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Improving the health and healthfulness of beef J.M. Reecy, and D.C. Beitz Iowa State University. Overview. Disease resistance Infectious Bovine Keratoconjunctavitus Respiratory Disease Improving the Healthfulness of Beef. Pink Eye. Reported in the USA since 1889 - PowerPoint PPT Presentation
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Improving the health and
healthfulness of beef
J.M. Reecy, and D.C. Beitz
Iowa State University
Overview
• Disease resistance– Infectious Bovine Keratoconjunctavitus– Respiratory Disease
• Improving the Healthfulness of Beef
Pink Eye• Reported in the USA since 1889
• 45% of Missouri herds have endemic IBK
• Average prevalence = 8%
• More common in the young – 10-60%
• Immunity develops with age
• No gender affinity
What Causes “Pink Eye”• Moraxella bovis• Brannamella ovis?• High UV light• Dust• IBR infection• IBR vaccination• Mycoplasma infection Mycoplasma bovoculi• Trauma• Face flies- Musca autumnalis (since 1946)
Options For Control/ Prevention
• Are the technologies up to the job?
Options For Control/ Prevention
• Not up to the job–Vaccines–Fly control–Dust control–Pasture clipping
What are the Future Options
• Genetic selection
• Improved vaccines
• Better treatment
Requirements of the project• Serve as a model for disease
resistance/susceptibility research– Internal parasites - nematodes– Respiratory
• Use field records– Need to develop data collection scheme
Data Collection
• Two seasons–When cases are actively
observed–Weaning
• Scoring system• Data sheets
Score 2 – An active lesion involving one-third to two-thirds of the cornea.
Score 1 – An active lesion involving less than one-third of the cornea.
Score 4 – An active lesion with perforation of the cornea
Score 3 – An active lesion involving more than two-thirds of the cornea.
Pinkeye Data Analysis1823 head (Indiana, Iowa, Missouri, Wisconsin)
HeritabilityMTDFREMLModel Y = + CG +animal +PE + error
• CG = Sex-weaning group (4)• PE = permanent environmental
h2 = 0.18
Effect of Pinkeye on Weaning Weight
440
450
460
470
480
490
500
Infected Non-Infected
lb
Effect of Pinkeye/Corneal Abrasion on Weaning Weight
Wea
ning
Wei
ght (
Lbs
)
Additional Results
No evidence of prior exposure to bovine rhinotracheitis as having an effect
No evidence of Carrier status (M. bovis and B. Ovis) effecting incidence
Tear Film
Lipid layer: Reduces evaporation , prevents contamination
Aqueous layer: Lubrication and protection
Mucus layer: Lubricates and protect the cornea.
Ocular defense factors affecting susceptibility
sIgA and Lactoferrin (Lf) as candidate factors in the tear film influencing susceptibility
Antigen binding: protection against invading microorganisms
Hypothesis: Cattle susceptible to pink eye produce higher levels of sIgA and lower Lf
IgA Levels in Bovine Tears
400450500550600650
Healthy Infected
ng/ml
IGA levels and probability of infection
0.00.20.40.60.81.01.2
0100 200 300 400 500 600 700 800
IgA levels
Predicted
Mean
Prob
abili
ty o
f Cor
neal
Sca
rrin
g
MARC Pinkeye data
Gary Snowder (JAS 2005 83(3):507-18. )19 years of data
Calves listed as being treated in the herd book
Number of records907 to 10,947 head per breed1.3 to 22.4% incidence
Breed N Incidence h2
Angus 6,347 3.7 0.25Hereford 4,579 22.4 0.28Red Poll 998 3.1 0.09Charolais 2,878 6.5 0.00Simmental 1,775 7.6 0.10Limousin 961 3.4 0.11Gelbvieh 2,391 2.1 0.05Pinzgauer 908 1.3 0.02Braunvieh 907 1.8 0.12MARC I 4,336 3.9 0.03MARC III 10,947 5.9 0.26
PREVALENCE BIK HEREFORD AND ALL OTHERS
0
10
20
30
40
50
60
70
1983 1986 1989 1992 1995 1998 2001
Respiratory Disease
• Bovine Respiratory Disease is the most common and costly disease in the U.S.
