Transportation Effects on Stress Response and Pork Quality
Dr. Jennifer Brown Research Scientist- Ethology
Prairie Swine Centre, Saskatoon, SK
Outline • Introduction: Transport losses in Canada • Transport research
– Phase 1: Benchmarking study – Phase 2: Effects of long transports – Trailer conditions, pig behavior, stress
response and meat quality
• Conclusions • Transportation research: looking forward
Introduction Transport losses in Canada:
• Dead on arrival (DOA) rate for Canada is 0.10% – Excess of 16,000 pigs/year – Higher in summer (up to 0.3%) – Variation due to farm (50%), packer (25%) and
trucker (19%) (Dewey et al., 2004)
• Additional losses due to carcass damage and reduced meat quality – Scratching and bruising of carcass – Meat quality defects (PSE, DFD)
Transport conditions • In Western Canada:
– Large distances: long transport times to slaughter
– Extreme weather conditions (-40 to 30°C) • In Eastern Canada:
– Shorter transports – Hot summer, mild winter – High humidity
• EU research: short transport times best…
Transport research • 4 year, Multidisciplinary study
– Participants: AAFC, PSC, University of Guelph, University of Saskatchewan
– Applied ethology, meat science, engineering
• Objectives: Study transport effects on stress and meat
quality under Canadian conditions • Phase 1: Eastern & Western studies • Phase 2: Transport duration in West • Sprinkling study: Eastern Canada
Acknowledgements Collaboration partners • Harold Gonyou- PSC • Luigi Faucitano- AAFC • Laurie Connor- U Manitoba • Tina Widowski- U Guelph • Trever Crowe- U Saskatchewan
PhD students: Jorge Correa, Sebastien Goumon
Funding agencies • Alberta Pork, Sask Pork, Manitoba Pork, Ontario Pork • Maple Leaf Foods • NSERC - Natural Sciences and Engineering Research Council
• Agriculture and Agri-Food Canada
Research questions • How does transport of market pigs affect:
– Behavior and stress physiology? – Meat quality?
• Canadian conditions – East & West, Trailer types, distances
• Other objectives: – Improve transport practices, self-regulation – Identify knowledge gaps- target future research
Research overview • Phase 1: Benchmarking
– West: 7h transport, dual purpose trailer – East: 2h transports, flat deck and pot-belly – 36 loads (6 summer, 6 winter replicates)
• Phase 2: Transport duration – 6, 12 and 18 h transport – 24 loads (4 summer, 4 winter replicates)
Today’s presentation- a selection of findings from both studies…
Meat quality assessment pH- 24 h Drip loss Colour reflectance
(CIE L* a* b*)
Research measures – Trailer temperature and humidity – Behavior during transport – Heart rate and body temperature – Blood stress indicators (Cortisol, CPK, lactate) – Meat quality- loin, ham (16 pigs/load)
12pm 1pm 1.20pm 6pm 7pm 7.20 pm 12am 1am 1.20am 7.30am 8am 9.30am
18 h truck
12 h truck
6 h truck
Phase 2: Transport periods
Pre travel Initial Travel Pre-arrival 1 Pre-arrival 2 Lairage
Trailer monitoring
1 2 3 4
5 7 8
9 10
iButton data loggers- 5 per compartment Monitor temp & humidity (5 min intervals)
Western trials: dual purpose pot belly trailer Nine compartments, 195 pigs per load
Trailer temperatures • Compartment temp and humidity vary significantly
• Comp. 5 and pot warmest (summer & winter)
• Top deck: cooler than other levels
• Pigs transported at night for early plant arrival
Avg Compartment Temp (°C)
Comp 1 Comp 4 Comp 5 Comp 10
Top deck Middle deck Pot belly
Summer 19.8a 18.4a 20.6a 21.5a
Winter -4.3c -5.3c 1.8b 5.1a
The Stress response Physiological markers of stress: • Heart rate, body temperature • Blood measures: cortisol, CPK, lactate
• Behavior measures- useful for interpreting changes in stress response – Eg. HR increase activity/postural changes?
