ABSTRACT.- This study aimed to estimate variance components (VCs) for growth and reproductive traits in Nellore cattle using two relationship matrices (pedigree relationship A matrix and pedigree plus genomic relationship H matrix), and records collected before and after genomic selection (GS) implementation. The study also evaluated how genomic breeding values (GEBV) are affected by variance components and discarding old records. The analysed traits were weight at 120 days (W120), weight and scrotal circumference at 450 days (W450 and SC450, respectively).

ABSTRACT.- Animal nutrition plays a key role in the productivity and economic impact of animal production systems. Its interactions with genetics, health and animal management are crucial to understanding the complexity of the factors involved and thepotential responses to be obtained. The production of natural fibres is not an exception to this complex phenomenon that occurs in different regions of the world, particularly in those mainly oriented towards wool production. @CABI Digital Library, 2023.

Llos servicios ecosistémicos son esenciales para el desarrollo de una ganadería sostenible, donde el aprovechamiento y promoción de estos servicios no solo mejora la salud y productividad de las recursos naturales, sino que también contribuye a la sostenibilidad ambiental, económica y social de los productores y su entorno territorial y de los servicios conexos asociados a los diferentes actores incorporados en la producción, industrialización, transporte, servicios de apoyo, agronegocio, exportación, alimentación, etc.

ABSTRACT.- Runs of Homozygosity (ROH) are continuous homozygous segments in an individual's genome, typically resulting from inbreeding or population bottlenecks (Ceballos et al., 2018).

ABSTRACT.- Throughout their domestication, sheep have adapted to environmental heterogeneity, from the tropics to the highlands. Climate and human selection have shaped the genome and left genetic 'fingerprints' on breeds bred in diverse regions worldwide. The small ruminants have evolved to be highly efficient and provide
a valuable model for identifying the genetic pathways and mechanisms underlying adaptation.

INTRODUCTION: In livestock, the advancement of genotyping technology has introduced new methods for assessing inbreeding based on single nucleotide polymorphism. Homozygosity runs (ROH) provide a more accurate method for estimating past and recent inbreeding rates at the individual/population level compared to traditional pedigree-based estimations or in the absence of pedigree records. Furthermore, ROH metrics can be used for the identification of regions under strong selection and
provide insights into evolutionary trends over time.

Introduction: Flight distance (FD) is a temperament test associate to lying time of dairy cows in early lactation and under a conventional millking system. Objective: To determine the relationship between FD test of Holstein cows in late lactation and grazing behavior under conventional milking system.

Los parásitos gastrointestinales (PGI) han sido y continúan siendo una de las principales causas de pérdidas productivas y económicas en los sistemas productores de ovinos a nivel mundial. Debido a la grave situación que ha alcanzado la resistencia a los antihelmínticos, al cambio climático y cambio en los sistemas de producción, se ha vuelto muy difícil el control de H. contortus y de otros PGI. Por ello, el método Famacha© es una herramienta que amerita mayor exploración e implementación a
nivel de majadas comerciales, sobre todo en los planes integrados de control parasitario.