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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 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