## 3 Results  
The analysis of the 288 h of video footage produced a total of 18,364 observations divided into 9950 tail-biting behaviour events and 8414 ear-biting behaviour events. The mean, standard deviation and range of the four types of behaviour analysed (initiating tail-biting behaviour, receiving tail-biting behaviour, initiating ear-biting behaviour and receiving ear-biting behaviour) according to the observation periods used are shown in Table 2. There is a wide span between the mean and extreme values. The results of comparison \(1\) (comparison of different observation periods to the reference of 12 h continuous observation) are shown in Figure 2a-d according to behaviour analysed and measurement of accuracy used. Generally, the accuracy scores range from 0 to 1, whereas the mean accuracy scores range from 0.03 to 0.77. The differences between continuous sampling observation periods and time sampling observation periods come mainly from an overall trend of longer observation periods producing better accuracy scores. Apart from this, the accuracy scores are on a similar level. The accuracy scores of the different behaviours are on a similar level as well, although initiating tail-biting behaviour has slightly better scores. Comparing the different measurements of accuracy shows better accuracy scores for the measurement based on the ranking order. In Figure 3a-d, the results of comparison 2 (comparison between the observation periods of the same kind and length) are displayed. Here, the mean accuracy scores range from 0.05 to 0.47. Analogous to the comparison 1, the initiating tail-biting behaviour produces slightly better accuracy scores. Additionally, the measurement PA produces the best accuracy scores for observation periods of 1 h or shorter. \begin{table}
\begin{tabular}{c c c c c c} \hline  & & \multicolumn{2}{c}{**Initiating Behaviour**} & \multicolumn{2}{c}{**Receiving Behaviour**} \\ \cline{3-6}
**Behaviour** & **Observation Period** & **Mean \(\pm\) Standard Deviation** & **Range** & **Mean \(\pm\) Standard Deviation** & **Range** \\ \hline Tail-Biting & 12 h & \(1.45\pm 1.77\) & 0–17.67 & \(1.45\pm 1.18\) & 0–9.33 \\ Tail-Biting & 6 h & \(1.45\pm 2.10\) & 0–25.33 & \(1.45\pm 1.42\) & 0–12 \\ Tail-Biting & 3 h & \(1.57\pm 2.42\) & 0–26.67 & \(1.57\pm 1.62\) & 0–13 \\ Tail-Biting & 1 h & \(1.57\pm 3.12\) & 0–54 & \(1.57\pm 2.16\) & 0–24 \\ Tail-Biting & 0.5 h & \(1.57\pm 3.69\) & 0–74 & \(1.57\pm 2.66\) & 0–26 \\ Tail-Biting & 24 \(\times\) 10 min & \(1.45\pm 1.93\) & 0–21.25 & \(1.45\pm 1.31\) & 0–12.25 \\ Tail-Biting & 12 \(\times\) 10 min & \(1.45\pm 2.34\) & 0–31.5 & \(1.45\pm 1.63\) & 0–13.5 \\ Tail-Biting & 2 \(\times\) 6 \(\times\) 10 min & \(1.57\pm 2.22\) & 0–23.5 & \(1.57\pm 1.56\) & 0–13 \\ Tail-Biting & 6 \(\times\) 10 min & \(1.57\pm 2.84\) & 0–40 & \(1.57\pm 2.01\) & 0–17 \\ Ear-Biting & 12 h & \(1.23\pm 1.00\) & 0–7.33 & \(1.23\pm 0.83\) & 0–5.08 \\ Ear-Biting & 6 h & \(1.23\pm 1.27\) & 0–13 & \(1.23\pm 1.06\) & 0–6.33 \\ Ear-Biting & 3 h & \(1.36\pm 1.60\) & 0–15.33 & \(1.36\pm 1.34\) & 0–9 \\ Ear-Biting & 1 h & \(1.36\pm 2.22\) & 0–33 & \(1.36\pm 1.88\) & 0–15 \\ Ear-Biting & 0.5 h & \(1.36\pm 2.79\) & 0–54 & \(1.36\pm 2.40\) & 0–22 \\ Ear-Biting & 24 \(\times\) 10 min & \(1.23\pm 1.16\) & 0–9 & \(1.23\pm 0.98\) & 0–7.25 \\ Ear-Biting & 12 \(\times\) 10 min & \(1.23\pm 1.52\) & 0–16.5 & \(1.23\pm 1.28\) & 0–9.5 \\ Ear-Biting & 2 \(\times\) 6 \(\times\) 10 min & \(1.36\pm 1.48\) & 0–13 & \(1.36\pm 1.30\) & 0–10.5 \\ Ear-Biting & 6 \(\times\) 10 min & \(1.36\pm 2.00\) & 0–21 & \(1.36\pm 1.74\) & 0–12 \\ \hline \end{tabular}
\end{table} 
Table 2: Mean \(\pm\) standard deviation and the range of the amount of behaviour per hour per pig according to the behaviour and observation period. Figure 2: _Cont_. Figure 2: Agreement to reference of 12 h observation period.