Genetic parameter estimates for early growth traits in Naeini goat

Abstract

The present study was carried out to estimate variance components for growth traits in Naeini goats. Bodyweight records were collected for two flocks under supervision of the Agriculture Organisation of the Esfahan province between 2000 and 2007. Investigated traits were birthweight (BW; n = 2483), weaning weight (WW; n = 1211) and average daily gain from birth to weaning (ADG; n = 1211). Environmental effects were investigated using fixed-effect models, while (co)variance components and genetic parameters were estimated with single- and three-trait analyses using REML methods and WOMBAT software. Six different animal models were fitted to the traits, with the best model for each trait determined by log-likelihood ratio tests (LRT). All traits were significantly influenced by herd, birth year, sex of the kid, birth type and dam age (P < 0.01). On the basis of LRT, maternal permanent environmental effects (c2) were significant for WW and ADG, while BW was affected only by direct genetic effects. Direct heritability estimates for BW, WW and ADG were 0.25 ± 0.05, 0.07 ± 0.06 and 0.21 ± 0.11, respectively. The estimate of c2 was 0.16 ± 0.06 for both WW and ADG. Estimates of genetic correlation for BW–ADG, BW–WW and ADG–WW were 0.49, 0.61 and 0.94, respectively. The estimated phenotypic correlations were positive and were between 0.03 (BW–ADG) and 0.95 (ADG–WW). These results indicate that selection can be used to improve growth traits in this goat breed.

The Influence of Non-Genetic Factors on Early Growth of Halaba Kids Under Smallholder Management Systems, Southern Ethiopia

“…Sex effect is not important at birth weight while as kids grew up, from 30 to 120 days, it becomes an important source of variation. These results agree with the previous reports (Annor et al, 2012;Baneh et al, 2012;Bedhane et al, 2013) while others reported the significant effect of sex on birth weight (Mabrouk et al, 2010) and subsequent body weights (Dadi et al, 2008). The superiority of males over females may be explained by the precocity, the sexual dimorphism in favour of body growth in males than females (Mabrouk et al, 2010).…”

Early Growth of Adilo Kids under Smallholder Management Systems, Southern Ethiopia: Influences of non-Genetic Factors

“…These results agree with the previous reports (Annor et al, 2012;Baneh et al, 2012;Bedhane et al, 2013) while others reported the significant effect of sex on birth weight (Mabrouk et al, 2010) and subsequent body weights (Dadi et al, 2008). The superiority of males over females may be explained by the precocity, the sexual dimorphism in favour of body growth in males than females (Mabrouk et al, 2010).…”

“…The superiority of single kids over their multiple counterparts found in this study agrees with reports of other studies (Dadi et al, 2008;Zahraddeen et al, 2008;Baneh et al, 2012). This is due to the competition of young's for suckling the limited amount of milk of their dams among multiple births than single.…”

“…Indigenous goats are resistant to diseases and parasites, tolerant to adverse climatic conditions, have endurance to sustain droughts and low and fluctuating nutrient availability. However, extreme climatic stresses and poor quality feeds limit the potential expression of genetic merits in goat flock (Mabrouk et al, 2010;Baneh et al, 2012). Knowledge of non-genetic factors on production traits allows a more accurate assessment of breeding values (Dadi et al, 2008).…”

Effect of Fixed Factors and Estimation of Genetic Parameters of Growth Traits for Mountain Kids

“…Such effect could be attributed to availability of quality and quantity of forage as well as some environmental effects like temperature and humidity over years. Earlier studies conducted in several countries using different breeds of goat noticed that year of kidding affect body weights of kids significantly (7,17,27,34,57). However, Bingol et al (12) reported that the effect of year of kidding on BWT, WWT and WT6M was not significant.…”