Basic Principles of Animal Breeding

Basic Principles of Animal Breeding

• Animal breeding is the process of selecting and mating animals to produce offspring with specific traits.
• Key principles include understanding genetics and using selection methods.
• Breeders aim to improve traits like growth rate, milk production, and disease resistance.

Course Objectives

• Understand the basic principles of animal breeding.
• Learn about selection methods, the history of animal breeding and basic terminologies.
• Familiarize yourself with breeding systems for farm animals.

Flow of Discussion

• Overview of animal breeding
• Trends in animal breeding
• History of animal breeding
• Animal breeding terminology
• Methods of selection
• Systems of breeding

Overview

• Animal breeding involves selecting and mating animals to achieve desired traits in their offspring.
• Understanding genetics, how traits are passed down, is crucial.
• Selection methods are used to choose the best animals based on visible characteristics.

History of Animal Breeding

• Animal survival and reproduction are influenced by factors like climate, season, nutrition, and disease.
• Natural and artificial selection play a role in the concept of survival.
• Animal breeding is the application of genetic principles to identify the best breeding pairs.
• Early animal breeding was largely focused on environmental factors but has evolved to incorporate genetic information.
• Charles Darwin's work emphasized environmental influence on selection trends.
• Modern breeding uses quantitative genetics and genetic information to improve animal performance (Jay Lush).
• Modern selection methods include sensory evaluation and chemical composition analysis of meat quality, in addition to standard traits.
• Statistical techniques like BLUP (Best Linear Unbiased Prediction) are used to evaluate breeding values.

Definition of Terms

• Animal breeding aims to reproduce high-producing animals, and eliminate those with physical abnormalities.
• A breed is a group of animals within a species with uniform physical characteristics (coat color, presence of horns, body conformation, etc), sharing a similar ancestry.
• Breeds are often grouped based on their use. (meat, egg, dairy, sport, dual purpose)

Heritability Estimates

• To achieve breeding goals, the traits of interest must be heritable.
• Heritability estimates the degree of resemblance between parents and their offspring.
• Estimates range from 0-1, with 0 implying traits are lowly heritable and 1 implying traits are highly heritable.

Selection for Quantitative Traits

• Phenotypic traits can be qualitative (description of physical characteristics) or quantitative (measurable characteristics like weight and height).
• Quantitative traits are economically important traits.
• Selection is the process of choosing animals as breeders to produce the next generation of desirable animals.

Methods of Selection

• Tandem Method: focuses improvement on one trait at a time.
• Independent Culling Method: Evaluates potential breeders on a set of criteria and culls those that fail to meet one or more criteria.
• Selection Index Method: Considers all traits and gives each a merit score, based on evaluating their importance for desirable traits in animal offspring.

Systems of Breeding

• Purebreeding: Crossing pure-bred animals of the same breed that are not closely related.
• Crossbreeding: Involves mating animals from two different breeds to achieve desirable traits in offspring (Two-way cross, three-way cross, four-way cross)
• Inbreeding: Mating closely related animals to increase homozygosity
• Linebreeding: Mating distantly related animals
• Upgrading: Gradually improving the quality of animals by mating with a superior breed (e.g., using purebred animals to improve non-purebred animals to a standard)

Explore the fundamental concepts of animal breeding, including genetics, selection methods, and breeding systems. This quiz will help you understand how traits are improved in farm animals through careful selection and mating practices.