Response to temperature: Thermoregulation
• Posture/behaviour adjustments- Cool and Warm zones • Energy expended to maintain temp- Cold and Hot zones
Heart rates in Summer and Winter
80
85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
165
170
15 45 75 105
0.5 1.5 2.5
3.5
4.5 5 15 25 35 45 55 65 75 85 95 105
115 5 15 25 35 45 55 65 75 85 95 105
115
125
135
145
155
165
175
185 10 20 30 40 50 60 70 80 90 100
110
120
130
140
150
160
170
180 10 20 30 40 50 60 70 80 90
Hea
rt r
ate
(bea
t/min
)
SUMMER TOTAL
WINTER TOTAL
Second transport P<0.001
Loading P<0.001
Farm P<0.001
First stop P<0.001
Wait at loading NS
First transport P<0.001
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
165
170
175
180
15 45 75 105
0.5
1.5
2.5
3.5
4.5 5 15 25 35 45 55 65 75 85 95 105
115 5 15 25 35 45 55 65 75 85 95 105
115
125
135
145
155
165
175
185 5 15 25 5 15 25 35 45 55 65 75 85 95 105
115
125
135
Hea
rt r
ate
(bea
ts/m
in)
SUMMER Middle Deck SUMMER Upper deck SUMMER Bottom nose SUMMER BELLY
FARM NS
LOADING P<0.05
WAITING AT LOADING P<0.05
FIRST TRANSPORT P<0.05
FIRST STOP NS
SECOND TRANSPORT P<0.05
15°C
Heart rate and location in the PB trailer: summer
ab
a
a
a
a
ab
a a
a
ab ab
b
b
b
b
a
0
20
40
60
80
100
120
Hear
t rat
e (b
eats
/min
)
Season
Pre-arrival 1
Heart rate
Heart rate higher in winter than summer Standing requires more effort (shivering?)
0
20
40
60
80
100
120
Season
Pre-arrival 2
0
20
40
60
80
100
120
Season
Unloading
summer
winter
a b
a
b a
b
38.0
38.2
38.4
38.6
38.8
39.0
39.2
39.4
tem
pera
ture
°C
transport duration
Pre-arrival 2
summer-6h
summer-12h
summer-18h
winter-6h
winter-12h
winter-18h
a
c
b ab ab
a
Body temperature
In winter, pigs in the 18 hour truck had highest temperatures Compensate in cold temperatures by increasing metabolic rate
*
Behavior measurement • Monitored during
transport and lairage • Digital cameras used in
transport – Mounted in compartments – Pictures at 5 min intervals
• Live observations used in lairage
Posture during transport
0
5
10
15
20
25
30
35
40
45
50
Summer Winter
Avg
% StandingSitting Lying
*
- Data loss in winter due to camera freezing - Lying behavior was most sensitive measure
* More pigs lie down in summer than in winter (P = 0.02)
Posture during transport
29% 36% 45% 55%
35% 32%
35%
Significant compartment effects (P= 0.04) More pigs lying at back (C4) than front (C1)
(no correlation between posture and truck temp)
Percentage of pigs lying down
Heat stress in summer, Cold floors in winter?
During initial and pre-arrival 2 periods, pigs spent more time lying in summer than winter Similar to results for Phase 1
0
5
10
15
20
25
30
35
40
% o
f pig
s lyi
ng
Season
Initial travel
summer
winter
0102030405060708090
% o
f pig
s lyi
ng
Season
Pre-arrival 2
summer
winter
a
b
b
a
Phase 2: Posture during transport
0
2
4
6
8
10
12
% o
f pig
s drin
king
Drinking behaviour
summer-6h
summer-12h
summer-18h
winter-6h
winter-12h
winter-18ha
a a
a a
b
Phase 2: Lairage behaviour
In winter, pigs on 18 h transport drank more Dehydration due to increased metabolic rate
Phase 2: Lairage behaviour
0
5
10
15
20
25
30
Late
ncy
(sec
)
Latency to lie down
summer-6h
summer-12h
summer-18h
winter-6h
winter-12h
winter-18h
Pigs transported in for 18 h in winter took longer to lie down in lairage
a ab
ab ab
b
c
Meat quality assessment pH- 24 h Drip loss Colour reflectance
(CIE L* a* b*)
Blood measures – Cortisol- HPA axis, stress response – CPK- muscle damage, exercise, bruising, – Lactate- anaerobic glycolysis
Stress and Meat Quality
Acute stress- adrenaline! Increase muscle temperature, lower pH Produces lighter meat with high drip loss Pale, soft, exudative (PSE)
Longer-term stress - fatigue Depletes glycogen stores in muscle Produces high pH meat Dark, firm, dry (DFD)
Blood CPK and Cortisol
b
5993
a
9770
0
2000
4000
6000
8000
10000
12000
Summer Winter
CPK
(UI/L
)
P<0.001
a
5695
a
5892b
4760
a
6327
0
1000
2000
3000
4000
5000
6000
7000
Upper deck Bottom nose Middle deck Belly
CPK
(UI/L
)P<0.05
Seasonal effects: CPK and cortisol
-CPK higher in winter
-Cortisol higher in summer
Compartment effects: CPK
- Lower on Middle deck
Blood lactate
b
12.2
a
14.2
c
10.1
b
11.9
0
2
4
6
8
10
12
