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A longitudinal study of the effects of providing straw at different stages of life on tail-biting and other behaviour in commercially housed pigs
- Statham, Poppy, Green, Laura, Mendl, Michael
- Applied animal behaviour science 2011 v.134 no.3-4 pp. 100-108
- commercial farms, finishing, floors, longitudinal studies, parturition, risk, rooting, stocking rate, straw, swine, weaning
- Tail-biting (TB) is a welfare concern. Recent studies indicate that early provision of straw may help prevent TB, however, many of these studies were carried out on small groups of pigs and may have limited applicability to commercial farms. The effect of providing straw at different stages of life was studied in large groups of pigs (21â39) on a commercial farm. Six replicates of four treatments were used (No Straw (NS), Straw in Finishing (12 weeks of age onwards) (SF), Straw from Weaning (SW), Straw Throughout Life (ST)). Based on previous studies, it was predicted that levels of TB would be lowest in ST and highest in NS. A total of 706 pigs were followed from birth to slaughter, however one replicate (all four groups) was excluded due to circumstances beyond our control. All pigs were housed on solid floors, and shavings were provided in pens without straw. Fresh bedding was provided twice per week. Behaviours were recorded at regular intervals and all tail-biting outbreaks were recorded. The timing of straw provision had limited effect on pigsâ behaviour. Before weaning there was no difference in the time spent exploring the substrate between groups with straw and those without. After weaning, the time spent rooting was significantly different between treatments (Fââ,ââ=3.796, p<0.05) with post hoc testing indicating that levels were significantly higher in SW than NS but that there was no difference between ST and the other treatments. Of the 20 groups, fourteen had tail-biting outbreaks (NS=3, SF=2, SW=4, ST=5), eight of these were classed as severe (NS=2, SF=0, SW=1, ST=3). Provision of straw did not have a significant effect on the distribution of tail-biting outbreaks (p=0.336). This unexpected finding was not explained by other variables (e.g. stocking density). It may have been related to the finding that straw provision did not increase the amount of rooting as expected, perhaps because the provision of solid floors and shavings allowed rooting in non-straw treatments. Most TB was seen in the finishing pigs where straw levels increased for SF but declined for ST and SW relative to earlier in life due to the farm's management practice. The levels of tail-biting were higher than expected in ST/SW and lower than expected in SF, suggesting that the novelty of straw for SF might have decreased the risk of TB whilst the decline in straw provision for ST/SW might have increased the risk.