Principal Component Factor Analysis of the Morphostructure of Immature Uda Sheep

Ten body measurements were taken on 30 Uda sheep aged 0-14 months within the humid southwest Nigeria. The body measurements were wither height (WH), body length (BL), rump length (RL), rump height (RH), rump width (RW), foreleg length (FL), shoulder width (SW), face length (FaL), tail length (TL) and heart girth (HG). The aim was to investigate the variance structure and provide an objective description of the body shape (conformation) of the sheep within the first years of life using a cluster analysis. This was possible sequel to the application and permission of the Pearson’s correlation coefficient. Applying the traditional use of wither height for size estimation, the animal measured 65.83±5.81cm. Other body measurements for that age group were: BL=59.37±4.50, RL=22.1±1.12, RH=65.18±6.06, RW=12.90±1.24, FL=41.62±2.29, SW=14.40±1.45, FaL=21.47±1.82, TL=40.72±2.71 and HG=71.98±4.30cm. Variability was generally high within body measurements. Correlations among body dimensions were positive and significant (P<0.05, 0.01; r=0.40-0.99). The factor solution from Principal component analysis (PCA) produced two clusters after a promax rotation of the transformation matrix. The first and second principal components explained 67.6 and11.03% of the generalized variance in body measurements and gave approximately equal emphasis to each variable. The first component contained measurements that are closely associated with bone growth (FL, TL, FaL, RH, WH and BL) while the second one appeared to produce dimensions that are relatively less associated it (RW, SW and RL). The underlying factors are explained.