Multivariate principal component analysis of the morphometric traits of some cattle breeds in Nigeria

Abstract

The conservation of Nigerian cattle is of increasing concern because of their historical and genetic value. Phenotypic characterization involves the differentiation of groups and/or breeds and provides support for conservation programmes. In this study, we reported quantitative examination of four Nigerian cattle breeds using multivariate technique. Data were collected from a total of 2,120 randomly selected trade cattle of both sexes (1,008 males and 1,112 females) comprising 859 Bunaji, 674 Sokoto Gudali, 409 Rahaji and 178 Kuri transported from the northern parts to the south western part of the country for sale. The animals were divided into four ages viz., 2-tooth, 4-tooth, 6-tooth and 8-tooth ages, respectively based on the eruption of permanent incisors. Eight biometric traits were taken on each animal namely height at withers (HTW), height at shoulders (HTS), body length (BDL), shoulder to tail drop (STD), heart girth (HTG), cannon circumference (CNC), ear length (ERL) and tail length (TLL). The fixed effects of breed, sex and age including their interactions on body traits were tested using General linear model (GLM). Pearson's coefficients of correlation among the various linear body measurements were computed. The multivariate approach involved the use of principal component (PC) analysis. Based on univariate analysis, the Kuri cattle had significantly (P<0.05) higher morphometric variables compared to other breeds. Sex and age also influenced (P<0.05) all the body parameters while there were breed and sex; breed and age; sex and age; and breed and sex and age interaction effects on the body traits. Phenotypic correlation Coefficients among the traits were positive and significant (P<0.01), ranging from 0.13-0.92. In the PC analysis, two parameters (STD and HTS) were sufficient for breed differentiation based on eigenvalue lower than 0.7. The present information may be useful for animal evaluation and when complemented with molecular diversity analysis, could be exploited in future efforts aimed at conserving the indigenous cattle.