Reproductive and Maternal Behavior of Livestock - Genetics and the Behavior of Domestic Animals - page 175

reflex, of approximately 20 and 30% respectively; estimates supported by
Knauer et al. (2010) . Thus, selection for estrous traits in swine could be eco-
nomically attractive in terms of reduced age at puberty, reduced seasonal
infertility, and increased sow reproductive lifetime ( Rydhmer, 2000 ).
However, selection for reproduction traits is not always favorably reflected
in production traits, so these relationships, as well as environmental factors
such as housing and handling, should be considered in multi-trait breeding
programs ( Rydhmer, 2000 ).

Maternal Behavior in Swine
In modern swine production systems, sows are often kept in crates which
limit maternal behaviors due to space confinements. However, when straw
and branches are provided to provide a semi-natural environment, sows read-
ily engage in nest building behavior prior to parturition (1 7 h) and this can

increase time spent in lateral recumbency during the process ( Damm et al.,
2000 ). Both farrowing and nest building behaviors appear to be associated
with stress reaction patterns, especially in gilts. Gilts that reacted calmly to
stress exhibited better nest building and farrowing behaviors than did more
behaviorally active individuals ( Thodberg et al., 2002 ).
Further, personality traits, as reflected by fear and anxiety expressed in
the presence of humans, have been linked with maternal ability. Higher
levels of fear and anxiety were associated with a longer duration of farrow-
ing and more stillborns ( Janczak et al., 2003 ) whereas sows that were more
responsive to piglet demands and not afraid of people had better piglet sur-
vival ( Grandinson et al., 2003 ). Losses could possibly be reduced by geneti-
cally selecting for the maternal component of farrowing survival which
would reduce stillbirths while not negatively affecting total piglets born
( Leenhouwers et al., 2003 ). Further, genetic selection targeting piglet
survival by reducing crushing of piglets could be considered in breeding
programs ( Baxter et al., 2011 ). The pre-lying behavior of sows tends to be
crucial for piglet survival. Sows that perform “sniffing”, “looking around”,
and “nosing” before lying down tend to be less likely to crush piglets than
sows that don't perform these behaviors ( Wischner et al., 2010 ).
Additionally, sows that did not crush piglets were more restless pre-partum
and engaged more frequently in nest building than more relaxed sows. There
may be differences between the best genetic selection program for inten-
sively housed sows and extensively raised pastured sows.
Poor maternal behaviors, such as savaging and eating piglets, have been
linked to certain (QTL) quantitative trait loci ( Chen et al., 2009 ). Vangen
et al. (2005) reported that possible behaviors that could be influenced by
genetic selection are a sow's reaction to people, including fear and aggres-
sion, especially when her piglets are handled. Selection of sows for calm
behavior during farrowing may help make intensively raised sows more