novel approaches to expression and detection of oestrus in dairy cows

1.4 FACTORS AFFECTING OESTROUS EXPRESSION
Poor oestrous detection arises due to lack of oestrous expression;
decreased duration and intensity and decreased standing behaviour.
Factors related to poor expression can be cow related factors; health,
nutrition and milk yield, or environmental factors; housing, flooring and
stocking density for example.
1.4.1 Environmental Factors
1.4.1.1 Housing
Housing design affects oestrous expression. If cows are loose housed in
barns then they have the freedom to exhibit oestrous behaviours and the
chance of these being observed is improved (Phillips and Schofield, 1990).
However, if cows are housed in tie stalls with little cow to cow interaction
then they cannot exhibit standing behaviour, so detection is based solely
on secondary signs of oestrus, which result in a high incidence of detection
error and consequently low conception rates (Ranasinghe et al., 2009).
Mounts in cubicle houses have been reported to be less frequent than in
open barn housing, 7 mounts per hour compared to 11 mounts per hour
respectively. At pasture the number of mounts has been reported to be
even lower, 5 mounts per hour (De Silva et al., 1981), possibly due to less
frequent contact when in an open space and feeding taking priority (Phillips
and Schofield, 1990).
1.4.1.2 Floor Type
Floor type has a dramatic effect on oestrous expression. It is documented
that cows do not like to be mounted on concrete, particularly when wet,
preferring softer surfaces underfoot such as grass, dirt or straw bedding
(Britt et al., 1986). When observed on dirt compared to concrete the
duration of oestrus was longer, with more total mounts and stands. The
duration of oestrus on dirt averaged more than 12 hours for 11 out of 13
cows, whereas only 2 cows displayed on average more than 12 hours on
concrete (Britt et al., 1986). The duration of behaviour and number of
mounts on rubber covered slats, pasture and straw were all similar, but
significantly increased compared to duration and number of mounts on
concrete (Boyle et al., 2007). Cows walking on rubber have also been
reported to move with a more natural gait, have less bruising of the corium
and a lower incidence of lameness. Therefore they are more likely to
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