New morphological and weight measurements by visual image analysis in sheep and goats

Abstract

This study presents the application of opto-informatic techniques as Visual Image Analysis (VIA) in the area of sheep and goats production. The main purpose of the research was to bring innovation in terms of both technical and organizational aspects in the field of zootechnic biometry, a discipline where traditional tools are still in use. Such a novelty should not be confined only to research activities, but hopefully also lead to practical applications in farming as well as in production. Morphological traits and weight estimations have been performed on 36 Comisana sheep and 50 Saanen goats. The advanced VIA system has been completely computerised by the implementation of a laser measurement of the distance to allow the automatic calculation of the morphological parameters here reported, and it has become possible to get new angular and surface measurements. Evaluations of animal weight were carried out with the aim to set up regression equations for the indirect determination of live weight. To achieve such a task we measured a surface parameter (Surface Area of the Lateral Profile, SLP) that can only be determined by VIA techniques and has been demonstrated to be highly correlated with live weight (LW) in several zootechnical animals as buffaloes, sports horses, milk- and beef-cattle. In sheep and goats correlations between SLP and LW were 0.95 and 0.96, respectively (P<0.01). The regression equation (LW= -59.25+0.03 × SLP) has been utilised in sheep, while (LW= -3.5+0.014 × SLP) has been utilised to estimate live weight in goats.