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novel approaches to expression and detection of oestrus in dairy cows

novel approaches to expression and detection of oestrus in dairy cows

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Au<strong>to</strong>mated analysis <strong>of</strong> oestrous behaviour provided quantitative<br />

<strong>in</strong>formation about <strong>oestrus</strong> (Table 5.8). Average duration <strong>of</strong> <strong>oestrus</strong> as<br />

determ<strong>in</strong>ed by UWB was 8.4 hours mount<strong>in</strong>g <strong>and</strong> 8.9 hours st<strong>and</strong><strong>in</strong>g <strong>to</strong> be<br />

mounted, with a strong positive correlation (r=0.88) between these<br />

behaviours for <strong>in</strong>dividual <strong>cows</strong>. These results also show that mount<strong>in</strong>g<br />

began before st<strong>and</strong><strong>in</strong>g behaviour <strong>and</strong> ended earlier. Total duration <strong>of</strong><br />

<strong>oestrus</strong> differed between <strong>cows</strong> <strong>and</strong> ranged from 2.0 hours <strong>to</strong> 14.0 hours,<br />

averag<strong>in</strong>g 10.7 hours. Duration <strong>of</strong> <strong>oestrus</strong> reported by UWB is shorter than<br />

the average duration <strong>of</strong> susta<strong>in</strong>ed <strong>in</strong>creased activity, 12.6 hours. However<br />

the duration <strong>of</strong> <strong>in</strong>creased activity is more consistent between <strong>in</strong>dividual<br />

<strong>cows</strong> rang<strong>in</strong>g from 10 <strong>to</strong> 16 hours, but maximum activity at <strong>oestrus</strong> had a<br />

wide range from 67 <strong>to</strong> 133 activity units. Duration <strong>of</strong> <strong>in</strong>creased activity <strong>and</strong><br />

maximum activity bore no relationship <strong>to</strong> each other (r=-0.14), nor did<br />

maximum activity at <strong>oestrus</strong> <strong>and</strong> duration <strong>of</strong> <strong>to</strong>tal <strong>oestrus</strong> (r=-0.45).<br />

5.3.1 Milk Progesterone Concentration Pr<strong>of</strong>iles<br />

The daily progesterone concentrations <strong>in</strong> milk throughout the trials are<br />

reported <strong>in</strong> Figures 5.6, 5.7 <strong>and</strong> 5.8, from POC 1, POC 2 <strong>and</strong> POC 3,<br />

respectively. In all <strong>cows</strong> synchronised with CIDRs the progesterone<br />

concentration <strong>in</strong>creased upon <strong>in</strong>sertion <strong>and</strong> decl<strong>in</strong>ed steadily thereafter,<br />

decl<strong>in</strong><strong>in</strong>g rapidly upon CIDR removal <strong>to</strong>

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