benefits of grass-fed beef
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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) - PowerPoint PPT PresentationTRANSCRIPT
Benefits of Grass-fed Benefits of Grass-fed BeefBeef
Susan DuckettErnest L. Corley, Jr. Trustees Endowed Chair
Department of Animal and Veterinary SciencesClemson University
OutlineOutline Fat and CholesterolFat and Cholesterol
Good, bad, and neutral fatsGood, bad, and neutral fats Grass-fed vs. Grain-fed BeefGrass-fed vs. Grain-fed Beef
Results from Appalachia Beef Project (2002-2004)Results from Appalachia Beef Project (2002-2004) Comparison to Chicken and SalmonComparison to Chicken and Salmon
Forage Species for finishingForage Species for finishing Results from Appalachia Beef Project (2005-2007)Results from Appalachia Beef Project (2005-2007) Results from Clemson SARE Project (2007-2008)Results from Clemson SARE Project (2007-2008)
Animal Age and TendernessAnimal Age and Tenderness Results from Appalachia Beef Project (2008)Results from Appalachia Beef Project (2008)
Dietary Fat and Dietary Fat and CholesterolCholesterol
0
100
200
300
400
500
600
700
x 100
0
Heart Disease Cancer Stroke
Chronic respiratory Accidents Diabetes
Alzheimer's Influenza
Heart Disease – #1 Cause of Death in US
Dietary Cholesterol Dietary Cholesterol IntakeIntake
Two Sources of cholesterolTwo Sources of cholesterol Diet – 25%Diet – 25% Body (endogenous synthesis) – 75%Body (endogenous synthesis) – 75%
150 mg reduction150 mg reduction in dietary in dietary cholesterolcholesterol Reduce from average (450 mg/d) to AHA Reduce from average (450 mg/d) to AHA
recommended levels (300 mg/d)recommended levels (300 mg/d) Reduce blood cholesterol about 2%Reduce blood cholesterol about 2%
StatinsStatins (i.e. Lipitor, Zocor, etc.) (i.e. Lipitor, Zocor, etc.) Lower cholesterol synthesis in liverLower cholesterol synthesis in liver Reduce blood cholesterol levels about 40-Reduce blood cholesterol levels about 40-
60%60%
Results from Pasture Results from Pasture Based Beef Based Beef
Systems for AppalachiaSystems for Appalachia
Multi-State, Multi-Multi-State, Multi-Institutional Research Institutional Research
CollaborationCollaboration
Pasture Based Beef Systems for Pasture Based Beef Systems for AppalachiaAppalachia
In 2002, 2003, and 2004, 216 Angus-cross In 2002, 2003, and 2004, 216 Angus-cross steers steers
42-d backgrounding period after weaning - VT42-d backgrounding period after weaning - VT Winter Stocker System – WVU (Nov. – April)Winter Stocker System – WVU (Nov. – April)
Low (0.55 lb/d), Medium (1.10 lb/d), High (1.65 Low (0.55 lb/d), Medium (1.10 lb/d), High (1.65 lb/d) growth rateslb/d) growth rates
Finishing System (April – October)Finishing System (April – October) Concentrate (Concentrate (GRAINGRAIN) – Corn grain/corn silage diet ) – Corn grain/corn silage diet
at VTat VT Pasture (Pasture (GRASSGRASS) – high quality forage at all times ) – high quality forage at all times
in Beaver, WV in Beaver, WV Harvested at Taylor-Excel in PA, carcass data Harvested at Taylor-Excel in PA, carcass data
collectedcollected Whole rib from each carcass obtained for meat Whole rib from each carcass obtained for meat
quality analysesquality analyses
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
Fat and Serum Fat and Serum CholesterolCholesterol Most Important:Most Important:
Type and amount of fat consumedType and amount of fat consumed Why:Why:
Influences lipoproteins (LDL or HDL) Influences lipoproteins (LDL or HDL) LDL-cholesterolLDL-cholesterol or or BADBAD cholesterol cholesterol
Carries cholesterol from liver to tissuesCarries cholesterol from liver to tissues Excess builds up in arteries (plaques)Excess builds up in arteries (plaques)
