تحلیل بیزی فراسنجه‌های ژنتیکی صفات جفت‌ماندگی و سخت‌زایی در گاوداری فکا

The aim of this study was to estimate genetic components and parameters of retained placenta and dystocia traits in FOKA dairy farm. The non-genetic factors affecting these traits were evaluated using logistic regression implemented in GENMOD procedure of SAS 9.1 software. In order to do genetic evaluations, 5 Bayesian threshold models of repeat records and a Bayesian bivariate model were used. The genetic model parameters were obtained using Bayesian and Gibbs sampling method implemented in THRGIBBS1F90B software. The results shown effects that the season and year of birth were significant on the retained placenta; however, only effect of the birth year was significant for the dystocia. For both traits, the best fitted model was selected using DIC measure. Direct heritability, maternal genetic effect, maternal permanent environmental effect and repeatability estimates for retained placenta using best fitted model on repeated records were obtained as 0.15(0.002), 0.03(0.007), 0.14(0.01) and 0.29(0.02), respectively. In multivariate analysis, these parameters were estimated as 0.005(0.003), 0.001(0.030), 0.002(0.001) and 0.008(0.002) respectively. These parameters for dystocia trait using best fitted model over repeated records were as 0.03(0.001), 0.02(0.002), 0.27(0.003) and 0.30(0.01), respectively. In multivariate analysis, aforementioned parameters were estimated as 0.003(0.01), 0.005(0.002), 0.004(0.001) and 0.007(0.002), respectively. The results of this research showed that, considering the economic importance of these two traits on the profitability of FOKA dairy farm, and on the other hand, estimated a low direct, maternal heritability and different correlations i.e. direct genetic (0.41), maternal genetics (0.18), phenotypic (0.55), environmental (0.58) permanent environment (0.81), much attention should be paid on management of environmental factors affecting these traits. In this regards, it is not expected that manipulating of direct and maternal genetic would be crucial on aforementioned traits.