novel approaches to expression and detection of oestrus in dairy cows
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>