Genetic and phenotypic parameters for early growth traits in Emirati goat

The Emirati goat is the most common native breed of the United Arab Emirates adapted to the harsh environment. The data used in the present study were collected from a conservation flock at the Faculty of Agricultural Sciences Experimental Station. The traits recorded were body weights at birth (BWT), 30 days (WT30) and weaning weight (WWT), and average daily gains for the periods 0-30 (ADG1), 30-90 (ADG2) and 0 to weaning (ADG3) days of age. Season of birth, type of birth or rearing, sex of kid and dam age at kidding were the environmental factors investigated. Genetic parameters, and phenotypic and genetic correlations were estimated by REML procedures. By ignoring or including maternal genetic or environmental effects, five different models of analysis were fitted in order to determine the most effective model for each trait. Additive maternal effect was important (P < 0.05) for BWT, when compared with a model containing only additive direct effects. Inclusion of maternal permanent environmental effect provided a better fit (P < 0.05) for WT30, WWT and ADG1. Estimates of direct heritability from the most appropriate models were 0.18 for BWT, 0.16 for WT30, 0.32 for WWT, 0.11 for ADG1, 0.09 for ADG2 and 0.42 for ADG3. The estimates of genetic and phenotypic correlations were high and showed no genetic antagonisms among the growth traits analyzed. It can be concluded that maternal effects have to be accounted for when estimating genetic parameters for BWT, WT30, WWT and ADGI. (C) 2002 Published by Elsevier Science B.V.