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Animal Breeding Systems. Chapter 12. Objectives. Name and explain common breeding systems used in livestock production Explain the effects, advantages, and disadvantages of using various breeding systems. Objectives (cont.). Identify the factors involved in selecting a breeding system
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Animal Breeding Systems Chapter 12
Objectives • Name and explain common breeding systems used in livestock production • Explain the effects, advantages, and disadvantages of using various breeding systems
Objectives (cont.) • Identify the factors involved in selecting a breeding system • Calculate the percentage of parental stock in offspring, using various breeding systems
Systems of Breeding • Two basic systems of breeding in livestock production • Straightbreeding: mating animals of the same breed • Crossbreeding: mating animals of different breeds
Systems of Breeding (cont.) • Purebred Breeding • Possess characteristics of particular breed to which animal belongs • Eligible for registry if no disqualifications • Tends to be genetically homozygous • Provides foundation stock for crossbreeding
Systems of Breeding (cont.) • Inbreeding • Mating of related animals • Closebreeding • Animals very closely related, traced back to more than one common ancestor • Linebreeding • More distantly related, one common ancestor • Increases genetic purity
Systems of Breeding (cont.) • Outcrossing • Mating from different families within same breed • Brings in desirable traits not present in original animals • Linecrossing: mating from two different lines of breeding within a breed
Systems of Breeding (cont.) • Grading Up • Mating of purebred sires to grade females to improve quality of animals on farm • Improvement time depends on species • Greatest percentage of improvement comes in the first cross
Systems of Breeding (cont.) • Crossbreeding • Mating of two animals from different breeds, in effort to elicit improved traits in offspring • Resulting offspring called a hybrid • Beef, swine, and sheep producers typically use crossbreeding for production of market animals
Systems of Breeding (cont.) • Crossbreeding (cont.) • Crossbreeding Systems for Beef • Terminal sire crossed with F1females • Rotate herd bull every three or four years • Two, three, four, and five-breed rotations • Static terminal sire system • Rotational-terminal sire system • Composite breeds
Systems of Breeding (cont.) • Crossbreeding (cont.) • Crossbreeding Systems for Swine • Rotational crossbreeding • Terminal crossing system • Rotaterminalsystem
Systems of Breeding (cont.) • Crossbreeding (cont.) • Crossbreeding Systems for Sheep • Rotational • Static • Rotostatic