Genetic parameter estimation of mohair production traits in Angora goats

Abstract

Data collected from 1984 until 1997, representing 42 sires from the fine mohair selection research project which is run by the Texas Agricultural Experiment Station based in San Angelo, Texas, was utilized to estimate genetic parameters. The traits analyzed included fiber diameter (FD; n = 4329), grease fleece weight (FW; n = 7073), body weight (BW; n = 4171) and fertility (FERT; n = 2118). Heritability estimates were obtained for all the traits using REML procedures with a multivariate animal model for animals ranging in age from .5 to 8 years. The animal model for FW and FD had fixed effects for sex-age-season, production year, and herd; while the model for BW and FERT had age, production year and herd as fixed effects. The models for all traits had the additive genetic and pen-permanent environmental components as random effects. Heritability estimates for FW(.15),FD(.41),BW(.41),and FERT(.02)were obtained. Positive genetic correlations were obtained between FW and FD (.32), FW and BW (.29), FW and FERT (.33), FD and BW (.23), FD and FERT (.63), and BW and FERT (.90). Estimated phenotypic correlations were.44 between FW and FD, .35 between FW and BW, . 1 0 between FW and FERT, .31 between FD and BW, . 1 1 between FD and FERT as well as .23 between BW and FERT. Heritability estimates suggest that FW, FD and BW would respond to mass selection but genetic response in FERT would be small. The correlations also indicate that selecting to decrease fiber diameter by 1. 19 [um will lead to correlated decreases in FW (.020 kg), BW (.467 kg) and FERT (.005). Results showed that Fall fleece is heavier and coarser than Spring fleece and that comparisons of animal records have to account for differences due to age of animals and type of birth (for younger ages). Older does showed higher fertility than younger does and all traits studied increased with age.