Transcript No Slide Title

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 1 – An active
lesion involving less
than one-third of the
cornea.
Score 2 – An active
lesion involving onethird to two-thirds of
the cornea.
Score 3 – An active
lesion involving more
than two-thirds of the
cornea.
Score 4 – An active
lesion with perforation
of the cornea
Percent of Infection per Eye
50
40
30
20
10
0
Left
Right
Bilateral
Pinkeye Data Analysis
1823 head (Indiana, Iowa, Missouri, Wisconsin)
Heritability
MTDFREML
Model Y =  + CG +animal +PE + error
• CG = Sex-weaning group (4)
• PE = permanent environmental
h2 = 0.18
(Lbs)
Weaning Weight
lb
Effect of Pinkeye/Corneal
Effect of Pinkeye
Weaning Weight
Abrasion
ononWeaning
Weight
500
490
480
470
460
450
440
Infected
Non-Infected
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
ng/ml
IgA Levels in Bovine Tears
650
600
550
500
450
400
Healthy
Infected
1.2
1.0
0.8
Predicted
0.6
Mean
0.4
0.2
IgA levels
0
80
0
70
0
60
0
50
0
40
0
30
0
20
10
0
0.0
0
Probability of Corneal Scarring
IGA levels and probability of
infection
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 records
907 to 10,947 head per breed
1.3 to 22.4% incidence
Breed
Angus
Hereford
Red Poll
Charolais
Simmental
Limousin
Gelbvieh
Pinzgauer
N
6,347
4,579
998
2,878
1,775
961
2,391
908
Incidence
3.7
22.4
3.1
6.5
7.6
3.4
2.1
1.3
h2
0.25
0.28
0.09
0.00
0.10
0.11
0.05
0.02
Braunvieh
MARC I
907
4,336
1.8
3.9
0.12
0.03
PREVALENCE BIK HEREFORD
AND ALL OTHERS
70
60
50
40
30
20
10
0
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 Disease
PRIMARILY
NURTURE
(Environment)
(Genetics)
Heart
Disease
Motor vehicle
accidents
Osteoporosis
Stroke
Pneumonia,
influenza
Diabetes
Obesity
Nutritional deficiencies,
nutritional anemias
Cirrhosis of
the liver
Colon cancer
Breast cancer
Lung cancer
PRIMARILY
NATURE
Dwarfism
Two Leading Causes of
Human Deaths in the U.S.
Cause of death
Rank1
All causes
--Diseases of heart
1
Malignant neoplasms
2
Cerebrovascular diseases
3
Chronic lower respiratory distress 4
Accidents (unintentional injuries)
5
Diabetes mellitus
6
Influenza and pneumonia
7
Alzheimer’s disease
8
Nephritis, nephrotic syndrome, and
nephrosis
9
Septicemia
10
1Rank
Deaths
2,443,387
696,947
557,271
162,672
124,816
106,742
73,249
65,681
58,866
Percentage
100.0
28.5
22.8
6.7
5.1
4.4
3.0
2.7
2.4
40,974
33,865
1.7
1.4
based on number of deaths; total = 79% of all deaths.
Source: National Vital Statistics Report, Vol. 15, No. 17
Obesity in U.S. in 2004
BMI > 30, or ~ 30 lbs. overweight for 5'4" person
2004
What are Americans
eating?
An Average American Diet
Calories
from Fat
SFA
MUFA
PUFA
34%
16%
11%
7%
What should Americans be 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%
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
12:0 + 4*(14:0) + 16:0
=
(MUFAs) + (PUFAs)
The atherogenic index as proposed
by Ulbricht and Southgate, 1991
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
Food
HPI
Soy oil
7.69
Olive oil
7.14
Beef PL(Knight) 3.03
Chicken
2.27
Pork
2.13
Lard
1.92
Beef(Eichhorn) 1.67
Margarine
1.61
Beef(Knight)
1.52
Beef(Garret)
1.49
Food
HPI
Beef(NLMB)
Beef TG(Knight)
“Extreme” milk fat
Beef(Beitz)
Tallow
“Greatest” milk
“Average” milk fat
“Low” milk fat
Palm kernel oil
Coconut oil
1.43
1.27
1.30
1.16
1.12
0.94
0.44
0.30
0.15
0.06
Genotype
Environment
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)
Fatty acid
synthesis
Fatty Acid
Synthesis and
Modification
14:0
16:0
18:0
14:1
16:1
18:1
Triacylglcyerols
Sample
Processing
974 Steaks
from beef cattle
Phospholipids
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
175
150
Phospholipid
Composite
Triacylglycerol
Number of Cattle
125
100
75
50
25
0
1
2
3
Health-Promoting Index
4
5
Composite
Fatty Acid Composition
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
Composite
Fatty Acid Indexes
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
-
-
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
Significant Differences in
Fatty Acid Composition
Exist Between Breeds
Fatty Acid
14:0
Low
3.40
High
3.96
P-value
<.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 Indexes
Exist Between Breeds
Index
AI
Low
High
P-value
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 Acids
Exist Between Breeds
Index
Low
High
P-value
18:1t11
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
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
16:1/16:0
Lipid
VA
VV
P-Value
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