An assessment of embryonic mortality stages in Chukar partridge (Alectoris chukar) by means of classification tree method

Abstract

Classification tree method is a potentially powerful tool to predict membership of cases in the classes of a categorical dependent variable. The use of classification tree is not widespread in the fields of agriculture. Egg weight, shell thickness, shell weight, shell ratio, egg width, egg length, egg volume, shell surface area were chosen for investigating of their influence on embryonic mortality stages in fertilized eggs of Chukar partridge. All measured and calculated egg parameters were analyzed by classification tree method in this study. According to CTM, the embryonic mortality stages were affected by egg weight (EW), egg volume (EV), blunt-edge shell thickness (BST) and average shell thickness (AST). EW appeared as root terminal node at the classification tree. Embryonic mortality stages were influenced by EV when EW was less than 22.1 g and by BST when EW was greater than 22.1 g. EEM occurred more often than MEM and LEM when EW was less than 22.1 g. However, when EW was higher than 22.1 g, LEM was higher than EEM and MEM. When EW and BST were higher than 22.1 g and 22.3 ?, respectively, LEM was about 80.0%. EEM was about 81.2% when EW was less than 22.1 g and EV was higher than 25.1. EEM and LEM occurred but MEM did not occur when AST was higher than 22.3 ?m. CTM estimated with an accuracy of 75.6% that EW, EV, BST, and AST primarily affected embryonic mortality stages. Finally, the results of this study showed that this method could be used in the fields of agriculture. © Verlag Eugen Ulmer, Stuttgart.