Tail biting in fattening pigs: Associations between frequency of tail biting and other abnormal behaviours
Publication Type: |
Journal Article |
Year of Publication: |
2011 |
Authors: |
Emma Brunberg, Anna Wallenbeck, Linda J. Keeling |
Publication/Journal: |
Applied Animal Behaviour Science |
Keywords: |
abnormal behaviour, injurious behaviour, pig, tail-biting, welfare |
ISBN: |
0168-1591 |
Abstract:
This study investigated the association between tail biting (TB) and other abnormal behaviours in a group of non-tail docked pigs. Behavioural data were collected from 742 pigs housed on a commercial farm. The prevalence of performed and received TB, belly nosing, bar biting, ear biting and mounting was recorded during two 30 min observation periods. Pigs were categorized based on the number of performed tail bites/hour; non-performers (NP, TB = 0, n = 643), low performers (LP, TB = 1-4, n = 79), high performers (HP, TB > 4, n = 20) and the number of received tail bites; non-receivers (NR, TB = 0, n = 559), low receivers (LR, TB = 1-2, n = 133) and high receivers (HR, TB > 2, n = 50). Based on the intensity of the receivers’ response to being bitten, TB behaviour was further classified into three grades; no, mild or severe reaction. Tail-in-mouth behaviour, which did not involve biting, was also recorded. The proportion of performed bites classified as severe was significantly higher (P < 0.001) in HP (mean ± s.d.: 0.30 ± 0.21) than in LP (0.11 ± 0.28). The HR category received a lower proportion of mild tail bites (P < 0.003, 0.14 ± 0.15) than LR (0.31 ± 0.41). The fact that the HP category also performed a higher proportion of severe tail bites may be of use in practice when wanting to identify the main tail biting pigs in the pen. The three performer categories differed in the amount of performed tail-in-mouth (P < 0.001). HP performed most (4.30 ± 5.64) followed by LP (0.90 ± 1.26) and NP (0.19 ± 0.66). A higher frequency (P < 0.05) of ear biting was performed by HP (0.45 ± 0.69) than NP (0.26 ± 1.32) and both tail biter categories performed more bar biting than non-performers (HP: 1.10 ± 2.13, LP: 0.73 ± 2.03, NP: 0.28 ± 1.32). These results suggest that the tail biters, especially the HP category, perform a higher frequency of abnormal behaviours that involve biting behaviour. LP performed more belly nosing (0.80 ± 1.31) and [`]other abnormal' behaviours (1.41 ± 2.58, P < 0.001) than NP (belly nosing: 0.44 ± 1.73, P = 0.002; [`]other abnormal': 0.48 ± 1.56, P < 0.001). These results may suggest that LP pigs are more general in their repertoire of performed abnormal behaviour and HP more specialised in behaviours including biting. The receiver categories differed in the amount of received [`]other abnormal' behaviours, for which HR (1.16 ± 1.89) received significantly more than both LR (0.68 ± 1.10, P < 0.01) and NR (0.52 ± 1.24, P < 0.001). This could support the earlier proposed hypothesis that some animals are predisposed to receive more of these abnormal behaviours than others.