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Investigating Opportunities Available in Genetic Selection for Healthy Beef

Investigating Opportunities Available in Genetic Selection for Healthy Beef. J R Tait and James Reecy Iowa State University. Product Branding. Product Branding. Fatty Acids. Fatty acid concentrations determine healthfulness of the lipid Fatty acid concentration is influenced by:

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Investigating Opportunities Available in Genetic Selection for Healthy Beef

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  1. Investigating Opportunities Available in Genetic Selection for Healthy Beef J R Tait and James Reecy Iowa State University

  2. Product Branding

  3. Product Branding

  4. Fatty Acids • Fatty acid concentrations determine healthfulness of the lipid • Fatty acid concentration is influenced by: • Nutrition (Duckett et al., 1993) • Breed (Pitchford et al., 2002) S. K. Duckett et al. 1993. J. Anim. Sci. 71:2079-2088. W. S. Pitchford et al. 2002. J. Anim. Sci. 80:2825-2832.

  5. Triacylglcyerols Phospholipids Sample Processing Steaks from beef cattle

  6. Fatty Acid Synthesis and Modification Fatty acid synthesis 14:0 16:0 18:0 14:1 16:1 18:1

  7. 12:0 + 4*(14:0) + 16:0 = (MUFAs) + (PUFAs) Atherogenic index The atherogenic index as proposed by Ulbricht and Southgate, 1991 Ulbricht, T.L.V., and D.A.T. Southgate. 1991. Lancet 338:8773

  8. (MUFAs) + (PUFAs) = 12:0 + 4*(14:0) + 16:0 Health Promoting Index

  9. Variation in Health-Promoting Index of Beef

  10. 200 180 160 140 120 100 80 60 40 20 0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6 3.8 4.0 4.2 4.4 <1.0 Variation in C14:0 Concentration of Beef Number of Cattle Percentage C14:0

  11. Men Female Variation in Iron Content of Beef

  12. Genetic Analysis • Estimate h2 of fatty acids in Angus beef: • 14:0, myristic acid • 14:1, myristoleic acid • 16:0, palmitic acid • 16:1, palmitoleic acid • 18:0, stearic acid • 18:1, oleic acid • 18:2, linoleic acid

  13. Data Description • Data collected from 2001-2004 • 916 Angus-sired bulls and steers • 87 sires with 1 to 41 progeny • Calf-fed management • Corn-based finishing rations

  14. Data Description • Longissimus dorsi sample • External connective tissue was removed • Fatty acids evaluated by gas chromatography

  15. Data Descriptors

  16. Genetic Analysis • MTDFREML • Sire model • Contemporary group definition: • Herd of origin • Sex • Feedlot management treatment • Harvest date

  17. Genetic Analysis • Model: Y = Xb + Zu + e Fixed effects (b): • Model I: Contemporary group only • Model II: Cont group & lipid covariate Random effects (u & e): • Sire • Error

  18. Heritability Estimates (% of lipid)

  19. Heritability Estimates (% of lipid)

  20. Heritability Estimates (% of lipid)

  21. Discussion • Generally, little change in h2 estimates with Model II • Short-chain, saturated fatty acids are heritable • 14:0 (0.49) • 16:0 (0.43) • Monounsaturated fatty acids are heritable • 16:1 (0.49) • 18:1 (0.38)

  22. Genetic Correlation Estimates

  23. Conclusions • Opportunities exist to select for fatty acid composition of beef • Genetic correlations? • Fatty acid relationships to consumer acceptability need to be investigated

  24. Where do we go from here? • Genetic variability exists for fatty acids • Very expensive traits to measure • Are there other characteristics which make beef “healthful” to consumers? • Jan. 2008 release of BovineSNP50

  25. Where do we go from here? • Iowa State University, in collaboration with NBCEC, proposed a Healthfulness of Beef study utilizing the BovineSNP50 • Discovery and Validation both in the experimental design • Pfizer Animal Genetics chose to invest in this project and vision for the beef industry

  26. Management National Cow Herd Bulls and/or Genotypes with Superior Genetic Merit for Beef Healthfulness EPDs/DNA Markers Beef Cattle Seed Stock Populations Selection Longissimus Dorsi Samples Collection of Collection of Collection of Tenderness / Taste Data Carcass Data Nutrient Composition Data Used for Used for Used for Genetic Evaluation Develop Guidelines for Selection of New Breeding Stock

  27. Acknowledgements • ISU – Center for Designing Foods to Improve Nutrition • ISU – Burroughs Endowment • National Cattlemen’s Beef Assoc. • U.S. Meat Animal Research Center • NBCEC – National Beef Cattle Evaluation Consortium • Pfizer Animal Genetics • Jim Reecy Research Group – Mary Sue Mayes, Matt Schneider • Don Beitz Research Group – Travis Knight, Shu Zhang, Jon Schoonmaker, Grace Duan, Matt O’Neil • Dorian Garrick • Rohan Fernando

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