HDL-cholesterolHDL-cholesterol or or GOODGOOD cholesterol cholesterol Removes cholesterol from blood back to liver Removes cholesterol from blood back to liver
for elimination from bodyfor elimination from body NCEP: NCEP:
> 40 mg/dL HDL > 40 mg/dL HDL < 100 mg/dL LDL< 100 mg/dL LDL
HeartHeart Disease Disease
Fatty Acid TypesFatty 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
Fat and Serum Fat and Serum CholesterolCholesterol
Not all saturated fats (SFA) are Not all saturated fats (SFA) are created equalcreated equal
Bad SFABad SFA Increase LDL (Bad) cholesterolIncrease LDL (Bad) cholesterol Myristic (C14:0) and Palmitic (C16:0) Myristic (C14:0) and Palmitic (C16:0)
acidsacids Okay SFA Okay SFA
No change in LDL or HDL CholesterolNo change in LDL or HDL Cholesterol Stearic (C18:0) acidStearic (C18:0) acid
Saturated Fatty Acids Saturated Fatty Acids (SFA)(SFA)
Greater concentrations of okay SFA (Stearic acid) and lower concentrations of Bad SFA (myristic
and palmitic acids) in grass-fed beef
Fat and Serum Fat and Serum CholesterolCholesterol
Good MUFAGood MUFA (1 double bond) (1 double bond) Oleic (C18:1) acid – major fatty acid in beef (30-Oleic (C18:1) acid – major fatty acid in beef (30-
50%)50%) Lowers bad (LDL) and increases good (HDL) Lowers bad (LDL) and increases good (HDL)
cholesterolcholesterol Good PUFAGood PUFA (2 or more double bonds) (2 or more double bonds)
PUFA-6PUFA-6 Linoleic (C18:2) and arachidonic (C20:4) acidLinoleic (C18:2) and arachidonic (C20:4) acid Lower bad (LDL) and tend to lower good (HDL) Lower bad (LDL) and tend to lower good (HDL)
cholesterolcholesterol PUFA-3PUFA-3
Linolenic acid (C18:3), EPA (C20:5), DPA (C22:5), DHA Linolenic acid (C18:3), EPA (C20:5), DPA (C22:5), DHA (C22:6)(C22:6)
Lower bad (LDL) cholesterolLower bad (LDL) cholesterol Reduce risk of heart disease, stroke and cancerReduce risk of heart disease, stroke and cancer
Monounsaturated fatty acid (MUFA)
25.0
27.5
30.0
32.5
35.0
37.5
40.0
42.5
45.0
MU
FA
, % Grain-fedGrass-fed
Lower levels of Good MUFA fat for Grass-fed
Polyunsaturated fatty acid
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
%
Grain-fedGrass-fed
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
Greater percentages of Good PUFA-3 fat for Grass-fed
PUFA-6 PUFA-3
Cancer Fighting Cancer Fighting CompoundsCompounds
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%)
Conjugated Linoleic Acid (CLA)
Grass vs. Grain: 9.4-fold greater TVA and 1.2-fold greater CLA
Total Fat per serving: Beef vs. Total Fat per serving: Beef vs. OthersOthers
Grass vs. Grain: 46% reduction in total fat content
BAD SFA: Beef vs. OthersBAD SFA: Beef vs. Others
Grass vs. Grain: 53% reduction in bad saturated fat content
PUFA 3: Beef vs. OthersPUFA 3: Beef vs. Others
Omega-6 to Omega-3 Omega-6 to Omega-3 RatioRatio
Health professionals recommend ratio of 4:1 or less
Changes in American Changes in American DietDiet
Increased intake of omega-6 and trans fat
Omega-3Omega-3 Levels Levels Health professionals recommend diets with Health professionals recommend diets with
ratio of less than 4:1ratio of less than 4:1 Lyon Heart StudyLyon Heart Study
Dietary intervention study in patients after 1Dietary intervention study in patients after 1stst myocardial infraction; reduced linoleic to linolenic myocardial infraction; reduced linoleic to linolenic ratio to 4:1ratio to 4:1
76% decrease in mortality after 2 yrs on intervention 76% decrease in mortality after 2 yrs on intervention dietdiet
Source of omega-3, Australian dietSource of omega-3, Australian diet Red meat supplied over 70% of total dietary DPARed meat supplied over 70% of total dietary DPA
