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Live Market Hog Evaluation and Grading. Developed by: B. A. Reiling, Ph.D. University of Nebraska-Lincoln. Visual Evaluation. Subjective Less accurate than real-time ultrasound Less expensive, more convenient Still important for selection decisions Still important for marketing decisions. - PowerPoint PPT Presentation
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Live Market Hog Evaluationand Grading
Developed by:B. A. Reiling, Ph.D.
University of Nebraska-Lincoln
Visual Evaluation• Subjective• Less accurate than real-time ultrasound• Less expensive, more convenient• Still important for selection decisions• Still important for marketing decisions
Value-determining Traits• Weight
– Live weight (LW)– Carcass weight (HCW)
• Dressing Percent (DP)– Relates LW to HCW– HCW = LW X DP
• Leanness– 10th rib fat thickness– Last rib fat thickness
• Muscle– Loin muscle area– USDA muscle score
Average Values• Live Weight
– Range: 230 – 300 lbs
– Average: 272 lbs• Dressing Percentage
– Range: 68 – 78%– Average: 75%– Affecting factors
• Fill, muscle, fat
• Carcass Weight– = LW * DP– ~ 200 lbs
• Length– First rib to aitch bone– Shoulder point to ham– Range: 28-34 in– Avg: 31 in ()
How Do Animals Get Fat?
• Top to Bottom• Front to Rear• Gender Effects
– Gilts leaner than barrows
Body Shapes – Rear View• Heavy muscled hogs are wide based
Desirable Undesirable
Body Shapes – Top View• Lean hogs = “hourglass shape”• Fat hogs = “boat shape”
Desirable Undesirable
Evaluation of Fat Deposition
16 4
23
1) Jowl2) Blades3) Forerib
4) Elbow pocket5) Loin edge6) Flank
7) Tail head8) Ham seam
5 5
8
7
Average Values• Last rib fat thickness
– Used for calculation of lean content in the industry• 10th rib fat thickness
– ¾ length of the eye muscle; corresponds with “loin edge”– Used to calculate % muscle– Range: 0.35 – 1.2 in ()– Avg: .7 in – But, carcasses are NOT ribbed
Last Rib vs. 10th Rib Backfat
Last rib BF, in. 10th rib BF, in. .60 .45 .80 .80 1.00 1.20 1.20 1.55 1.40 1.95
Lean Hog
Fat Hog
How Lean? How Fat?Wt = 247 lbs Wt = 252 lbs
How Lean? How Fat?LRF, in 0.6010th rib fat, in 0.30LEA, sq in 9.50% Lean 63.16
LRF, in 1.0010th rib fat, in 1.60LEA, sq in 4.50% Lean 39.82
Evaluation of Muscle
1
2
3
1) Shoulder2) Forearm
3) Loin (top)4) Ham/stifle
4 Thick Ended
Average Values• Loin Eye Area (LEA)
– Loin Muscle Area (LMA)– Longissimus dorsi– Ultrasound measure– Range: 4.5 – 10.0 in2
– Avg: ~ 6.0 in2 ()
USDA Carcass GradingTwo Factors:• Last rib backfat (LRBF)• Muscle Score (MS)
– Thick = 3– Average = 2– Thin = 1
• = (4 * LRBF) – MS– Thin muscled hogs
ineligible for USDA #1
USDA Muscle Scores
Thin = 1 Average = 2 Thick = 3
Cutability Values• Various equations to predict % muscle (lean)
– May include 0 (fat-free), 5 (marbling), or 10% fat• Observations
– As live weight , % muscle – As fat cover , % muscle – As LEA , % muscle
Critical Factors = Fat Cover and Weight
Percentage Fat-Free Lean
• Short-cut Method– 250 lb live weight = base
• For every 10 lbs below; add 0.2%• For every 10 lbs above; subtr 0.2%
– 0.8 inches 10th rib fat = base• For every 0.1 in below; add 1%• For every 0.1 in above; subtr 1%
– 5.5 in2 LMA = base• For every 0.1 in above; add 0.2%• For every 0.1 in below; subtr 0.2%
• Typical range: 48-60%– Extremely lean pigs >60%
• With heavy-weight hogs– Frame very important
Convert percentage lean pounds of fat-free lean
live weight X 100
• Can use ultrasound • Pounds of fat-free lean:
.833 * Sex (barrow = 1, gilt = 2)+ .291 * live weight, lbs- 16.498 * 10th rib fat, in+ 5.425 * LMA, in2
- .534
Practice 1
Dress %Hot Carcass WtLRBF10th Rib FatLEAMuscle ScoreUSDA Grade% Lean
77.6%187 lbs0.60 in0.50 in8.0 in2
20.458.1%Live Weight = 241 lbs
Practice 2
Dress %Hot Carcass WtLRBF10th Rib FatLEAMuscle ScoreUSDA Grade% LeanLive Weight = 274 lbs
77.9%214 lbs1.00 in1.05 in7.4 in2
22.050.2%
Practice 3
Dress %Hot Carcass WtLRBF10th Rib FatLEAMuscle ScoreUSDA Grade% Lean
73.0%186 lbs0.70 in1.00 in5.9 in2
20.848.9%Live Weight = 254 lbs
Let’s Look at Some Live Pigs!