Selecting Swine TEKS: 130.2(C)(12)(D)

Objectives List 3 ways to evaluate swine; List traits we can visually evaluate; Label the parts of a pig; Describe what we should look for in structure from a side view; Describe what angle a pig s pastern should sit at; Explain why we should select against uneven toes;

Objectives Describe how the hind legs on a pig should stand; List 5 structural faults we should select against; Explain how proper angularity in the legs and maximum cushion benefits the hog; Explain why we should select for pigs that have volume and dimension of rib and body cavity;

Objectives Explain why natural curvature in the rib cage is important for sows and gilts; List 3 areas we can easily find fat disposition at; Identify areas where muscle is expressed at; Distinguish correct and incorrect underlines from multiple different pictures; Identify what PSS stands for; Solve a Pearson square problem for PSS;

Objectives Identify indications of PSS; Define PSE; Define DFD; Label the cuts of a hog carcass; Define what a Pedigree is; Identify what EPD stands for; and Choose the best boar out of 4 that you would pick to be in your herd.

Introduction What do you want to produce? Market animals? Breeding animals? Photo by Tim McCabe courtesy of USDA Natural Resources Conservation Service.

Introduction Market hog Combination of carcass & production traits Breeding hog Combination of carcass & production traits Reproductive & breeding potential

Select for Structurally sound Healthy Big volume Thick muscled Efficient type

Ways to Evaluate Visual Performance data Pedigree evaluation

Short Generation Interval Allows for rapid change Swine 2.5 litters per year Cattle 1 calf crop per year Sheep 2 litters per year

Visual Evaluation Skeletal Correctness Capacity Leanness Muscling Size & Scale Sex Character Health Breed Character

Parts of a Pig Back Loin Rump Tail Shoulder Neck Length of Side Ham Snout Jowl Knee Pastern Belly or Underline Fore Flank Elbow Pocket Rear Flank Stifle Toe Hock Dew Claw

Skeletal Correctness Raised under Confinement Conditions Concrete Wire mesh Slatted floors Photo by Gene Alexander courtesy of USDA Photography Center.

Structure Unsoundness of leg or feet get worse under confinement Structurally correct hog has cushion in the bones & joints

Structure From side view Long-bodied Strong, level top & rump High set tail Select against: Arch to the topline Shoulder blades pushed forward

Structure Angle on forelegs should approach 90 degrees Pastern angle 60 to 45 degrees Provides maximum shock absorption

Hind legs should have similar angularity.

Structure View from front: Straight-legged Adequate bone Toes even in size Short toe will cause abnormal wear on the other toe Results in lameness

Structure View from behind Stand squarely on rear legs Hind feet should toe out slightly

Structural Faults Post-legged Buck-kneed Straight pasterns Cow-hocked Sickle-hocked Splay-footed Pigeon-toed Swollen joints Crooked or Uneven toes

Structure Proper Angles + Maximum cushion = Adequate shock absorption & balanced weight distribution

Capacity Moderate depth of body Moderate length of leg Extremely long or short legs & shallow bodies are undesirable Volume & Dimension of rib & body cavity Allows for adequate feeding & breeding capacity

Capacity Equally deep in fore & rear ribs Long-bodies Moderate depth in rear flank Photo from IMS.

Capacity Natural Curvature of Rib Cage is important! Flat rib shape Hinders female from rolling onto feet while in farrowing crates

Leanness Highly heritable trait! Consumer demands lean meat! Lean down top & over loin edges Show adequate shoulder blade movement as they walk

Areas for Fat Disposition Rib cage Jowl Elbow pockets Fore & Rear flanks Underline Seam & base of ham Photo from IMS. Photo from IMS.

Round top = leanness Square top = excessive fat Photo from IMS. Photo from IMS.

Muscling Muscle + Leanness = most important components! Highly heritable! Observed in live animal Expressed in: Shoulders Top (back) Loin Rump Ham

Photo from IMS. Photo from IMS.

Muscling Shape & Expression are important when selecting! Extremeness in muscle may result in undesirable reproductive & mobility problems

Size & Scale Selecting lean, large-frames, long-bodied animals ensures they will produce faster & more efficient market hogs for offspring. Should be market-ready @ 240-280lbs w/o slowing down in growth w/o depositing excess body fat while reaching heavier weights

Ideal Market Hog 1. Clean jowl 2. Expressive top 3. Trim middle & underline 4. Muscular ham 5. Good leg structure (front & rear) 1. Wide, expressive hams 2. Correct turn & shape to top 3. Clean, trim crotch 4. Bulge & expression of muscle In stifle region 1. Wide shoulder 2. Lean turn to top 3. Expression of muscle down the top 4. Flare of ham from top view

Sex Character Boar? Barrow? Gilt? Sow? Subjective measurement of physical traits Indicates masculinity in boars & femininity in gilts & sows

Boars Adequate testicle development Rugged but not vicious appearance Photo from IMS.

Boars Select against masculinity at a very young age! Sign of early maturity Excess finish or fat when they reach market weight

Females Moderately refined Clean jowl, neck & head Photo from IMS.

