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 rate recording (Polar monitors)

Gastrointestinal tract temperature (GTT)

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

Standing Sitting

Lying Undefined

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)

Meat Quality

Quality categories

PSE MODERATE PSE MODERATE DFD DFD NORMAL

RSE PFN

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

Effect of Truck Compartment on Meat Quality

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

Darker loins in C4

P = 0.04

Phase 2: Muscle color Compartment effects

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

Thank you!