novel approaches to expression and detection of oestrus in dairy cows

or that the cows were in an area of poor signal strength causing spiking
and an erroneous position. However, having only 2 erroneous mounts in
total was considered very promising for these preliminary trials, as this did
not indicate oestrus and hence cows would not be inseminated on the basis
of 1 episode of standing to be mounted or mounting another cow.
Limitations from this trial were that the UWB, laptop for data collection and
CCTV times were not synchronised, therefore no conclusion can be drawn
about the real-time characteristics of UWB. However these data did show
that UWB could effectively detect oestrus and distinguish between cows in
oestrus, eligible for AI, and cows not in oestrus.
In conclusion, these results provided a strong basis for progression with
the UWB system in that cows in oestrus could be clearly distinguished from
control cows. When cows are in oestrus, mounting and standing to be
mounted, the height changes could be identified and relative positions and
changing dynamics of cow position could be used to identify oestrus. Also
when cows were not in oestrus, mounting and standing behaviour were not
identified. Although there were 2 incidences of false positive results, these
were only one per cow, which would not be taken as confirmatory evidence
that a cow was in oestrus.
4.3.3.2 Increasing MU Number
To further develop UWB for the purpose of oestrous detection it was
necessary to monitor several cows at once. These trials involved increasing
the number of MUs to test how much UWB positioning data could be
collected and recorded at once. MUs were mounted on cows in backpacks
as discussed previously. Initially 10 cows were equipped with UWB in
backpacks and their position recorded. This meant that 18 UWB units (MU
and BU) were communicating at once. The UWB set up worked well and
data collection was possible. Trials then progressed into monitoring 15
cows in a 24 hour trial (detailed below), however problems were
encountered as units ‘dropped out’ (as highlighted in Table 4.1), except
there was no resolution of this issue as on each occasion 3 units failed to
communicate. With 15 MU and 8 BU the total number of units sampling at
once equalled 23 UWB units. It was concluded upon reflection that only 20
UWB units were capable of communicating simultaneously (a current
Thales system constraint), sampling at a rate of 2Hz, which could be
increased to 40 UWB units if sampling rate was decreased to 1Hz. This
101