• National mortality rate for bovine respiratory disease is 6% (NAHMS, 1997)
• Lung lesions are routinely observed in animals that exhibited no clinical signs
Respiratory Disease
•Use field records–Need to develop data collection scheme
–Treatment data
–Lung Score
Designing Beef to Produce a Healthier Product
Overview• Goal of Research
– Develop the tools to allow breeders to select for healthier beef
• What does this mean to the beef industry?– It will be able to actively address human
health concerns with respect to consumption of beef
Interaction of Genetics and Environment in Causing
Human DiseasePRIMARILY NURTURE(Environment)
PRIMARILY NATURE(Genetics)
Motor vehicle accidents
Heart Disease
Stroke
Pneumonia, influenza
Nutritional deficiencies, nutritional anemias
Cirrhosis of the liver
Lung cancer
Osteoporosis
Diabetes
Obesity
Colon cancer
Breast cancer
Dwarfism
Two Leading Causes of Human Deaths in the U.S.
Cause of death Rank1 Deaths PercentageAll causes --- 2,443,387 100.0Diseases of heart 1 696,947 28.5Malignant neoplasms 2 557,271 22.8Cerebrovascular diseases 3 162,672 6.7Chronic lower respiratory distress 4 124,816 5.1Accidents (unintentional injuries) 5 106,742 4.4Diabetes mellitus 6 73,249 3.0Influenza and pneumonia 7 65,681 2.7Alzheimer’s disease 8 58,866 2.4Nephritis, nephrotic syndrome, and nephrosis 9 40,974 1.7Septicemia 10 33,865 1.4
1Rank based on number of deaths; total = 79% of all deaths.Source: National Vital Statistics Report, Vol. 15, No. 17
Obesity in U.S. in 2004BMI > 30, or ~ 30 lbs. overweight for 5'4" person
2004
Calories from Fat
SFA MUFA PUFA
An Average American Diet 34% 16% 11% 7%
What are Americans
eating?
Calories from Fat
SFA MUFA PUFA
American Heart Association Step I Diet
30% 9% 14% 7%
American Heart Association Step II Diet
25% 7% 12% 6%
What should Americans be eating?
How Do We Name Fatty Acids?• Carbon chain length and # of
unsaturated bonds (e.g. 18:0 or 18:1) • Name
• Palmitic (16:0) or Palmitoleic (16:1)9
• Stearic (18:0) or Oleic (18:1) 9
• Linoleic (18:2) 9,12
Atherogenic index
The atherogenic index as proposed by Ulbricht and Southgate, 1991
= (MUFAs) + (PUFAs)12:0 + 4*(14:0) + 16:0
Health Promoting Index
=(MUFAs) + (PUFAs)12:0 + 4*(14:0) + 16:0
How Does Beef Compare to Other Sources of Fat?
Health-promoting index of several foods
Soy oil 7.69Olive oil 7.14Beef PL(Knight) 3.03Chicken 2.27Pork 2.13Lard 1.92Beef(Eichhorn) 1.67Margarine 1.61Beef(Knight) 1.52Beef(Garret) 1.49
Food HPI
Beef(NLMB) 1.43Beef TG(Knight) 1.27“Extreme” milk fat 1.30Beef(Beitz) 1.16Tallow 1.12“Greatest” milk 0.94“Average” milk fat 0.44“Low” milk fat 0.30Palm kernel oil 0.15Coconut oil 0.06
Food HPI
Environment
Genotype
Phenotype
Feeding systems affecting fatty acid composition
Ruminant species
- Rumen biohydrogenation
- Forage increases reductive potential of the rumen
- Rumen can be overloaded with PUFA (CLA increase in pasture-fed cattle)
16:0 18:0
16:1 18:1
Fatty acid synthesis
14:1
14:0
Fatty Acid Synthesis and Modification
Triacylglcyerols PhospholipidsSample
Processing974 Steaks
from beef cattle
Statistical analysis• Steers and bulls slaughtered at normal
finishing weight.
• Contemporary groups based on year, farm of origin, feedlot, and harvest date.
• 63 contemporary groups (1-65 cattle per group).
• 77 sires (1-40 progeny per sire).
