Mohadeseh Namvar; Gholam Reza Dashab; Mohammad Rokouei; Hadi Faraji Arogh; Davoud Ali Saghi
Volume 19, Issue 2 , August 2017, , Pages 281-298
Abstract
This study was performed to compare different models for estimation of direct and maternal heritability and also for obtaining of genetic trend for body weight traits in Kurdi sheep of North Khorasan. The records of body weight in birth (BW, 7345 records), 3-month (3W, 5905 records), 6-month (6W ,5294 ...
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This study was performed to compare different models for estimation of direct and maternal heritability and also for obtaining of genetic trend for body weight traits in Kurdi sheep of North Khorasan. The records of body weight in birth (BW, 7345 records), 3-month (3W, 5905 records), 6-month (6W ,5294 records), 9-month (9W, 3800 records) and 12-month (12W, 3863 records) weight that collected during 1990 to 2013 by Sheep Breeding Station of Shirvan were used. Estimation of genetic parameters for different traits by using of six animal models was carried out by ThrGibbsf90 software. The most suitable model for each trait was determined based on Deviance Information Criterion (DIC). The estimates of direct heritability for BW, 3W, 6W, 9W and 12W traits were 0.172± 0.0007, .0.257± 0.0007, 0.351± 0.0006, 0.120± 0.0007 and 0.131± 0.0009, respectively. In this study, the material genetic effect was significant for BW, 3W and 6W traits (P<0.01) and proportion of maternal permanent environmental variance to phenotypic variance was varied from 0.055 (12W) to 0.186 (BW). Although estimated heritability of maternal effects for body weight was lower in older ages, the result of this study showed that including maternal effects (maternal genetic and permanent environmental effect) in the statistical model could lead to more accurate estimation of genetic parameters for growth traits in all ages. The phenotypic trend for BW, 3W, 6W, 9W and 12W were 8.4, 74.6, 8.3, 54.3, 78.3 gr/year, respectively and direct additive genetic trend for mentioned traits were -0.07, 14.2, -21.9, 13.7, 24.9 gr/year, respectively. Therefore, the results of bayesian analysis are more reliable than convientioal statistical methods.