Impacts of genetics and housing conditions on performance and health of growing pigs

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Impacts of genetics and housing conditions on performance and health of growing pigs

Nathalie Le Floc’H, Anne Boudon, Alexandra Chatelet, Marie-Christine Meunier-Salaün

To cite this version:

Nathalie Le Floc’H, Anne Boudon, Alexandra Chatelet, Marie-Christine Meunier-Salaün. Impacts of genetics and housing conditions on performance and health of growing pigs. 38. Simposium de Anaporc, Sep 2017, Seville, Spain. �hal-02791764�

Impacts of genetics and housing conditions on performance and health of growing pigs

N. LE FLOCH, A. BOUDON, A. CHATELET, M.C. MEUNIER-SALAUN UMR INRA PEGASE 35590 SAINT GILLES, FRANCE

Does genetic contribute to pig susceptibility to production diseases?



Production diseases have multifactorial origins



Influence of genetics ?



Belief or reality : Animals genetically selected for high productive potential would be more at risk to develop diseases in suboptimal housing conditions ?



Hypothesis behind this idea ?



High productive pigs may fail to adapt their physiology, metabolism and immune response to cope with environmental

Rauw 2009, Prunier et al, 2012

An experimental approach conducted on genetic lines divergently selected by INRA



Large-White pigs selected for Residual Feed Intake or RFI

• RFI a measure of feed efficiency (35-95 kg)

difference between measured FI and predicted FI



2 divergent lines for RFI

• High RFI (HRFI) : eats more than predicted

less efficient

• Low RFI (LRFI) : eats less than predicted

more efficient

• Compared to HRFI : LRFI  feed intake, physical activity, heat

production and body fat

An experimental approach conducted on genetic lines divergently selected by INRA



Our question : do these 2 lines respond in a same way to housing conditions at risk for their health and welfare?



If no : what are the biological basis of the differences between the 2 lines ?



Our initial hypothesis : the pigs from the LRFI line, the most efficient,

would be more affected by non optimal housing conditions

An experimental approach conducted on genetic lines divergently selected by INRA



Our question : do these 2 lines respond in a similar way to housing conditions at risk for their health and welfare?

• Trial 1 : leg disorders, lameness and osteochondrosis occurrence when pigs are housed on concrete floor and forced to increase their physical activity

• Trial 2 : respiratory and inflammatory diseases caused by poor

hygiene of the housing conditions

Trial 1

Comparison of the susceptibility of the 2 RFI lines to osteochondrosis and lameness

 Osteochondrosis (OC)

Local failure of blood circulation at the top of long bones

lesions of joint cartilage

A cause of lameness ?



Hypotheses of the trial :

• LRFI pigs would be more at risk to develop OC lesions because they deposit more protein as muscle and they are less actif

• Physical activity would prevent OC through improvement of

cartilage nutrition by synovial fluid

Experimental design

 Group of 80 pigs, initial age 10 weeks

 Sex-ratio 1:1 : females and males

 50% LRFI and 50% HFI

 Experimental room equipped with an

electronic weighting device and electronic self-feeders

 Pigs equipped with ear tags for their individual electronic identification

Experimental design

 2 levels of physical activity (between 12 and 22 weeks of age)

• A+ increased physical activity :

2 passages through the sorter to the feeding area

• A « normal » physical activity :

1 passage through the sorter to the feeding area

Measurements



Physical activity : video recording and passages through the automatic feeding device



Body weight



OC lesions at slaughter (22 weeks of age) : humerus and femur of right legs



Lameness : weekly evaluation

Stavrakakis, 2014 Score 0 (no lésion) to Score 5 (severe lesion) van Grevenhof et al. 2011

Slice score

Etterlin et al. 2014

Score 0 (no lésion) to Score 5 (severe lesion)

Surface score

Score 0 (normal) to Score 5 (unable to move)

Effects of Line and Physical Activity on OC lesions

 LRFI : more severe lesions (Surface examination)

 No effect of physical activity

 Recommendation : visual inspection of cartilage surface

LRFI HRFI L

Surface examination Prox humerus 2.25 1.56 ^***

Prox femur 1.78 1.41 ^*

Slice examination Distal femur 0.30 0.47 *

>

<

Average score

 Between 55 and 90% of pigs had OC lesions !!!!!

Prox humeral

head Prox

femoral condyle

Distal femoral condyle Distal

humeral condyle

Effects of Line and Physical Activity on scores of lameness

Line LRFI HRFI P

Physical activity A A+ A A+ L Act L × Act.

