Comparative study of morphological traits of adult male and female West African Dwarf goats

Abstract

Linear body measurements and live body weights were taken on two hundred (200) adult West African Dwarf (WAD) goats comprising of 115 does and 85 bucks from keeper’s backyard in some selected communities (Iwata, Isundunrin and Ola) in Ejigbo Local Government Area of Osun State. The objectives of the study were to compare the morphological traits between sexes and describe the body morphology of adult WAD goats using a multivariate approach. Variables measured included: Body weight (BW), Face length (FL), Ear width (EW), Ear length (EL), Horn length (HL), Neck length (NL), Neck circumference (NC), Heart girth (HG), Body length (BL), Hind leg length (HLL), Tail length (TL) and Shoulder length (SL). Others were: Scrotal length (SCL) and Scrotal circumference (SCC) in bucks. Data obtained were subjected to univariate, Welch’s t-test and multivariate analysis with the use of SAS (2002) to determine means, significant differences between means for different sexes and principal components of the variables in the sexes. Results showed that, the mean BW, FL, EW, EL, HL, NL, NC, HG, BL, HLL, TL and SL of does were: 15.05±0.49 kg, 18.88±0.26, 6.12±0.09, 10.46±0.17, 7.78±0.30, 17.16±0.38, 31.31±0.89, 52.05±1.42, 53.62±0.92, 43.43±1.81, 8.12±0.28 and 35.22±0.59 cm respectively. The corresponding values in bucks were: 14.06±0.32 kg, 19.44±0.20, 5.42±0.10, 9.97±0.17, 6.69±0.13, 14.32±0.14, 29.84±0.43, 51.55±0.60, 53.33±0.29, 40.87±1.20, 8.73±0.17 and 32.22±0.75 cm. The means for scrotal length and scrotal circumference in males were 8.73±0.16 and 17.66±0.17 cm respectively. Significant differences (p<0.001) were detected between most of the variables in the two sexes except in EW, EL and BL. Two principal components (PCs) of PC1 (50.1%) and PC2 (31.9%) were retained for does while three PCs 52%, 25% and 10% respectively were retained for bucks. Body length showed highest PC loadings for does in PC1 (0.95) whiles face length showed highest PC loadings for bucks in PC1 (0.97); suggesting that these variables are the most discriminating traits between the sexes. This study concluded that, sexual dimorphism was observed in the linear body measurements in the WAD goats; thus, does and bucks could be selected based on body length and face length respectively. The results herein could be used in evaluating the present goat population for selection programme.