ABSTRACT.- Potential trade-off among weaning (WWT) and yearling weights (YWT), greasy fleece weight (GWT) genetic resistance to gastrointestinal nematodes assessed by faecal worm egg account (FEC), residual feed intake (RFI) and methane (CH4) and carbon dioxide (CO2) emissions were investigated in 217 Corriedale female lambs. Improving RFI was strongly associated with lower dry matter intake (DMI) and independent of metabolic body weight (MWT) and average daily gain (ADG).

ABSTRACT.- Residual feed intake (RFI) and methane (CH4) emissions are potential new selection objectives in beef and sheep breeding programmes to assist reaching greenhouse gas mitigation targets and to support economic, social, and environmental sustainability. Phenotyping platforms in both species are in place in Uruguay, linked with the genetically evaluated populations of main breeds (Hereford, Merino, Corriedale, Dohne and Texel), being the basis of the reference populations for genomic selection. Current progress and main findings are described here.

ABSTRACT.- Residual feed intake (RFI) and methane (CH4) emissions are potential new selection objectives in beef and sheep breeding programmes to assist reaching greenhouse gas mitigation targets and to support economic, social, and environmental sustainability. Phenotyping platforms in both species are in place in Uruguay, linked with the genetically evaluated populations of main breeds (Hereford, Merino, Corriedale, Dohne and Texel), being the basis of the reference populations for genomic selection. Current progress and main findings are described here.

ABSTRACT.- The purpose of the present study was to estimate genetic parameters of growing globally important traits such as feed intake, residual feed intake, methane, carbon dioxide, oxygen consumption and greasy fleece weight in Uruguay. Data of three Australian Merino generations which integrate the Uruguayan National Genetic Evaluation for sheep were recorded (from 2019 to 2021). Heritabilities and genetic and phenotypic correlations were estimated for 930 animals sired by 19 rams.

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.

ABSTRACT.- BLUPF90 is a flexible software suite that estimates variance components, cross-classified and covariate effects, breeding values, accuracies, and SNP effects, among others. It is based on mixed models and focuses mainly on animal breeding and genetics applications. This collection of software is continually under development to incorporate new methods and algorithms, improve efficiency, and broaden usage. A significant change undergoing BLUPF90 is the merge of variance components and breeding values estimation software.

ABSTRACT.- The objective of this study was to estimate variance components and to analyze the possibility of carrying out a genetic evaluation of the longevity trait in animals of the Uruguayan dairy production system of the Holstein breed. Longevity was defined as a binary trait with values of 1 and 0 whether or not the cow survived a lactation, respectively.

ABSTRACT.- National dairy evaluations use mostly multistep methods, where a nongenomic BLUP evaluation is followed by extraction of pseudo-phenotypes, genomic analyses, and merging nongenomic and genomic evaluations. With genomic preselection and many females genotyped, pseudo-phenotypes are biased, and it is hard to accommodate female genotypes fully. Such problems were successfully solved in other species by ssGBLUP, but large biases and expensive computing were experienced in dairy. This paper documents several improvements that made ssGBLUP feasible for national dairy evaluations.