Genetic factors affecting fertility, growth, health and longevity in dairy cattle

Description

Inclusion of secondary or ‘functional’ traits in breeding objectives began in earnest only in the late 1990. By 2009, production traits accounted for less than 50% of the indices in most advanced countries. Breeding for fertility, health traits and herd life (HL) was hindered due to difficulty of measurement and analysis and generally low heritability. Statistical methods have been developed that overcome these problems. The advantages and limitations of breeding for disease traits and HL via selection on correlated traits and via cross-breeding are discussed. Methodologies for detection and analysis of the actual segregating genes that affect functional traits are presented.

Table of contents

1 Introduction
2 Important principles of multi-trait selection index
3 Statistical methods for the genetic analysis of non-production traits
4 Non-production traits and selection strategies: fertility
5 Non-production traits and selection strategies: health
6 Non-production traits and selection strategies: growth rate and longevity
7 Alternative methods to genetically improve functional traits
8 Mapping and identifi cation of quantitative trait loci (QTL) affecting functional traits
9 Summary
10 Future trends in research
11 Where to look for further information
12 Acknowledgements
13 References