Bas Rodenburg_The Role of Breeding and Genetics in Animal Welfare

8/20/2019 Bas Rodenburg_The Role of Breeding and Genetics in Animal Welfare

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The role of breeding and genetics

in animal welfare

T. Bas Rodenburg, Animal Breeding & Genomics Centre

Simon P. Turner, Scottish Agricultural College (SAC)


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Introduction

Domestication startedthousands of years ago

Past 50-60 years:

intensive selection forincreased production

Genetic selection

● Contributed to welfare issues: lameness broilers

● Can also be used to alleviate welfare issues

(Rauw et al., 1998)


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Variation between species

Domestic species vary greatly in:

● Traits under selection

● Selection intensity

● Application of breeding technologies

Intensive versus extensive systems

Differences in genetic progress


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Focus on intensive sectors

Breeding-related welfare challenges

● Mainly associated with the

highly selected poultry,

dairy and pig sectors

Also play a role in the extensivelymanaged breeds

● Increased lambing rate:

reduction in lamb survival

●

Calving difficultiesin beef cattle


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Variation within species

Breeds and hybrids

Generalist- versus specialist-type

● Intensive production: generalist-type

● Rare breeds: specialist-type

Rare breeds more hardy inspecific environments

● Easy care sheep


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High-yield crosses

Pigs and poultry: pure-bred lines used for selection

● Commercial product is a hybrid cross (4 lines)

● Female lines: reproductive traits

Male line: fast growth, low feed conversion

Sheep production: low-maintenance ewes

● Mated to less hardy,

but more productive sires

● Crossbreds for fatteningon lower ground


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Selection for increased growth in broilers

Extremely successful:

● 25 to 100 grams/day

Increased incidences of● Lameness

● Ascites

● Sudden death syndrome

(Knowles et al., 2008)


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0

5

10

15

20

25

30

35

40

1 6 14 16 21 29 42 49

Age (days)

T e m p e r

a t u r e

Control

Test

Van Horne et al., 2004

Suboptimal conditions

(van Horne et al., 2004)


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Slow growing Fastgrowing

A B C

Sudden Death 0 1.7 1.7 0

Heart Failure 0 0 1.7 1.3

Ascites 0 0 0.8 13.8

Total Heart +

circulation

0 1.7 4.2 15.0

Van Horne et al., 2004

Mortality

(van Horne et al., 2004)


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Slower growing broilers

Grow to slaughter weight in 56 rather than 42 days

Much less welfare issues

●

Reduced mortality● Reduced lameness

● Reduced footpad dermatitis

Limited feed restriction required inparent stock (dwarf mothers)


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Dairy cows

Selection for increased milk yield

● Decreased fertility and longevity

● Increased lameness

● Increased metabolic problems

● A higher incidence of mastitis

Future: automatic collection ofdata in/around milking parlour

● Incorporate informationin breeding program

(Oltenacu and Broom, 2010)


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Selection enhancing undesired behaviour

Genetic correlation tail biting with (Breuer et al., 2005):

● Lean tissue growth rate (0.27)

● Backfat thickness (-0.28)

Selection for early sexual maturation laying hens

● Correlated to increased feather pecking

(Jensen et al., 2005)


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Selection for improved welfare

Direct selection against undesired behaviours feasible

● Aggression in pigs (Turner, 2011)

● Feather pecking in laying hens

(Kjaer et al., 2001)

Helpful in understandingbehaviours

● Unravel underlying

mechanisms0

1

2

3

4

5

0 1 2 3

Generation

F r e q u

e n c y

o f f e a t h e r p e c k i n g

High feather

pecking

Low feather

pecking


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Breeding for improved group performance

Traditional: focus onindividual performance

Risk to select animalsthat are harmfulfor group performance

Alternative methods needed that take groupperformance into account


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23 5.7

15 15

19 6.3

26 6.5

Group Selected

Per

cagePer

individual

Eggs

Individual Selected

Group selection (Muir, 1996)


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Cumulative mortality (Muir, 1996)

0

50

100

150

200

250

300

350

400

450

1 8 2 1 2 4 2 7 3 0 3 3 3 6 3 9 4 2 4 5 4 8 5 1 5 4 5 7

AGE (WEEKS)

CONTROL

GROUP SELECTED 7

COMMERCIAL


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New methods

Kin selection method

● Combine individual performance

with information from sisters in

group housing (Ellen et al., 2007)

Social breeding values

● Estimate the genetic effect an animal

has on the performance of its group mates

(Muir, 2005; Bijma et al., 2007)


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Kin selection on low mortality

White leghorn line

(Ellen et al., 2007)

Control line:• Selection candidate individual• Selection on production

Low mortality line• Selection candidate individual• Selection on production• Full sisters in group (4)• Selection on low mortality

Non-beak trimmed in cages:mortality due to cannibalism


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Results after one generation

0

10

20

30

40

50

Control Low

M o r t a l i t y %

Generation 1


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Effects on behaviour

Birds selected on low mortality:

● Less fearful

● Young age

● Adult age

● Reduced stress response

● Less cannibalistic pecking

● Changes in the serotonergic system

compared with control birds

(Bolhuis et al., 2009; Rodenburg et al, 2009ab;Nordquist et al., 2011)


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Role of the serotonergic system

