Reproductive and Maternal Behavior of Livestock - Genetics and the Behavior of Domestic Animals - page 176

productive ( Snieder et al., 2011 ). In addition, behavior of gilts assessed at
five months of age associated with subsequent economically important traits
such as piglets born alive and wean to estrus interval ( Snieder et al., 2011 ).
Olfactorial, thermal, and tactile cues are used by piglets to locate the teats
( Rohde Parfet et al., 1990 ). Newborn pigs engage in teat seeking very rap-
idly after birth, with an established and relatively consistent teat order being
evident after about 4 days ( de Passill´ et al., 1988 ). Although larger, faster-
growing piglets tend to suckle the more anterior teats, exceptions regularly
occur ( Winfield et al., 1974 ), with less stable teat orders being more evident
in larger litters than in smaller ones. However, survival of piglets appears to
be sex biased. Even though maternal investment in male piglets is higher,
male-mortalities exceed female ones ( Baxter et al., 2012 ). It is speculated
that piglet survival represents a combination of the maternal genetic compo-
nent (genotype of the sow) and the direct genetic component (genotype of
the piglet) ( Leenhouwers et al., 2001 ). In contrast to other species, sows are
tolerant of foreign young, particularly in the first few days postpartum, and
fostering can be achieved relatively easily at this time ( Signoret et al., 1975 ).
Biostimulation in Swine
Biostimulation is used as a management tool in swine which can accelerate
puberty in gilts and reduce the postpartum period in sows ( Brooks and Cole,
1970; Kirkwood et al., 1981 ). The effects on puberty are most pronounced in
gilts raised in confinement, where the introduction of a mature boar can
lower the age at puberty by approximately 30 days in concert with a marked
degree of synchrony when the gilts are approximately 190 days of age
( Brooks and Cole, 1970 ). The ability of boars to act as biostimulators is
related to their age with more mature boars (2 years old) being more effec-
tive than young (6.5 months old) boars in inducing puberty in gilts
( Kirkwood et al., 1981 ).
The major stimulus associated with pubertal advancement is probably
olfactory, as exposing gilts to a pen which previously contained a boar is
also effective. Here, the mechanism appears to be the release of boar phero-
mone(s) secreted in saliva ( Kirkwood et al., 1981 ). In addition, biostimula-
tion significantly enhances the standing reaction of sows in estrus ( Rekwot
et al., 2001 ). These phenomena are widely utilized in confinement swine
management systems where, for example, re-breeding of sows at the lac-
tational estrus and thus reducing time to re-breeding, is an important eco-
nomic consideration.
REPRODUCTIVE BEHAVIOR IN HORSES
Horses have several reproductive behavioral aspects which distinguish them
from many other livestock species. In females, these include a prolonged