I OWA S TATE U NIVERSITY Department of Animal Science Terminal Traits

I OWA S TATE U NIVERSITY Department of Animal Science Heterosis Review u What is Heterosis - offspring performance difference over the average performance of an offspring’s parents n Why maximize heterosis? l It is FREE producers are wasting money if you do not take advantage of it. u Performance of Sire = 2.00 ADG of Dam= 1.80 ADG u Parental Average = 1.90 u Offspring Average ADG = 2.10 u Offspring – Parental Average = 2.10 – 1.90 =.20 u Percent Heterosis =.20 /1.90 = 10.5%

I OWA S TATE U NIVERSITY Department of Animal Science Types of Heterosis 1.Individual n Advantage of a crossbred offspring over purebred parents 2.Maternal n Advantage of a crossbred mother over a purebred mother n Primarily due to mothering ability 3.Paternal n Advantage of a crossbred father over a purebred father n Due to fathering ability? n Not as important as maternal heterosis

I OWA S TATE U NIVERSITY Department of Animal Science Heterosis advantage for production traits (Ahlschwede et al., 1988) Item First Cross purebred sow Multiple cross crossbred sow Crossbred boar Reproduction Conception rate Pigs born alive Littersize at 21 days Littersize weaned

I OWA S TATE U NIVERSITY Department of Animal Science Heterosis advantage for production traits (Ahlschwede et al., 1988) Item First Cross purebred sow Multiple cross crossbred sow Crossbred boar Production 21 – day litter weight Days to 250 lbs Feed Efficiency

I OWA S TATE U NIVERSITY Department of Animal Science Heterosis advantage for production traits (Ahlschwede et al., 1988) Item First Cross purebred sow Multiple cross crossbred sow Crossbred boar Carcass Composition Length Backfat Loin muscle area Marbling

I OWA S TATE U NIVERSITY Department of Animal Science Crossbreeding Systems u Rotational crossbreeding systems n Three-breed

I OWA S TATE U NIVERSITY Department of Animal Science Types of Crossbreeding Systems Rototerminal

I OWA S TATE U NIVERSITY Department of Animal Science Crossbreeding Systems u Rotaterminal crossbreeding systems n A good compromise between specific and rotational systems n More heterosis realized than with rotational alone n Still can save replacement breeding stock l Still must buy terminal sire n Can select traits in individual breeds via the terminal sire l Can focus on strengths and weaknesses of certain breeds

I OWA S TATE U NIVERSITY Department of Animal Science Heterosis percentage in rotational crosses Generation number Equilibrium Crossbreeding System breed rotation breed rotation breed rotation breed rotation breed rotation

I OWA S TATE U NIVERSITY Department of Animal Science Using Heterosis u Disadvantage n Superior performance observed in crossbred individuals is not transmitted upon mating n Gene combinations are not transmitted to progeny l Only individual genes are transmitted to progeny l Additive gene action = heritability, EPDs, EBVs n Gene combinations are rearranged or lost when crossbred animals are mated together l Random segregation of alleles during meiosis

I OWA S TATE U NIVERSITY Department of Animal Science Swine Production Goals u Primary goal = Maximize Profit u Genetics has a permanent effect on profit through influence or economically important production traits. n Start with the best genetic merit nucleus animals n Improve their merit n Use the most efficient Genetic System n Provide an adequate environment for the animals to express their genetic merit

I OWA S TATE U NIVERSITY Department of Animal Science Development of a Breeding Program u Identify production and carcass traits that influence profitability u Assess relative economic value of traits u Evaluate economic goals and production restrictions u Evaluate packer buying program used u Use records to evaluate current situation

I OWA S TATE U NIVERSITY Department of Animal Science Selection Indexes u Indexes are used for multiple trait selection u Indexes combine the traits that economically influence a selection decision u MLI = Maternal Line Index n used for selection of sows and maternal line males u TSI = Terminal Sire Index

I OWA S TATE U NIVERSITY Department of Animal Science Terminal Sire Index (TSI) u Days to 250 Pounds (114 kg) u Backfat u Loin Muscle Area u Pounds of Lean in 185 pound (84 kg) carcass

