ABSTRACT. Three different procedures were implemented to calculate weights for a genomic relationship matrix to restrict the shrinkage along iterations of weighted single-step genomic BLUP (WssGBLUP). The procedures as well as BayesC were tested with 3 simulated data sets. Prediction accuracy for WssGBLUP improved at 2nd or 3rd iteration by updating only the top number of SNP equal to 1 × or 3 × the number of QTL; accuracy increased after 3rd iteration and remained stable by using weights proportional to 2pi(1- pi)ui2+ constant.

ABSTRACT. Three different procedures were implemented to calculate weights for a genomic relationship matrix to restrict the shrinkage along iterations of weighted single-step genomic BLUP (WssGBLUP). The procedures as well as BayesC were tested with 3 simulated data sets. Prediction accuracy for WssGBLUP improved at 2nd or 3rd iteration by updating only the top number of SNP equal to 1 × or 3 × the number of QTL; accuracy increased after 3rd iteration and remained stable by using weights proportional to 2pi(1- pi)ui2+ constant.

ABSTRACT. The objective of this study was to evaluate the advantage of the YAMS package over the FSPAK package in average-information (AI) REML for single-step GBLUP models. Data sets from broiler and Holsteins were used in this study. (Co)variance components were estimated with the AIREMLF90 program which could switch YAMS and FSPAK for sparse operations. The YAMS package used the BLAS and LAPACK libraries using all the 16 cores on CPU.

ABSTRACT. The objective of this study was to compare a conventional genomic model (GBLUP) and its extension to a linear reaction norm model (GLRNM) specifying genotype by environment interaction (G*E) for tick resistance in Brazilian cattle. Tick counts (TC) from 4,363 Hereford and Braford cattle from 146 contemporary groups (CG) were available of which 3,591 animals had BovineSNP50 Illumina v2 BeadChip genotypes. The reaction norm covariate was based on CG estimates of TC from a first-step model. Analysis was conducted based on adapting the single step GBLUP/REML procedure.

ABSTRACT. Genetic parameters for weaning weight (WW) and cow weight (CW) at different age, were estimated through a multiple trait model for the Hereford in Uruguay. Posterior mean marginal estimates were obtained using Bayesian inference with the GIBBSF90 program. WW heritability was 0.13±0.03 using a dataset of 17875. Estimated heritabilities for CW1 through CW5 were 0.39±0.07, 0.48±0.04, 0.68±0.05, 0.59±0.06 and 0.47±0.08. Genetic correlation between CW1 and CW2, CW2 and CW3, CW3 and CW4, CW4 and CW5 were 0.93±0.06, 0.69±0.09, 0.90±0.04, and 0.90±0.05 respectively.

ABSTRACT. This work aimed to determine the accuracy and bias of genomic predictions of Braford (BO) and Hereford (HH) cattle genetic resistance to ticks. Repeated 10,673 tick counts were obtained from 3,435 BO and 928 HH cattle from Delta G Connection breeding program. A subset of 2,803 BO and 652 HH samples were genotyped and 41,045 markers remained after quality control. Log transformed records were adjusted by a pedigree repeatability model to estimate breeding values (EBV), subsequently used to obtained deregressed EBV.

ABSTRACT. Datasets of US and Israeli Holsteins were used to evaluate the impact of older generations on ability to predict EBV of young genotyped animals in traditional and single-step genomic BLUP. Inclusion of two (A2) or all (Af) ancestor generations was also evaluated. A total of 34,506 US and 1,305 Israeli bulls were genotyped. Thresholds for data deletion were based on 5 years interval. The number of generations deleted without reduction in accuracy depended on data structure and trait.

ABSTRACT. Our objective was to conduct a genome-wide association study on cow mortality and 305-d milk yield for three lactations and determine if there were differences in the genetic architecture in three US regions. Genomic EBV of mortality and milk yield were estimated with a single-step genomic BLUP using a threshold-linear model. Genomic information was included on 34,506 bulls. Data consisted of the entire US data and three regions SE:southeast, SW:southwest, and NE:northeast for first three lactation cows calving from 1999 to 2008.

ABSTRACT. Single Step methods combine pedigree relationships and marker genotypes in a single conceptual and streamlined framework based on extending animal model BLUP to include marker genotypes. The extension can be done because genotypes at markers follow covariances described by the pedigree. This results in a relationship matrix that combines pedigree and markers, called H. Fitting H-1 in Henderson?s Mixed Model Equations gives the Single Step Genomic BLUP, which is a single estimator of breeding values that includes all available information.

The objective of this study was to obtain an heritability estimate of uIMF fat to determine feasibility of a future genetic evaluation for uIMF in Aberdeen Angus cattle in Uruguay. The second objective of this study was to estimate genetic parameters for the three ultrasound measurements in 18-months old Angus cattle.