Can straw based enrichment treat tail biting in pigs?

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Appraisal, application and reflection

In the Haigh et al. (2019) paper it is necessary to note that all the pigs had 75% of their tails docked prior to commencement of the study which is likely to have influenced the occurrence and severity of tail biting injuries. Tail scoring was done fortnightly in the Haigh et al. (2019) study, allowing time for injuries to potentially heal between scorings. Strengths of the study are the moderate population size plus the study design. To further the credibility of the study a control group could be used, alongside regular scoring. Considering the sample group had docked tails, which could potentially reduce severity of tail biting injuries as opposed to increase, with the addition of the scoring being fortnightly, it would be reasonable to suggest the result, that straw based enrichment did not successfully reduce tail biting incidents, is accurate under these circumstances.

Veit et al. (2016), has a strong study design along with a moderate population size and regular scoring which was completed by the same person, reducing subjectivity. The study found that straw based enrichments reduced the incidences of tail biting in comparison to the control group. However, the scoring chart itself was vague which could have impacted the accuracy of the results.

Larsen et al. (2018) provided a strong level of evidence due to the study design, the number of observations contributing to the results and the presence of a control group to assess the comparative impact of adding straw. However, the study did not assess the ability of straw to stop or reduce tail biting outbreaks once they had started, it focused solely on straw as a preventative measure. Overall, the study found that straw was an effective preventative measure against tail damage, however the greatest preventative measure is still tail docking. There is a suggestion that environmental management, i.e., lower stocking density and straw, could be used in combination to prevent tail biting outbreaks.

It is important to note that preventing tail damage and treating tail damage will involve differing approaches. These studies highlighted whether tail damage was reduced by using straw based enrichments. Overall, it was found that by introducing straw based enrichment, tail damage could be reduced in some cases (Veit et al., 2016). The rearing stage has been highlighted as a time when the most tail damage has been noted and this information could be used in further studies to identify what factors in a pig’s life influence this. In practice, it is expected that farmers should introduce enrichment to reduce tail biting outbreaks alongside targeting other husbandry practices to reduce tail biting further. It may be impractical to expect commercial farms to identify and introduce novel enrichment with sufficient time to prevent an outbreak.

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