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.

The Rio de la Plata region (Argentina, Uruguay, and southern Brazil) is currently characterized by a mosaic of intensively managed croplands and remaining areas of livestock production on native grasslands. The production of crops and animals in this scenario is usually spatially segregated as a result of mindset and structural constraints developed over decades of agricultural specialization. However, several studies have suggested that crop-livestock integration across various spatio-temporal scales can improve land-use efficiency and ecosystem services provisioning.

ABSTRACT.- Variability of methane (CH4) emission in sheep and impact of selecting low emitting individuals are investigated as part of greenhouse gas mitigation strategies. This study aimed to estimate the correlations between CH4 and different production traits in Australian Merino.

ABSTRACT.- Breeding sheep for low methane (CH4) emissions is an attractive mitigation strategy which implementation requires exploring the impact on other traits. This study aimed to explore these associations by comparing the performance of animals classified by CH4 emission.

Abstract:A series of trials were conducted in different experimental and feeding conditions to evaluate a purified and enriched lignin extracted from Eucalyptus grandis (LIPE®) as a marker to estimate faecal output in sheep fed temperate and tropical grasses.