Table 2.

Estimates of summary statistics for comparison of raw camera, refined camera, and visual body condition score (BCS) measurement methods. Each statistic relates to the response and/or precision of a cow by week mean. Under both camera methods each mean was an average of approximately 14 camera measurements, and under the visual scoring method, each mean was an average of 3 independent scores.

Summary Statistics	Raw Camera	Refined Camera	Visual Scoring
For change within animal over time:
Actual SD, ${\sigma }_a$, (BCS)	0.149	0.164	0.139
Error SD, ${\sigma }_m$, (BCS)	0.041	0.026	0.083
Sensitivity, $\Theta$	3.6	6.2	1.7
Relative Sensitivity, RS, of camera to visual scoring	2.1	3.7
Rate of change in BCS, β, (BCS/Month)	−0.18	−0.19	−0.17
Time to detect BCS change of $3{\sigma }_m$, (Days)	21	12	44
For differences between animals at the same week:
Actual SD, ${\sigma }_a$, (BCS)	0.207	0.232	0.288
Error SD, ${\sigma }_m$, (BCS)	0.048	0.030	0.090
Sensitivity $\left(\Theta ={\sigma }_a/{\sigma }_m\right)$	4.3	7.8	3.2
Relative Sensitivity, RS, of camera to visual scoring	1.3	2.4

SD—Standard deviation.