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.

ABSTRACT. Pedigree information is required to estimate breeding values accurately and to ensure high rates of genetic gain. DNA markers information can be used as an alternative to traditional recording of pedigree, being SNPs the markers of choice for parentage verification.

ABSTRACT.. Heat stress reduces milk production, depresses fertility and increases the incidence of health disorders in dairy cows. Our first goal was to estimate genetic components of milk yield (MY) and somatic cell score (SCS) across lactations considering heat stress. Our second goal was to reveal genes responsible for thermotolerance. Data included 254k MY and 356k SCR test-day records of 20k Holstein cows. Multi-trait repeatability test-day models with random regressions on THI values were used to estimate variance components.

ABSTRACT. Due to the complexity of selection in beef cattle where numerous traits are involved, identification of breeding objectives and developing a selection index to improve a global goal is required. A selection index was developed to maximize genetic gain for a beef cattle operation system. Breeding objective includes calving rate, carcass weight, calving ease, feed intake, direct and maternal weaning weight. Indexes were constructed from traits which EPDs are available so it can be implement to make comparisons between animals with different genetic merit.

ABSTRACT. This study aimed to compare results of genome-wide associations obtained from various methodologies for GWAS when applied to two lines of broiler chicken. Each line contained >250k birds with 3 traits and 5k SNP60k genotypes. Methods included single-step GWAS, single marker model and BayesB. Mannhattan plots were based on variances of 20-SNP segments, as shorter segments produced noisy plots. Only a few segments explained >1 % of the additive variance.

ABSTRACT. With the increasing availability of marker information in livestock, genomic selection methods can allow breeders to preselect animals on genotypes early in life. The combination of pedigree, phenotypic and genotypic data will increase genetic progress by decreasing the generational interval and increasing the accuracy of genetic merit estimates.

The objective of this study was to apply the SSP for genomic evaluation in broiler chickens to determine if accuracy of prediction could be enhanced using phenotypic data from pedigreed animals to augment information obtained on animals genotyped (FULL).

The objective of this study was to apply the SSP for genomic evaluation in broiler chickens to determine if accuracy of prediction could be enhanced using phenotypic data from pedigreed animals to augment information obtained on animals genotyped (FULL).