I OWA S TATE U NIVERSITY Department of Animal Science Terminal Traits u Terminal traits have greatest economic impact when the commercial offspring are marketed u Traits related to n Growth l Average daily gain (ADG) l Average daily lean growth (ADLG) l Days to market (Days) l Days to some constant weight (Days to 250 lbs or 113 kg)

I OWA S TATE U NIVERSITY Department of Animal Science Terminal Traits u Terminal traits have greatest economic impact when the commercial offspring are marketed u Traits related to n Carcass Composition l Backfat (BF) l Loin muscle area or loin muscle depth (LMA or LD) l Carcass lean % l Fat free lean (FFL)

I OWA S TATE U NIVERSITY Department of Animal Science Terminal Traits u Terminal traits have greatest economic impact when the commercial offspring are marketed u Traits related to n Efficiency l Feed intake (ADFI) l Feed efficiency (F:G or G:F) l Lean efficiency (F:LG or LG:F) l Role that gain plays with feed efficiency

I OWA S TATE U NIVERSITY Department of Animal Science Terminal Traits u Terminal traits have greatest economic impact when the commercial offspring are marketed u Traits related to n Carcass Quality l pH l Drip loss l Color Minolta – Objective color scoring Scoring – Subjective color scoring l Marbling or IMF

I OWA S TATE U NIVERSITY Department of Animal Science Terminal Traits u Terminal traits have greatest economic impact when the commercial offspring are marketed u Traits related to n Eating quality l Instron tenderness l Cooking loss l Consumer acceptance l Sensory meat panel scores Juiciness Tenderness Flavor Off-flavor

I OWA S TATE U NIVERSITY Department of Animal Science Heritability Estimates Trait Heritability Estimate u Number born.10 u 21-d litter weight.15 u Number weaned.05 u Average feed intake.24 u Average daily gain.30 u Days to 250 lbs..35 u Feed efficiency.30 u Backfat.40 u Loin muscle area.45

I OWA S TATE U NIVERSITY Department of Animal Science Relative Economic Value of Swine Traits

I OWA S TATE U NIVERSITY Department of Animal Science NBS Breed Differences for ADG

I OWA S TATE U NIVERSITY Department of Animal Science NBS Breed Differences for BF10

I OWA S TATE U NIVERSITY Department of Animal Science NBS Breed Differences for LMA

I OWA S TATE U NIVERSITY Department of Animal Science NBS Breed Differences for pH

I OWA S TATE U NIVERSITY Department of Animal Science NBS Breed Differences for Hunter L

I OWA S TATE U NIVERSITY Department of Animal Science NBS Breed Differences for IMF

I OWA S TATE U NIVERSITY Department of Animal Science NBS Breed Differences for Instron

I OWA S TATE U NIVERSITY Department of Animal Science Sex Differences in NBS Progeny Test TraitBarrowGilt Interaction ADG Yes BF Yes LMA Yes pH No Hunter L No IMF Yes INST No

I OWA S TATE U NIVERSITY Department of Animal Science Growth and Carcass Traits in the NGEP Sire LineADG (lb/d)LGOTBF10 (in.)LMA Berkshire1.85 c.63 c 1.25 d 5.74 c Danbred HD1.83 c.72 a 0.98 a 6.75 a Duroc1.95 a.70 ab 1.13 c 6.14 b Hampshire1.87 bc.71 a 1.01 a 6.58 a NGT LW1.87 bc.65 c 1.17 cd 5.62 c NE SPF Dur.1.97 a.73 a 1.11 bc 6.35 ab Newsham1.90 ab.73 a 0.98 a 6.45 a Spotted1.84 c.63 c 1.24 d 5.83 c Yorkshire1.84 c.68 b 1.05 ab 6.17 b

