Development of selection indexes for a beef cattle production system from available EPDs.

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. Genetic responses obtained from the use of a propose index were compared with simpler indexes. Selection through the proposed index achieved higher genetic progress in the breeding objective and resulted in an increased economic return to the system. The lack of national genetic parameters for some of the most important traits is a limitation and some implications were discussed

Genome-wide association study of residual feed intake in Hereford cattle.

The aim of this study was to detect genomic regions and putative candidate genes associated with RFI in Hereford cattle by single-step GWAS (ssGWAS)

Incorporación de información genómica en la estimación del mérito genético de consumo residual de alimento.

El objetivo de este trabajo es el estudio del efecto de la incorporación de información genómica sobre las predicciones del mérito genético para RFI

Alternative models to predict residual feed intake in Hereford breed and effects on their breeding values accuracy.

ABSTRACT.- Residual feed intake (RFI) is a relevant trait, but expensive to measure so few candidates are phenotyped and have accurate GEBVs. Genetic evaluation corresponds to a single trait evaluation, where RFI are the residual from a lineal regression on feed intake on performance traits during feed-test. This study evaluates two approaches to predict a GEBV for RFI. First combing feed performance traits in a multitrait model to calculate a single measure of RFI using selection index, and 2nd the inclusion of weaning weight (WW) as an indicator trait combined with previous model. The GEBVs for the alternatives proposed were equivalent to conventional RFI. Using WW as a predictor trait on reference animals and candidates could be an inexpensive way to increase the accuracy of GEBVs. It allows to remove possible bias due to preselection of animals that participate on feed test and to extend prediction to more selection candidates

Índice de ciclo completo. Índice de cría: herramientas que mejoran el retorno económico. [cartilla]

Un Índice de Selección resume el mérito genético de un reproductor en un único valor. La mejora genética lograda a través del uso de los índices, maximiza el retorno económico en un sistema de producción definido