Livestock species. Livestock production: meat and milk production. Reproductive efficiency. Elements of production systems. Elements of quantitative genetics. The traits objective of selection in livestock. Study of monogenic traits and polygenic traits. Single locus model. Infinitesimal model. Heritability, repeatability and genetic correlation. Resemblance between individuals. Elements of Basic Statistics. Linear regression. Crossbreed. Purebred Selection. Breeding scheme. coordination of selection in Italy. Assessment of genetic merit of individuals: breeding values. Example of biotechnology applied to animal breeding.