Exam_3_Review_Fall_2 - Animal Breeding and Genetics Fall 2009 A mating system that uses crossbreeding to maintain desirable level of hybrid vigor

Info iconThis preview shows pages 1–16. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Animal Breeding and Genetics Fall 2009 A mating system that uses crossbreeding to maintain desirable level of hybrid vigor or breed complimentarity Hybrid vigor decreases over time as breed becomes more like purebreds Merit of component breeds Hybrid Vigor Breed Complimentarity Replacement considerations Important for retention of hybrid vigor May be difficult if certain breeds are used Are you generating replacements? What level are hybrid vigor are you gunna have? Simplicity Accuracy of genetic prediction Breed complimentarity must be accounted for EPD’s are breed specific A crossbreeding system in which generations of females are rotated among sire breeds in such a way that they are mated to sires whose breed composition is most different from their own Maternal females crossed with Paternal breed sires Progeny exclusively for market No replacements Not a good sustainable strategy Synthetic breed A hybrid with at least two and typically more breeds in its background Expected to breed to their own breed composites Retain a level of hybrid vigor normally associated with traditional crossbreeding systems Spatial Rotation A rotational crossbreeding system in which all sire breeds are used simultaneously Spatially separated Replacement females leave the location of their birth to mated to sires with different breed composition Advantages Retain hybrid vigor Create your own replacements Disadvantages Need separate breeding facilities or pastures Provides little breed complimentarity Inconsistent offspring ▪ Variability in retained hybrid vigor Advantages Retained hybrid vigor ▪ 2 breed 83% ▪ 3 breed 93% Maintain breed complimentarity Consistent offspring Produces replacement Disadvantages Separate breeding facilities or pastures Accuracy of genetic predictions difficult ▪ Multiple breed sires ▪ Difficult to generate EPD’s for cross bred sires, even with multiple progeny A rotational crossbreeding system where sire breeds are not used simultaneously Sire breeds are introduced in sequence All females are exposed to sires of a specific breed at the same time Static Terminal System A terminal crossbreeding system in which replacement females are either purchased or produced from separate purebred populations with the system Synthetic breed A hybrid with at least two and typically more breeds in its background Expected to breed to their own breed composites Retain a level of hybrid vigor normally associated with traditional crossbreeding systems Without crossing other breeds...
View Full Document

This note was uploaded on 03/09/2010 for the course MARB 1000 taught by Professor Hayes during the Spring '07 term at Texas A&M University-Galveston.

Page1 / 93

Exam_3_Review_Fall_2 - Animal Breeding and Genetics Fall 2009 A mating system that uses crossbreeding to maintain desirable level of hybrid vigor

This preview shows document pages 1 - 16. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online