, LWB, BW4, BW6, BW8 and BW10, respectively. All phenotypic and genetic correlations among traits studied were positive and ranged from 0.21 to 0.90 for phenotypic correlations and from 0.04 to 0.78 for genetic correlations. Annual phenotypic changes for LSB, LWB, BW4, BW6, BW8 and BW10 were positive and equal to 0.06, 15.96 g, 18.70 g, 23.15 g, 27.72 g and 50.69 g, respectively. Genetic changes for LSB, LWB, BW4, BW6, BW8, and BW10 were 0.20, 12.50 g, 14.20 g, 16.25 g, 20.09, and 40.10 g, respectively. The moderate estimates of heritability for body weights confirmed that improvement of these traits can be achieved by genetic selection. Positive and significant phenotypic and genetic trends for the studied traits implied that current breeding programmes are efficient in this rabbit population. Likewise, positive genetic trends along with positive genetic correlations among traits indicated that improvement of production and reproduction traits of New Zealand White rabbits seems feasible in selection programmes.