novel approaches to expression and detection of oestrus in dairy cows

5.4 DISCUSSION
The aim of this work was to develop a novel method of oestrous detection
in order to improve oestrous detection rates and hence improve herd
productivity. This study investigated using positioning technology to
demonstrate proof of concept that UWB could detect oestrus. The
objectives were to demonstrate: i) identification of cows approaching
oestrus; cows mounting other cows in oestrus; cows standing to be
mounted, by monitoring their position in real-time, ii) develop techniques
to analyse data such that this information could be used in a commercial
situation together with the use of physiological information to determine
stage of the oestrous cycle and iii) to develop associated communications
technology to be able to monitor a herd of cows and detect cows in oestrus
automatically.
The data presented here supports the proof of concept that UWB can be
used as a method of oestrous detection. Here it is reported that both cows
coming into oestrus and cows in oestrus can be identified in real-time,
where oestrous behaviour can be distinguished from the normal behaviour
of non-oestrus cows. This was confirmed by visual observation, milk
progesterone concentration and activity monitoring, which all serve as
methods of oestrous detection for comparison.
5.4.1 UWB
UWB accurately measured 3 dimensional positioning of cows when
monitoring was continuous. The interactions been 2 cows in 3 dimensions
could be recorded and the height increases when mounting occurs during
oestrus could be identified in real-time (Figures 5.2 to 5.5). UWB provides
a high degree of horizontal accuracy, where vertical accuracy and changes
in height (such as those that occur during mounting) have been difficult to
achieve. This is because the physical geometry of BU networks provide
many horizontal observations, from one side of the dairy barn to the other
in both X and Y dimensions, but the vertical observations are all from
overhead with none available from below. Therefore there are not as many
observations in the Z dimension and thus it is more difficult to achieve as
high accuracy in the vertical dimension (the same principle applies to GPS
satellite positioning, with all satellites visible being overhead).
Furthermore, vertical signals are thus more at risk of obstruction, and
reflection is more common, affecting accuracy of precision. However, this
137