The effect of mixed or single sex

rearing and mineral supplementation

on gestating gilt welfare

Phoebe Hartnett

Laura Boyle, Bridget Younge and Keelin O’Driscoll

Introduction

2

• 54% sow replacement rate; lameness major factor

• +90% of Irish farms breed their own replacement gilts; reared in

pens with finisher pigs until 105kg

• More aggression and sexual behaviour in mixed sex pens than

in single sex pens

(Hartnett et al. 2017 and Teixeira and Boyle, 2014)

• Replacement gilts showed improvements in different aspects of

limb health when:

– reared separate from finisher pigs (Hartnett et al., 2017 and Quinn, 2013)

– fed a ‘developer diet’ designed for slower growth, fat deposition and

including trace minerals (Quinn et al., 2015)

• Zn, Mn and Cu are NB for horn production due to roles in cell

repair and replacement (Mohammadina, 2008; Tomlinson et al., 2008; van Riet et al., 2013)

3

Exp: 1

Rearing period

▪ 4 treatments applied

Exp: 2

Gestation period

• Service - weaning

• No longer on treatment

• Post treatment effect

Remainder of life until culling

Exp: 3

First offspring

Timeline of project

Hypothesis

Mineral supplemented diet and SS pens during

rearing in the previous study will improve stress

levels, locomotory ability and hoof health of gestating

gilts

4

Objective ▪ Effects of rearing strategy on gestating gilts welfare

Materials and methods▪ 2x2 factorial design

▪ 4 replicates over time

Factors:

1. Group composition

2. Mineral supplementation

Gilt rearing treatments:

5

Mineral diet

n = 8

Female only (SS)

n = 16

Mixed sex (MS)

n = 16

Control diet

n = 8Mineral diet

n = 8

Control diet

n = 8

Mineral inclusion

Availa sow® Control total Mineral total NRC Control % Mineral %

Mn 20 25.1 51.45 25 101% 206%

Zn 50 55.6 122.29 100 56% 122%

Cu 10 4.5 17.89 10 45% 179%

6

NRC = National Research Council, Nutrient Requirements for Swine, V.11 2012

Materials and methods

7

▪ 80 maternal line gilts

▪ 20 per treatment

Gestation Mgt. • Group housing

• Electronic Sow Feeder (ESF)

Timeline and measurements

8

• Salivary cortisol

WeaningFarrowingSlaughter Service Mid gestation Mid

finisher

d63 d74 d96 d108 d110

Timeline and measurements

9

• Salivary cortisol

• Locomotion scores

WeaningFarrowingSlaughter Service Mid gestation Mid

finisher

d32d10 d53 d73 d109

Timeline and measurements

10

• Salivary Cortisol

• Locomotion scores

• Hoof scores

WeaningFarrowingSlaughter Service Mid gestation Mid

finisher

d73 d143

Salivary Cortisol

▪ Saliva collected between 9.30am-

10.30am

▪ Analysed using an enzyme-linked

immunosorbent assay (ELISA)

11

Locomotion Scoring

• Direct observations – 30 metres, solid

concrete, front and rear view

• Scoring range 0-5, (adapted from

Calderon-Diaz et al., 2014)

Hoof scoring• 7 disorders

• Heel erosion, sole heel separation,

white line disease

• Vertical and horizontal cracks

• Dew claw length and cracks

❑ hoof disorder range (0 – 3)

12

13

▪ Heel erosion

▪ Heel sole separation

▪ Vertical crack

▪ Horizontal crack▪ White line disease

Results

14

Salivary cortisol

15

MS reared groups had higher cortisol levels (0.667 ± 0.077 ug/Dl)

than those in SS groups (0.471± 0.057 ug/Dl; P<0.05).

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

1,8

63 74 96 108 110

Co

rtis

ol u

g/D

I

gestation days

SS

MS

P = 0.06

Locomotion scores

16

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

1,8

Control MineralL

oc

om

oti

on

sc

ore

0,0

0,2

0,4

0,6

0,8

1,0

1,2

1,4

1,6

1,8

SS MS

Lo

co

mo

tio

n s

co

re

NSP = 0.02

Hoof scores

17

P = 0.0003 P= 0.02

7

8

9

10

11

12

13

SS MS

Su

m o

f h

oo

f s

co

res

7

8

9

10

11

12

13

Control Mineral

Su

m o

f h

oo

f s

co

res

Hoof scores

18

0

5

10

15

20

25

Mid-finisher Slaughter Service Midgestation

Weaning

Ho

of

in

jury

sc

ore

SS MS

0

5

10

15

20

Mid-finisher Slaughter Service Midgestation

Weaning

Ho

of

inju

ry s

co

re

Control Mineral

P= 0.1 NS

19

Hoof scores• Mineral supplemented gilts had reduced scores of;

• heel erosion (P<0.05)

• horizontal cracks (P<0.01)

• The SS reared gilts had reduced scores of

• white line disease (P<0.001)

• vertical cracks (P<0.05)

During rearing…

▪ Aggression in MS pens compared to SS pens

▪ Sexual behaviour (mounting) only in MS pens

▪ Salivary cortisol levels were in gilts reared in

MS pens when they reached breeding age

▪ No effect of mineral supplementation

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Discussion

▪ SS rearing improved hoof score

• Driven by lower white line disease + vertical crack scores

• Why?

▪ Mineral supplementation improved hoof score

• Driven by lower heel erosion + horizontal crack scores

• Why?

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Discussion

▪ Mineral supplementation during rearing improved locomotion score

• A diet including Zn, Cu + Mg improved replacement gilts locomotory ability and limb health (Quinn et al., 2014)

• Other factors – joint disorders

▪ No effect of group composition on locomotion scores

• Related to pain associated with internal damage/OCD?

• Severity

▪ SS reared gilts had lower cortisol levels than those in MS groups

• Similar to during rearing

• Perhaps related to social stress rather than injury?

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Conclusion

Both SS rearing and mineral

supplementation appeared to have

benefits for gilt welfare during gestation

23

24

Thank you for listening

Acknowledgements

- Teagasc Walsh Fellowship Fund

- Farm staff and fellow students

- Visiting student Alicia Galteau