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...

the purpose of this study was to describe the association between grain yield and its components. the experiment was conducted in a randomized complete block design with three replicatsions. results of analysis showed that similar trends were observed for genotypic and phenotypic correlations and in most cases, the value for genetic correlation was greater than phenotypic value. 100-seed weight...

influence of maternal and sire-generation interaction effects on day-old chick' weight was investigated in two commercial broiler sire and dam lines, and in mazandaran native fowls. the data were analysed through restricted maximum likelihood (reml) procedures, using asreml software. ten different animal models were implemented and compared with likelihood ratio test. all models consisted ...

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...