The main objective of this study was to estimate the genetic parameters for multi-trait evaluation of birth weight (BW), gestation length (GL) and calving difficulty (CD) in first-parity Iranian Holstein dairy cattle. The data included 29,950 calving records collected during 1995 to 2014 by the Animal Breeding and Improvement Center of Iran. A threshold-linear sire-maternal grandsire model was ...

in this research in order to estimate genetic parameters for milk yield at different milking times for holstein cows of razavi khorasan, a total of 180,462 monthly test day records belonging to first lactation cows calved from 2000 to 2009 were utilized. the records were analysed by a random regression test day model. in the model, the fixed effects of contemporary group of geographical locatio...

(Co)variance components and genetic parameters for test day ewe body weight of Lori-Bakhtiari sheep were estimated using a random regression model (RRM). The data consisted of 22153 individual body weight records, obtained from 1994 ewes (progeny of 205 sires and 1010 dams) between 371 and 3416 days of age, collected from the flock stud of Lori-Bakhtiari Sheep Breeding Station in Shahrekord, Ir...

in order to providing selection indices using heritability and correlation effective traits on yield and multiple regression an experiment was conducted by 265 f3 families as well as parents and f1 related to gharib × khazar population in 2009 at gonbad high education center fields. days to repining (0.97) and panicle number and flag leaf length (0.66) had maximum and minimum heritability, resp...

genetic analysis of growth traits including body weight recorded at birth (bwt), 3 (3bwt), 6 (6bwt), 9 (9bwt) and 12 (12bwt) months of age was carried out using 4107 records on raieni cashmere goats born from 206 sires and 1402 dams, during years 1992 to 2006. the records were collected from a resource flock in baft research station, situated in kerman province, iran. the importance of addition...

in this research, 6517 records, collected by khojir sheep breeding station (tehran, iran), during 1991 to 2011 were used to estimate genetic parameters of lamb survival in zandi sheep. genetic parameters were estimated using 16 different models of animal model, sire and threshold models using reml procedures. the aic criterion was used to evaluate the models. the effects in the most suitable an...