novel approaches to expression and detection of oestrus in dairy cows

engage in more natural behaviours including expression of oestrus.
However rubber flooring can also be slippery when either wet or worn. If
the floor surface is slippery or coarse then mounting behaviour is deterred
as cows are hesitant, especially if they have existing foot problems or have
previously sustained a fall caused by slippery surfaces (Blowey, 2005).
Inclusion of rubber covered slats, with grooves and raised ridges, can
improve friction and prevent slipping as well as providing additional
cushioning, facilitating increased mounting behaviour (Boyle et al., 2007).
Although, Boyle et al., (2007) concluded that flooring surface had little
effect on standing oestrus their data suggested that the use of rubber
flooring reduced foot injuries, which can also affect oestrus expression (see
section 1.4.2.1).
1.4.1.3 Stocking Density
Stocking density is the number of cows per unit of space and can affect
oestrous behaviour both positively and negatively. Increasing the stocking
density can increase the frequency of cows in oestrus meeting and
interacting (Orihuela, 2000) as cows in free stall barns display more
mounting behaviour than grazing cattle through closeness (De Silva et al.,
1981). Conversely, in overcrowded situations cows may not have enough
space to display oestrous behaviour and any oestrous expression could be
undetected because observation is more difficult with larger numbers of
cows in close proximity (Diskin, 2008). If there is insufficient area per cow
mounting activity can be indiscriminate, directed towards any cows or
nearest herd mates because of the close confinement (Metz and Mekking,
1984). In contrast in spacious areas cows in oestrus can choose who they
mount and non-oestrus cows can resist mounting (Diskin, 2008). Close
confinement has adverse effects on oestrous detection because animals
can be wrongly identified as being in oestrus. Misidentification can occur
because of increased number of buttings and aggression which can be
mistaken for signs of secondary oestrous behaviour, combined with
increased interactions in general (Metz and Mekking, 1984). High stocking
densities also can affect expression through related factors; aggression
(Metz and Mekking, 1984), overcrowding decreasing the lying time of cattle
leading to higher incidence of lameness (Blowey, 2005) and decreases in
feed intake because of an increased number of displacements from the
feeding area (DeVries et al., 2004). These all have adverse effects on
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