1. Mark Heitstuman, WSU Asotin County Extension; Dr. Jan Busboom, WSU Meats
Specialist; Dr. Mark Nelson, WSU Dept. of Animal Sciences; Nick Larson, WSU
Animal Sciences Student.
ABSTRACT STUDY PROCEDURES STUDY RESULTS (continued)
Local consumers and processors of Asotin County Fair (ACF) 4-H and FFA pigs indicate the meat from fair pigs lack marbling, are
pale colored and exhibit excessive water loss compared to non-fair pork. Research indicates pigs bred specifically for the show ring
• All 152 fair pigs had ultrasound measurements for 10th rib fat and Time pigs were comingled & time from stunning to cooler varied
are leaner and more heavily muscled than commercial pigs. Show pigs are also often carriers of the Rendement Napole (RN) and
Halothane Stress genes. Hogs expressing the dominant RN allele will have lower ultimate pH levels, affecting the water-holding
loineye area taken at weigh-in on April 22, 2010. Hair samples considerably among the 50 pigs. Ideally the time from stunning
capacity of pork. Both genes are known to affect pork quality. All 152 pigs were ultrasounded for backfat and loineye area at weigh-in
during the 2010 fair. Sex and breed were recorded and hair samples collected for DNA analyses of each pig. Carcass data were
were also collected for DNA testing. to cooler should be 30 minutes or less.
collected on 50 pigs that were processed locally following the fair. Sixty percent (30 of 50) of the sampled pigs were carriers of the RN
gene. RN carriers produced pork that had lower pH values (P<0.0001), lower daily gains and were more muscular than non-carriers.
• 50 pigs processed locally in Clarkston had the time from
Carriers also had loin muscles that tended to be paler in color with less marbling, and greater drip loss. As expected, gilts grew
slower, were leaner, had larger loineyes and less marbling than barrows (All significant P<0.05). Genetic differences are probably
stunning to cooler recorded. Research has shown that cooling Harvest Date 12 pigs on 21 pigs on 17 pigs on
contributing to the poor pork quality of ACF pigs; however, pre-harvest handling and post-harvest chilling could also be factors. the muscles quickly can help prevent low pH and mild cases of
Educational programs and materials will be developed to address pork quality issues with breeders, youth exhibitors, processors and
`
4/25 pm 4/26 pm 4/27 am
consumers. PSE (Pale, Soft, Watery pork).
• The 50 pigs processed at either Heights Meats or NW Specialty
Meats in Clarkston had actual loin eye area, muscle color, Stun to 112 minute 110 minute 178 minute
BACKGROUND marbling score and firmness recorded. Cooler time avg. avg. avg.
• A 2” sample of each loin was measured at WSU for pH and
Issues affecting Pork Quality water drip loss. Drip Loss 8.1% 9.5% 7.1%
• Genetics- Some breeds produce higher quality pork than others. • The 50 pigs processed locally and 5 additional pigs were
Genetic mutations can also negatively affect quality. genetically tested for the Stress Gene and the Rendement
Ultimate pH 5.50 5.52 5.61
• Feeding and Nutrition. Napole Gene.
• Processing procedures. Lean Color 2.1 2.4 2.7
• Consumer/Cooking Procedures.
STUDY RESULTS Lean 2.0 1.6 1.9
2 deleterious Genetic Mutations have been identified which Genetic Testing Firmness
affect Pork Quality Of the 55 pigs that were tested for the Napole & Stress genes:
1. Stress Gene- Produces higher feed efficiency, muscle and Marbling 1.1 1.1 1.3
carcass lean (positives). •60% (33 of 55) were Napole (RN) carriers.
Negative Affects- Associated with Porcine Stress Syndrome and •13% (7 of 55) were Stress Gene carriers.
pale, watery pork.
Quality Differences in 2 pigs
2. Rendement Napole (RN) Gene- Known to create more tender
RN Status by Breed (Color) 274 lb Crossbred,
meat (positive). Pig Color Number RN Status % RN Homozygous Napole
Gene Carrier
Negative Affects- Pigs that are carriers will suffer from reduced Carriers
pH levels. Most often found in Hampshire and Hamp crosses. Too Lean and Very
White 42 pigs 2 of 16 carriers 12.5% Watery
Marbling Red Belt 5 1 of 3 carriers 33.3% AVG DAILY GAIN: 1.76 lbs./day MUSCLE FIRMNESS: 2.0
Most consumers ULTRASOUND BACKFAT: 0.4 inches MARBLING: 1.0
prefer between 2%
Blue Butt 83 21 of 27 carriers 77.8% CARCASS LOINEYE AREA: 10.2 sq.in. DRIP LOSS: 7.52%
LOINEYE COLOR: 2.5 pH: 5.6
and 4% marbling.
Show pigs often
Hampy 22 6 of 6 carriers 100%
lack marbling. Spot 1 Non-carrier 0% 272 lb Crossbred,
Heterozygous
Carcass Traits of Asotin County Fair Pigs Napole Gene Carrier
As expected, there were significant differences between Acceptable Backfat
Barrows and Gilts for carcass traits. and Low Drip Loss
Barrows Gilts Significant AVG DAILY GAIN: 1.96 lbs./day MUSCLE FIRMNESS: 2.0
ULTRASOUND BACKFAT: 0.9 inches MARBLING: 2.0
Water Drip Loss (25) (25) CARCASS LOINEYE AREA: 6.2 sq.in. DRIP LOSS: 1.95%
Many of the pigs in LOINEYE COLOR: 2.5 pH: 5.6
this study had Average Daily Gain 1.91 1.79 P=0.04
excessive drip loss.
Backfat (ultra) .90 .64 P<0.001 CONCLUSIONS
Loin Eye Area 6.57 7.00 P=0.02 Genetics are one factor affecting the high drip loss, pale color, and
(ultrasound) low marbling exhibited by ACF pigs.
LEA (measured) 7.19 7.74 P=0.03 Post-fair handling procedures, stress during the fair, and the time
from stunning to the carcasses actually beginning the cooling
Marbling 1.31% 1.09% P=0.03 process are also likely contributing factors.