Biology Reference
In-Depth Information
LITTER
LITTER
MATES
Social experience
in early-life
Social skills
in adulthood
SOCIAL litter effects
GROUP
DIRECT
genetic
effects
SOCIAL genetic
effects
GROUP
MATES
FIGURE 11.3 The direct genetic effect and the social genetic effect on the performance of
pigs can be used to estimate direct and social breeding values. The social skills of a pig that
influence its social interactions with other group mates are determined by its social experience
in early life (achieved in contact with litter mates) and its genotype. Illustration: Laurianne
Canario
larger genetic progress than only using the direct breeding value ( Rodenburg
et al., 2010 ).
Bergsma et al. (2008) used the social model to study growth rate. The
results indicated that pigs cooperate rather than compete (r DS 5
0.2). In
another study the correlation was estimated at
0.1 ( Canario et al., 2010 ).
Chen et al. (2009a) found a range from negative to positive social interac-
tions in different American populations (r DS 52
2
0.4 to 0.7). This confirms
that the genetic background of aggressive behavior varies between pig
populations.
What characterizes pigs with high breeding values for the social genetic
effect? From a Swedish data set, we have both behavioral and lesion score
data on the animals and can compare pigs with high and low breeding values
for direct and social effects on growth rate ( Canario et al., 2012 ). We simu-
lated different situations in which the pigs displayed negative social interac-
tions (genetic antagonism between own growth and the growth of group
mates; r DS ,
0) or positive social interac-
tions (genetic mutualism between own growth and the growth of group
0), neutral social interactions (r DS B
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