I OWA S TATE U NIVERSITY Department of Animal Science Meat Quality Traits in the NGEP Sire LineMin.pHDrip (%)IMF(%) Berkshire21.8 a 5.91 a 2.43 a 2.43 bc Danbred HD22.6 b 5.75 cd 3.34 cd 2.61 b Duroc22.3 ab 5.85 ab 2.75 ab 3.19 a Hampshire23.3 c 5.70 d 3.56 d 2.61 b NGT LW21.4 a 5.84 ab 2.92 bc 2.25 c NE SPF Dur.22.6 b 5.88 ab 2.81 ab 3.30 a Newsham22.2 ab 5.82 bc 2.99 bc 2.27 c Spotted22.9 bc 5.83 bc 2.88 b 2.65 b Yorkshire22.1 a 5.84 ab 2.85 b 2.42 c

I OWA S TATE U NIVERSITY Department of Animal Science Eating Quality Traits in the NGEP Sire LineC. L. (%)Instr. (kg)Tend. (1-5)Moist.(%) Berkshire22.5 a 5.33 a 3.50 a 66.0 a Danbred HD24.3 b 5.85 c 3.45 ab 65.3 ab Duroc23.1 ab 5.64 b 3.38 ab 65.0 b Hampshire26.0 d 5.82 c 3.36 ab 65.0 b NGT LW22.9 ab 5.75 bc 3.16 c 65.5 ab NE SPF Dur.22.5 a 5.52 ab 3.36 ab 65.3 ab Newsham24.2 bc 5.87 c 3.25 bc 65.1 b Spotted23.4 ab 5.68 b 3.16 c 65.5 ab Yorkshire23.5 bc 5.87 c 3.26 bc 65.3 ab

I OWA S TATE U NIVERSITY Department of Animal Science NGEP Terminal Line Results -- Ranked on % Lean %LeanMinpHIMFInst. Danbred HD Newsham Hampshire Yorkshire NE SPF Dur Duroc NGT LW Spotted Berkshire

I OWA S TATE U NIVERSITY Department of Animal Science Heritabilities and Genetic Correlations on the NGEP

I OWA S TATE U NIVERSITY Department of Animal Science Heritabilities and Genetic Correlations for Selected Traits in the NGEP

I OWA S TATE U NIVERSITY Department of Animal Science Heritabilities and Genetic Correlations for Production Traits Estimated from NGEP Data Ave. Daily Feed Intake.50 Ave. Daily Gain-SEW Days/ Ave. Daily Gain Lean Gain Per Day Soundness ADG ADFISEWD250ADGLNGNSOUN. Heritabilities on diagonal and genetic correlations below diagonal.

I OWA S TATE U NIVERSITY Department of Animal Science “Quality” Indicators u Color u Marbling u Firmness u Water holding capacity u pH u Tenderness u Taste

I OWA S TATE U NIVERSITY Department of Animal Science Measurement of Color u Minolta Chromameter n Minolta (range of 17-33) n Hunter L (range of 40-60) u New NPPC Color Standards (1-6)

I OWA S TATE U NIVERSITY Department of Animal Science Color Scores

I OWA S TATE U NIVERSITY Department of Animal Science Water Holding Capacity u Kauffman filter paper method u Measures amount of moisture on the cut loin surface u Low numbers indicate less moisture loss u Visual Firmness/Wetness Scores (Very Firm, Firm, Soft) u Drip loss -- measures purge

I OWA S TATE U NIVERSITY Department of Animal Science Ultimate pH u Measured 24 hours after slaughter u Insert pH probe into the muscle u Higher pH = darker color, low drip loss, more firmness, increased tenderness u Predictor of water holding capacity u 45 minute pH is indication of PSE

I OWA S TATE U NIVERSITY Department of Animal Science Intramuscular Fat (IMF) u Marbling or lipid content u Laboratory analysis u Minimum amount is necessary for desirable eating quality ( %) u New NPPC Marbling Standards (1-10) u Standards correspond to intramuscular lipid content

I OWA S TATE U NIVERSITY Department of Animal Science Marbling Scores

I OWA S TATE U NIVERSITY Department of Animal Science Tenderness u Instron tenderness using star probe u Measures pressure to compress cooked sample u Less pressure = more tender

I OWA S TATE U NIVERSITY Department of Animal Science Sensory Panel Scores u Trained sensory panel u Evaluation of palatability n Tenderness n Juiciness n Chewiness n Flavor

I OWA S TATE U NIVERSITY Department of Animal Science Objectives of the Study: An evaluation of pH and hydrogen ion concentration (H+) was conducted to determine if the mathematical conversion of H+ to pH could affect 1. prediction of genetic merit of animals when pH or H+ is used as an indicator in the assessment of pork quality.

