An evaluation of sexual size dimorphism in Uda sheep using multifactorial discriminant analysis

Abstract

This investigation aimed at evaluating sexual size dimorphism in Uda sheep using multivariate discriminant analysis. Eleven morphological traits were measured on a total of 296 adult sheep of both sexes randomly selected in Nasarawa State, north-central Nigeria. The univariate analysis showed that Uda rams had significantly (P<0.05) higher values in nine of the morphological traits examined. Measurements that were best able to separate the rams and the ewes as revealed by the canonical discriminant analysis were head width and face length. These two variables were included in the single discriminant function used to classify the two sexes. The discriminant model was able to allocate correctly 70.8% of Uda ewes and 58% of rams to their a priori sexes. Ward's option of the cluster analysis further revealed the morphological distinctness of the population. The discriminant function obtained in the present study could be useful in management, ecological and conservation studies.