Document Type : (original research)
Authors
1
Animal Science Research Department, Ilam Agriculture and Natural Resources and Education Center, Agriculture Research, Education and Extension Organization, Ilam, Iran
2
Animal Breeding and Genetic Department, Animal Science Research Institute, Agricultural Research Education and Extension Organization, Karaj, Iran
3
Animal and Poultry Nutrition Research Department, Animal Science Research Institute, Agricultural Research Education and Extension Organization, Karaj, Iran
Abstract
Estimation of genetic parameters for economic traits has a practical and prerequisite role for the implementation of animal breeding programs. Therefore, the aim of current study was to evaluate direct and maternal genetic effects for growth traits of Sanjabi sheep. Used data was related to Sanjabi herd of Mehregan station in 2016 to 2021. For the traits, 6 animal models differed on maternal genetic abd permanent environmental effects were taken into accounts. Proper model was identified for the final trait analysis based on a comparison of the log likelihood ratio and the Akaike criterion. Significant model for birth, 3 and 6 months’ weights, daily weight gain from birth to 3 and 3 to 6 months, and kleiber ratios from birth to 3 and 3 to 6 months was 2, 2, 2, 5, 5, 2 and 5, respectively (P<0.05). Direct heritabilities based on appropriate model for birth, 3 and 6 months’ weights, daily weight gain from birth to 3 and 3 to 6 months, and kleiber ratios from birth to 3 and 3 to 6 months were 0.05, 0.103, 0.182, 0.422, 0.004, 0.135 and 0.001, respectively. Also, maternal heritabilities for birth, 3 and 6 months’ weights, daily weight gain from birth to 3 and 3 to 6 months, and kleiber ratios from birth to 3 and 3 to 6 months were 0.122, 0.191, 0.166, 0.087, 0.024, 0.156 and 0.004, respectively. The ratio of maternal permanent environmental effect on phenotypic variance for daily weight gain from birth to 3 and 3 to 6 months, and kleiber ratio from 3 to 6 months were 0.088, 0.001, and 0.016, respectively. Estimated direct heritabilities were moderate to high, representing abilitiy for response to selection. Maternal effects, genetic and permanent environmental, were significant. Neglecting maternal effects in the final model of analysis make the genetic parameters overestimated. Estimated heritabilities showed that growth traits of Sanjabi sheep can response to selection.
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