14
16
Upper deck Bottom nose Middle deck Belly
Lac
tate
(mm
ol/L
)P<0.05
b
10.4
a
13.3
0
2
4
6
8
10
12
14
16
Summer Winter
Lac
tate
(mm
ol/L
)
P<0.001
Phase 2: Blood CPK • CPK increased with trip duration • Compartments can either mitigate (C1) or
aggravate stress (C4, C10)
0
5000
10000
15000
20000
25000
30000
35000
6 12 18
Transport duration (h)
CPK
(IU/L
) Comp 1Comp 4Comp 5Comp 10
a abab
aa
c
d
aebef
cf
d
c
Effects of Season on Meat Quality
VehicleSeason Summer Winter Significance SEM
N 257 215
Longissimus dorsipH 6h 6.02 6.02 NS 0.02
pH 24h 5.64 5.73 *** 0.01
L* 49.19 49.04 NS 0.26
JCS y 2.94 3.11 * 0.06
Drip loss (% ) 4.05 3.39 *** 0.14
SemimembranosuspH 6h 6.32 6.07 *** 0.02
pH 24h 5.63 5.71 *** 0.01
PQM 6.88 6.98 NS 0.18
L* 46.84 46.19 * 0.21
Drip loss (% ) 3.77 4.15 * 0.13
AdductorpH 24h 5.81 6.01 *** 0.02
*P < 0.05; ** P < 0.01; NS: non-significanty According to Japanese Color Scales (from 1 = pale to 6 = dark; Nakai et al., 1975)
PB
Phase 2: Driploss • Comp x season effects
– driploss higher in C10 in summer than winter – C1 and C4 show little seasonal change – Similar results in both loin and ham
Driploss from Semimembranosus Muscle
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
Summer Winter
Dri
plos
s (%
)Comp 1Comp 4Comp 5Comp 10
b
a
bab
a
bab
b
Driploss from Longissimus muscle
0
0.5
1
1.5
2
2.5
3
3.5
4
Summer Winter
Season
drip
loss
(%)
Comp 1
Comp 4
Comp 5
Comp 10
Phase 2: Driploss
• Comp x trip duration – Driploss in C10
higher after 6h, lower after 18h
– Similar results in loin and ham
Driploss from Longissimus muscle
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
6 h 12 h 18 h
Trip length
drip
loss
(%) Comp 1
Comp 4Comp 5Comp 10
Driploss from Semimembranosus muscle
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
6 h 12 h 18 h
Trip length
drip
loss
(%) Comp 1
Comp 4Comp 5Comp 10
Phase 2: pHu
• Comp x trip duration • Final pH in C10
lowest after 6h and highest at 18h
• Energy depleted in C10 pigs after 18h transport
pH from Semimembranosus muscle
5.5
5.55
5.6
5.65
5.7
5.75
5.8
5.85
5.9
5.95
6
6 h 12 h 18 h
Trip length
drip
loss
(%) Comp 1
Comp 4Comp 5Comp 10
aaaab abab abab abab ab
b
pH from Longissimus muscle
5.5
5.6
5.7
5.8
5.9
6
6.1
6 h 12 h 18 h
Trip length
dri
plo
ss (
%) Comp 1
Comp 4Comp 5Comp 10
Temperature and Meat Quality
Summer Winter pH 6h Loin 0.21
* -0.04 NS
Ham 0.33 *
-0.25 *
pH 24h Loin -0.15 *
-0.186 *
Ham -0.10 NS
-0.31 *
Driploss Loin 0.20 *
0.061 NS
Ham 0.29 *
0.08 NS
Pearson correlation coefficients
Warm winter - decrease 6h pH - decrease 24h pH
Summer heat - Increase 6h pH - Increase drip
Opposite effects on 6h pH- extreme hot & cold
* P ≤ 0.01
Acute stress at loading and unloading key management consideration, esp in hot weather
Transport in winter may be more detrimental than in summer- esp long transports Pigs reluctant to lie down, increased metabolic rate and signs
of dehydration
Long transports can accentuate transport stress But effects vary significantly with trailer compartment
Meat quality varies with season, trip length and compartment PSE traits in summer (loin)/ DFD-RSE traits in winter (ham)
Summary
Conclusions • Meat quality problems can cause downgrading, but
can generally be managed by packers • Stress resulting in NANI and DOA pigs is greatest
economic and welfare concern • Long transports caused few problems in summer,
more problematic in cold winters • Compartment differences: research is needed to
improve trailer design and improve problematic compartments
• Improve air flow in summer, heat retention in winter
Future research- what next?
• Summer transport – Use of misting or sprinkling for cooling – Forced air ventilation – Loading density- axle position?
• Winter transport – Air flow- trailer boarding – Insulation, bedding
Acknowledgements Collaboration partners • Harold Gonyou- PSC • Luigi Faucitano- AAFC • Laurie Connor- U Manitoba • Tina Widowski- U Guelph • Trever Crowe- U Saskatchewan
PhD students: Jorge Correa, Sebastien Goumon
Funding agencies • Alberta Pork, Sask Pork, Manitoba Pork, Ontario Pork • Maple Leaf Foods • NSERC - Natural Sciences and Engineering Research Council
• Agriculture and Agri-Food Canada