1 / 53

Benefits of Grass-fed Beef

Benefits of Grass-fed Beef. Susan Duckett Ernest L. Corley, Jr. Trustees Endowed Chair Department of Animal and Veterinary Sciences Clemson University. Outline. Fat and Cholesterol Good, bad, and neutral fats Grass-fed vs. Grain-fed Beef Results from Appalachia Beef Project (2002-2004)

nubia
Download Presentation

Benefits of Grass-fed Beef

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Benefits of Grass-fed Beef Susan Duckett Ernest L. Corley, Jr. Trustees Endowed Chair Department of Animal and Veterinary Sciences Clemson University

  2. Outline • Fat and Cholesterol • Good, bad, and neutral fats • Grass-fed vs. Grain-fed Beef • Results from Appalachia Beef Project (2002-2004) • Comparison to Chicken and Salmon • Forage Species for finishing • Results from Appalachia Beef Project (2005-2007) • Results from Clemson SARE Project (2007-2008) • Animal Age and Tenderness • Results from Appalachia Beef Project (2008)

  3. Dietary Fat and Cholesterol Heart Disease – #1 Cause of Death in US

  4. Dietary Cholesterol Intake • Two Sources of cholesterol • Diet – 25% • Body (endogenous synthesis) – 75% • 150 mg reduction in dietary cholesterol • Reduce from average (450 mg/d) to AHA recommended levels (300 mg/d) • Reduce blood cholesterol about 2% • Statins (i.e. Lipitor, Zocor, etc.) • Lower cholesterol synthesis in liver • Reduce blood cholesterol levels about 40-60%

  5. Results from Pasture Based Beef Systems for AppalachiaMulti-State, Multi-Institutional Research Collaboration

  6. Pasture Based Beef Systems for Appalachia • In 2002, 2003, and 2004, 216 Angus-cross steers • 42-d backgrounding period after weaning - VT • Winter Stocker System – WVU (Nov. – April) • Low (0.55 lb/d), Medium (1.10 lb/d), High (1.65 lb/d) growth rates • Finishing System (April – October) • Concentrate (GRAIN) – Corn grain/corn silage diet at VT • Pasture (GRASS) – high quality forage at all times in Beaver, WV • Harvested at Taylor-Excel in PA, carcass data collected • Whole rib from each carcass obtained for meat quality analyses

  7. Cholesterol Content of Meat Animal products contain cholesterol. Cholesterol is present in all cell membranes including muscle and fat. No difference in cholesterol content of grass vs. grain-fed beef

  8. Fat and Serum Cholesterol • Most Important: • Type and amount of fat consumed • Why: • Influences lipoproteins (LDL or HDL) • LDL-cholesterol or BAD cholesterol • Carries cholesterol from liver to tissues • Excess builds up in arteries (plaques) • HDL-cholesterol or GOOD cholesterol • Removes cholesterol from blood back to liver for elimination from body • NCEP: • > 40 mg/dL HDL • < 100 mg/dL LDL

  9. Heart Disease

  10. Fatty Acid Types Saturated, SFA (Stearic acid, 18C) C1-C2-C3-C4-C5-C6-C7-C8-C9-C10-C11-C12-C13-C14-C15-C16-C17-C18OOH Monounsaturated, MUFA (Oleic acid, 18C) C1-C2-C3-C4-C5-C6-C7-C8-C9=C10-C11-C12-C13-C14-C15-C16-C17-C18OOH Omega-6 polyunsaturated, PUFA-6 (Linoleic acid, 18C) C1-C2-C3-C4-C5-C6=C7-C8-C9=C10-C11-C12-C13-C14-C15-C16-C17-C18OOH Omega-3 polyunsaturated, PUFA-3 (Linolenic acid, 18C) C1-C2-C3=C4-C5-C6=C7-C8-C9=C10-C11-C12-C13-C14-C15-C16-C17-C18OOH = denotes double bond location

  11. Fat and Serum Cholesterol • Not all saturated fats (SFA) are created equal • Bad SFA • Increase LDL (Bad) cholesterol • Myristic (C14:0) and Palmitic (C16:0) acids • Okay SFA • No change in LDL or HDL Cholesterol • Stearic (C18:0) acid

  12. Saturated Fatty Acids (SFA) Greater concentrations of okay SFA (Stearic acid) and lower concentrations of Bad SFA (myristic and palmitic acids) in grass-fed beef

  13. Fat and Serum Cholesterol • Good MUFA (1 double bond) • Oleic (C18:1) acid – major fatty acid in beef (30-50%) • Lowers bad (LDL) and increases good (HDL) cholesterol • Good PUFA (2 or more double bonds) • PUFA-6 • Linoleic (C18:2) and arachidonic (C20:4) acid • Lower bad (LDL) and tend to lower good (HDL) cholesterol • PUFA-3 • Linolenic acid (C18:3), EPA (C20:5), DPA (C22:5), DHA (C22:6) • Lower bad (LDL) cholesterol • Reduce risk of heart disease, stroke and cancer

