collected data in animal breeding center of iran from 1983 to 2003 was used to estimate the genetic parameters of milk yield in iranian holstein cattle. genetic parameters were estimated, using single and three trait animal models. records of three lactations were divided into thre esub groups according to average milk yield, climitical regions and herd sizes. all variance components in the thr...

in order to evaluation of genotype by environment interactions in holstein cows, iran was divided into cold, middle cold, temperate and hot climate regions. for this purpose used from 39570, 35813 and 18955 records for milk, fat and protein yields, respectively, to progeny test for 35 sires that have 50 daughters in each climate. the data were collected by the centre of breeding and improvement...

The objective of this study was to estimates the genetic and environmental components for the lactation curve parameters, milk yield, age at first calving (AFC), calving interval (CI) and somatic cell count (SCC) in Iranian Holstein cows. The dataset consisted of 210625 test day records from 25883 cows with milk yield in the first parity recorded from July 2002 to September 2007 in a total of 9...

Milk yield records from 1st to 5th lactations of Iranian Holstein cows were analyzed using repeatability and a number of multivariate models that varied in additive genetic variance structure. A total of313,006 milk yield records were used. The records were obtained from 116,531 cows born between 2001 and 2005. The animals originated from 2,355 sires and 91,212 dams. A multivariate model with h...

to study the effects of environmental factors on milk and fat yields (240day) traits of iranian buffaloes, 22596 and 22165 records were utilized for milk and fat yield traits, respectively. uni and bivariate analysis for estimation of (co)variation components of the traits were done in five lactations. milk yield in the 1st lactation had the highest number of records (4482), collected through c...

The aim of the present study was to estimate genetic and phenotypic parameters of milk production traits in the first and second lactations of Romanian Simmental dairy cattle. For the estimation of variance, heritability, genetic and phenotypic correlations among milk yield, fat yield, protein yield, and percentages of fat and protein, 3400 first and second lactation records over a period of fi...