Lameness average

score 0.39 0.49 0.46 0.33 NS NS †

Days with score ≥ 1

Fore‐limbs 0.70 0.38 0.49 0.29 NS * NS

Hind‐limbs 1.95 2.88 2.38 1.81 NS NS *

 Low prevalence and score of lameness # OC lesions

 No effect of line # OC lesions

 Higher score for hind-limbs with a different effect of activity for the 2 lines

Trial 2

Poor hygiene of housing conditions during the growing phase

 2 hygiene of housing conditions

• Dirty room : no biosecurity precautions, no cleaning and disinfection after previous occupation by non-experimental pigs, ↘ aeration rate, pigs were mixed with non-experimental pigs

• Clean room : cleaning and disinfection, optimal aeration rate, no mixing with non-experimental pigs

 Dirty housing conditions : immune stimulation, inflammation, low growth rate, changes in fecal microbiota, in digestion and metabolism Le Floc’h et al, 2014

 Hypothesis : LRFI pigs will be more affected because they fail to adapt

Experimental design

 160 growing – finishing pigs (50% females 50% males)

 4 Experimental groups (40 pigs per groups)

 Feed and water ad libitum

 Individual pen

 13 Weeks (W), 2 periods:

 Period 1 : 6 weeks of challenge (12-18 wks of age)

 Period 2 : 7 weeks of recovery (18-25 wks of age)

LRFI Clean

Dirty HRFI

Dirty

Clean

Period 1 : hygiene Challenge

HRFI Dirty LRFI Dirty HRFI Clean

LRFI Clean

12 wks 15 wks 18 wks

Body Weight Feed Intake Blood Samplings

Period 2 : recovery

HRFI Dirty LRFI Dirty HRFI Clean

LRFI Clean

12 wks 15 wks 18 wks

Body Weight Feed Intake Blood Samplings

20 wks 22 wks 24 wks 25 wks

- Slaughtering (80 animals): respiratory tract lesion scoring - Carcass characteristics Body Weight

Feed Intake Blood Samplings

Results : Health

 Respiratory lesions

• End of Period 1: pneumonia prevalence Dirty n=19/40 > Clean n = 3/40 average score HRFI (11.2) > LRFI (6.8)

• End of Period 2 : pleurisy et pericarditis Dirty (20/40) > Clean (2/40)

 Blood biomarkers : Period 1

0 1 2 3 4 5

3 8 13 18

ns

Haptoglobin, g/L Granulocytes, 10⁶/mm³

W12 W15 W18

HRFI Clean

LRFI Clean HRFI Dirty

LRFI Dirty ns

L**

H***

L***

H***

LxH**

L***

H***

LxH*

L*

W12 W15 W18

Results : Performance

 Growth rate

0 200 400 600 800 1000 1200

Period 1

0 200 400 600 800 1000 1200

Period 2

G/Day

HRFI Clean LRFI Clean HRFI Dirty

LRFI Dirty L***

H***

LxH**

ns

Poor hygiene induced a difference in body weight HRFI > LRFI

9.7kg vs 3.8 kg end of Period 1 13.4kg vs 5.5kg end of Period 2

 Feed intake

• Period 1 : Dirty > Clean for LRFI  unexpected!!!!

• Period 2 : Dirty < Clean  « Dirty » pigs were lighter

0 0,1 0,2 0,3 0,4 0,5 0,6

W0‐W6

HRFI Clean HRFI Dirty LRFI Clean LRFI Dirty H *** , L ***, H x L *

0 0,1 0,2 0,3 0,4

W6‐W12 H ns, L t (0.07), L x H ns

Period 1 Period 2

Results : Performance

HRFI Clean

LRFI Clean HRFI Dirty

LRFI Dirty

 Feed efficiency

Poor hygiene affected feed efficiency HRFI > LRFI

No more difference between groups

Conclusions



Trial 1. High prevalence of OC in both lines with no effect of physical activity. Osteochondrosis is not correlated to lameness in young

growing pigs.



Trial 2. Poor hygiene and the non respect of biosecurity rules is

clearly at risk for health and performance of growing-fattening pigs.



In our experimental conditions : pigs selected for a better feed

efficiency are not more susceptible to lameness, inflammatory and

respiratory diseases.

Aknowledgements

Nathalie Le Floch

INRA

T +33 223 485 039 Nathalie.lefloch@inra.fr

www.fp7-prohealth.eu