Effect of long term selection on genetic parameters of economic traits in white leghorn

Estimation of genetic parameters of various economic traits in a closed population of female line layer type chickens under short term selection

“…The negative genetic and phenotypic association obtained between egg weight average and egg production suggest that the relationship could become more antagonistic during the process of selection. The result obtained between egg weight and egg 280 days is in agreement with the reports of Sharma et al (1996), Singh et al (1992), Atkare and Khan (1998). This result also corresponds with findings of Oni et al (1992 and, Adeyinka (1998) and Nwagu (2004).…”

“…The results reveal moderate to high estimates which were in agreement with the reports of Wei and Van der Werf (1995), Chaudhary et al (1996), Sharma et al (1996), Chaterjee and Misra (2001), Singh et al (2002), Rahman et al (2003) and Khalil et al (2004). The higher estimate obtained from the sire component for BW20 and BW40 agrees with the report of Chaubal et al (1994).…”

Genetic Analysis of Egg Production and Allied Characters in Two Long Term Selected Strains of White Leghorn

“…The magnitude of heritability for AFE was high (0.349) in IWN strain compared to IWP (0.09). The heritability estimates for AFE observed in the present study was in agreement with those reported by Ahlawat et al, (1982), Johari et al, (1988), Sharma et al, (1996) and Singh and Singh (2005) but lower than the report of Savegnago et al, (2011).…”

“…This may be due to the fact that the growth traits are well expressed at faster rate of growth, which minimize effects of environmental factors compared to later age. Moderate to high heritability estimated for body weights at various ages obtained in this study were in conformity with the reports of Johari et al, (1988); Sharma et al, (1996) and Singh and Singh (2005) but lower than an estimate of 0.68 for 54 week body weight reported by Savegnago et al, (2011).…”

“…Results of long term studies can provide valuable information for scientific community and commercial breeders as well. Although there is considerable literature on genetic parameters of various economic traits in White Leghorn for a specific short or medium period or pooled over few generations of study (Johari et al, 1988;Chaudhary et al, 1996;Sharma et al, 1996), there is, a dearth of information on genetic estimates from populations which were undergone selection for a long period. Moreover, heritability estimates for part-period egg production upto 40 weeks of age is commonly reported but one calculated for full-record egg production is scarce.…”