introduction lamb production is the largest part of income in sheep industry. therefore, the mortality rate of lambs is a key factor in profit of the sheep breeding. mortality rate of lambs (or lamb mortality rate) in different breeds of sheep under different climatic conditions is varying from 15% to 50% and an average of 9% to 20% has been reported. survival rate is a combination trait that i...

Perinatal calf mortality affects profitability of beef cattle production systems, hence, it would eventually be beneficial to include this trait in a breeding goal. The objectives of this study were to estimate the environmental effects and heritabilities of and genetic correlations among birth weight (BW), calving ease (CE) and calf survival (CS) in Charolais cattle, in the Czech Republic. The...

Sibling interaction effects are suggested by a difference in phenotypic variance between monozygotic (MZ) twins and dizygotic (DZ) twins, and a pattern of twin correlations that is inconsistent with additive genetic influences. Notably, negative sibling interaction will result in MZ correlations which are more than twice as high as DZ correlations, a pattern also seen in the presence of genetic...

one of the problems encountered in ce separations of basic compounds is the adsorption of analytes onto the negatively charged capillary wall which could lead to poor repeatability of migration time and peak area. additionally, separation of enantiomers of chiral of basic drugs is commonly carried out in low ph buffer which contributes to strong ionic interaction of the cationic drug ions with ...

Longitudinal height and weight data from 4649 Dutch twin pairs between birth and 2.5 years of age were analyzed. The data were first summarized into parameters of a polynomial of degree 4 by a mixed-effects procedure. Next, the variation and covariation in the parameters of the growth curve (size at one year of age, growth velocity, deceleration of growth, rate of change in deceleration [i.e., ...

A model with two diallelic loci controlling two additive quantitative characters is suggested. One of the loci has a similar effect on both characters, whereas the second locus has an antagonistic effect on the two characters. Both characters experience direct stabilizing selection. The model yields a stable polymorphic state, with both characters maintaining genetic variation. The genetic corr...

the genetic parameters and (co) variance components of body weight at birth (bw), weaning (ww) and six months of age (bw6) and average daily gain (adg) pre and post-weaning of afshari sheep were estimated using restricted maximum likelihood (reml) methodology and animal model implemented in dfreml software. the likelihood ratio test (lrt) was used to compare the models. year of birth, age of mo...

The objective of the present study was to estimate heritability values for some performance and egg quality traits of native fowl in Isfahan breeding center using REML and Bayesian approaches. The records were about 51521 and 975 for performance and egg quality traits, respectively. At the first step, variance components were estimated for body weight at hatch (BW0), body weight at 8 weeks of a...

Reproductive data were collected on 4,595 cow exposures and subsequent calvings over four generations in a rotational crossbreeding study involving Angus, Brahman, Charolais and Hereford breeds. Direct and maternal additive (Ig and Mg) and nonadditive (Ih and Mh) genetic effects were estimated for calving rate, calf survival, weaning rate, calving assistance and calf birth date. Genetic effects...

in order to study of combining ability and heterosis in cotton (gossypium hirsutum l.), six hopeful genotypes were crossed in a half-diallel scheme at gonbad research station. fifteen f1 hybrids along with six parents were grown in randomized complete block design with 3 replications, in 2004. combining ability estimates were calculated according to method 2, model 1 of griffing (1956a,b). rela...