Feather pecking is redirected foraging

● In response to fear and stress inducing stimuli

The serotonergic (5-HT) system central role:

● Involved in coping with fear and stress,

● Involved in foraging and in feather pecking(van Hierden et al., 2004)

Selection for low mortality: changes in the peripheralserotonergic (5-HT) system (Bolhuis et al., 2009)


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FP and the serotonergic system

Associations between feather pecking and genesinvolved in the serotonergic system

Comparison of lines selected

for high an low FP

Frequency differenceDEAF1 polymorphisms

● Regulatory gene

serotonergic system

(Flisikowski et al., 2009)


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FP and the serotonergic system

Association study onfeather damage

●

Nine different linesof laying hens

● Brown and white lines

●

Association between feather damage and HTR2C● Receptor gene serotonergic system

0

0.2

0.4

0.6

0.8

1

Brown White

A l l e l e

f r e q u e n c y

(after Biscarini et al., 2010)


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Plumage condition

(after Uitdehaag et al., 2008)

4

4.5

5

5.5

Brown White

P l u m a g e c o n d i t i o n


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Fearfulness

(after Uitdehaag et al., 2008)

0

0.1

0.2

0.3

0.4

23 46 69

P r o b a b i l i t y

o f s h o w i n g a

f e a r f u l r e s p o n s e

Age (weeks)

BrownWhite


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Coherent with selection experiment

Birds selected on low mortality

● Less fearful

● Reduced stress response

● Less cannibalistic pecking

●

Changes in the serotonergic systemcompared with control birds

Further developing genetic fingerprint associated with FPwill enhance possibilities for genetic selection

(Bolhuis et al., 2009; Rodenburg et al, 2009ab;Nordquist et al., 2011)


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Aggression in pigs

Observed after mixing but also under stable conditions

● Mixing is a routine procedure

Results in skin lesions

Aggression can negativelyaffect performance

(Turner et al., 2006)


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Breeding against aggression

Technically possible

● Fighting and bullying have

moderate heritabilities in pigs

(between 0.17 and 0.43)

● Number of resulting skin lesions(between 0.21 and 0.26)

(Lovendahl et al., 2005; Turner et al., 2006; 2009)

Genetic correlations indicate that skin lesions can be

used as an indicator of being aggressive



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Effects of selection

Genetic correlation between aggression around mixingand under stable conditions: selection reduces both

Associated changes in:

● Genes involved in coping

with stress (HPA-axis)

● Brain gene expression

vasopressin and serotonin

●

Altered cholesterol metabolism

(Murani et al., 2010, 2011; D’Eath et al., 2005)


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Effects of selection

Selection might alter basic pathways that govern a rangeof biological functions

● Aggressive animals also

faster to enter weighing

scale (D’Eath et al., 2009)

No differences in general activitylevels to underlie reduced aggressiveness

● No adverse effects on lean tissue growth



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Social breeding values

Traditional selection methods lack attention for socialinteractions

Social genetic effects contribute profoundly to geneticvariance in growth rate in pigs

(Bergsma et al. 2008)


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Number of lesions

De Vries, unpublished results

Post mixing Steady situation

HighSBV

Low SBV High SBV Low SBV

Anterior 17.03a 11.59b ** 4.27 4.77Middle 7.80 7.46 1.84 2.33

Rear 1.95 2.10 0.90 1.28

Back - - 1.08a 1.63b *

* p < 0.05, ** p < 0.01

Similar results found by Canario et al. (2008)

(Rodenburg et al. 2010, Canario et al. 2008)


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Effects on manipulative behaviour

High SBV pigs showed:● Showed 15% more

comfort behaviour

● Spent 14% less time

on ear biting

● Spent 35% less time

on chewing objects

● Had less tail damage

This may indicate that low SBV pigs have a strongertendency to perform oral manipulation

(Camerlink et al. 2012, Ursinus et al. 2012)


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Conclusion selection experiments

Scope to use novel selection methodsto improve welfare of group-housedanimals

● Kin selection laying hens

● Social breeding value pigs

Progress may be slower than expected

● Hens: easier to select for increased damage

● Pigs: realised genetic progress relatively small

Increased understanding of genetics of social behaviour


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General conclusion

Breeding and genetics: important role in the welfare ofdomestic animals

If focused only on

increasing production:● Clear risk of increasing

welfare problems

Wider perspective is needed that encompasses both

production and welfare traits


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General conclusion

Genomics era could offer opportunities● More precise information on the biological

impact of certain breeding decisions

Help breeders to make more informedchoices in their selection programs

● Facilitate selection for complex

behavioural traits:

5-HT polymorphisms

● Genetic fingerprint: targeted

genomic selection approaches


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Open to collaboration!

Main topic:

● Improving social behaviour in group-housedanimals by genetic selection and improvingearly-life conditions

Future position (from 1 August):

● Assistant Professor Behavioural Ecology at WUR

● Focus on research + teaching

applied animal behaviour and welfare

●

Centre of Animal Welfare and Adaptation(CAWA)


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Thank you!

This paper will be published in theJuly 2012 issue of Animal Frontiers

(special issue on Animal Welfare,edited by Don Lay)

Bas Rodenburg_The Role of Breeding and Genetics in Animal Welfare

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