in this study, a total of 101,147 monthly test day records of somatic cell count collected from 13,977 first lactation holstein cows (in 183 herds) calved between 2002 and 2006 were used. for the genetic analysis, a random regression test day model was utilized. somatic cell score (scs) was calculated based on natural logarithm of somatic cell count. in the model, fixed effect of contemporary g...

a number of 5558 lambing records of 2245 mehraban ewes, collected during years 1995 to 2010 were utilized to estimate the variance components and heritability for the number of lambs per lambing,  making use of b-spline random regression models. the fixed factors affecting the studied trait were identified using general linear model analysis as well as sas software, where flock-year-season and ...

A. H. Falkovich, E. R. Graber , G. Schkolnik, Y. Rudich, W. Maenhaut, and P. Artaxo Department of Environmental Sciences, Weizmann Institute, Rehovot 76100, Israel Permanent affiliation: Institute of Soil, Water and Environmental Sciences, The Volcani Center, ARO, Bet Dagan 50250, Israel Department of Analytical Chemistry, Institute for Nuclear Sciences, Ghent University, Proeftuinstraat 86, B-...

Traditional methods of variance component estimation for traits under maternal influence consist of partitioning the variance into direct additive genetic, maternal additive genetic, permanent maternal environmental, and error variance components. This partitioning is based on the assumption that each calf is nurtured and fed exclusively by its own dam. However, under extensive pastoral systems...

Fertility is a discrete trait with two categories (1, successful mating, 0, unsuccessful mating). A Bayesian analysis with a binary threshold animal model has been performed with 18 695 AI mating records from 1987 to 1997, concerning 4085 sows and 187 boars. The pedigree included all individuals genetically linked with data. The binary response was modeled under a probit approach. The model for...

in this study the data of 2332 lambs from 815 dams and 61 sires, collected during 1993-2004 in kermani sheep breeding station were used to estimate phenotypic, genetic and environmental trends for birth weight (bw), weaning weight (ww), 6 months weight (6mw), 9 months weight (9mw) and yearling weight (yw). heritability estimates were determined for each trait using derivative free reml procedur...

objective: the main objective of this research was estimation of genetic parameters for five consecutive measurements of egg weights in isfahan fowl using multi trait model and random regression models. methods: the statistical models included generation-hatch as a fixed effect, weeks of age as a covariate and additive genetic and individual permanent environmental effects as random effects. th...

a total of 2000 records of egg quality of 746 birds and body weight data from 17th generation of fars native fowl breeding station were used to estimate the genetic parameters of egg quality and body weight traits. six univariate animal models with different random effects were fitted for each trait. a model with direct additive genetic and maternal permanent environmental effects was the most ...

Birth and weaning weights adjusted for age of dam from four lines of Hereford cattle were analyzed to determine the relationships among grandmaternal, maternal, and direct genetic effects. Three lines were selected for 1) weaning weight (WWL), 2) yearling weight (YWL), and 3) an index of yearling weight and muscle score (IXL). The fourth line was an unselected control line (CTL). Numbers of obs...

The objective of this study was to evaluate the effect of parentage misidentification on estimation of genetic parameters for the Italian buffalo population for milk yield from 45,194 lactation records of 23,104 Italian buffalo cows. Animals were grouped into 10 data sets in which sires and dams were DNA identified, or reported from the pedigree, or unknown. A derivative-free restricted maximum...