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

Abstract

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).

Advances in molecular genetic techniques applied to selection for litter size in goats (Capra hircus): a review

“…Regarding the litter size of goats, selection programmes have generally considered only the phenotypic and pedigree information of the animals (Shrestha and Fahmy 2007;Mohammadi et al 2012;Castañeda-Bustos et al 2014;Zhou et al 2014). Due to the low heritability of litter size (0.08-0.18), its rate of genetic improvement is slow (Hamed et al 2009;Gunia et al 2010;Santos et al 2013;Menezes et al 2016).…”

Implementation of a cashmere goat breeding program amongst nomads in Southern Iran

“…Breeding objective traits need to be heritable to be modified through breeding. Reproduction traits such as fertility, prolificacy and kid survival have low heritability (Mohammadi et al, 2012) and therefore depend largely on management issues rather than on genetic differences. Early growth traits and maternal traits such as total weight of kids weaned over a does' lifetime are also of low heritability (Bigham et al, 1993;Maghsoudi et al, 2009).…”

“…Early growth traits and maternal traits such as total weight of kids weaned over a does' lifetime are also of low heritability (Bigham et al, 1993;Maghsoudi et al, 2009). As opposed to reproduction traits, fleece traits and yearling body weights are moderately to highly heritable (Gifford et al, 1990;Bigham et al, 1993;Zhou et al, 2002;Bai et al, 2006;Mohammadi et al, 2012;Wang et al, 2013) and are therefore more obvious candidates to be improved Fig. 1.…”

“…In the past some herders near the city of Baft have had access to bucks from a governmental breeding station through an artificial breeding program. These bucks were selected for reproduction (total weight of kids weaned per doe joined), growth and fleece weight but not for cashmere quality (Maghsoudi et al, 2009;Mohammadi et al, 2012). Thus, most nomads have no access to improved cashmere producing bucks and have no guideline or model to establish a breeding program in their herds.…”

“…,Gifford et al (1990),Rose et al (1992),Bigham et al (1993),Zhou et al (2002),Ma et al (2005),Bai et al (2006),Maghsoudi et al (2009),Mohebinejat et al (2010),Mohammadi et al (2012) andWang et al (2013).…”