GENETIC PARAMETER ESTIMATES OF PRODUCTION TRAITS OF ANGORA-GOATS IN ARGENTINA

The objective of this study was to estimate genetic parameters for fle ece traits in an experimental Angora goat flock. The fleece traits ana lyzed in this study were: greasy fleece weight (GFW), average fiber di ameter (AFD), percentage of medullated fiber (MF) and corrected greasy fleece weight (CGFW). Direct and maternal variance components and res ulting heritabilities were estimated using an animal model and DFREML procedures on the first shearing. Six different animal models were fit ted ranging from a simple model with animals as the only random effect to the most comprehensive model allowing for both genetic and environ mental maternal effects and a genetic correlation between genetic dire ct and maternal effects. The models were tested by the Likelihood Rati o Test which indicated that the maternal effects (genetic and environm ental) can be ignored. Direct heritabilities estimated with a single t rait model were 0.26 +/- 0.06, 0.33 +/- 0.06, 0.10 +/- 0.04 and 0.22 /- 0.06 for GFW, AFD, MF and CGFW, respectively. Genetic correlations were estimated with a multivariate model. The pattern of correlations showed that GFW was positively correlated with AFD and CGFW, 0.51 and 0.53 respectively and negatively correlated with MF -0.72. AFD was neg atively correlated with MF and CGFW (-0.18 and -0.37, respectively) an d MF was negatively correlated with CGFW -0.65. The repeatability esti mates were based upon other files containing information on all sheari ngs. The repeatabilities were 0.64, 0.70, 0.58 and 0.68 for GFW, AFD, MF and CGFW, respectively. Genetic parameters estimated in this study appear reliable and provide a better basis for the Argentina genetic A ngora goat improvement program. The moderate heritability level for CG FW added to the negative genetic correlation with AFD may be an altern ative solution for selection programs based on a single trait. The hig h levels of repeatability estimates confirm the benefits of the select ion program based on objective measurements observed at the age of yea r. (C) 1998 Elsevier Science B.V.