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...

the objective followed in this study was to compare six software packages (dfreml, wombat, asreml, matvec, dmu and thrgibbsf90) as based on some such features as being user friendly, easing computational facilities as well as accuracy and precision of the estimated genetic vs. environmental parameters. for conduction of the study, simulated and field data (birth weights and weaning weight of ba...

the data of this study were collected by indigenous chicken breeding centers in the west azerbaijan for 11 generations. the (co) variance components, heritability's, correlations between traits and breeding values were estimated by multi-trait animal model using wombat software. the genetic trends of traits over 11 generations of selection, using average function of breeding values per gen...

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...

to estimate heritability and genetic trend for 305-d milk production and lactation persistency, a total of 130,668 monthly test day milk yields belonging to 15,183 first lactation holstein cows in 131 herds and calved from 2000 to 2009 were used. to calculate 305-d milk yield as well as lactation persistency, estimated parameters of wilmink’s exponential function were applied. the parameters of...

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...

introduction milk solid no-fat is economically very important in cheese industry. compared to the other kinds of milk, ewe’s milk contains higher amount of milk solids no-fat. milk solids no-fat (msnf) contains lactose, caseins, whey proteins, and minerals. the use of test day records in random regression method has several benefits including flexibility to account for the environmental and gen...

data related to holstein dairy cattle from 1987 to 2004 were obtained from animal breeding center of iran to estimate the genetic and phenotypic trends. variance components and genetic parameters of the first lactation records were estimated using restricted maximum likelihood method and aireml algorithm through matvec program. animal breeding values were predicted through multiple-trait animal...

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...