Estimation of genetic trends is necessary to monitor and evaluate selection programs. The objective of this study was to estimate the genetic trends for milk yield in Iranian Holsteins cows using random regression test day model. Data set was consisted of 743205 test-day records from 1991 to 2008, which were collected by the Animal Breeding Centre of Iran. Breeding, environmental and phenotypic...

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...

e-learning model is examined of three major dimensions. and each dimension has a range of indicators that is effective in optimization and modeling, in many optimization problems in the modeling, target function or constraints may change over time that as a result optimization of these problems can also be changed. if any of these undetermined events be considered in the optimization process, t...

replacement of a tractor is an influential factor affecting timely farm operation. the accurate prediction of repair and maintenance costs is essential to selection of a replacement model. this study used empirical data for 60 two-wheel drive (2wd) tractors from astan ghods-e razavi agroindustry. the types and numbers of tractors used were the massey ferguson 285 (17), fiat (10), john deere 314...

with the growth in customers’ demand diversification, mixed-model u-lines (mmul) have acquired increasing importance in the area of assembly systems. there are generally two different approaches in the literature for balancing such systems. some researchers believe that since the types of models can be very diverse, a balancing approach without simultaneously sequencing of models will not yield...

in this paper a non linear integrated fuzzy multi-objective production planning model with the labor learning and machines deterioration effects is presented. the objective function consists of two quantitative objectives namely increase profits and reduces the cost of system failure and a qualitative objective namely increases the satisfaction rate of the customers. different weights for objec...

using crop simulation models is an efficient complement to experimental research. crop models can also be helpful with respect to decision-making in sustainable farming system. this study was done to estimate genetic coefficients and evaluate performanced dssat in prediction of development, growth and yield in wheat. data from various field experiments for four wheat cultivars koohdasht, shirou...

(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...

genetic parameters for birth weight (bw), weaning weight (ww), 6 months weight (6mw), 9 months weight (9mw) and yearling weight (yw) in baluchi sheep were estimated using data collected during a 26-year period (1984-2010). estimates of (co)variance components were obtained by reml procedures by fitting a linear mixed animal model. significant random effects for each trait were explored by fitti...