15  Swine Breeding

15.1 Overview

This chapter provides a comprehensive overview of commercial swine breeding programs, traits, and industry structure.

15.2 Learning Objectives

By the end of this chapter, you should be able to:

  1. Describe the three-tier swine breeding structure
  2. Explain the distinction between terminal and maternal breeding objectives
  3. Identify key traits and their genetic parameters in swine
  4. Design a crossbreeding program for commercial swine production
  5. Understand the role of genomic selection in modern swine breeding

15.3 Global Swine Industry Structure

Chapter Status

This chapter is currently under development. Content will cover:

  • Major breeding companies (Genus/PIC, Topigs Norsvin, Genesus, etc.)
  • Three-tier breeding pyramid (nucleus, multiplier, commercial)
  • Pure lines vs. crossbreds
  • Global genetics flow and regional adaptation

15.4 Key Traits and Heritabilities

15.4.1 Maternal Traits

  • Litter size (TNB, NBA, NW): h² = 0.10-0.15
  • Piglet survival
  • Weaning weight
  • Maternal ability

15.4.2 Growth Traits

  • Average daily gain (ADG): h² = 0.30-0.50
  • Backfat depth: h² = 0.30-0.50
  • Loin depth: h² = 0.30-0.50
  • Feed efficiency (RFI): h² = 0.30-0.50

15.4.3 Meat Quality

  • pH: h² = 0.20-0.40
  • Color: h² = 0.20-0.40
  • Marbling: h² = 0.20-0.40
  • Drip loss: h² = 0.20-0.40

15.5 Crossbreeding Systems

Content to be developed covering:

  • Terminal sire lines (Duroc, Pietrain, synthetic lines)
  • Maternal lines (Large White, Landrace)
  • F₁ females in commercial production
  • Rotational systems for maintaining heterosis

15.6 Selection Indices

Content to be developed covering:

  • Terminal sire index
  • Maternal index
  • Economic weights and derivation

15.7 Genomic Selection in Swine

Content to be developed covering:

  • Implementation timeline
  • Genomic tools (PorcineSNP60, GeneSeek GGP-Porcine)
  • Impact on accuracy and generation interval

15.8 Summary

This chapter introduced the commercial swine breeding industry, emphasizing the distinction between terminal and maternal breeding objectives and the role of genomic selection in modern swine improvement.

15.9 Key Points

  • Swine breeding is highly structured with distinct maternal and terminal lines
  • Crossbreeding exploits heterosis for reproductive traits
  • Genomic selection has accelerated genetic progress
  • Economic weights differ dramatically between maternal and terminal objectives