Transcript The Search for the Relationship Between Spatial and Social

Correlating Spatial Learning, Social
Recognition, and Aggression
in Young Pigs
J.M. Siegford, A. Souza, J. Jansen, & A.J. Zanella
Animal Behavior and Welfare Group
Department of Animal Science
Michigan State University
East Lansing, MI 48824
Introduction
Spatial learning is mediated by the
hippocampus.
e.g., Rosenzweig et al., 2003; Castro et al., 1989; Smith &
Miller, 1981; O’Keefe & Dostrovsky, 1971
Learning to recognize conspecifics (social
learning) may also be mediated by the
hippocampus.
e.g., Bannerman et al., 2002; Kogan et al., 2000; Becker
et al., 1999; Maaswinkel et al., 1997
Study Hypothesis
If spatial learning and social recognition ability
are correlated, pigs that have good spatial
memory will better recognize and remember
other pigs.
Study Prediction
Good performers will use their better memory
of previous social encounters to minimize
fighting when later mixed with familiar pigs.
Study Design—Spatial Task I
Water maze (Laughlin et al., in press) on days 13
& 14 to assign piglets to performance groups.
Good Performers (GP): < ~55s latency.
Poor Performers (PP): > ~70s latency.
Spatial Task I—Results
GP and PP were significantly different from
each other.
Time (seconds)
Average Latency to Escape Water
Maze
80
70
60
50
40
30
20
10
0
GP
PP
(P < 0.01)
Study Design—Social Task
Social recognition test on days 19-21 to
evaluate social learning and memory of
piglets.
Predictions
GP will investigate
familiar animals less than
PP.
GP will remember
familiar piglets better 4
and 24 h later.
Study Design—Social Task
Treatments:
Spatial Performance: GP, PP
Social Recognition: Familiar, Unfamiliar
Length of SR Interval: 4h, 24h
8 treatments
2 x 2 x 2 factorial design
6 animals/treatment group
Social Task—Results
Previous research showed less social
investigation by familiar pigs compared with
unfamiliar pigs (Souza et al., 2003).
No effects of spatial performance, familiarity,
or duration of interval were seen in time
spent in social investigation, largely due to
individual variability.
Spatial Task II—Design & Results
Piglets remember the task 10 days later and after
weaning on day 22.
No difference between GP and PP (P > 0.1) on d24.
Significant interaction of test day and performance
on time (P < 0.01).
Average Test Times by Performance
Time (seconds)
120
a
100
GP
80
60
b
40
PP
b
c
c
Day 14
Day 24
c
20
0
Day 13
Study Design—Post-Mixing
Observe behaviors of pigs when mixed with
non-littermates on day 25.
Predictions
Pigs will fight more with unfamiliar animals at
mixing.
GP will fight less than PP at mixing.
Post-Mixing—Results
Pre-mixing familiarization leads to a
decrease in number of fights on the morning
of mixing.
Number of Post-Mixing Fights by
Familiarity
*
12
Famililar
Unfamiliar
# Fights
10
8
6
4
2
0
AM
Time of Day
PM
(P < 0.01)
Post-Mixing—Results
PP fight more often than GP on the morning
of mixing.
Number of Post-Mixing Fights by Spatial
Performance
12
*
10
# Fights
GP
PP
8
6
4
2
0
AM
Time of Day
PM
(P < 0.05)
Implications
Providing pigs with safe ways to interact prior
to mixing could reduce aggression between
pigs.
Thank You
Special thanks to:
ABWG
Swine Teaching and
Research Center
Per Nielsen
USDA NRI #2001-2440
awarded to A.J. Zanella
funded this study.