نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه علوم دامی، واحد علوم و تحقیقات تهران، دانشگاه آزاد اسلامی، تهران، ایران
2 گروه علوم دامی، واحد شهرقدس، دانشگاه آزاد اسلامی، تهران، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
The aim of this study was to evaluate the mutual effects of genotype and environment and also to estimate genetic parameters for fertility traits (age of first calving and interval between two calvings) in Holstein cows in different climates of Iran. The required information was collected at Karaj Livestock Breeding Center between 2001 and 2017. This information was divided into three moderate, semi-cold and cold environments based on climatic conditions. Covariance components and genetic correlation were estimated based on the three-trait model and the restricted maximum likelihood method. Each attribute in each climate was considered as independent attributes. The heritability of fertility traits was higher in cold climate and the age of the first birth and the interval between two births were 0.217 and 0.058, respectively. Also, these traits performed better in cold climates. The genetic correlation for the age of the first birth trait was in the range of 0.857 to 0.897, and for the trait of the interval between two births, it was between 0.487 and 0.859. The estimation of genetic correlation in this research showed that the mutual effects of genotype and environment, especially for the trait of interval between two births, caused different genetic expression of animals in different climates. These results showed that the mutual effects of genotype and environment between different climates can change the performance of male cattle and not considering these effects may cause errors in breeding programs.
کلیدواژهها [English]