MULTIFACTORIAL DISCRIMINANT ANALYSIS OF CEPHALIC MORPHOLOGY OF INDIGENOUS BREEDS OF RAMS IN NIGERIA

Résumé

The study aimed at classifying Nigerian indigenous rams on the basis of their head conformation using multivariate analyses. Twelve cephalic traits or 1,200 rams belonging to four breeds (Balami, Yankasa, Uda and WAD) were measured. The traits were subjected to principal component analysis to reduce data dimensionality. A discriminant canonical analysis was. also applied to differentiate between the breeds. The cephalic index reveals that the ram breeds are brachyprosopic except Uda which is mesocephalic breed. The first principal component (PC) had variables related to length and diameter amplitudes and explained 37.5 percent of the variance. The second PC gave major relevance  to skull, face and neck lengths of the rams and contributed to 21.30 percent of the total variance. while the third PC loaded highly for skull length, head depth and neck length and contributed 17.35 percent of the total variance. The stepwise discriminant analysis revealed that skull width, head width, head length and head depth were the most discriminating variables to separate the four breeds of rams.