Potential Indices For Calculating Economic Values For Resistance To Gastrointestinal Helminths

Abstract

Introduction Use of incorrect economic values (EVs) in index calculation results in incorrect selection criterion and hence in suboptimal direction of selection. Appropriate economic values are important for selection within a population as well as in choices among breeds or crosses, evaluation of gene effects and for design of optimum breeding programmes (Ollivier 1986). Sivarajasingam (1995) described a method of estimating economic value for disease resistance. The method was used by Gicheha, M., Kosgey, I., Bebe, B. et al. (2005) in estimation of economic value for resistance to gastro-intestinal (GI) helminths (RES) in meat sheep using a two traits index. The current study presents economic values based on potential indices for estimating RES utilising multiple traits. Material and methods A method of estimating economic values for disease resistance described by Sivarajasingam (1995) was used. In that method, for a given set of assumptions, the breeding objective is matched to the expected responses in production traits and responses in these traits maximized relative to overall gains. Detailed description of the traits used in constructing alternative indices is presented in Gicheha and Bett (2009) using information from smallholder and pastoral production systems in the tropics (Kosgey, I., van Arendonk, J. and Baker, R. 2003).