Have Phenotypic Trends for Carcass Traits Followed Genetic Trends?

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Have Phenotypic Trends for Carcass Traits
Followed Genetic Trends?

• Dan W. Moser
• Department of Animal Sciences and Industry
• Kansas State University, Manhattan
• http//www.asi.ksu.edu

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Reasons Why?

• Market conditions
• More calf feds
• Harvesting younger
• Pounds still drive profit

• Implants
• Drought
• Select grade results in fewer no rolls
• Graders

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All the previous excuses assume genetic
improvement has been masked by management.
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Angus Carcass Genetic Trend
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Hereford Carcass Genetic Trend
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Limousin Carcass Genetic Trend
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Gelbvieh Carcass Genetic Trend
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Why has genetic progress been so slow?
Response per generation Heritability X
Selection Differential
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Why has genetic progress been so slow?

• Generation interval is /- 5 years
• Add another generation from seedstock to
  commercial cattle.
• Variation within breeds is limited
• A significant segment of every breed still
  ignores carcass traits

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How can we speed genetic progress?

• Collect more carcass and ultrasound data
• Use breed differences to increase rate of change
  in hybrids/composites
• At some point, DNA technology may increase
  accuracy of selection for young animals

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How can we speed phenotypic progress?

• Use appropriate breed combinations in
  crossbreeding systems
• 50 British, 50 continental optimizes quality
  and yield grade

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Do Trends Need to Change?

• Depends on supply/demand ratios of various
  product specifications
• Better yield grades are always desirable
• Grid factors should better reflect true value
  differences
• Next round of the cattle cycle?

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Questions/Comments?