Females Fully development & properly positioned vulva Permits ready penetration by boar during mating Undeveloped vulva indicated: Poorly developed reproductive tract Poor fertility

Underline Highly heritable For both boars & gilts! At least 12 teats 6 on each side Prominent Uniform in size Evenly spaced

Even spacing allows for larger udder sections & more mammary tissue that consequently will produce more milk. Photo by Ken Hammond courtesy of USDA Photography Center.

Correct or Incorrect?

Health Constitution general overall hardiness & ability to withstand adverse conditions Photo courtesy of USDA Photography Center.

Constitution Indicated by: Stoutness of head Fullness of heart girth Depth of forerib Width of chest floor Ample amount of bone Strength & soundness of feet & legs

PSS Porcine Stress Syndrome Associated w/ extremely heavily muscled hogs May result in sudden death Failure of circulatory system Unable to withstand stress of normal management: Handling Crowding Transporting Sudden changed in environment

PSS Genetic condition that is carried & transmitted by a recessive gene. If a heterozygous boar (Pp) is mated to a homozygous gilt with Porcine Stress Syndrome (pp recessive), the probability of offspring having PSS is 50% x P p p Pp pp p Pp pp Pp = 50% carriers of the PSS condition, but do not exhibit symptoms. pp = 50% carriers of the disease that do exhibit the symptoms.

Solve the Problem Porcine Stress Syndrome: A homozygous recessive (pp) Yorkshire boar is crossed with a homozygous dominant (PP) Yorkshire Gilt. What is the percentage of the offspring will be carriers of PSS, will show signs of PSS, and those that will not have PSS?

Solve the Problem Porcine Stress Syndrome: A heterozygous (Pp) Yorkshire boar is crossed with a homozygous dominant (PP) Yorkshire Gilt. What is the percentage of the offspring will be carriers of PSS, will show signs of PSS, and those that will not have PSS?

Solve the Problem Porcine Stress Syndrome: A homozygous recessive (pp) Yorkshire boar is crossed with a heterozygous (Pp) Yorkshire Gilt. What is the percentage of the offspring will be carriers of PSS, will show signs of PSS, and those that will not have PSS?

Solve the Problem Porcine Stress Syndrome: A homozygous recessive (pp) Yorkshire boar is crossed with a homozygous recessive (pp) Yorkshire Gilt. What is the percentage of the offspring will be carriers of PSS, will show signs of PSS, and those that will not have PSS?

Indications of PSS Abnormal nervousness Constant movement Tail switching Muscle tremors Trembling ears Red blotches on white hogs when excited Purple blotched on black hogs when excited Elevated body temperature

PSS Produces unacceptable quality meat PSE = Pale, Soft, & Exudative (watery) DFD = Dark, Firm, & Dry Either type is unacceptable! Should be culled from the herd Taken out

Breed Character Breed standards Color, shape of head, & ear shape Breeder s preference

Photo from IMS. Photo from IMS. Photo from IMS. Photo from IMS.

Performance Data Actual record of individual animal Reproductive Productive Carcass traits

Sow Productivity # born alive Number @ 21 days Litter birth weight

Performance Ability Growth rate Feed efficiency

Carcass Traits Backfat Loin Eye Area Percent lean

Lean cuts

Performance Data Emphasis what you want for your production system

3 Degrees of Muscling: Superior (thick) Average & Inferior (thin)

Pedigree Record of animal s ancestry Carries impressive production records Lends confidence when projecting how well young animals will perform Names & registration numbers are meaningless unless the superior individuals & outstanding producers are close in lineage.

Expected Progeny Differences EPDs Estimates of expected performance of an animal s offspring (progeny) Most accurate means of selection Takes into account the individual s performance, Parents & siblings performances, and Progeny performance

EPDs Calculated for 4 main traits: # pigs born alive (NBA) 21-day litter weight (LWT) Adjusted backfat (BF) Days to reach 250lbs (DAYS)

EPDs Expressed either as a + different or - difference from population average Positive # is favorable for NBA & LWT Negative # is favorable for DAYS & BF

EPDs of Yorkshire Boars Boar Number DAYS (lb.) BF (in.) LWT (lb.) NBA 1-1.4-0.01 +1.5 0.00 2 +2.3 +0.03-3.7-0.60 3-1.5-0.03 +1.7 +0.15 4-1.1 +0.02 +3.9 +0.60

EPDs of Duroc Gilts Gilt Number Days to 250 (lb.) Adjusted Backfat (in.) Adjusted LEA* (in 2 ) Dam s SPI** 1 168 0.60 6.4 108 2 165 0.65 6.2 104 3 178 1.00 4.6 99 4 169 1.33 5.5 98 * LEA = Loin Eye Area (in square inches); ** SPI = Sow Productivity Index

ALL RIGHTS RESERVED Reproduction or redistribution of all, or part, of this presentation without written permission is prohibited. Instructional Materials Service Texas A&M University 2588 TAMUS College Station, Texas 77843-2588 http://www-ims.tamu.edu 2007