Reproductive and Maternal Behavior of Livestock - Genetics and the Behavior of Domestic Animals - page 164

( Walsh et al., 2011 ). Despite this, the expression of standing heat and its
visual detection by trained observers is still regarded as a reliable manage-
ment tool ( Lyimo et al., 2000 ). In turn, the intensity of estrus expression has
been associated with conception rates in both Bos taurus ( Bonfert, 1955;
Evans and Walsh, 2012 ) and Bos indicus derived females ( Morales et al.,
1983 ). An heritability estimate of 0.21 was obtained for estrous intensity by
Rottenstein and Touchberry (1957) , who also obtained a within-year repeat-
ability for estrus behavior score of 0.29.
In many of the studies quoted above, human observation was employed to
detect and quantify estrus behavior. This has limitations due to human inability
to provide both 24 h quality observation as well as detect subtle behavioral
cues. In addition, factors such as climate, confinement, type of housing and
flooring can influence estrus expression in female cattle ( Landaeta-Hern ´ ndez
et al., 2002a; Rodtian et al., 1996 ). The relatively recent advent of electronic
devices to monitor mounting behavior in cattle allows more accurate monitoring
of such behaviors ( At-Taras and Spahr, 2001 ), particularly with Bos indicus
cattle ( Cavalieri and Fitzpatrick, 1995 ). One study using this method found that
measures of estrus activity were more heritable than fertility traits in several
dairy breeds ( Løvendahl and Chagunda, 2009 ).
Cattle Maternal Behavior
Cows in free-ranging herds are reported to leave the herd for calving, although
this is understandably less common in more intensive pasture systems. Red
Angus cattle appear to show a considerable degree of behavioral plasticity in
calving behavior and calf defense patterns when approached by a strange
object (e.g., a vehicle that differed from the familiar trucks on the ranch)
( Floercke et al., 2012 ). In post-parturient cows, individual differences in pro-
tection-, aggression-, and vocalization-behaviors towards the newborn calf
exist when cows are approached by a vehicle. In the former study, 99% of
cows were protective, 13% showed signs of aggression by lowering the head
or pawing the ground and 78% vocalized towards the calf. The expression of
these behaviors reflects individual differences in temperament and cows also
differed in the level of “vigilance” towards the surroundings. Important crite-
ria for selection of a birthing site include dry, soft bedding with provision of
cover. Further influencing factors are the availability of nutrition, type of ter-
rain, threat of predation, and the need for bonding with the calf.
The time of day at which most births occur varies in different reports.
Edwards (1979) found no bias towards day or night calving whereas
Keyserlingk and Weary (2007) reported increased calving in the late afternoon
and evening; nevertheless both findings may simply reflect routine manage-
ment practices. Females bond with their newborn very early in the postpartum
period and this sensitive period between mother and young is triggered
by amniotic fluids ( Gonyou and Stookey, 1987; L´vy and Keller, 2009 )