I OWA S TATE U NIVERSITY Department of Animal Science Introduction u Use of pH is becoming widely accepted as an indicator of pork quality. u Meat scientists and geneticists are focusing on pork quality traits and their indicators in an attempt to improve the quality of commercially produced pork. u Pork harvesting and processing industries are concerned with identifying environmental factors that can improve pork quality and its indicator traits so that more of their products can be sold as premiums products at the market place.

I OWA S TATE U NIVERSITY Department of Animal Science Definition of pH u pH = - log base 10 * Hydrogen Ion Concentration (Zubay, 1988). u This transformation was made not to normalize the distribution, but to reduce the size of the decimal evaluated. u The transformation can present a potential problem.

I OWA S TATE U NIVERSITY Department of Animal Science Table 1. An example of two sires with three progeny and each having identical pH averages, but differing hydrogen ion concentration. 1 Progeny phenotypic pH values Average pH Value Mean Hydrogen Ion Concentration -log 10 (mean H+), (pH units) Sire A5.6, 6.2, E Sire B5.7, 6.0, E Mean hydrogen ion concentration values have been converted to pH values (taking the negative log base 10 of the original value) in order to compare them on the same scale.

I OWA S TATE U NIVERSITY Department of Animal Science Procedures u Data from the National Barrow Show™ (George A. Hormel Company, Austin, MN) Purebred Progeny Test was utilized u Complete three-generation pedigrees, fixed and random classifications used for analyses, and pertinent muscle quality data were obtained from the National Pork Board (Des Moines, IA) u Existing carcass longissimus pH data was converted to its original hydrogen ion concentration »H + = 10 -pH

I OWA S TATE U NIVERSITY Department of Animal Science Procedures cont’ u Hydrogen ion concentration and pH genetic predictions and heritabilities were estimated using the ASREML software (Gilmour et al., 2001) u A sire model with the full relationship matrix was incorporated

I OWA S TATE U NIVERSITY Department of Animal Science Heritability estimates (± SE), genetic gain estimations, and breeding value correlations of pork carcass longissimus pH and hydrogen ion concentrations from the National Barrow Show™ Progeny Test. TraitH 2 ± SE Overall mean 1 Correlation of BLUP breeding values 2 pH0.52 ± (20.84 * ) (-0.85) Hydrogen ion concentration 0.62 ± * (5.631) 1 pH and Hydrogen ion concentration means have been converted to their corresponding values and are presented in parenthesis. 2 Values are Pearson correlation coefficient and (Spearman rank correlation coefficient).

I OWA S TATE U NIVERSITY Department of Animal Science Residual distribution of pork carcass longissimus pH and hydrogen measures from the National Barrow Show ™Progeny Test

I OWA S TATE U NIVERSITY Department of Animal Science Discussion of results u Both heritability estimates would be considered relatively high u Greater genetic progress would be expected if selection were based on H + concentration rather than pH u The Pearson correlation ( -0.92) between the pH and H + concentration breeding values was expected

I OWA S TATE U NIVERSITY Department of Animal Science Discussion of results cont’ u Spearman rank correlation between the breeding values for pH and H + concentration was u While relatively strong, the rank correlation does indicate that some difference in ranking of sires is likely to occur depending whether they are ranked based on pH or H + concentration breeding values

I OWA S TATE U NIVERSITY Department of Animal Science Example truncation selection for pH and Hydrogen ion concentration based on top 5 percent breeding values.

I OWA S TATE U NIVERSITY Department of Animal Science Example truncation selection for pH and Hydrogen ion concentration based on top 1, 5, and 25% percent breeding values. H + Selection differential Selection Intensity Select on pH Select on H + Selection Differential Selection differential loss, % 25% % %