Reproductive and Maternal Behavior of Livestock - Genetics and the Behavior of Domestic Animals - page 159

usually measured by male approach responses such as numbers of flehmens.
Proceptive behaviors are those female behaviors that initiate or maintain male
sexual interest or activity. Representative behaviors here include male-seeking
behavior and female

female mounting. Receptivity represents those female
actions or postures that enable successful copulation by the male. Such
behaviors include immobility ( Becke and Serrano, 2002 ) and tail diversion
( Katz and McDonald, 1992 ). Estrus behavior has also been described in terms
of both duration and intensity, with the latter including such observations as
mounting activity and mobility ( Landaeta-Hern´ndez et al., 2004b ).
Although the estrous cycle is governed by hormonal events, which in
turn may be seasonally influenced, the expression, or signaling, of estrus is
behavioral and can be influenced by a number of factors including stress and
genetics ( Landaeta-Hern ´ ndez et al., 2002a ). Examples of the former include
suppressive effects of extreme weather or social stress. Breed, line, and indi-
vidual differences in the intensity of estrus behavior have been reported in
livestock ( Landaeta-Hern ´ ndez et al., 2004b ; Løvendahl and Chagunda,
2009; Price, 1985; Rydhmer et al., 1994 ). Other factors influencing estrus
expression include nutritional (such as estrogenic feedstuffs), pathological
(such as granulose cell tumors in horses), pain (e.g., foot abscess in dairy
cattle), different forms of intersex (such as male pseudohermaphrodites), and
stability and type of flooring in cattle.
Male livestock, in general, share a number of commonalities in their sex-
ual behavior. Libido, or sex drive, has a strong genetic basis, tends to be
active year-round and can often be revived by exposure to new stimuli. The
copulatory process is usually rapid, particularly in prey species such as most
food animals. A behavioral progression can often be observed in which
males tend to be first attracted to individual females in late pro-estrus and
where the ultimate cue for attempted copulation is immobility, or standing
behavior of the female. Male courtship behaviors vary, but all seek to elicit
or detect standing behavior in the female. In turn, females play a major role
in mate selection and often determine the timing of mating and the identity
of the successful male(s). Males tend to be hierarchical and compete for eli-
gible females, with successful males generally being those higher in social
rank. In general males of high status have greater access to females than
those of lower rank ( Price, 1987 ). This may be advantageous if dominance is
associated with other favorable reproduction and production traits.
Unfortunately, however, social dominance in male livestock does not appear
to be synonymous with either fertility or mating ability ( Price, 1985 ), leading
to the possibility that dominant males may, on occasion, act to depress herd
or flock fertility ( Chenoweth, 1994a ). Competition can increase male sexual
response ( Mader and Price, 1984 ), although audience effects may also act to
inhibit male sexual activity ( Lindsay and Ellsmore, 1968 ).
Maternal behavior includes those behaviors of the dam which occur
around the time of birth and which are associated with the responsiveness,