Performance of the "quasi-REML" method for estimating correlations between a continuous trait and a categorical trait, and between two categorical traits, was studied with Monte Carlo simulations. Three continuous, correlated traits were simulated for identical populations and three scenarios with either no selection, selection for one moderately heritable trait (Trait 1, h2 = .25), and selecti...

A directed search for QTL affecting carcass traits was carried out in the region of growth differentiation factor 8 (GDF8, also known as myostatin) on ovine chromosome 2 in seven Texel-sired half-sib families totaling 927 progeny. Weights were recorded at birth, weaning, ultrasound scanning, and slaughter. Ultrasonic measures of LM cross-sectional dimensions and s.c. fat above the LM were made,...

We report on a complete genome scan for quantitative trait loci (QTL) affecting milk protein percentage (PP) in the Italian Holstein-Friesian cattle population, applying a selective DNA pooling strategy in a daughter design. Ten Holstein-Friesian sires were chosen, and for each sire, about 200 daughters, each from the high and low tails of estimated breeding value for PP, were used to construct...

The aim of the paper was to analyse congenital disorders in the Czech cattle population in 1986–2001. The offspring of 474 sires – 215 Czech Simmental, 236 Holstein, and 23 beef – were diagnosed with congenital disorders which were unevenly distributed because only 18 occurred in the progeny of 10 and more sires, in contrast to 88 occurring in the progeny of 1 sire only. Umbilical hernia was th...

The objectives of this study were to estimate effects of sire breed (Dorset, Finnsheep, Romanov, Texel, and Montadale), and dam breed (Composite III and Northwestern whiteface) on survival, growth, carcass, and composition traits of F1 lambs. Effects of mating season (August, October, and December) were estimated for survival and growth traits. Data were collected on 4,320 F1 lambs sired by 102...

The objective of this study was to detect QTL associated with the incidence of multiple pathogenic diseases in offspring from half-sib bovine families. Four F(1) sires were used to produce offspring: Brahman x Hereford (BH; n = 547), Piedmontese x Angus (PA; n = 209), Brahman x Angus (n = 176), and Belgian Blue x MARC III (n = 246). Treatment records for bovine respiratory disease, infectious k...

Genotype-by-environment interaction (GxE) has been widely reported in dairy cattle. One way to analyze GxE is to apply reaction norm models. The first derivative of a reaction norm is the environmental sensitivity (ES). In the present study we conducted a large-scale, genome-wide association analysis to identify single-nucleotide polymorphisms (SNPs) that affect general production (GP) and ES o...

Validation of economic indexes under a controlled experimental environment, can aid in their acceptance and use as breeding tools to increase herd profitability. The objective of this study was to compare intake, growth and carcass traits in bull and steer progeny of high and low ranking sires, for genetic merit in an economic index. The Beef Carcass Index (BCI; expressed in euro (€) and based ...

New services that provide pedigree discovery, breed composition, mating programs, genomic inbreeding, fertility defects, and inheritance tracking all are possible from low-cost genotyping in addition to genomic evaluation. Genetic markers let breeders select among sibs before their phenotypes became available, and 50,000 markers combined with larger reference populations greatly increased the r...