Application of morphological indices in the assessment of type and function in sheep

Abstract

Live weight and eight body measurements records taken on 284 sheep comprising 226 West African Dwarf and 58 Yankasa sheep were analysed. The sheep were extensively managed within the south west Nigeria. The aim was to achieve a preliminary assessment of type and function from zoometrical indices produced from combinations of different morphometric scores. The indices used were weight, height slope, length index, width slope, depth index, foreleg length balance and cumulative index. The body measurements used were wither height, body length, hip length, hip width, rump height, foreleg length, chest width and heart girth. The body measurements showed that the Yankasa is bigger than the WAD sheep. The measured parts are highly correlated. Tested indices showed that both sheep are typical meat animals. This was shown by the cumulative index, length and balance indices which were 2.80, 1.01 and 0.59 in WAD and 1.18, 0.93 and 0.75 for Yankasa respectively. The distribution of the indices among the different age groups revealed that weight index is highest at the 8-tooth age for both breeds , this trend is the same for length index, foreleg length index and cumulative indices. The respective coefficient of variation between breeds indicates the amount of opportunity available for improving the breeds through selection. Further, height slope index/length index and weight index and height slope/cumulative index were significantly (p<0.05) correlated. The implications for the respective varieties are discussed. © 2006 Sociedad Chilena de Anatom.