genetic trend for production traits were estimated in iranian holstein cattle using the first lactation data recorded by cattle breeding and dairy product improvement center of the state from 1991 to 2006. effect of some factors on genetic trend was investigated using data from 18 large herds. (co) variance components and genetic parameters were estimated, using five trait animal model and em-a...

Records from the El-Serw research station belonging to Animal Production Research Institute were used to estimate the genetic parameters for the economically most important milk and growth traits in the Zaraibi goat breed. There were 99 and 110 half-sib families over the periods 1995-2003 and 1990-2003 for milk and growth traits, respectively. Milk traits were, milk yield during the first 90 da...

The objective of this study was to compare test-day (TD) models with autoregressive covariance structures for the estimation of genetic and environmental components of variance for milk, fat and protein yields, and somatic cell score (SCS) in Holstein cows. Four models were compared: model I (CS model) was a simple TD repeatability animal model with compound symmetry covariance structure for en...

introduction kurdish sheep breed is one of the most important native breeds of iran. they are fat-tailed, large-sized, well adapted to the mountainous regions in northern khorasan province and mainly raising for meat production under pastoral production system (28). feed efficiency is a major component in the profitability of the small ruminant enterprise, because quality of range and pasture i...

Genetic parameters for birth weight (BW), weaning weight (WW), 6 months weight (6MW), 9 months weight (9MW) and yearling weight (YW) in Baluchi sheep were estimated using data collected during a 26-year period (1984-2010). Estimates of (co)variance components were obtained by REML procedures by fitting a linear mixed animal model. Significant random effects for each trait were explored by fitti...

OBJECTIVE This study estimated the genetic parameters for productive and reproductive traits. METHODS The data included production and reproduction records of animals that have calved between 1979 and 2013. The genetic parameters were estimated using multivariate mixed models (DMU) package, fitting univariate and multivariate mixed models with average information restricted maximum likelihood...

introduction: lactation yield and persistency are two economic important traits in dairy cow. the production level of a dairy cow is determined by a joint effect of genetic and environmental factors.the main factors determining the total amount of milk production are milk yield at the peak of lactation and persistency as well as length of lactation period. persistency are defined as a extent to...

objective: estimation of genetic parameters for kleiber ratio (kr) and genetic trends for pre-weaning weights of arabi sheep has not been previously conducted.methods: data and pedigree information were collected at the khuzestan ramin agricultural and natural resources university, animal science research station, located in southwest iran, from 2001 to 2008. (co)variance components and corresp...

Dairy cattle breeding programs have been based in the selection for traits related to milk production. In this research a data set of 63 herds of East Azerbaijan province Holstein cattle, collected during 2002-2013 by the Iranian Animal Breeding Center was used to estimate the repeatability and heritability of three traits of economic importance. Genetic parameters for first three lactations of...