Variation in Health-Promoting Index
of Beef
1 2 3 4 50
25
50
75
100
125
150
175
Number of Cattle
Health-Promoting Index
Phospholipid Composite Triacylglycerol
Fatty Acids Average (wt%) Heritability
14:0 2.81 0.39 ± 0.21
16:0 26.28 0.40 ± 0.21
16:1 3.35 0.54 ± 0.24
18:0 3.35 0.27 ± 0.19
18:1 41.05 0.33 ± 0.20
18:2 7.46 0.23 ± 0.18
CompositeFatty Acid Composition
Index Average Heritability Extreme EPD (-)
Extreme EPD (+)
AI 0.66 0.45 ± 0.22 -5.70 8.36
16:1/16:0 0.13 0.44 ± 0.22 -6.77 6.92
18:1/18:0 3.25 0.30 ± 0.19 - -
X:1/X:0 1.14 0.37 ± 0.21 - -
16:0/14:0 9.62 0.10 ± 0.14 - -
18:0/16:0 0.49 0.34 ± 0.20 - -
Composite Fatty Acid Indexes
Does Breed to Breed Variation Exist in Fatty
Acid Composition• Collaborative project with Larry Cundiff at
Meat Animal Research Center• 588 animals
– Sire Lines• Angus BeefMaster• Hereford Bonsmara• Brangus Romosinuano
– Dam Lines• Angus MARC III
Fatty Acid Low High P-value14:0 3.40 3.96 <.0001
16:0 27.18 29.38 <.0001
16:1 3.47 3.78 0.0075
18:0 12.51 14.31 <.0001
18:1 33. 90 35.73 <.0001
18:2 1.51 1.87 0.0007
Significant Differences in Fatty Acid Composition
Exist Between Breeds
Index Low High P-valueAI 0.87 1.01 <.0001
16:1/16:0 12.51 13.78 <.0001
18:1/18:0 240.05 274.77 <.0001
x:1/x:0 88.07 96.41 <.0001
16/14 706.97 802.43 <.0001
18/16 43.49 51.34 <.0001
Significant Differences in Fatty Acid Indexes
Exist Between Breeds
Index Low High P-value18:1t11 4.49 6.17 0.0016
18:1c11 1.05 1.25 <.0001
18:3n3 0.20 0.24 <.0001
CLAc9,t11 0.35 0.42 0.0133
22:5n3 0.16 0.25 0.0378
22:6n3 0.02 0.03 0.0073
Significant Differences in Fatty Acids
Exist Between Breeds
New Compounds• Conjugated Linoleic Acid
– Anti-cancer, anti-obesity, anti-diabetic• Heme and non-Heme Iron
– correlated positively with hematological status • Spingolipids
– may inhibit colon cancer in humans • Creatine
– improves muscle strength • Vitamin E
– negatively correlated with risk of prostate cancer
Are Single Nucleotide Polymorphisms Associated
with Fatty Acid Composition• 172 purebred American Angus Bulls and Steers ISU
Meat Quality Selection Herd• Stearoyl-CoA Desaturease SNPs
– Enzyme responsible for desaturating fatty acids– SCD 316, SCD536, SCD1278
Amino Acid Genotype # Animals Percentage
VV CC 115 67
VA CT 57 33
Effect of a Stearoyl-CoA Desaturase
DNA polymorphism
Lipid
16:1/16:0
P-ValueVA VV
Phospholipid 6.3% 6.8% 0.13
TAG 14.5% 13.9% 0.02
Summary• Triacylglycerol fatty acid composition is more
heritable than phospholipid fatty acid composition.
• Fatty acid desaturation is more heritable in beef cattle than is fatty acid elongation.
• Health Promoting index/AI is highly heritable.
• Differences in fatty acid composition exist between breeds.
• DNA markers can be used to identify more healthful beef.
Conclusions
Fatty acid composition is a heritable trait.
Lipid composition can be improved with respect to human health by genetic selection.
Where Do We Go From Here?
1) Obtain Research Funding
2) Develop resource populations• American Angus (have in hand)• Meat Animal Research Center
3) Correlation With Other Traits
4) Identify Molecular Markers
Where Do We Go From Here?
5) Human Studies• Taste Test Panels • Feeding Studies
6) Identification of Novel Health Compounds
7) Development of New Analytical Techniques
Acknowledgements•National Beef Cattle Evaluation Consortium
•USDA Center for Designing Foods to Improve Nutrition at the Iowa State University
•The Wise and Hellen Burroughs Endowment
•National Cattleman’s Beef Association
•Collaborators