the aim of this study was to estimate the genetic and phonotypic trends of somatic cell score in iranian holstein cows. also, the environmental factors affecting this trait are investigated. a total of 375351 test day records of somatic cells take from 54374 animals between year 2002 and 2007 were used in this study. the breeding values were estimated by fitting animal model in asreml software....

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...

genetic parameters were estimated for somatic cell score (scs) in dairy cattle of iran using test day records. the records of first lactation were extracted from the database of national animal breeding center for cows calved between 2001 and 2010. data included 222923 test-day records, obtained from 29668 animals distributed in 100 different herds. estimates were carried out through gibbs samp...

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 conserve the genetic resources and identify the strong and weak points in sistan watermelon accessions and compare these with improved cultivars of: sugarbaby and fairfax, an experiment was carried out, based on rectangular lattic design of two replications in 2007. the morphological traits studied, included plant length, plant weight, seed weight, fruit number, fruit length, fruit width, su...

The breeding data relating to Hariana herd spread over 18 years (1979-96) were analysed to estimate genetic, phenotypic and environmental changes in characters of economic importance which might have taken place during the several years of selective breeding practiced in the herd. The average genetic changes in a given character were estimated by four methods. The phenotypic trends observed for...