2 servings/d of grass-fed beef vs. grain-fed2 servings/d of grass-fed beef vs. grain-fed +11 g/yr omega-3 fatty acids+11 g/yr omega-3 fatty acids -1460 g/yr of total fat-1460 g/yr of total fat
Cancer-Fighting Cancer-Fighting CompoundsCompounds
19% to CLA
VitaminsVitamins
Antioxidants B-vitamins
Warner-Bratzler Shear Force
Forage Species; WVForage Species; WV
Mixed: Bluegrass/White Clover
Mixed Alfalfa Pearl Millet
First 93 d
Final 41 d
128 Angus-cross steers, 3 yr. study
abMeans with uncommon superscripts differ (P < 0.05)
Carcass Weight
abMeans with uncommon superscripts differ (P < 0.05)
Total Lipid ContentTotal Lipid Content
b b b
a
Monounsaturated fatty acidsMonounsaturated fatty acids
a
PUFA-6 and PUFA-3PUFA-6 and PUFA-3
Ratio of Omega-6:Omega-3
b b b
a
Cancer Fighting Cancer Fighting CompoundsCompounds
a
aaa
b
Warner-Bratzler Shear Warner-Bratzler Shear ForceForce
Descriptive Flavor PanelDescriptive Flavor PanelFlavor Mean Intensity TablesFlavor Mean Intensity Tables11
TreatmentA 10.30 b 11.61 a 0.12 b 2.98 a 2.98 a
F 11.12 a 11.68 a 0.07 b 2.94 a 2.94 a
N 9.99 b 11.61 a 0.31 a 2.85 a 2.85 a
PM 10.38 b 11.65 a 0.08 b 2.91 a 2.91 a
P-value 0.00 0.97 0.01 0.01 0.45
MetallicBeef Flavor
IDBrown
Roasted Organ MeatBloody/Serumy
TreatmentA 0.13 a 0.71 a 2.11 a 1.64 a 2.68 ab
F 0.08 a 0.18 b 2.01 b 1.77 a 2.54 b
N 0.13 a 0.77 a 2.14 a 1.63 a 2.74 a
PM 0.13 a 0.57 ab 2.10 ab 1.62 a 2.67 ab
P-value 0.93 0.02 0.05 0.36 0.20
Sour Salty BitterRancid Off-Note
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
A = Alfalfa; F = Concentrate, C; N = Mixed pasture, MP; PM = Pearl Millet
Forage Species Alters Animal Forage Species Alters Animal Performance, Performance,
Carcass Quality, and Fatty Acid Carcass Quality, and Fatty Acid Composition of Composition of
Forage-Finished Beef Produced in Forage-Finished Beef Produced in Summer Months Summer Months
J. Schmidt, J. Andrae, S. Duckett, M. Miller, S. J. Schmidt, J. Andrae, S. Duckett, M. Miller, S. EllisEllis
Clemson University, Clemson, SCClemson University, Clemson, SC
Forage Species for Summer Forage Species for Summer FinishingFinishing
Alfalfa (Alfalfa (Medicago sativaMedicago sativa) – ) – perennial legumeperennial legume September establishment with a seeding rate of 20 kg haSeptember establishment with a seeding rate of 20 kg ha-1-1
Bermudagrass (Bermudagrass (Cynodon dactylonCynodon dactylon) – ) – warm season warm season perennial grassperennial grass
Existing paddocks (c.v. ‘Coastal’) were utilizedExisting paddocks (c.v. ‘Coastal’) were utilized
Chicory (Chicory (Cichorium intybusCichorium intybus) – ) – short-lived perennial forbshort-lived perennial forb September establishment with a seeding rate of 9 kg haSeptember establishment with a seeding rate of 9 kg ha-1-1
Cowpea (Cowpea (Vigna unguiculataVigna unguiculata) – ) – warm season annual warm season annual legumelegume
May establishment with a seeding rate of 56 kg haMay establishment with a seeding rate of 56 kg ha-1-1
Pearl Millet (Pearl Millet (Pennisetum glaucumPennisetum glaucum) – ) – warm season warm season annual grassannual grass
May establishment with a seeding rate of 28 kg haMay establishment with a seeding rate of 28 kg ha-1-1
Materials & MethodsMaterials & Methods 30 Angus-cross steers 30 Angus-cross steers 2-ha paddocks; 2-reps per forage species 2-ha paddocks; 2-reps per forage species Grazing began when adequate forage growth was Grazing began when adequate forage growth was
presentpresent alfalfa & chicory: April - Julyalfalfa & chicory: April - July bermudagrass, cowpea & pearl millet: June – Sept./Oct.bermudagrass, cowpea & pearl millet: June – Sept./Oct.
