variace / covariance components of 227118 first lactaiom test-day milk yield records belonged to 31258 iranian holstein cows were estimated using nine random regression models. afterwards, different measures of persistency based on estimation breeding value were evaluated. three functions were used to adjust fixed lactation curve: ali and schaeffer (as), quadratic (le3) and cubic (le4) order of...

introduction genetic evaluation and estimation of breeding value are one of the most fundamental elements of breeding programmes for genetic improvement. recently, genomic selection has become an efficient method to approach this aim. the accuracy of estimated genomic breeding value is the most important factor in genomic selection. different studies have been performed addressing the factors a...

in order to study on the effect of incomplete sire's pedigree on the prediction of breeding value and estimation of genetic trend, two quantitative traits such as weaning weight and average daily gain with heritabilities 0.15 and 0.30 were simulated. phenotypic, genetic and environmental correlations were assumed 0.5. resulted data files with different proportion of missed sire pedigree (0...