in order to estimate the genetic parameters and comparison legendre polynomials for production traits of iranian holstein dairy cattle test-day records of first lactation cows for milk yield, fat yield, protein yield, fat percentage and protein percentage traits were used. these records collected from 2006 to 2010, by the animal breeding center of iran. the genetic parameters were estimated usi...

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...

maternal effects on body weight at 8 weeks of age (bw8w), egg weight (ew), egg number (en) and age at sexual maturity (asm) from 13 generations of mazandaran native fowl were investigated. the data were analyzed using restricted maximum likelihood procedures and animal model with dfreml software. with or without using maternal effects, six different animal models were fitted. likelihood ratio t...

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...

in this study, a total of 101,147 monthly test day records of somatic cell count collected from 13,977 first lactation holstein cows (in 183 herds) calved between 2002 and 2006 were used. for the genetic analysis, a random regression test day model was utilized. somatic cell score (scs) was calculated based on natural logarithm of somatic cell count. in the model, fixed effect of contemporary g...

The Cochran-Armitage trend test is a standard procedure in genetic association studies. It is a directed test with high power to detect genetic effects that follow the gene-dosage model. In this paper, the author proposes optimal trend tests for genetic association studies of heterogeneous diseases. Monte-Carlo simulations show that the power gain of the optimal trend tests over the conventiona...

Genetic trends for weaning weight were evaluated in 15 purebred herds in the United States participating in the Angus Herd Improvement. Records production testing program. Regression techniques were used for separate estimates of sire and dam contributions that were summed to estimate total herd trend. Sire contributions, calculated as the pooled within sire regression of weaning weight ratio o...