ABSTRACT
In the meat-producing livestock species, substantial genetic gains in production (e.g., growth, lean yield, carcass composition, and feed efciency) and reproduction traits (e.g., survival and litter size) continue to be delivered by breeding programs. In further developing these breeding programs in cattle, pigs, and sheep over recent decades, effort has been directed toward gathering the information necessary to also include the genetic improvement of meat quality traits in breeding programs, either to inuence protability or to address emerging consumer preferences for better quality and healthier meat products. As for any meat production trait, the major strategies that can be used for genetic improvement of meat quality traits are (1) selection between breeds, where a genetically superior breed is substituted for another breed; (2) selection within breeds, where genetically superior animals within a breed are chosen to be parents; and (3) crossbreeding, where animals derived from two or more breeds are mated (Simm 1998). Selection between breeds exploits the large additive genetic
9.1 Introduction .................................................................................................. 257 9.2 Impacts of Meat Production Breeding Programs on Meat Quality .............. 258
9.2.1 Relationships between Beef Production and Meat Quality Traits ........ 259 9.2.2 Relationships between Pork Production and Meat Quality Traits .........261 9.2.3 Relationships between Sheep Meat Production and
Meat Quality Traits ........................................................................... 263 9.3 Breeding Strategies for Improvement of Meat Quality ................................ 267
9.3.1 Selection Indexes .............................................................................. 267 9.3.2 Crossbreeding ................................................................................... 270
9.4 Phenotyping of Meat Quality Traits ............................................................. 270 9.5 Live Animal Measurements to Predict Meat Quality .................................. 272
9.5.1 Current Techniques ........................................................................... 272 9.5.1.1 Invasive Methods with Application as
Biochemical Markers ......................................................... 272 9.5.1.2 Noninvasive Physical Methods .......................................... 275
9.5.2 Techniques in Development .............................................................. 276 9.6 Conclusions ................................................................................................... 276 References .............................................................................................................. 277
differences between breeds that may exist in traits that are to be improved and allows the opportunity to have a better performing population as the basis of a ock’s or herd’s breeding program that implements within-breed selection. Variation between breeds has been identied for many meat quality traits of meat-producing livestock breeds, as reviewed for pigs by Ciobanu et al. (2011) and Chapter 12 of this volume; for cattle by Marshall (1999), Burrow et al. (2001), and Chapter 11 of this volume; and for sheep by Thompson and Ball (1997), Bishop and Karamichou (2009), and Chapter 13 of this volume. With breeds continuing to change due to selection and/or as novel breeds come under consideration to form the parental sources for breeding programs, breed comparison studies continue to be undertaken and reported.
