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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 1 – An active     Score 2 – An active
lesion involving less   lesion involving one-
than one-third of the   third to two-thirds of
cornea.                 the cornea.
Score 3 – An active      Score 4 – An active
lesion involving more    lesion with perforation
than two-thirds of the   of the cornea
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
                          Effect of Pinkeye/Corneal
                        Abrasion on Weaning Weight
                         Effect of Pinkeye on Weaning Weight
Weaning Weight (Lbs)



                       500

                       490

                       480
        lb




                       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
         IgA Levels in Bovine Tears

        650
        600
ng/ml




        550
        500
        450
        400
               Healthy       Infected
                                    IGA levels and probability of
                                              infection
Probability of Corneal Scarring




                                  1.2
                                  1.0
                                  0.8
                                                                                     Predicted
                                  0.6
                                                                                     Mean
                                  0.4
                                  0.2
                                  0.0
                                        0
                                             0
                                                  0
                                                       0
                                                             0
                                                                  0
                                                                       0
                                                                            0
                                                                                 0
                                            10
                                                 20
                                                      30
                                                           40
                                                                 50
                                                                      60
                                                                           70
                                                                                80
                                                           IgA levels
      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      N     Incidence    h2
Angus       6,347          3.7   0.25
Hereford    4,579         22.4   0.28
Red Poll      998          3.1   0.09
Charolais   2,878          6.5   0.00
Simmental   1,775          7.6   0.10
Limousin      961          3.4   0.11
Gelbvieh    2,391          2.1   0.05
Pinzgauer     908          1.3   0.02
Braunvieh     907          1.8   0.12
MARC I      4,336          3.9   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
PRIMARILY
NURTURE                                                                           NATURE
(Environment)                     Heart                                           (Genetics)
                                  Disease
       Motor vehicle                              Osteoporosis         Dwarfism
       accidents                  Stroke


                    Pneumonia,                              Diabetes
                    influenza
                                            Obesity
      Nutritional deficiencies,
      nutritional anemias

                                                 Colon cancer
                            Cirrhosis of
                            the liver

                                                 Breast cancer

                          Lung cancer
         Two Leading Causes of
        Human Deaths in the U.S.
Cause of death                     Rank1              Deaths    Percentage
All causes                          ---             2,443,387    100.0
Diseases of heart                   1                696,947      28.5
Malignant neoplasms                 2                557,271      22.8
Cerebrovascular diseases            3                162,672       6.7
Chronic lower respiratory distress 4                 124,816       5.1
Accidents (unintentional injuries)  5                106,742       4.4
Diabetes mellitus                   6                 73,249       3.0
Influenza and pneumonia             7                 65,681       2.7
Alzheimer’s disease                 8                 58,866       2.4
Nephritis, nephrotic syndrome, and
 nephrosis                          9                  40,974      1.7
Septicemia                         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 2004
BMI > 30, or ~ 30 lbs. overweight for 5'4" person

                     2004
           What are Americans
                       eating?
                             Calories   SFA   MUFA   PUFA
                             from Fat
An Average American Diet       34%      16%   11%    7%



What should Americans be eating?
                             Calories   SFA   MUFA   PUFA
                             from Fat
American Heart Association     30%      9%    14%    7%
Step I Diet
American Heart Association     25%      7%    12%    6%
Step II Diet
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     Food                 HPI
 Soy oil         7.69   Beef(NLMB)           1.43
 Olive oil       7.14   Beef TG(Knight)      1.27
 Beef PL(Knight) 3.03   “Extreme” milk fat   1.30
 Chicken         2.27   Beef(Beitz)          1.16
 Pork            2.13   Tallow               1.12
 Lard            1.92   “Greatest” milk      0.94
 Beef(Eichhorn) 1.67    “Average” milk fat   0.44
 Margarine       1.61   “Low” milk fat       0.30
 Beef(Knight)    1.52   Palm kernel oil      0.15
 Beef(Garret)    1.49   Coconut oil          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 and
  Fatty acid
  synthesis
                Modification

14:0           16:0            18:0




14:1           16:1            18:1
                    Triacylglcyerols   Phospholipids
 Sample
Processing
    974 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
                   175
                           of Beef
                   150


                   125                        Phospholipid
                                              Composite
Number of Cattle




                                              Triacylglycerol
                   100


                    75


                    50


                    25


                     0
                         1     2          3            4        5
                             Health-Promoting Index
       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
                                   Extreme   Extreme
 Index      Average Heritability
                                   EPD (-)   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    Low       High      P-value
14:0              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 Indexes
        Exist Between Breeds
     Index    Low       High      P-value
AI               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

				
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posted:4/10/2011
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