University of Khartoum

Growth Curve and Inheritance of Body Weight Prior to Sexual Maturity in Indigenous Chicken

Growth Curve and Inheritance of Body Weight Prior to Sexual Maturity in Indigenous Chicken

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Title: Growth Curve and Inheritance of Body Weight Prior to Sexual Maturity in Indigenous Chicken
Author: Ahmed Mohamed Ismail, Adam
Abstract: This work was done to study the growth pattern of the indigenous (large Baladi) chicken from hatch up to 22nd week of age under relatively improved management. Genetic and phenotypic parameters of body weight were estimated from biweekly records from l0th to 22nd week of age. Growth curve was also plotted. Forty cockerels and 120 pullets were used as a foundation stock in 1: 3 sex ratio. Egg production of individually caged pullets was well marked, weighed and incubated to obtain ten consecutive hatches at weekly intervals. At hatching date chicks of each hatch were weighed, wing banded and brooded for 8 weeks in a brooder. They were then reared in a deep litter house up to 18th and 22nd week of age for males and females, respectively. 2842 chicks were produced in this study, however only 1068 chicks (578 males and 490 females) were used in the genetic analysis. Body weights of each chick were recorded from hatch up to 18th and 22nd week of age for males and females, respectively, at biweekly intervals. Heritability estimates for body weight from sire, dam and sire plus dam components of variance were obtained for male, female and sex combined data. Genetic, phenotypic and environmental correlations between body weights at various ages were also estimated. Growth curves of male, female and sex combined were plotted at biweekly intervals. The average body weight at 10, 12, 14, 16 and 18 weeks of age were 424.6±63.3, 554.7±78.1, 684.2±59.6, 507.3±103.8 and 926.3±125.5 g, respectively for male progeny, whereas the corresponding results for females were 373.7±5S.6, 484.7±68.9, 590.0±72.8, 681.6±83.2, 769.8±97.0, 841.4±97.0 and 900.l±107.5 g. Hatch was found to affect body weights significantly (P< 0 .01) at all ages. Sex affected body weights significantly (P<0.01) at all ages with males being heavier than females. The C.V.s for body weight of males (30.2-35.7%) were relatively higher than those of the females (2 8. 9 - 31. 2 %). There was a significant hatch x sex interaction (P<0.01) at 14, 16 and 18th week body weights. Sire effects were significant (P<0.01) at 12 and 18 weeks of age in the male data; however it was only approaching significance in the sex combined data. On the other hand, darn effects were significant (P<0.01) except at 10 weeks in the sex combined, and 10 and 16 weeks in the female data. Growth curve was found to be sigmoid or S-shaped with males being heavier than females at all stages. Both sexes attained maximum weight gain at the 10th week, at which time males were heavier than females by 19.1. Heritability estimates at various ages ranged from low (0.02±0.12) to high (0.52±0.18). For the sex combined data, the estimates from darn component of variance at 16 and 18 weeks of age were higher than those from sire components. For male progeny the estimates from sire components were relatively higher than those from darn components. The reverse was true for the estimates on female progeny. However, several cases of non-estimable results were also reported. Genetic correlations were relatively high and positive in magnitude (0.77- 0.98). Phenotypic correlations were also relatively high and positive in magnitude for both male (0.5-0.88) and female (0.29 - 0.84) progenies. However, environmental correlations were also relatively high and positive (0.5-0.86) and showed a declining trend with age.
URI: http://khartoumspace.uofk.edu/handle/123456789/13945
Date: 2015-06-22


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