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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. Market conditions More calf feds Harvesting younger Pounds still drive profit. Implants Drought
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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
Market conditions More calf feds Harvesting younger Pounds still drive profit Implants Drought Select grade results in fewer no rolls Graders Reasons Why?
All the previous “excuses” assume genetic improvement has been masked by management.
Why has genetic progress been so slow? Response per generation = Heritability X Selection Differential
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
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
How can we speed phenotypic progress? • Use appropriate breed combinations in crossbreeding systems • 50% British, 50% continental optimizes quality and yield grade
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?