In a stochastic simulation study the effect of simultaneously changing the model for prediction of breeding values and changing the breeding goal was studied. A population of 100 000 cows with registrations on seven traits was simulated in two steps. In the first step of 15 years the population was selected for production and mastitis occurrence using a univariate model for prediction of breedi...

in this study, the number of 1802 longevity records of ewes collected during 1989 to 2010 in breeding station of lori-bakhtiari sheep flocks were used to estimate of genetic, environmental and phenotypic trends for economic lifetime. the breeding values of a ewe’s lifetime were estimated by restricted maximum likelihood procedure under an animal model of univariate analysis. the best linear unb...

The artificial neural networks, the learning algorithms and mathematical models mimicking the information processing ability of human brain can be used non-linear and complex data. The aim of this study was to predict the breeding values for milk production trait in Iranian Holstein cows applying artificial neural networks. Data on 35167 Iranian Holstein cows recorded between 1998 to 2009 were ...

Our initial RNA sequencing (RNA-seq) revealed that the Serum amyloid A1 (SAA1) gene was differentially expressed in the mammary glands of lactating Holstein cows with extremely high versus low phenotypic values of milk protein and fat percentage. To further validate the genetic effect and potential molecular mechanisms of SAA1 gene involved in regulating milk production traits in dairy cattle, ...

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...

Inheritance of economic traits was studied in Nili-Ravi dairy buffaloes through analysis of data comprising 5037 records of daughters of 79 sires. Data were collected from three large-sized state dairy farms. Heritability, genetic and phenotypic correlations of some indicator traits on important production and reproduction traits were worked out. Based upon analysis of records for first lactati...

KULIG, H., K. ŻUKOWSKI, I. KOWALEWSKA-ŁUCZAK and P. ŁAKOMY, 2016. SCD1 polymorphism and breeding value for milk production traits in cows. Bulg. J. Agric. Sci., 22: 131–134 The aim of this study was to estimate the associations between the g.10153G>A polymorphism and the breeding values for milk production traits (milk, fat and protein yield, fat and protein content) in Polish Holstein-Friesian...

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...

the genetic parameters for milk production and milk fat traits for first to third parities were estimated using single, multi trait and repeatability models. the genetic parameters for test day milk records were also estimated using random regression model. the test day records and 305 day milk records of 17055 cows from 10 herds collected between years 1996-2007 in khorasan razavi province wer...