introduction productive traits such as milk production and fat and protein percentage have economic importance in the livestock industry. accurate prediction of breeding value of animals is one of the best tools available for maximizing response to selection program. it is a fact that the main objective of the breeding program, is to achieve the maximum economic benefit. for breeders of dairy c...

the fixed regression test-day model (frm) and random regression test-day model (rrm) for genetic evaluation of milk yield trait of dairy cattle in khorasan razavi province were studied. breeding values and genetic parameters of milk yield trait from two models were compared. a total of 164391 monthly test day milk records (three times milking per day) obtained from 19217 holstein cows distribut...

osteopontin gene is located at the end of chromosome 6 in cattle and it is one of the most important genes influence on milk protein percentage and reproduction. in this study, blood samples were collected from100 brown swiss cows and dna was extracted from whole blood by modified salting out procedure. cows were genotyped for single nucleotide polymorphism of intron iv by pcr-rflp and bsri res...

to estimate the genetic parameters for production and reproduction traits in holstein cows, information from 15 herds recorded by animal breeding center of iran during 1980 – 2004, were employed. estimations were made using restricted maximum likelihood method under an animal model ranging df-reml and matvec software. estimates of heritabilities for yield traits were moderate and ranged from 0....

specific trait candidate genes are sequenced genes with known biological activity. the effects of pou1f1 and stat5a on milk production traits have been studied in several studies. pou1f1 affects on transcription of prolactin and growth hormone gene, as well as, stat5a is known as a main mediator of growth hormone action on target genes and intracellular mediator of prolactin signaling. since th...

the objective of this study was to estimate genetic parameters coupled with genetic and phonotypic trends for age at first calving (afc), open days(od) and milk yield(my) of first lactation in iranian holstein cows. records of reproduction and production for genetic evaluation from 1984 to 2005 for afc, od and my were 71736, 20126 and 20126, respectively. single and two-variable animal models w...

abstract             (co) variance components of milk, fat and protein yield of 11368 first lactation iranian holstein dairy cow were estimated by single trait random regression test-day models and restricted maximum likelihood (reml) method. in this study the homogeneous residual variance was assumed throughout lactation. estimated heritability for 305-day production traits ranged from 0.25 to...

Selection for breeding animals as parents of next generation, based on genetic analyses of most important traits, became a standard for selection practices in most of the farm animal species in Slovakia. In this respect, about ten years of experience could be traced in Slovakian dairy cattle (Candrák et al., 1997) and pigs (Groeneveld and Peškovičová, 1999 and Peškovičová et. al., 1999). First ...

the objective of the present study was to estimate genetic parameters and genetic trends of growth traits , fleece weight and reproductive traits. data collected from 1993 to 2007 by the kermani breeding station were analyzed .traits were included birth weight (bw, n=2614), 3 months weight (3mw,n=2312), 6 months weight (6mw, n=1890), 9 months weight (9mw,n=1380) and 12 months weight (12mw,n=105...

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...