  14. Monounsaturated fatty acid (MUFA) Lower levels of Good MUFA fat for Grass-fed

  15. Polyunsaturated fatty acid PUFA-6 PUFA-3 Greater percentages of Good PUFA-3 fat for Grass-fed

  16. Cancer Fighting Compounds • In ruminant animals, dietary PUFA are biohydrogenated in rumen • Produces intermediates that have anticarcinogenic properties: • Conjugated linoleic acid (CLA), cis-9 trans-11 isomer • Trans-11 Vaccenic acid (TVA) • In beef and milk, over 86% of CLA present in these animal products comes from desaturation of TVA • In humans, 19% of supplemented TVA was converted to CLA (range 0 - 40%)

  17. Conjugated Linoleic Acid (CLA) Grass vs. Grain: 9.4-fold greater TVA and 1.2-fold greater CLA

  18. Total Fat per serving: Beef vs. Others Grass vs. Grain: 46% reduction in total fat content

  19. BAD SFA: Beef vs. Others Grass vs. Grain: 53% reduction in bad saturated fat content

  20. PUFA 3: Beef vs. Others

  21. Omega-6 to Omega-3 Ratio Health professionals recommend ratio of 4:1 or less

  22. Changes in American Diet Increased intake of omega-6 and trans fat

  23. Omega-3 Levels • Health professionals recommend diets with ratio of less than 4:1 • Lyon Heart Study • Dietary intervention study in patients after 1st myocardial infraction; reduced linoleic to linolenic ratio to 4:1 • 76% decrease in mortality after 2 yrs on intervention diet • Source of omega-3, Australian diet • Red meat supplied over 70% of total dietary DPA • 2 servings/d of grass-fed beef vs. grain-fed • +11 g/yr omega-3 fatty acids • -1460 g/yr of total fat

  24. Cancer-Fighting Compounds 19% to CLA

  25. Vitamins Antioxidants B-vitamins

  26. Warner-Bratzler Shear Force

  27. Forage Species; WV First 93 d Mixed: Bluegrass/White Clover Final 41 d Alfalfa Pearl Millet Mixed 128 Angus-cross steers, 3 yr. study

  28. Carcass Weight abMeans with uncommon superscripts differ (P < 0.05) abMeans with uncommon superscripts differ (P < 0.05)

  29. Total Lipid Content a b b b

  30. Monounsaturated fatty acids a

  31. PUFA-6 and PUFA-3

  32. Ratio of Omega-6:Omega-3 a b b b

  33. Cancer Fighting Compounds a a a a b

  34. Warner-Bratzler Shear Force

  35. Descriptive Flavor Panel Flavor Mean Intensity Tables1 A = Alfalfa; F = Concentrate, C; N = Mixed pasture, MP; PM = Pearl Millet 1 a, b Means with the same letter within a column are not significantly different at the 95% Confidence Level 1 Means based on 15-point scale with 0.5-increments. 0.0 = none -- 15.0 = extreme

  36. Forage Species Alters Animal Performance, Carcass Quality, and Fatty Acid Composition of Forage-Finished Beef Produced in Summer Months J. Schmidt, J. Andrae, S. Duckett, M. Miller, S. EllisClemson University, Clemson, SC

  37. Forage Species for Summer Finishing Alfalfa (Medicago sativa) – perennial legume • September establishment with a seeding rate of 20 kg ha-1 Bermudagrass (Cynodon dactylon) – warm season perennial grass • Existing paddocks (c.v. ‘Coastal’) were utilized Chicory (Cichorium intybus) – short-lived perennial forb • September establishment with a seeding rate of 9 kg ha-1 Cowpea (Vigna unguiculata) – warm season annual legume • May establishment with a seeding rate of 56 kg ha-1 Pearl Millet (Pennisetum glaucum) – warm season annual grass • May establishment with a seeding rate of 28 kg ha-1

  38. Materials & Methods • 30 Angus-cross steers • 2-ha paddocks; 2-reps per forage species • Grazing began when adequate forage growth was present • alfalfa & chicory: April - July • bermudagrass, cowpea & pearl millet: June – Sept./Oct. • Alternate stocking was utilized to provide forage rest period • Put and take stocking was utilized to maintain recommended herbage allowance • Slaughtered when forage mass inadequate or live weight exceeded 568 kg • Carcass data collected at 48 h postmortem

  39. Hot Carcass Weight

  40. Carcass Quality Results 1Quality Grade: 3 = Low Select, 4 = High Select, 5 = Choice- a,bMeans with uncommon superscripts in the same row differ (P<0.05) c,dMeans with uncommon superscripts in the same row differ (P<0.1)

  41. Warner-Bratzler Shear Force

  42. Shear Force, d 14

  43. Consumer Panel

  44. Monounsaturated Fatty Acids MUFA: AL and PM > CH

  45. Cancer-Fighting Compounds Grasses (BG and PM): higher Vaccenic and CLA levels

  46. Animal Age Animal age and Postmortem Aging Time – Critical for Beef Tenderness Medium or Large frame sires; 3 time endpoints (1=July 17, 2=Sept. 3, 3=Oct. 30, 2008)

  47. Summary • Grass-fed beef • Leaner with low n-6 to n-3 ratio • Greater concentrations of n-3, CLA and vaccenic • Greater antioxidant and B-vitamin contents • Tender and tastes great • Forage species • Alter animal performance, carcass quality, tenderness, fatty acid composition, and flavor • Develop forage chains to expand finishing window • Animal age and tenderness • Young = tender • Greater animal age – increased postmortem aging

  48. Supplementation on Forage Corn Grain: Reduced TVA and CLA compared to Forage only but values greater than Concentrate

More Related