Principal Components Analysis Applied to Live Body Weight and Carcass Traits in ISA Brown and Kurdish local Roosters
The study was conducted in the poultry unit at Gardarash station, college of Agriculture, University of Salahaddin, during June – July 2014. A total of (53) roosters aged 6 months were belongs to Kurdish local roosters (N=41), and ISA brown (N= 12). The live body weights of the rosters as well their carcass measurements were described earlier.Means, and standard errors where calculated using descriptive statistics of SPSS/PASW. T test was used to test the differences between the two groups in their studied traits. Person’s coefficients of correlation among carcass traits were estimated for each group. Data were generated for the principal component factor analysis. Anti-image correlations, Kaiser-Meyer- Olkin measures of sampling adequacy rotation component matrix, and Bartlett’s Test of Spherity were computed to test the validity of the factor analysis of the data sets. The appropriateness of the factor analysis was further tested using communalities.
Kurdish local roosters were superior (P<0.05) comparing with ISA brown roosters in many traits including TolWt, ThiWt, NecWt, HerWtandWinWt. Not significant differences were observed (P>0.05) in LivWt, LeWt, BacWt, CheWt, LiverWt, andGizWt.In Kurdish local roosters, the highest positive and significant correlation was found between TolWt and ThiWt (0.970) while the lowest value was found between HerWt and GizWt (0.170) which was not significant. In ISA brown roosters, the highest positive and significant correlation was found between TolWt with LeWt (0.978) while the lowest value was found between HerWt and GizWt (-0.051) which was negative and not significant.
Results of the Bartlett test of sphericity for carcass measurements of Kurdish local roosters (chi square= 644.757, p<0.000), and ISA brown (chi square=149.409, p<0.000) were significant. The communalities ranged (0.499 – 0.957) and (0.629 – 0.966), in Kurdish local roosters, and ISA brown roosters respectively.
Two principal components were extracted from Kurdish local roosters with eigenvalues of the first (7.177) and second (1.152) principal component. Also the same components were extracted from ISA brown roosters, and were (7.403), and (1.487) on the same trend respectively.
It can be concluded that the correlations between each pair were mostly positive and significant in both groups, which indicate that measuring any trait can be used as indicator to have a good idea about the other traits.The three principal components that extracted from black, white, and ISA brown roosters can be used for genetic improvement, body size characterization, and also to predicting carcass parts weight.
Keywords - Poultry Genetic Groups, Carcass, PCA, and Body Weight.