the effect of mixed or single sex rearing and mineral
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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
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
20
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?
21
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?
22
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
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