novel approaches to expression and detection of oestrus in dairy cows

with changes of power occurring once every 24 hours. In both POC 2 and 3
UWB data collection was continuous from day 6 to day 13.
5.2.5.2 Milk Sampling
Milk samples were collected via a Lely Shuttle Milk Sampler from the start
of oestrous synchronisation on day 0 until day 17. As cows entered the
robot for milking they were identified to be sampled and approximate 20ml
milk samples were collected. Samples were preserved with one potassium
dichromate tablet (Broad Spectrum Microtabs II; D&F Control Systems,
Inc., USA) per sample and refrigerated at 4°C until measurement.
Sufficient samples were collected per trial in order to analyse hormone
concentrations, before, during and after oestrus. However, because of the
automated nature of the sampling method occasionally a sample would be
missed. Furthermore during POC 3 a communication error occurred causing
robotic system failure which meant that a couple of days had no samples,
although these were post oestrus.
5.2.5.3 Activity Recording
The current method of oestrous detection on farm is by activity monitors,
worn around the cows’ necks, which are detailed in Chapter 2. Activity data
collection was continuous over the trial period from day 0 to day 17, before
oestrus, during and post oestrus.
5.2.5.4 CCTV & Visual Observation
CCTV video recording and visual observations were used to confirm oestrus
and the cows’ actual behaviour in order to compare and aid development of
UWB data analysis. During POC 1 CCTV (PTZ Dome Camera, Pelco-D 2400)
videos continuously recorded over the period of UWB recording. In POC 2
CCTV recording was unavailable due to cow location, therefore continuous
visual observation was used to record cow behaviour. Visual observation
began 24 hours after CIDR device removal, commencing with hourly
observations for periods of 15 minutes as cows began to show early signs
of oestrous behaviour and increased interest in other cows, increasing to
more frequent observations, eventually resulting in continuous observation
as cows began mounting and then standing to be mounted by others. Four
hours after the last episode of standing to be mounted occurred, oestrus
was deemed to be over if cows were no longer showing any interest in each
other. Information recorded was; mounting cow ID, standing cow ID, date
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