novel approaches to expression and detection of oestrus in dairy cows

in elastic silicone moulded over a nylon spine, used to synchronise oestrus
in ruminants. Insertion was carried out using an applicator disinfected in
Savlon solution (Novartis Consumer Health, Horsham, UK; 1:100 dilution).
The CIDR was loaded into the applicator and lubricant applied (Vet Lubigel;
Dechra Veterinary Practice, Shropshire, UK) to the protruding end of the
device. The vagina of the cow was cleaned immediately prior to device
insertion and the loaded applicator inserted with a slight upward
orientation into the vagina and the CIDR expelled by depressing the end of
the applicator. The applicator was withdrawn and disinfected. Following
insertion the animal’s blood progesterone reached maximum concentration
within an hour of insertion and was maintained until removal. On day 6
2.0ml Estrumate (Cloprostenol sodium; Cockburns Veterinary Group, Leics,
UK) was administered to each cow intramuscularly. Estrumate is a
synthetic prostaglandin analogue structurally related to PGF 2α , which
facilitated regression of the CL if present. At day 7 CIDRs were removed
causing progesterone concentration to decline, which allowed oestradiol
concentrations to increase due to increased LH pulses (see Chapter 1).
Devices were removed by gently pulling on the exposed removal tag. This
resulted in oestrus approximately 48 hours later.
5.2.5 Data Collection
5.2.5.1 Ultra-wide Band (UWB) Recording
The UWB network was set up (as described in section 4.2.2) with 8 base
units (BUs) forming a network to cover the 2 locations in which cows from
these studies were housed. All BUs were in direct line of sight to one BU
nominated as the master unit, set up in optimal positions to reflect
accurate positioning coordinates of the MUs assigned to each cow. Each
cow was equipped with 1 MU, the number of each UWB unit recorded
against cow number, and one battery. The UWB MUs were set to sample at
2Hz, twice per second, and send their position to the control unit connected
to the computer where data was recorded and stored. UWB data recording
began on the morning of day 6 and was scheduled to end on the morning
of day 13 thus recording cow position by UWB continually for 7 days.
Battery changes were scheduled at intervals throughout the trials in order
to maintain continuity of data collection. Unfortunately in POC 1 failing
battery power and recharging batteries became too frequent and the
decision was made to end the trial prematurely at day 11. During POC 2
three different batteries were used to ensure power failure was avoided,
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