Genetic parameter estimates for growth traits and prolificacy in Raeini Cashmere goats

The main objectives of this study were to estimate genetic and phenotypic parameters for growth traits and prolificacy in the Raeini Cashmere goat. Traits included, birth weight (BWT), weaning weight (WWT), 6-month weight (6WT), 9-month weight (9WT), 12-month weight (12WT), average daily gain from birth to weaning (ADG1), average daily gain from weaning to 6WT (ADG2), average daily gain from 6WT to 12WT (ADG3), survival rate (SR), litter size at birth (LSB) and litter size at weaning (LSW) and total litter weight at birth (LWB). Data were collected over a period of 28 years (1982-2009) at the experimental breeding station of Raeini goat, southeast of Iran. Genetic parameters were estimated with univariate models using restricted maximum likelihood (REML) procedures. In addition to an animal model, sire and threshold models, using a logit link function, were used for analyses of SR. Age of dam, birth of type, sex and of kidding had significant influence (p < 0.05 or 0.01) all the traits. Direct heritability estimates were low for prolificacy traits (0.04 +/- 0.01 for LSB, 0.09 +/- 0.02 for LSW, 0.16 +/- 0.02 for LWB and 0.05 +/- 0.02 for SR) and average daily gain (0.12 +/- 0.03 for ADG1, 0.08 +/- 0.02 for ADG2, and 0.07 +/- 0.03 for ADG3) to moderate for production traits (0.22 +/- 0.02 for BWT, 0.25 +/- 0.02 for WWT, 0.29 +/- 0.04 for 6WT, 0.30 +/- 0.02 for 9WT, 0.32 +/- 0.05 for 12WT). The estimates for the maternal additive genetic variance ratios were lower than direct heritability for BWT (0.17 +/- 0.03) and WWT (0.07 +/- 0.02).