Random regression models for estimation of covariance functions of growth in Iranian Kurdi sheep
Body weight (BW) records (n=11,659) of 4961 Kurdi sheep from 215 sires and 2085 dams were used to estimate the additive genetic, direct and maternal permanent environmental effects on growth from 1 to 300 days of age. The data were collected from 1993 to 2015 at a breeding station in North Khorasan province; Iran. Genetic parameters for growth traits were estimated using random regression test-day models. The residual variances were modeled by a step function with various classes. The model 16 with a polynomial of 3 order for fixed effect, 6 order for direct genetic effect, 6 order for direct permanent environmental and 6 order for maternal permanent environmental effects with the lowest Bayesian information criterion (BIC) was considered to be the best model. The direct heritability ranged from 0.01 at day 1 of age to 0.36 at 300 days of age. Genetic correlations ranged from 0.03 to 0.98 for body weight between different days of age. The small value of genetic correlation (0.03) among early (day 1) and late (300 days) weights showed that early weights were not under the same genetic control as weights at older ages. Genetic progress was realized and the estimated genetic parameters obtained could be used for further improvement of sheep and small ruminants.
Estimation of Variance Components for Body Weight of Moghani Sheep Using B-Spline Random Regression Models
The aim of the present study was the estimation of (co) variance components and genetic parameters for body weight of Moghani sheep, using random regression models based on B-Splines functions. The data set included 9165 body weight records from 60 to 360 days of age from 2811 Moghani sheep, collected between 1994 to 2013 from Jafar-Abad Animal Research and Breeding Institute, Ardabil province,...متن کامل
Random regression models for the estimation of genetic and environmental covariance functions for growth traits in Santa Ines sheep.
Polynomial functions of different orders were used to model random effects associated with weight of Santa Ines sheep from birth to 196 days. Fixed effects included in the models were contemporary groups, age of ewe at lambing, and fourth-order Legendre polynomials for age to represent the average growth curve. In the random part, functions of different orders were included to model variances a...متن کامل
a contrastive study of rhetorical functions of citation in iranian and international elt scopus journals
writing an academic article requires the researchers to provide support for their works by learning how to cite the works of others. various studies regarding the analysis of citation in m.a theses have been done, while little work has been done on comparison of citations among elt scopus journal articles, and so the dearth of research in this area demands for further investigation into citatio...
Genetic parameters for a random regression model of growth in Gelbvieh beef cattle were constructed using existing estimates. Information for variances along ages was provided by parameters used for routine Gelbvieh multiple-trait evaluation, and information on correlations among different ages was provided by random regression model estimates from literature studies involving Nellore cattle. B...متن کامل
estimation of variance components for body weight of moghani sheep using b-spline random regression models
the aim of the present study was the estimation of (co) variance components and genetic parameters for body weight of moghani sheep, using random regression models based on b-splines functions. the data set included 9165 body weight records from 60 to 360 days of age from 2811 moghani sheep, collected between 1994 to 2013 from jafar-abad animal research and breeding institute, ardabil province,...متن کامل
genetic analysis of milk solid no-fat percentage by fixed and random regression models in kurdi sheep of shirvan
introduction milk solid no-fat is economically very important in cheese industry. compared to the other kinds of milk, ewe’s milk contains higher amount of milk solids no-fat. milk solids no-fat (msnf) contains lactose, caseins, whey proteins, and minerals. the use of test day records in random regression method has several benefits including flexibility to account for the environmental and gen...متن کامل
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دوره 7 شماره 1
صفحات 55- 62
تاریخ انتشار 2019-10-14
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