Alternate stocking was utilized to provide forage Alternate stocking was utilized to provide forage rest periodrest period
Put and take stocking was utilized to maintain Put and take stocking was utilized to maintain recommended herbage allowancerecommended herbage allowance
Slaughtered when forage mass inadequate or live Slaughtered when forage mass inadequate or live weight exceeded 568 kgweight exceeded 568 kg
Carcass data collected at 48 h postmortemCarcass data collected at 48 h postmortem
Hot Carcass WeightHot Carcass Weight
Carcass Quality ResultsCarcass Quality Results
AL BG CH CO PM
Fat Thickness, in
.31c .21d .22cd .29c .18d
Dressing % 63.4a 59.2b 63.0a 63.2a 60.5b
Ribeye Area, in2
13.1 12.9 12.4 12.7 12.2
Yield Grade 2.2 2.0 2.1 2.4 1.9
Quality Grade1
4.17ab 3.83ab 3.67b 4.83a 3.23b
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)
Warner-Bratzler Shear Warner-Bratzler Shear ForceForce
Shear Force, d 14Shear Force, d 14
Consumer PanelConsumer Panel
Monounsaturated Fatty Acids
MUFA: AL and PM > CH
Cancer-Fighting Cancer-Fighting CompoundsCompounds
Grasses (BG and PM): higher Vaccenic and CLA levels
Animal AgeAnimal Age Medium or Large frame sires; 3 time Medium or Large frame sires; 3 time
endpoints endpoints (1=July 17, 2=Sept. 3, 3=Oct. 30, 2008)(1=July 17, 2=Sept. 3, 3=Oct. 30, 2008)
Animal age and Postmortem Aging Time – Critical for Beef Tenderness
SummarySummary Grass-fed beefGrass-fed beef
Leaner with low n-6 to n-3 ratioLeaner with low n-6 to n-3 ratio Greater concentrations of n-3, CLA and Greater concentrations of n-3, CLA and
vaccenicvaccenic Greater antioxidant and B-vitamin contentsGreater antioxidant and B-vitamin contents Tender and tastes greatTender and tastes great
Forage speciesForage species Alter animal performance, carcass quality, Alter animal performance, carcass quality,
tenderness, fatty acid composition, and flavortenderness, fatty acid composition, and flavor Develop forage chains to expand finishing Develop forage chains to expand finishing
windowwindow Animal age and tendernessAnimal age and tenderness
Young = tender Young = tender Greater animal age – increased postmortem Greater animal age – increased postmortem
agingaging
Supplementation on Forage
0.0
0.5
1.0
1.5
2.0
2.5
3.0
Trans-11 vaccenic CLA
% o
f to
tal f
atty
aci
ds
Forage onlyForage + GrainConcentrate
Corn Grain: Reduced TVA and CLA compared to Forage only but values greater than Concentrate
Supplementation on Forage
0
1
2
3
4
5
6
Rat
io o
f O
meg
a6:O
meg
a3
ForageForage + OilForage + GrainConcentrate
Oil and Grain Supplementation: Increased omega-6:Omega-3 ratio due to greater intake of omega-6 fat
Subcutaneous Fat Color
0
2
4
6
8
10
12
14
16
18
20
b*
MixedAlfalfaPearl MilletConcentrate
b
a a a
S.C. b* Distribution
Treatments1=AL, 2=C, 3=MP, 4=PM
1 2 3 4
S.C
. b*
10
12
14
16
18
20
22
24